suction module mud pump free sample

This application is a continuation of pending U.S. patent Ser. No. 12/220,876 entitled “A Reinforced Smart Mud Pump” which take priority to provisional application for patent filed Jul. 30, 2007 bearing Ser. No. 60/962,637 and is incorporated by reference herein as if fully set forth.

This invention relates generally to the field of mud pumps and more specifically to a reinforced smart mud pump. Mud pumps that use piston displacement, produce imposed forces that cause wear and tear on various pump components, including pump cross head piping, cylinders, inlet and discharge valves, seal components including piston or plunger seals, the pump cylinder block or so-called fluid end, and other components. There has been a need to provide increased longevity and performance for such pumps and to determine if deteriorations in pump performance are occurring, to analyze the source of decreased performance and to further real time control and data to monitor and in some cases change the operating characteristics before damage occurs to the pump. The use of greatly strengthened components in combination with a computer controlled system integrated with a real time monitored and controlled reset relief valve may be integrated into an oilfield application to prevent catastrophic pump failure and extend pump life.

Pump operating characteristics often have a deleterious effect on pump performance. For example, delayed valve closing and sealing can result in loss of volumetric efficiency. Factors affecting pump valve performance include fluid properties, valve spring design and fatigue life, valve design and the design of the cylinder or fluid end housing. Delayed valve response also causes a higher pump chamber pressure than normal which in turn may cause overloads on pump mechanical components, including the pump crankshaft or eccentric and its bearings, speed reduction gearing, the pump drive shaft and the pump prime mover. Moreover, increased fluid acceleration induced pressure “spikes” in the pump suction and discharge flowstreams can be deleterious. Fluid properties are also subject to analysis to determine compressibility, the existence of entrained gases in the pump fluid stream, susceptibility to cavitation and the affect of pump cylinder or fluid end design on fluid properties and vice versa.

Still further, piston or plunger seal or packing leaking can result in increased delay of pump discharge valve opening with increased hydraulic flow and acceleration induced hydraulic forces imposed on the pump and its discharge piping. Moreover, proper sizing and setup of pulsation control equipment is important to the efficiency and long life of a pump system. Pulsation control equipment location and type can also affect pump performance as well as the piping system connected to the pump

In prior art, the control of a mud pump has been disclosed focused on piston position for acquiring information about the pump and its performance characteristics. For example, U.S. Pat. No. 6,882,960 to Miller, shows a system for monitoring and analyzing performance parameters of reciprocating piston, or power pumps and associated piping systems. This patent fails to disclose the innovative aspects of the present invention.

Nothing in the prior art shows a computer integrated mud pump with significant strengthening features that increase the life cycle of a pump in the manner of the present invention with real time control of significant operating functions and feedback from various sensors and reset relief valves.

Another advantage of the invention is to provide a mud pump that utilizes transducers in line with the ambient pressure in conjunction with a computer controlled pressure relief valve to record and monitor pump characteristics and control the pump to prevent catastrophic failure.

Another advantage of the invention is to provide a mud pump that transmits data to a computer for later analysis of important operating characteristics.

A further advantage of the invention is to provide a mud pump that can be controlled during its operation to prevent certain damaging events to the pump or underlying pressurized system.

In accordance with a preferred embodiment of the invention, there is shown a pump system for movement of fluids having a reciprocating piston power pump having at least three reciprocating pistons operable to displace fluid from a housing having a pumping chamber, an integrally forged crankshaft operably connected to the pistons, at least one sensor operable to sense ambient conditions on the pump, and a computer control for processing data from the sensor to regulate the operation of the pump in response to the data.

In accordance with a preferred embodiment of the invention, there is shown a pump system for movement of fluids having a reciprocating piston power pump having at least three reciprocating pistons operable to displace fluid from a housing having a pumping chamber, an integrally forged crankshaft operably connected to the pistons, polyflorocarbon infused treatement applied to at least one crosshead and one crosshead slide in the system, and at least one sensor operable to sense ambient conditions on the pump.

In accordance with a preferred embodiment of the invention, there is shown a pump system for movement of fluids having a reciprocating piston power pump having at least three reciprocating pistons operable to displace fluid from a housing having a pumping chamber, an integrally forged crankshaft operably connected to the pistons, at least one sensor operable to sense ambient conditions on the pump, a computer control for processing data from the sensor to regulate the operation of the pump in response to the data; and pressure sensors for monitoring fluid pressure operably connected to the computer control. In addition, upper and lower limits to temperature, vibration and pressure can be set. Further, in a preferred embodiment, all lubrication and water pumps must be on before the control system will permit unit to be operated.

In a preferred embodiment of the present invention, there is shown a reciprocating plunger or piston power pump. The pump includes additional features not found in conventional reciprocal pumps as heretofore described. The basic operation of the pump is similar to a triplex plunger pump configured to reciprocate three spaced apart plungers or pistons, which are connected by suitable connecting rod and crosshead mechanisms, to a rotatable crankshaft or eccentric. FIG. 1 shows a side view of the pump and auxiliary equipment according to a preferred embodiment of the invention. Pump housing 100 covers the internal pump components and allows for a variety of conventional means to move the rotatable crankshaft 114 such as an electric motor 102 and belt drive 104. Within pump housing 100 may be disposed a pressurized lubrication spraying system that continuously feeds lubricant such as oil around the crankshaft and associated internal pump components.

A suction module 104 of conventional design houses each plunger which operates each section of the triplex plunger pump. A pressure relief valve mount 110 allows for attachment of a reset relief valve (show in FIG. 5) to at least one suction module 106 in a system for pumping drilling mud composed of water, clay and chemical additives, down through the inside of a drill pipe of an oil well drilling operation. The drilling mud is pumped at very high pressure so the mud is forced out through a bit at the lower end of the drill pipe and returned to the surface, carrying rock cuttings from the well. In this illustrative example the drilling mud from the pump system is fed into the attached vessel 112 sometimes known as a dumping ball. In a preferred embodiment all components are installed on a full unitized skid 120 providing room for motors, starters, sheaves, belts and any associated test equipment and a solid platform for installation of bracing 122 for component parts. Vessel 112 smoothes out the pulsation caused by the pumping action of the system to deliver pumped fluid out of port 115 in a more controlled manner.

