mud pump houston free sample

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Mud-Pump Gear Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

With factories located in the Minnesota heartland as well as the heart of the Houston, TX energy industry; American Mfg utilizes cutting edge CNC machining centers and lathes; state-of-the-art CMM quality control machines, and an experienced work force to manufacture the highest quality product in the Water-Well, Geothermal, Mineral Exploration and Oil&Gas drilling industries.

Triplex mud pumps pump drilling mud during well operations. An example of a typical triplex mud pump 10 shown in FIG. 1A has a power assembly 12, a crosshead assembly 14, and a fluid assembly 16. Electric motors (not shown) connect to a pinion shaft 30 that drives the power assembly 12. The crosshead assembly 14 converts the rotational movement of the power assembly 12 into reciprocating movement to actuate internal pistons or plungers of the fluid assembly 16. Being triplex, the pump"s fluid assembly 16 has three internal pistons to pump the mud.

As shown in FIG. 1B, the pump"s power assembly 14 has a crankshaft 20 supported at its ends by double roller bearings 22. Positioned along its intermediate extent, the crankshaft 20 has three eccentric sheaves 24-1 . . . 24-3, and three connecting rods 40 mount onto these sheaves 24 with cylindrical roller bearings 26. These connecting rods 40 connect by extension rods (not shown) and the crosshead assembly (14) to the pistons of the pump"s fluid assembly 16.

In addition to the sheaves, the crankshaft 20 also has a bull gear 28 positioned between the second and third sheaves 24-2 and 24-3. The bull gear 28 interfaces with the pinion shaft (30) and drives the crankshaft 20"s rotation. As shown particularly in FIG. 1C, the pinion shaft 30 also mounts in the power assembly 14 with roller bearings 32 supporting its ends. When electric motors couple to the pinion shaft"s ends 34 and rotate the pinion shaft 30, a pinion gear 38 interfacing with the crankshaft"s bull gear 28 drives the crankshaft (20), thereby operating the pistons of the pump"s fluid assembly 16.

When used to pump mud, the triplex mud pump 10 produces flow that varies by approximately 23%. For example, the pump 10 produces a maximum flow level of about 106% during certain crankshaft angles and produces a minimum flow level of 83% during other crankshaft angles, resulting in a total flow variation of 23% as the pump"s pistons are moved in differing exhaust strokes during the crankshaft"s rotation. Because the total flow varies, the pump 10 tends to produce undesirable pressure changes or “noise” in the pumped mud. In turn, this noise interferes with downhole telemetry and other techniques used during measurement-while-drilling (MWD) and logging-while-drilling (LWD) operations.

In contrast to mud pumps, well-service pumps (WSP) are also used during well operations. A well service pump is used to pump fluid at higher pressures than those used to pump mud. Therefore, the well service pumps are typically used to pump high pressure fluid into a well during frac operations or the like. An example of a well-service pump 50 is shown in FIG. 2. Here, the well service pump 50 is a quintuplex well service pump, although triplex well service pumps are also used. The pump 50 has a power assembly 52, a crosshead assembly 54, and a fluid assembly 56. A gear reducer 53 on one side of the pump 50 connects a drive (not shown) to the power assembly 52 to drive the pump 50.

As shown in FIG. 3, the pump"s power assembly 52 has a crankshaft 60 with five crankpins 62 and an internal main bearing sheave 64. The crankpins 62 are offset from the crankshaft 60"s axis of rotation and convert the rotation of the crankshaft 60 in to a reciprocating motion for operating pistons (not shown) in the pump"s fluid assembly 56. Double roller bearings 66 support the crankshaft 60 at both ends of the power assembly 52, and an internal double roller bearing 68 supports the crankshaft 60 at its main bearing sheave 64. One end 61 of the crankshaft 60 extends outside the power assembly 52 for coupling to the gear reducer (53; FIG. 2) and other drive components.