With the use of computer modeling, high technology engineering, metallurgical and mechanical enhancements, the smart pump is revolutionary in design. The pump is manufactured using advanced materials and techniques including an integrally forged and balanced crank. This provides significant strength advantages and increases the life cycle of the pump. Unlike prior art pump systems, the crank is not a porous unbalanced crank casting, nor is it a fabricated with separate plates and bars and later welded together. As shown in FIG. 2 the crank 200 is fabricated from an integrally forged single ingot by the open hammer forging process resulting in a single piece with no welding or pinning of multiple pieces. A connecting rod 202 for each plunger is attached to the crank 200 such that the crank freely rotates and creates a reciprocating action in each connecting rod 202 attached to the crank 200. A crosshead 204 and crosshead slide 206 attach to each connector rod to help retain engine oil in the crankcase. A plunger connection 210 at each connector rod 202 end provides a means of attachment for a variety of rod and plunger components.

All of the ground crossheads 204 and honed crosshead slides 206 are treated with a polyflorocarbon coating for more lubricity and wear performance characteristics resulting in 15% less energy cost. This process has been used in the racing industry with much higher performance results. The poly-fluorocarbon coating is applied to each crosshead and slide and helps retain engine oil on the component surfaces during intense heat and extreme pressure. The oil is essentially absorbed into each crosshead 204 and slide 206 in such a way as to increase their lubricity. The crosshead 204 center line alignment is laser monitored for even wear. In a preferred embodiment of the invention the pump uses suction modules, discharge modules and discharge manifold and a double helical gear set. All gear sets are prepared with mesh test providing contact tapes accompanied by digitals to AGMS 11+ standards. All gear sets are further preferably chemically treated to 0.4 RMS or better to exponentially increase bearing life.

In the present invention, the crankshaft is a integrally forged piece to increase its operating strength significantly, and is an integral part of the crank 200. The terms crank 200 and crankshaft are used interchangably although in conventional pumps and engines the crank 200 and crankshaft may comprise separate components. Turning again to FIG. 1 we see the crankshaft includes a rotatable input shaft portion adapted to be operably connected to a suitable prime mover, such as an internal combustion engine or electric motor 102, as an exemplary installation. The crankshaft is mounted in a suitable, so-called power end housing 114 which is connected to a fluid end structure configured to have a plurality of pumping chambers, in this example, three separate pumping chambers exposed to their respective plungers or pistons. Plungers refer to the rod, rod joints and piston end portions of the plunger unless otherwise specified.

FIG. 3 shows a partial cutaway side view of the pump according to a preferred embodiment of the invention. The fluid end comprises a housing having the series of plural cavities or chambers for receiving fluid from an inlet manifold by way of conventional poppet type inlet or suction valves contained each suction module 300. The piston or plunger 304 projects at one end into the chamber and is connected to a suitable crosshead mechanism 306, including a crosshead extension. The crosshead extension is operably connected to the crankshaft using connecting rods 308 as described above. Each plunger 306 projects through a conventional packing 310 or plunger 306 seal. Each chamber for each plunger 306 is operably connected to a discharge piping manifold by way of a suitable discharge valve. Valves may be of a variety of conventional designs and are typically spring biased to their closed positions. Valves may also include or are associated with removable valve seat members. Each valve may also have a seal member formed thereon engageable with the associated valve seat to provide fluid sealing when the valves are in their respective closed and seat engaging positions. A unique feature of a preferred embodiment of the the smart pump is a positive air pressure plunger seal 312 to prevent leakage and prevent wear on the plunger. FIG. 3A shows a cross sectional view of the positive air pressure plunger seal about a synchronized plunger according to a preferred embodiment of the invention. As the plunger 350 moves reciprocally, pressurized air is introduced into through seal 352 through a plurality of pressurized air ports 354 preventing fluid leakage from the plunger 350 end which engages and moves drilling mud through the aforementioned valves. The pressurized air flow 356 isolates any material from scoring and etching the plunger 350 and reduces friction between the seal wall and the plunger 350.

In a preferred embodiment the pump may be fitted with a P-QUIP ® fluid end systems including P-QUIP ® kwik clamp liner retentions system, P-QUIP ® kwik rod system and cover system. The P-QUIP ® kwik-clamp valve and strainer cover retention system has a very fast and safe access with much reduced down time and LTAs (Lost Time Accidents) due to mishaps. Hammers or cheater bars are not required and the system includes an automatic clamping means which results in no more under or over tightening—caps will not loosen off in use. This all results in easy installation and easy operation with conventional air or hand operated hydraulic pump. Like the Liner Retention System, the valve and strainer covers are sealed firmly in the fluid end by means of a spring mechanism. Similarly, the outer cover is removed when the clamping force is released by means of the hydraulic pump. This system heightens safety as it is no longer necessary to tighten OEM type threaded cap retainers by hammer.

The P-QUIP ® kwik rod system allows for fast and safe piston changes and is constructed of 17.4 PH martensitic high-resistance stainless steel, eliminating corrosion. Three piece rod system is held together using pins, which eliminates prior systems and clamp type systems. The P-QUIP ® kwik cover system allows for fast and save valve access changes with no hammers or cheater bars. The cover offers a positive retention force against the plug eliminating the need for retightening. The P-Quip ® kwik rod pump rod system permits fast and safe piston changes resulting in reduced down time. There is no need for heavy clamps or connecting threads and studs. The clamping force is automatically controlled resulting in no broken rod ends. Due to its construction, its self alignment facility gives improved piston and liner life. There are no corrosion problems as all parts are stainless steel, including hard-surfaced stainless steel power end rods. It has an integral liner flushing systems.

On conventional mud-pump rod systems, the rod is held together by means of taper clamps and screw threads which are slow and awkward to assemble correctly and readily wear out. Due to their design, the clamps obscure vision of the rod joints, preventing a check being made that the rod is correctly aligned. Uneven loads are imposed on the flanged rod ends, resulting in premature failure.

The P-QUIP ® Kwik-Rod system avoids these problems as the rod components are held together by powerful spring-loaded ends on a release link in the center of the rod assembly. The ends of the release link are attached to the pony rod and piston rod by means of high tensile stainless steel pins held in shear. The shear force is very quickly and easily released by a few strokes of a small hydraulic pump.

Dismantling and re-assembly of the complete rod system takes under one minute. Furthermore, there are no flanged joints on the rods to chip, wear or break. Hence, rod life is enhanced and, because rod alignment is readily achieved, significantly improved swab and liner life is generally obtained. FIG. 4 shows a partial cutaway overhead of the pump housing according to a preferred embodiment of the invention. Plunger rods 400 are synchronized based on the crank speed and can be checked for alignment as described herein. In a preferred embodiment, a viewing port 402 or access cover allows access to plunger rods 400 for alignment and maintenance.

Further enhancement to the pump is achieved by use of ductile iron for the crossheads, the crosshead slides and the connecting rods. The connecting rods are solid ductile iron which reduces their elongation during setoff to zero. The typical rod experiences stretching or elongation during set-off when the relief valve is activated. The benefit of ductile iron in increased strength and higher tensile strength. All the major components, the crank, the crossheads, the slides and the rods by use of mettalurgical engineering are designed to bring the pump tensile strength up to 200,000 p.s.i.

The pump is network and web based with a data acquisition system to monitor pump performance and constantly evaluate pump valve dynamics. Pressure transducers are located in pump chambers used to determine valve sealing delays, fluid compression delays, chamber overshoot pressure, crosshead loading shock forces and chamber volumetric efficiency. Pressure transducers are also located in suction piping and manifolds and discharge piping and manifold. Temperature is similarly monitored for fluid temperature for mud properties and power end lubrication. Further, there is real time power input data to calculate system mechanical efficiency.

Those skilled in the art will recognize that the present invention may be utilized with a wide variety of single and multi-cylinder reciprocating piston power pumps as well as possibly other types of positive displacement pumps. However, the system and method of the invention are particularly useful for analysis of reciprocating piston or plunger type pumps. Moreover, the number of cylinders of such pumps may vary substantially between a single cylinder and essentially any number of cylinders or separate pumping chambers and the illustration of a so called triplex or three cylinder pump is exemplary.

The performance analysis system of the invention is characterized, in part, by a digital signal processor which is operably connected to a plurality of sensors via suitable conductor means well known in the art. The processor may be of a type commercially available as previously described and may wireless remote and other control options associated therewith. The processor is operable to receive signals from a power input sensor which may comprise a torque meter or other type of power input sensor. Power end crankcase oil temperature may be measured by a sensor. Crankshaft and piston position may be measured by a non-intrusive sensor including a beam interrupter mountable on a pump crosshead extension for interrupting a light beam provided by a suitable light source or optical switch.

A vibration sensor may be mounted on the power end or on the discharge piping or manifold for sensing vibrations generated by the pump. Suitable pressure sensors are adapted to sense pressures at numerous locations, including the inlet piping and manifolds. Other pressure sensors may sense pressures in the pumping chambers of the respective plungers or pistons. Other pressure sensors sense pressures upstream and downstream of a discharge pulsation dampener. Still further, a fluid temperature sensor may be mounted on discharge manifold or piping to sense the discharge temperature of the working fluid. Fluid temperature may also be sensed at the inlet or suction manifold.

Pump performance analysis using the system may require all or part of the sensors described above, as those skilled in the art will understand and appreciate from the description which follows. The processor may be connected to a terminal or further processor, including a display unit or monitor mounted in a housing connected to the pump system and main housing. Still further, the processor may be connected to a signal transmitting network, such as the Internet, or a local network.

FIG. 4A shows a schematic drawing of a representative computer controlled monitoring system. A computer 450 receives input from from sensors 452 and modules 454 in the pump system and uses software algorithyms to analyze pump performance, record and display operational data on a visual screen display 456. The computer controlled monitoring system may be adapted to provide a wide array of graphic displays and data associated with the performance of a power pump on a real time or replay basis. A substantial amount of information is available including pump identification (Pump ID) crankshaft speed, fluid flow rate, time lapse since the beginning of the display, starting date and starting time and scan rate. The display 456 displays discharge piping operating pressure, peak-to-peak pressures, fluid flow rate induced peak-to-peak pressure, fluid flow induced peak-to-peak pressure as a percentage of average operating pressure, pump volumetric efficiency and pump mechanical efficiency. The display 456 also indicates discharge valve seal delay in degrees of rotation of the crankshaft from a so called piston zero or top dead center (maximum displacement) starting point with respect to the respective cylinder chambers of the pump, as well as piston seal pressure variation during fluid compression and suction valve seal delay in degrees of rotation of the crankshaft or eccentric from the top dead center position of the respective cylinder chambers. Still further, the pump type may be displayed as well as suction piping pressures, as indicated. The parameters displayed are determined by the system of the invention which utilizes the various sensors.

Various pressure sensors 452 sense pressure in the respective pump chambers associated with each of the pistons and pressure signals are transmitted to the processor. These pressure signals may indicate when valves are opening and closing. For example, if the pressure sensed in a pump chamber does not rise essentially instantly, after the piston for that chamber passes bottom dead center by 0 degrees to 10 degrees of crankshaft rotation, then it is indicated that the inlet or suction valve is delayed in closing or is leaking. In situations like this, the display may show that a discharge valve is not closed for 16.7 degrees of rotation after piston top dead center position. Accordingly, pressure changes, or the lack thereof, are sensed by cylinder chamber pressure sensors.

Software embedded in the computer 450 processor is operable to correlate the angle of rotation of the crankshaft with respect to pressure sensed in the respective cylinder chambers to determine any delay in pressure changes which could be attributable to delays in the respective suction or discharge valves reaching their fully seated and sealed positions. These delays can, of course, affect volumetric efficiency of the respective cylinder chambers and the overall volumetric efficiency of the pump. In this regard, total volumetric efficiency is determined by calculating the average volumetric efficiency based on the angular delay in chamber pressure increase or pressure decrease, as the case may be, with respect to the position of the pistons in the respective chambers.