As shown in FIG. 4A, connecting rods 70 connect from the crankpins 62 to pistons or plungers 80 via the crosshead assembly 54. FIG. 4B shows a typical connection of a connecting rod 70 to a crankpin 62 in the well service pump 50. As shown, a bearing cap 74 fits on one side of the crankpin 62 and couples to the profiled end of the connecting rod 70. To reduce friction, the connection uses a sleeve bearing 76 between the rod 70, bearing cap 74, and crankpin 62. From the crankpin 62, the connecting rod 70 connects to a crosshead 55 using a wrist pin 72 as shown in FIG. 4A. The wrist pin 72 allows the connecting rod 70 to pivot with respect to the crosshead 55, which in turn is connected to the plunger 80.

In use, an electric motor or an internal combustion engine (such as a diesel engine) drives the pump 50 by the gear reducer 53. As the crankshaft 60 turns, the crankpins 62 reciprocate the connecting rods 70. Moved by the rods 70, the crossheads 55 reciprocate inside fixed cylinders. In turn, the plunger 80 coupled to the crosshead 55 also reciprocates between suction and power strokes in the fluid assembly 56. Withdrawal of a plunger 80 during a suction stroke pulls fluid into the assembly 56 through the input valve 82 connected to an inlet hose or pipe (not shown). Subsequently pushed during the power stroke, the plunger 80 then forces the fluid under pressure out through the output valve 84 connected to an outlet hose or pipe (not shown).

In contrast to using a crankshaft for a quintuplex well-service pump that has crankpins 62 as discussed above, another type of quintuplex well-service pump uses eccentric sheaves on a direct drive crankshaft. FIG. 4C is an isolated view of such a crankshaft 90 having eccentric sheaves 92-1 . . . 92-5 for use in a quintuplex well-service pump. External main bearings (not shown) support the crankshaft 90 at its ends 96 in the well-service pumps housing (not shown). To drive the crankshaft 90, one end 91 extends beyond the pumps housing for coupling to drive components, such as a gear box. The crankshaft 90 has five eccentric sheaves 92-1 . . . 92-5 for coupling to connecting rods (not shown) with roller bearings. The crankshaft 90 also has two internal main bearing sheaves 94-1, 94-2 for internal main bearings used to support the crankshaft 90 in the pump"s housing.

In the past, quintuplex well-service pumps used for pumping frac fluid or the like have been substituted for mud pumps during drilling operations to pump mud. Unfortunately, the well-service pump has a shorter service life compared to the conventional triplex mud pumps, making use of the well-service pump as a mud pump less desirable in most situations. In addition, a quintuplex well-service pump produces a great deal of white noise that interferes with MWD and LWD operations, further making the pump"s use to pump mud less desirable in most situations. Furthermore, the well-service pump is configured for direct drive by a motor and gear box directly coupling on one end of the crankshaft. This direct coupling limits what drives can be used with the pump. Moreover, the direct drive to the crankshaft can produce various issues with noise, balance, wear, and other associated problems that make use of the well-service pump to pump mud less desirable.

One might expect to provide a quintuplex mud pump by extending the conventional arrangement of a triplex mud pump (e.g., as shown in FIG. 1B) to include components for two additional pistons or plungers. However, the actual design for a quintuplex mud pump is not as easy as extending the conventional arrangement, especially in light of the requirements for a mud pump"s operation such as service life, noise levels, crankshaft deflection, balance, and other considerations. As a result, acceptable implementation of a quintuplex mud pump has not been achieved in the art during the long history of mud pump design.

What is needed is an efficient mud pump that has a long service life and that produces low levels of white noise during operation so as not to interfere with MWD and LWD operations while pumping mud in a well.

A quintuplex mud pump is a continuous duty, reciprocating plunger/piston pump. The mud pump has a crankshaft supported in the pump by external main bearings and uses internal gearing and a pinion shaft to drive the crankshaft. Five eccentric sheaves and two internal main bearing sheaves are provided on the crankshaft. Each of the main bearing sheaves supports the intermediate extent of crankshaft using bearings. One main bearing sheave is disposed between the second and third eccentric sheaves, while the other main bearing sheave is disposed between the third and fourth eccentric sheaves.