The volumetric efficiency of the pump is a combination of normal pump timed events and the sealing condition of the piston seal and the inlet and discharge valves. Pump volumetric efficiency and component status is determined by determining the condition of the components and calculating the degree of fluid bypass. Pump volumetric efficiency (VE) is computed by performing a computational fluid material balance around each pump chamber.

Pump chamber pressures, as sensed by the sensors may be used to determine pump timing events that affect performance, such as volumetric efficiency, and chamber maximum and minimum pressures, as well as fluid compression delays. Still further, fluid pressures in the pump chambers may be sensed during a discharge stroke to determine, through variations in pressure, whether or not there is leakage of a piston packing or seal, such as the packing seal. Still further, maximum and minimum chamber fluid pressures may be used to determine fatigue limits for certain components of a pump, such as the fluid end housing, the valves and virtually any component that is subject to cyclic stresses induced by changes in pressure in the pump chambers and the pump discharge piping.

As mentioned previously, the computer 450 processor may be adapted with a suitable computer program to provide for determining pump volumetric efficiency which is the arithmetic average of the volumetric efficiency of the individual pump chambers as determined by the onset of pressure rise as a function of crankshaft position (delay in suction valve closing and seating) and the delay in pressure drop after a piston has reached top dead center (delay in discharge valve closing and seating).

Additional parameters which may be measured and calculated in accordance with the invention are the so-called delta volumes for the suction or inlet stabilizer and the discharge pulsation dampener. The delta volume is the volume of fluid that must be stored and then returned to the fluid flowstream to make the pump suction and discharge fluid flow rate substantially constant. This volume varies as certain pump operating parameters change. A significant increase in delta volume occurs when timing delays are introduced in the opening and closing of the suction and discharge valves. The delta volume is determined by applying actual angular degrees of rotation of the crankshaft with respect the suction and discharge valve closure delays to a mathematical model that integrates the difference between the actual fluid flow rate and the average flow rate.

Another parameter associated with determining component life for a pump, is pump hydraulic power output for each pump working cycle or 360 degrees of rotation of the crankshaft. Still further, pump component life cycles may be determined by using a multiple regression analysis to determine parameters which can project the actual lives of pump components. The factors which affect life of pump components are absolute maximum pressure, average maximum pressure, maximum pressure variation and frequency, pump speed, fluid temperature, fluid lubricity and fluid abrasivity.

As mentioned previously, pressure variation during fluid “compression” is an indication of the condition of a piston or plunger packing seal. This variation is defined as an absolute maximum deviation of actual pressure data from a linear value representative of the compression pressure and is an indication of the condition of seals. A leaking seal results in a longer compression cycle because part of the fluid being displaced is bypassing or leaking through the seal. A pump chamber “decompression” cycle is also shorter because, after the discharge valve completely closes and seals against its seat, part of the fluid to be decompressed is bypassing a plunger seal or packing. The difference in volume required to reach discharge operating pressure over a “compression” cycle for each pump chamber determines an average leakage rate. This leakage rate is adjusted for a leak rate at discharge operating pressures by calculating a leak velocity based on standard orifice plate pressure drop calculations.

Suction valve leak rate results in a longer decompression cycle because part of the fluid being displaced by the pressurizing element is returning to the pump inlet or suction fluid flowline. The difference in volume required to reach discharge operating pressure over a compression cycle determines an average leakage rate. This compression leak rate is then adjusted for a leak rate at discharge operating pressures by calculating a leak velocity based on standard orifice plate pressure drop calculations. The leak rate is then applied to the duration of the discharge valve open cycle. So-called pump intake or suction acceleration head response is an indicator of the suction piping configuration and operating conditions which meet the pump"s demand for fluid. This is defined as the elapsed time between the suction valve opening and the first chamber or suction piping or manifold pressure peak following the opening.

Still further, the system of the present invention is operable to determine fluid cavitation which usually results in high pressure “spikes” occurring in the pumping chamber during the suction stroke. Generally, the highest pressure spikes occur at the first pressure spike following the opening of a suction valve. Both minimum and maximum pressures are monitored to determine the extent and partial cause of cavitation.

The system is also operable to provide signals indicating valve design and operating conditions which can result in excessive peak pressures in the pumping chambers before the discharge valve opens, for example. These peaks or so-called overshoot pressures can result in premature pump component failure and excessive hydraulic forces in the discharge piping. For purposes of such analysis, the overshoot pressure is defined as peak chamber pressure minus the average discharge fluid pressure.

The system of the present invention is also operable to analyze operating conditions in the pump suction and discharge flow lines, such as in the piping. A normally operating multiplex power pump will induce pressure variations at both one and two times the crankshaft speed multiplied by the number of pump pistons. Flow induced pressure variation is defined as the sum of the peak-to-peak pressure resulting from these two frequencies. Also, acceleration induced pressure spikes are created when the pump valves open and close. Acceleration pressure variation for purposes of the methodology of the invention is defined as the total peak-to-peak pressure variation.

Hydraulic resonance occurs when a piping system has a hydraulic resonant frequency that is excited by forces induced by operation of a pump. Fluid hydraulic resonance is determined by analysis of the pressure waves created by the pump to determine how close the pressure response matches a true sine wave. The computer 450 is programmed to activate an alarm when the flow induced pressure variation exceeds a predetermined limit. Alternatively the computer 450 monitoring software can be programmed to trigger the reset relief valve that is operably connected and controlled by the processor.

Those skilled in the art will appreciate that the system, including pressure sensors together with the reset relief valve and its associated sensors provides information which may be used to analyze a substantial number of system operating conditions for a pump. The processor is adapted to provide a visual display 456 which may be displayed on the monitor, providing graphical display of pressure versus crankshaft position for each cylinder chamber and other parameters.

The system"s computer 450 controller, hard drive or other digital storage device and display 456 can be used for predictive analysis of the pump and component parts providing data to the operator to reveal conditions and maintenance related required tasks including but not limited to:Hidden Failure—A functional failure whose effects are not apparent to the operating crew under normal circumstances if the failure mode occurs on its own.

In conjunction with the pump, is a fully controlled and monitored pressure relief valve that is situated to set off with excessive mud flow pressures. Turning now to FIG. 5, there is a partially exploded cross sectional view of a reset relief valve showing chamber 500 and in fluid communication therewith and pressure sensor assembly 502 of the relief valve. A break is shown in FIG. 5 between the upper and lower portion of the valve where the pressure sensor assembly 502 is placed for ease of illustration. Transducer 506 is positioned in a sealed ring 504 that is in fluid communication with the hydraulic fluid that moves between chambers 500 and 512 during operation. On the bottom of ring 504 are ports 514 that permit fluid flow from chamber 500 into the ring whereby the transducer 506 can sense pressure in the fluid. Pressure is sensed by the transducer 506 which is capable of sensing the pressure on the fluid which in turn transmits that pressure reading to a gauge 516 and electronically to a computer control system. Gauge 516 may be analog or digital depending on the application. As pressure is being monitored and data points stored, the user is capable of controlling the valve and making sure its operation is within desired operating limits before during and after the valve is activated. Further, the computer parameters can be set for high pressures to shut down the pump before the reset valve is set off.

By storing data on a recurring basis, the operator can design the system with greater degrees of control and can analyze the data associated with an activation of the valve to better utilize the valve and other pumps in the system. Set screw 520 permits access to the system for bleeding off pressure. Other ports are positioned around the pressure sensor assembly for insertion of oil or other hydraulic fluid.

One of the advantages of having a relief valve that is computer monitored and controlled is that upon set-off the operator obtains valuable real time information about the pump just prior to and during set-off. The system is capable of storing data about the operation of the pump such as the time of set-off, the exact pressure that caused the relief valve to activate and speed and pressure associated with the pump.

The processor may show pressure variation versus pump speed as determined by the system based on measuring chamber pressure and crankshaft position and speed.

The system may further display information showing crankshaft angle versus pump speed in strokes per minute showing discharge valve sealing delays in degrees of crankshaft rotation from piston top dead center. Suction valve sealing delays, from piston bottom dead center, may also be indicated.

The system of the invention may also be adapted to provide graphic displays such as a diagram of pump discharge pressure versus crankshaft angle showing the variation in pump discharge piping pressure, as well as the frequency and amplitude of pressure pulsations. Another display which may be provided by the system comprises a diagram of pump discharge piping pressure as measured by a pressure sensor versus pump speed in piston strokes per minute as calculated by the system. Still further, the system is operable to display fluid pressure conditions in the pump suction manifold, such as the manifold or piping. The system could also aid in de-synchronizing multiple pumps to decrease pulsation on the piping system.

A typical installation of a system for temporary or permanent performance monitoring and/or analysis requires that all of the pressure transducers be preferably on the horizontal center line of the pump piping or pump chambers, respectively, to minimize gas and sediment entrapment.

The system of the invention is also operable to determine pump piping hydraulic resonance and mechanical frequencies excited by one or more pumps connected thereto for both fixed and variable speed pumps. Preferably, a test procedure would involve instrumenting the pump, where plural pumps are used, that is furthest from the system discharge flowline or manifold. A vibration sensor, could be located at the position of the most noticeable piping vibration. The piping system should be configured for the desired flow path and all block valves to pumps not being operated should be open as though they were going to be operating. The instrumented pump or pumps should be started and run at maximum speed for fifteen minutes to allow stabilization of the system. A data acquisition system should then be operated to collect one minute of pumping system data. Alternatively, data may be continued to be collected while changing pump speed at increments of five strokes per minute every thirty seconds until minimum operating speed is reached. Data may be continued to be collected while changing suction or discharge pressures. The displays provided by the processor could be reviewed for pump operating problems as well as hydraulic and mechanical resonance. If a hydraulic resonant condition is observed, this may require the installation of wave blockers or orifice plates in the system piping.

The system is operable to provide displays comprising simulated three dimensional charts displaying peak-to-peak pressures occurring at respective frequencies for a given pump speed in strokes per minute. For a triplex pump, the normal excitation frequency is three and six times the pump speed. As pump speed increases, the excitation frequencies increase.

The software developed for the pump and valve is a method of acquiring multiple streams of analog data as real time occurrences and simultaneously displaying and storing them via digital interface using an interface system for later analysis. Using an application developed for this system, the control computer can monitor and record from 1 to 4 simultaneous analog pressure readings at a rate of 1 sample/sec per channel or faster. In addition a secondary capacity to monitor 4 digital only inputs is extant in the current system, with desired inputs undetermined. The data acquisition and its interaction and use with the software acts as a control system to the overal pump and its various operating compenents and attachments.

The computer system of a preferred embodiment may be of any of a variety of known systems with associated input and output devices, having adequate processing speed and storage capacity to analyze and process data associated with the operation of the pump. The system may also have wireless capability and preferably is capable of operating in temperature ranges of: 0 to 40° C.; Storage: −20 to 65° C., with Relative Humidity: 30% to 80%. It may use data processing of4 channels of 14-bit analog input

The present invention combines a computer controlled monitoring system for a pump and a reset relief valve with increased power characteristics and longevity by use of poly-fluorocarbon treated or infused materials and an integrally forged crank. By having the pump responsive to ambient conditions that are monitored real time, the reset valve, which is interconnected through sensors that sense operating conditions of the pump system, can send feedback to the motor to reduce pressure buildup before the valve is set off. Further, in certain conditions the reset valve can trip in advance of catastrophic failure of the pump through the computer control and feedback system of the present invention.

Developed using decades of drilling expertise and field proven performance, GD Energy Products’ Y-Shaped drilling module builds on our legacy of delivering innovative solutions. Featuring a unique bore geometry, our Y-Shaped module is designed to provide maximum performance and reliability. The module’s two-piece design simplifies routine maintenance and reduces total cost of ownership.

Our patented internal bore geometry features an API 7 valve assembly to allow fluid to flow smoothly through the module, providing maximum efficiency. The compact vertical dimensions minimize the percentage of un-swept, or “dead”, volume in the module, further maximizing efficiency.