One or more bull gears are also provided on the crankshaft, and the pump"s pinion shaft has one or more pinion gears that interface with the one or more bull gears. If one bull gear is used, the interface between the bull and pinion gears can use herringbone or double helical gearing of opposite hand to avoid axial thrust. If two bull gears are used, the interface between the bull and pinion gears can use helical gearing with each having opposite hand to avoid axial thrust. For example, one of two bull gears can be disposed between the first and second eccentric sheaves, while the second bull gear can be disposed between fourth and fifth eccentric sheaves. These bull gears can have opposite hand. The pump"s internal gearing allows the pump to be driven conventionally and packaged in any standard mud pump packaging arrangement. Electric motors (for example, twin motors made by GE) may be used to drive the pump, although the pump"s rated input horsepower may be a factor used to determine the type of motor.

Connecting rods connect to the eccentric sheaves and use roller bearings. During rotation of the crankshaft, these connecting rods transfer the crankshaft"s rotational movement to reciprocating motion of the pistons or plungers in the pump"s fluid assembly. As such, the quintuplex mud pump uses all roller bearings to support its crankshaft and to transfer crankshaft motion to the connecting rods. In this way, the quintuplex mud pump can reduce the white noise typically produced by conventional triplex mud pumps and well service pumps that can interfere with MWD and LWD operations.

Turning to the drawings, a quintuplex mud pump 100 shown in FIGS. 5 and 6A-6B has a power assembly 110, a crosshead assembly 150, and a fluid assembly 170. Twin drives (e.g., electric motors, etc.) couple to ends of the power assembly"s pinion shaft 130 to drive the pump"s power assembly 110. As shown in FIGS. 6A-6B, internal gearing within the power assembly 110 converts the rotation of the pinion shaft 130 to rotation of a crankshaft 120. The gearing uses pinion gears 138 on the pinion shaft 130 that couple to bull gears 128 on the crankshaft 120 and transfer rotation of the pinion shaft 130 to the crankshaft 120.

For support, the crankshaft 120 has external main bearings 122 supporting its ends and two internal main bearings 127 supporting its intermediate extent in the assembly 110. As best shown in FIG. 6A, rotation of the crankshaft 120 reciprocates five independent connecting rods 140. Each of the connecting rods 140 couples to a crosshead 160 of the crosshead assembly 150. In turn, each of the crossheads 160 converts the connecting rod 40"s movement into a reciprocating movement of an intermediate pony rod 166. As it reciprocates, the pony rod 166 drives a coupled piston or plunger (not shown) in the fluid assembly 170 that pumps mud from an intake manifold 192 to an output manifold 198. Being quintuplex, the mud pump 100 has five such pistons movable in the fluid assembly 170 for pumping the mud.

The cross-section in FIG. 10A shows a crosshead 160 for the quintuplex mud pump. The end of the connecting rod 140 couples by a wrist pin 142 and bearing 144 to a crosshead body 162 that is movable in a crosshead guide 164. A pony rod 166 coupled to the crosshead body 162 extends through a stuffing box gasket 168 on a diaphragm plate 169. An end of this pony rod 166 in turn couples to additional components of the fluid assembly (170) as discussed below.

The cross-section in FIG. 10B shows portion of the fluid assembly 170 for the quintuplex mud pump. An intermediate rod 172 has a clamp 174 that couples to the pony rod (166; FIG. 10A) from the crosshead assembly 160 of FIG. 10A. The opposite end of the rod 172 couples by another clamp to a piston rod 180 having a piston head 182 on its end. Although a piston arrangement is shown, the fluid assembly 170 can use a plunger or any other equivalent arrangement so that the terms piston and plunger can be used interchangeably herein. Moved by the pony rod (166), the piston head 182 moves in a liner 184 communicating with a fluid passage 190. As the piston 182 moves, it pulls mud from a suction manifold 192 through a suction valve 194 into the passage 190 and pushes the mud in the passage 190 to a discharge manifold 198 through a discharge valve 196.

As noted previously, a triplex mud pump produces a total flow variation of about 23%. Because the present mud pump 100 is quintuplex, the pump 100 offers a lower variation in total flow, making the pump 100 better suited for pumping mud and producing less noise that can interfere with MWD and LWD operations. In particular, the quintuplex mud pump 100 can produce a total flow variation as low as about 7%. For example, the quintuplex mud pump 100 can produce a maximum flow level of about 102% during certain crankshaft angles and can produce a minimum flow level of 95% during other crankshaft angles as the pump"s five pistons move in their differing strokes during the crankshaft"s rotation. Being smoother and closer to ideal, the lower total flow variation of 7% produces less pressure changes or “noise” in the pumped mud that can interfere with MWD and LWD operations.