GD Energy Products’ Y-Shaped module is engineered to provide unrivalled reliability. The unique design reduces the stress placed on the module’s cross-bore intersection, maximizing service life and reducing the risk of cavitation. Constructed from premium, heat-treated forgings ensures that our module can withstand the highest pressures, in even the most demanding conditions.

The module’s two piece construction and ergonomic, forward leaning orientation work to streamline maintenance. Compatibility with a range of standard GD Energy Products module hardware ensures that parts and spares are available, whenever and wherever you need them.

Cavitation is an undesirable condition that reduces pump efficiency and leads to excessive wear and damage to pump components. Factors that can contribute to cavitation, such as fluid velocity and pressure, can sometimes be attributed to an inadequate mud system design and/or the diminishing performance of the mud pump’s feed system.

When a mud pump has entered full cavitation, rig crews and field service technicians will see the equipment shaking and hear the pump “knocking,” which typically sounds like marbles and stones being thrown around inside the equipment. However, the process of cavitation starts long before audible signs reveal themselves – hence the name “the silent killer.”

Mild cavitation begins to occur when the mud pump is starved for fluid. While the pump itself may not be making noise, damage is still being done to the internal components of the fluid end. In the early stages, cavitation can damage a pump’s module, piston and valve assembly.

The imperceptible but intense shock waves generated by cavitation travel directly from the fluid end to the pump’s power end, causing premature vibrational damage to the crosshead slides. The vibrations are then passed onto the shaft, bull gear and into the main bearings.

If not corrected, the vibrations caused by cavitation will work their way directly to critical power end components, which will result in the premature failure of the mud pump. A busted mud pump means expensive downtime and repair costs.

As illustrated in Figures 1 and 2, cavitation causes numerous pits to form on the module’s internal surface. Typically, cavitation pits create a stress concentration, which can reduce the module’s fatigue life.

Washouts are one of the leading causes of module failure and take place when the high-pressure fluid cuts through the module’s surface and damages a sealing surface. These unexpected failures are expensive and can lead to a minimum of eight hours of rig downtime for module replacement.

To stop cavitation before it starts, install and tune high-speed pressure sensors on the mud suction line set to sound an alarm if the pressure falls below 30 psi.

Accelerometers can also be used to detect slight changes in module performance and can be an effective early warning system for cavitation prevention.

Although the pump may not be knocking loudly when cavitation first presents, regular inspections by a properly trained field technician may be able to detect moderate vibrations and slight knocking sounds.

Gardner Denver offers Pump University, a mobile classroom that travels to facilities and/or drilling rigs and trains rig crews on best practices for pumping equipment maintenance.

Severe cavitation will drastically decrease module life and will eventually lead to catastrophic pump failure. Along with downtime and repair costs, the failure of the drilling pump can also cause damage to the suction and discharge piping.

When a mud pump has entered full cavitation, rig crews and field service technicians will see the equipment shaking and hear the pump ‘knocking’… However, the process of cavitation starts long before audible signs reveal themselves – hence the name ‘the silent killer.’In 2017, a leading North American drilling contractor was encountering chronic mud system issues on multiple rigs. The contractor engaged in more than 25 premature module washes in one year and suffered a major power-end failure.

Gardner Denver’s engineering team spent time on the contractor’s rigs, observing the pumps during operation and surveying the mud system’s design and configuration.

The engineering team discovered that the suction systems were undersized, feed lines were too small and there was no dampening on the suction side of the pump.

Following the implementation of these recommendations, the contractor saw significant performance improvements from the drilling pumps. Consumables life was extended significantly, and module washes were reduced by nearly 85%.

Although pump age does not affect its susceptibility to cavitation, the age of the rig can. An older rig’s mud systems may not be equipped for the way pumps are run today – at maximum horsepower.

Embodiments of the invention relate to riserless mud return systems used in the oil production industry. More particularly, embodiments of the invention relate to a novel system and method for riserless mud return using a subsea pump suspended along a rigid mud return line.

Top hole drilling is generally the initial phase of the construction of a subsea well and involves drilling in shallow formations prior to the installation of a subsea blowout preventer. During conventional top hole drilling, a drilling fluid, such as drilling mud or seawater, is pumped from a drilling rig down the borehole to lubricate and cool the drill bit as well as to provide a vehicle for removal of drill cuttings from the borehole. After emerging from the drill bit, the drilling fluid flows up the borehole through the annulus formed by the drill string and the borehole. Because, conventional top hole drilling is normally performed without a subsea riser, the drilling fluid is ejected from the borehole onto the sea floor.

When drilling mud, or some other commercial fluid, is used for top hole drilling, the release of drilling mud in this manner is undesirable for a number of reasons, namely cost and environmental impact. Depending on the size of the project and the depth of the top hole, drilling mud losses during the top hole phase of drilling can be significant. In many regions of the world, there are strict rules governing, even prohibiting, discharges of certain types of drilling fluid. Moreover, even where permitted, such discharges can be harmful to the maritime environment and create considerable visibility problems for remote operated vehicles (ROVs) used to monitor and perform various underwater operations at the well sites.

For these reasons, systems for recycling drilling fluid have been developed. Typical examples of these systems are found in U.S. Pat. No. 6,745,851 and W.O. Patent Application No. 2005/049958, both of which are incorporated herein by reference in their entireties for all purposes. Both disclose systems for recycling drilling fluid, wherein a suction module, or equivalent device, is positioned above the wellhead to convey drilling fluid from the borehole through a pipeline to a pump positioned on the sea floor. The pump, in turn, conveys the drilling fluid through a flexible return line to the drilling rig above for recycling and reuse. The return line is anchored at one end by the pump, while the other end of the return line is connected to equipment located on the drilling rig.