Although a quintuplex mud pump is described above, it will be appreciated that the teachings of the present disclosure can be applied to multiplex mud pumps having at least more than three eccentric sheaves, connecting rods, and fluid assembly pistons. Preferably, the arrangement involves an odd number of these components so such mud pumps may be septuplex, nonuplex, etc. For example, a septuplex mud pump according to the present disclosure may have seven eccentric sheaves, connecting rods, and fluid assembly pistons with at least two bull gears and at least two bearing sheaves on the crankshaft. The bull gears can be arranged between first and second eccentric sheaves and sixth and seventh eccentric sheaves on the crankshaft. The internal main bearings supporting the crankshaft can be positioned between third and fourth eccentric sheaves and the fourth and fifth eccentric sheaves on the crankshaft.

The most common scheme for transmitting measurement information utilizes the drilling fluid within the borehole as a transmission medium for acoustic waves modulated to represent the measurement information. Typically, drilling fluid or "mud" is circulated downward through the drill string and drill bit and upward through the annulus defined by the portion of the borehole surrounding the drill string. The drilling fluid not only removes drill cuttings and maintains a desired hydrostatic pressure in the borehole, but cools the drill bit. In a species of the technique referred to above, a downhole acoustic transmitter known as a rotary valve or "mud siren", repeatedly interrupts the flow of the drilling fluid, and this causes a varying pressure wave to be generated in the drilling fluid at a frequency that is proportional to the rate of interruption. Logging data is transmitted by modulating the acoustic carrier as a function of the downhole measured data.

One difficulty in transmitting measurement information via the drilling mud is that the signal received is typically of low amplitude relative to the noise generated by the mud pumps which circulate the mud, as the downhole signal is generated remote from the uphole sensors while the mud pumps are close to the uphole sensors. In particular, where the downhole tool generates a pressure wave that is phase modulated to encode binary data, such as is disclosed in U.S. Pat. No. 4,847,815 and assigned to the assignee hereof, and where the periodic noise sources are at frequencies which are at or near the frequency of the carrier wave (e.g. 12 Hz), difficulties arise.

Mud pumps are large positive displacement pumps which generate flow by moving a piston back and forth within a cylinder while simultaneously opening and closing intake and exhaust valves. A mud pump typically has three pistons attached to a common drive shaft. These pistons are one hundred and twenty degrees out of phase with one another to minimize pressure variations. Mud pump noise is caused primarily by pressure variations while forcing mud through the exhaust valve.

The fundamental frequency in Hertz of the noise generated by the mud pumps is equal to the strokes per minute of the mud pump divided by sixty. Due to the physical nature and operation of mud pumps, harmonics are also generated, leading to noise peaks of varying amplitude at all integer values of the fundamental frequency. The highest amplitudes generally occur at integer multiples of the number of pistons per pump times the fundamental frequency, e.g., 3F, 6F, 9F, etc. for a pump with three pistons.

Mud pumps are capable of generating very large noise peaks if pump pressure variations are not dampened. Thus, drilling rigs are typically provided with pulsation dampeners at the output of each pump. Despite the pulsation dampeners, however, the mud pump noise amplitude is typically much greater than the amplitude of the signal being received from the downhole acoustic transmitter. To reduce or eliminate the mud pump noise so that the downhole signal can be recovered, different techniques have been proposed, such as may be found in U.S. Pat. Nos. 3,488,629 to Claycomb, 3,555,504 to Fields, 3,716,830 to Garcia, 4,215,425 to Waggener, 4,215,427 to Waggener et al., 4,262,343 to Claycomb, 4,590,593 to Rodney, and 4,642,800 to Umeda. What is common to all of the techniques is that they try to eliminate the mud pump noise by adding the mud pump noise to an inverted version of itself. Most of the techniques utilize two sensors in the mud stream (usually two pressure sensors) and take the difference of signals in an attempt to cancel the mud pump noise without canceling the data signal. Various of the techniques require particular physical arrangements.

The Umeda U.S. Pat. No. 4,642,800 takes a slightly different approach to eliminating mud pump noise. Umeda teaches that an average pump signature may be found by obtaining the pump signatures in the presence of data over a certain number of pump cycles. The updated average pump signature is corrected by interpolation to match the current pump cycle length and is subtracted from the current pump signature to provide the residual data signal. While the technique disclosed in Umeda may be effective for particular arrangements, it has several drawbacks. First, because Umeda averages pump signatures which include data pulses, unless the effect of the data signal over any averaging period is zero (i.e. non-carrier frequency systems), the data signal which is to be recovered will tend to be undesirably subtracted from itself. Second, because Umeda uses only a single strobe per pump cycle, estimates (e.g. interpolations) are utilized which can introduce significant error. Third, Umeda does not disclose in detail how to treat a multi-pump system. In particular, if Umeda assumes that the pump signature for each pump of a multi-pump system is the same as it would be for a single pump system, large errors are introduced in attempting to cancel out the pump noise, as pumps which are working in multi-pump systems will have different signatures than they would it they were working in a single pump system. In addition, because estimates are required for each pump in the multi-pump system, additional error in the multi-pump system is introduced.

It is therefore an object of the invention to provide methods and systems for accurately recovering data signals introduced into drilling mud in the presence of mud pump noise.

It is another object of the invention to provide methods and systems for accurately recovering logging-while-drilling (LWD) or measurement-while-drilling (MWD) information which is modulated in drilling mud by correlating mud pump piston positions to a mud pressure signature in a calibration procedure.

It is a further object of the invention to provide methods and systems for accurately obtaining LWD or MWD information in multiple mud pump systems by allocating noise attributable to each mud pump and by tracking the mud pump piston position of each mud pump.

Another object of the invention is to provide method and systems for recovering LWD or MWD information transmitted through drilling mud by varying the pressure of the drilling mud regardless of the manner in which the information is coded.

In accord with the objects of the invention, methods for recovering a LWD or MWD data signal in the presence of mud pump noise are provided, and generally comprise calibrating the drilling mud pressure as a function of the mud pump piston position, and then tracking the piston position during transmission of the LWD or MWD data signal and using the calibration information to subtract out the mud pump noise. More particularly, calibration is accomplished in the absence of the LWD or MWD data signal to provide a correlation between mud pump piston position and the drilling mud pressure; i.e., the pressure signature as a function of mud pump piston position is obtained. Then, when the LWD or MWD data signal is being provided, the mud pump piston position is tracked such that the pressure due to the pump can be subtracted; i.e., by knowing the mud pump piston position, the pressure due to the mud pump is found and subtracted from the total received signal to provide the LWD or MWD signal. Where a plurality of mud pumps are used, calibration is accomplished by running the mud pumps together in the absence of the LWD or MWD data signal, and processing the received mud pressure signals in the Fourier domain to allocated respective portions of the mud pressure signals to respective mud pumps such that each mud pump is provided with a signature as a function of its own piston position. With the piston position of each mud pump being tracked, the sum of the mud pressure signals generated by the mud pumps based on their piston positions is subtracted from the total received signal to provide the LWD or MWD signal.

According to a preferred aspect of the invention, the calibration procedure is periodically repeated, e.g., each time additional pipe is added to the drill string, thereby eliminating the effects of depth and mud property variation on the system.

FIGS. 8a, 8b, and 8c are respectively the total pump signal, and the signals from pump one and pump two in the multiple pump system calibrated according to FIGS 7a and 7b.

Referring to FIG. 1, the operation of the present invention in a typical drilling arrangement is illustrated schematically. Drilling mud 10 is picked up from mud pit 11 by one or more mud pumps 12 which are typically of the piston reciprocating type. The mud 10 is circulated through mud line 13, down through the drill string 14, through the drill bit 15, and back to the surface of the formation via the annulus 16 between the drill stem and the wall of the well bore 29. Upon reaching the earth"s surface 31, the mud is discharged through line 17 back into the mud pit 11 where cuttings of rock or other well debris are allowed to settle out before the mud is recirculated.