Positioning the pump on the sea floor requires that the pump be designed and manufactured to withstand hydrostatic forces commensurate with the depth of the sea floor. Also, positioning the pump on the sea floor may be undesirable in certain conditions due to the time needed to retrieve the pump in the event that the pump needs maintenance or bad weather occurs

Systems and methods for drilling a well bore in a subsea formation from an offshore structure positioned at a water surface and having a drill string that is suspended from the structure and including a bottom hole assembly adapted to form a top hole portion of the well bore. A drilling fluid source on the offshore structure supplies fluid through the drill string to the bottom hole assembly where the fluid exits from the bottom hole assembly during drilling and returns up the well bore. A suction module is disposed at the sea floor and collects the fluid emerging from the well bore. A pump module is disposed on a return line, which is in fluid communication with the suction module, at a position below the water surface and above the sea floor. The pump module is operable to receive fluid from the suction module and pump the fluid through the return pipe to the same or a different offshore structure,

Thus, embodiments of the invention comprise a combination of features and advantages that enable substantial enhancement of riserless mud return systems. These and various other characteristics and advantages of the invention will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention and by referring to the accompanying drawings.

FIG. 1 is a schematic representation of a drilling rig with a riserless mud return system comprising a subsea pump suspended along a rigid mud return line in accordance with embodiments of the invention;

Preferred embodiments of the invention relate to riserless mud return systems used in the recycling of drilling fluid. The invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the invention with the understanding that the disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.

Suction module 20 is positioned on the sea floor 25 above borehole 30. Drill string 35 is suspended from drill floor 10 through suction module 20 into borehole 30. Deployment and hang-off system 40 is disposed adjacent to moonpool 15 and supports the return string 45, which is secured to the sea floor 25 by anchor 50. Although this exemplary embodiment depicts return string 45 coupled to drilling rig 5, it is understood that, in other embodiments, return string 45 may be coupled to and supported by the same or another offshore structure and can return fluid to the same offshore structure as coupled to the drill string 35 or to a second offshore structure. Return string 45 further includes upper mud return line 55, pump module 60, docking joint 65, lower mud return line 70, and emergency disconnect 75.

Upper and lower mud return lines 55, 70 are both formed from pipe, such as drill pipe or other suitable tubulars known in the industry. Mud return lines 55, 70 are preferably formed from a series of individual lengths of pipe connected in series to form the continuous line. In preferred embodiments, mud return lines 55, 70 are rigid, having only inherent flexibility due to their long, slender shapes. As it is used herein, the term “rigid” is used to describe the mud return lines as being constructed from a material having significantly greater rigidity than the coiled tubing or flexible hose conventionally used in mud return lines. In other embodiments, mud return lines 55, 70 may be non-rigid or flexible, for example coiled tubing, flexible hose, or other similar structures.

Upper mud return line 55 is connected at its upper end to deployment and hang-off system 40 and at its lower end to docking joint 65, which is located below sea level 80. Pump module 60 is releasably connected to docking joint 65. Lower mud return line 70 runs from docking joint 65 and is secured to the sea floor by anchor 50. In certain embodiments, emergency disconnect 75 may releasably couple lower mud return line 70 to anchor 50. Suction hose assembly 85 extends from suction module 20 to lower mud return line 70 so as to provide fluid communication from the suction module to the mud return line.

Prior to initiating drilling operations, return string 45 is installed through moonpool 15. Installation of return string 45 includes coupling anchor 50 and emergency disconnect 75 (if desired) to lower mud return line 70. Anchor 50 is lowered to sea floor 25 by adding individual joints of pipe that extend the length of lower mud return line 70. As return string 45 is installed, docking joint 65 and upper mud return line 55 are added. Pump module 60 may be run with return string 45 or after the string has been completely installed. Upon reaching the sea floor 25, anchor 50 is installed to secure return string 45 to the sea floor 25. Return string 45 is then suspended from deployment and hang-off system 40 and drilling operations may commence.

During drilling operations, drilling fluid is delivered down drill string 35 to a drill bit positioned at the end of drill string 35. After emerging from the drill bit, the drilling fluid flows up borehole 30 through the annulus formed by drill string 35 and borehole 30. At the top of borehole 30, suction module 20 collects the drilling fluid. Pump module 60 draws the mud through suction hose assembly 85, lower mud return line 70, and docking joint 65 and then pushes the mud upward through upper mud return line 55 to drilling rig 5 for recycling and reuse. During operation, anchor 50 limits movement of return string 45 in order to prevent the return string from impacting other submerged equipment.

Inlet line 105 further includes inlet 140 that is coupled to housing 100, outlet 145 that connects to pump module 60, and flowbore 150 providing fluid communication therebetween. Similarly, outlet line 110 further includes inlet 155 that connects to pump module 60, outlet 160 coupled to housing 100, and a flowbore 165 providing fluid communication therebetween. Isolation valves 115, 120 are positioned along flowbore 150, 165, respectively, in order to selectively allow fluid communication along inlet line 105 and outlet line 110.

Mud return line 70 is coupled to housing 100 at lower end 132 via a threaded connection or other suitable type of connection. Upper connecting pipe 122 couples mud return line 55 to housing 100 at upper end 128 via threaded connections or other suitable type of connections known in the industry. Referring now to FIG. 2B, connecting pipe 122 further includes helix 138, which is configured to align pump module 60 with docking joint 65. Cover 170 provides a surface 180 on which pump module 60 is seated when pump module 60 is installed. Cover 170 further includes cut-outs 175, which permit pump module 60, when installed, access to isolation valves 115, 120, inlet line 105 and outlet line 110.

FIG. 3 illustrates one embodiment of a subsea pump module 60 that is operable to interface with docking joint 65, as shown in FIGS. 2A and 2B. Pump module 60 includes pump assemblies 200, flowlines 205, and isolation valves 210, all assembled and contained within frame 215. Pump assemblies 200 are arranged in series so that flowlines 205 provide fluid communication through pump module 60 that allows fluid from return line 70 to be successively pressurized by each pump assembly 200. Valves 210 allow for the flow to be directed to the pump assemblies 200 as desired for a particular application. Pump assemblies 200 are illustrated as disc or, alternatively, centrifugal pump units but it is understood that any type of pump can be used in pump module 60. Power for pump-motor assemblies 200 may be provided by electrical wiring from drilling rig 5. In some embodiments, isolation valves 210 may be electrically actuated also via electrical wiring from drilling rig 5. Additionally, isolation valves 210 may be manually actuated during operations involving ROVs.