A downhole pressure pulse signaling device 18 is incorporated in the drill string for transmission of data signals derived during the drilling operation by the measurement instrument package 19. Signaling device 18 may be of the valve or variable orifice type which generates pressure pulses in the drilling fluid by varying the speed of flow. A preferred signaling device which generates sinusoidal signals is disclosed in U.S. Pat. No. 4,847,815 assigned to the assignee hereof. Data signals are encoded in a desired form by appropriate electronic means in the downhole tool. Arrows 21, 22, and 23 illustrate the path taken by the pressure pulses provided by the downhole signaling device 18 under typical well conditions. Pump 12 also produces pressure pulses in the mud line 13 and these are indicated by arrows, 24, 25, 26 and 26a which also illustrate the flow of the mud through the annulus 16.

In order for the downhole pressure pulse signals to be recoverable at the surface, some means must be provided to remove or substantially eliminate the portion of the mud pressure signal due to the mud pumps. Subsystem 30, including pressure transducer 32, mud pump piston position sensors 34, and computer or processor 36, comprises such a means.

The preferred pressure transducer 32 of subsystem 30 is a piezoelectric pressure transducer which provides an analog signal which is preferably bandpass filtered by a filter (not shown) or by the computer 36. The preferred mud pump piston position sensor 34 may either comprise an LVDT which utilizes a linear position transducer, or an RVDT which utilizes a rotary position transducer. The LVDT, as shown in FIG. 2a, has an arm 40a, a rod 42a, and a linear position transducer 44a with leads 46a. Arm 40a is coupled to one of the piston rods 47 of the mud pump 12 as well as to rod 42a of the LVDT. Rod 42a moves coaxially within the linear position transducer 44a, which provides a high precision digital indication of the location of piston 48 in the mud pump 12. The RVDT, as shown in FIG. 2b, has an arm 40b, a cable 42b, and an encoder or rotary position transducer 44b with a spring loaded sheave takeup reel 45b. The RVDT also includes leads 46b. Arm 40b of the RVDT of FIG. 2b is coupled to one of the piston rods 47 of the mud pump 12 as well as to the cable 42b of the RBDT. As arm 40b moves with the pump piston rod 47, the cable 42b is let out or reeled onto the takeup reel 45b takeup reel. The rotation of the takeup reel 45b provides a high precision digital indication of the location of piston 48 in the mud pump 12.

Testing has shown that the drilling mud pressure generated by the mud pump 12 is determined by the position of the mud pump piston for a given set of operating conditions. FIG. 3 illustrates how mud pump piston position correlates to mud pump noise. By coupling the linear position transducer 44a or rotary position transducer 44b to the piston rod 47 of the mud pump, a calibration can be performed that measures the pressure generated as a function of piston position.

The preferred calibration procedure for correlating mud pressure generated as a function of piston position for a single mud pump system is seen in FIG. 4. After the pump noise stabilizes in the system, and before the LWD and MWD tool turns on (i.e. before the data signal starts), the signals output by the position sensor 34 and the signals output by the pressure transducer 32 which are bandpass filtered at 39 are preferably recorded at 52 as related position and pressure arrays 55, 57 in the computer (e.g. in computer memory). Preferably, approximately eight seconds of data (e.g., five to ten pump cycles) are accumulated. Then, averages of the pressure as a function of position are calculated (thereby reducing random pressure variations) at 58 to produced a single position vs. pump noise calibration array 59. Indications of the average calibration array or the inverse thereof are stored and used for canceling mud pump noise as is hereinafter described.

The noise cancellation procedure according to the invention is set forth in FIG. 5. Upon the turning on of the downhole tool and the transmission of LWD or MWD data (hereinafter referred to simply as LWD data for sake of brevity), the position sensor 34 and pressure transducer 32 continue to provide indications of piston location and mud pressure; except that the piston position data is used in real time to determine the electrical signal (based on the calibration array 59) which must be subtracted from the composite LWD/noise signal to cancel the noise component of the signal and leave only the LWD signal. Thus, as shown in FIG. 5, the position sensor signal is sampled at 62 (i.e. based on the position sensor signal, the average calibration array is accessed and a corresponding pump noise is provided), and the corresponding pump noise pressure 64 is subtracted at 66 from the real time sensed pressure 32 which was bandpass filtered at 67 to eliminate high frequency components. The difference between the real time sensed pressure and the pump noise pressure provides an indication of the LWD data signal 68.