Frame 215 protects pump assemblies 200 and their piping components and provides attachment points for lifting pump module 60 and facilitating the installation and retrieval of the module. Frame 215 includes an opening 220, which permits pump module 60 to be inserted over mud return line 55 (see FIGS. 1 and 2A) and lowered along mud return line 55 to docking joint 65 during installation. Frame 215 is also configured to interface with helix 138 so as to align pump module 60 with docking joint 65 during installation of the pump module.

As described above in reference to FIG. 1, docking joint 65 is installed with mud return lines 70, 55 to form return string 45. Prior to the installation of pump module 60, isolation valves 115, 120 on lines 105, 110 of docking joint 65 may be closed to prevent circulation of seawater into return string 45. Pump module 60 may then be installed along return string 45 with docking joint 65 or independently of docking joint 65.

During normal deployment procedures, pump module 60 may be installed with docking joint 65. In this scenario, pump module 60 is coupled to docking joint 65 and the two components are then lowered to the desired depth. To enable these procedures, docking joint 65 is designed to allow pick-up of pump module 60 without breaking return string 45. Installation of pump module 60 with docking joint 65 in this manner is less time consuming than conventional methods because it is not necessary to break return string 45. Retrieval of pump module 60 using docking joint 65 is also more efficient for this same reason.

Alternatively, during maintenance and/or emergency procedures, pump module 60 may be installed independently of docking joint 65. For example, when pump module 60 requires maintenance and/or bad weather approaches, it may be necessary to retrieve pump module 60 while return string 45, including docking joint 65, remains in place. After maintenance of pump module 60 is completed or the bad weather has passed, pump module 60 may be lowered along return line 55 to engage docking joint 65.

In either scenario, installation of pump module 60 preferably includes inserting mud return line 55 into opening 220 and lowering pump module 60 over the mud return line 55 to docking joint 65. As pump module 60 is lowered over connecting line 122 of docking joint 65, pump module 60 engages helix 138, causing pump module 60 to rotate as pump module 60 descends toward docking joint 65 such that when pump module is seated on docking joint 65, pump module 60 is aligned with cover 170 and engaged with inlet line 105 and outlet line 110. Aligning pump module 60 with cover 170 allows pump module 60 access, via cut-outs 175, to isolation valves 115, 120.

In some embodiments, seating pump module 60 on docking joint 65 automatically actuates isolation valves 115, 120 from closed positions to open positions. Conversely, unseating pump module 60 from cover 170 of docking joint 65 actuates isolation valves 115, 120 to closed positions. In other embodiments, seating and unseating of pump module 60 in this manner may not actuate isolation valves 115, 120. Rather, a signal transmitted to the isolation valves 115, 120 from a remote location, erg drilling rig 5, actuates isolation valves 115, 120. Additionally, isolation valves 115, 120 may be manually actuated during operations involving ROVS.

After pump module 60 is installed and isolation valves 115, 120 are opened, a fluid flowpath is established through pump module 60. Once pump module 60 is operational and top hole drilling operations begin, drilling fluid is permitted to flow from mud return line 70 into docking joint 65 through fluid inlet port 130. The drilling fluid then passes through inlet line 105, entering at inlet 140 and exiting at outlet 145. Upon exiting inlet line 105, the drilling fluid flows through pump module 60 to outlet line 110 at inlet 155. After exiting bypass line 110 through outlet 160, the drilling fluid then flows from docking joint 65 through fluid exit port 125, upward through connecting line 122, and into mud return line 55.

As described above, top hole drilling operations may commence after pump module 60 is installed. While operational, pump assemblies 200 of pump module 60 draw drilling fluid from the suction module 20 through suction hose assembly 85, mud return line 70, and bypass line 110 of docking joint 65. Pump-motor assemblies 200 preferably then push the mud through flowlines 205, through bypass line 110 of docking joint 65, and upward through return line 55 to drilling rig 5 for recycling and reuse. Isolation valves 210 are actuated, as needed, to direct the flow of the drilling fluid through flowlines 205 and back into docking joint 65.

In the event that pump module 60 requires maintenance and/or bad weather occurs necessitating the retrieval of pump module 60, drilling operations cease. The flow of drilling fluid through pump module 60 is discontinued, and isolation valves 115, 120 are actuated to closed positions. Pump module 60 is then disengaged from docking joint 65 and returned to drill floor 10 of drilling rig 5, either for maintenance or safe stowage. Closure of isolation valves 115, 120 prevents drilling fluid from dispersing into the surrounding water after pump module 60 is disengaged from docking joint 65.

Retrieval of pump module 60 in this manner is expedited for at least two reasons. First, pump module 60 may be disengaged from docking joint 65 without the need to break the return string 45. Second, pump module 60 is suspended above the sea floor 25, rather than seated on it. Once maintenance has been performed on pump module 60 and/or bad weather has passed, pump module 60 may be redeployed by lowering pump module 60 along return string 45 to docking joint 65 where, again, pump module 60 engages docking joint 65, as described above. Subsequent redeployment of pump module 60 is also expedited for these same reasons.

While preferred embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems are possible and are within the scope of the invention. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. In particular, the subsea pump module may comprise fewer or more pump-motor assemblies as needed to convey drilling fluid from the suction module through the return string to the drilling rig. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.

A well-placed suction stabilizer can also prevent pump chatter. Pump chatter occurs when energy is exchanged between the quick opening and closing of the reciprocating pump’s valves and the hammer effect from the centrifugal pump. Pump isolation with suction stabilizers is achieved when the charge pumps are isolated from reciprocating pumps and vice versa. The results are a smooth flow of pumped media devoid of agitating energies present in the pumped fluid.

Suction stabilizer units can mitigate most of the challenges related to pulsations or pressure surges, even in the most complex piping conditions. The resulting benefits prevent expensive unplanned downtime and decrease costs and inconvenience associated with system replacements and repairs.

Centrifugal pumps basically consi