Test results of a real time sensed pressure pump noise signal are seen in FIG. 6a, where the amplitude of the signal as expressed in dB (in 10 dB increments) is plotted versus the frequency expressed in Hz (in 4 Hz increments). As seen in FIG. 6a, the noise signal includes several peaks having amplitudes between -10 dB and 0 dB, and even includes a peak having an amplitude exceeding 10 dB. The noise signal of FIG. 6a was then subjected to the noise cancellation procedure of FIG. 5. The noise signal remaining after mud pump noise cancellation is seen in FIG. 6b, and shows that the calibration and noise cancellation procedures reduced noise considerably. In fact, the largest remaining noise peak found at about 5 Hz, has an amplitude of approximately -15 dB, which is more than 25 dB less than the largest peak seen in FIG. 6a prior to noise cancellation.

Turing to FIGS. 7, 7a and 7b, a flow chart of the mud pump calibration procedure for a system utilizing two mud pumps is seen. After the pump noise stabilizes in the system, and before the LWD tool turns on (i.e. before the data signal starts), the signals output by each position sensor 34a, 34b and the signal output by the pressure transducer 32 and filtered at 39 by a bandpass filter which measures composite pump noise are recorded as related position arrays 55a, 55b and pressure array 57 in the computer (e.g. in computer memory). Preferably, approximately twelve seconds of data are accumulated in computer memory at 52; FIG. 8a showing an example of the analog pressure signal which is digitized and stored as part of the array. A fast Fourier transform (FFT) of the composite pump noise signal is then conducted at 70 by the computer. As a result of the FFT, the amplitude and phase of all frequencies contained in the composite mud pump noise signal is obtained at 70 (see FIG. 9a). Utilizing the operating speed of each pump which can be computed from the position sensor of each mud pump, the fundamental frequency and harmonics for each pump are calculated at 72. The, at 75, the amplitude and phase information for each fundamental and harmonic frequency are extracted from the FFT and assigned to its source (i.e. a particular one of the mud pumps) to provide results as seen in FIGS. 9b and 9c. Taking an inverse Fourier transform of the frequency spectra of FIGS. 9b and 9c at 76a and 76b, signals attributable to each of the pumps are obtained as seen in FIGS. 8b and 8c. As indicated in FIG. 7b at 58a and 58b, the position of each mud pump position sensor is related to the mud pressure generated by the respective mud pump, and an average of the pressure as a function of position is calculated for each mud pump to produce two position vs. pump noise calibration arrays 59a and 59b. Indications of the average calibration arrays are stored in computer memory and used for canceling mud pump noise as is described above with reference to FIG. 10.

Referring now to FIG. 10, the noise cancellation procedure for a system using multiple mud pumps is seen. Upon the turning on of the downhole tool and the transmission of LWD data, the position sensors 34a and 34b and pressure transducer 32 continue to provide indications of piston location and mud pressure; except that the piston position data is used in real time to determine the electrical signal (based on the calibration arrays 59a and 59b) which must be subtracted from the composite LWD/noise signal to cancel the noise component of the signal and leave only the LWD signal. Thus, as shown in FIG. 10, the position sensor signals are sampled at 62a and 62b (i.e. based on the position sensor signals, the average calibration arrays 59a and 59b are accessed and corresponding pump noises are provided), and the corresponding pump noise pressures 64a and 64b are subtracted at 66 from the real time sensed pressure 32 which was bandpass filtered at 67 to eliminate high frequency components. The difference between the real time sensed pressure and the pump noise pressures provides an indication of the LWD data signal 68. That signal is then decoded according to techniques known in the art which are not part of the present invention.

Test results of a real time sensed pressure containing pump noise for two mud pumps is seen in FIG. 11a where amplitude is plotted against frequency. As seen in FIG. 11a, numerous noise peaks having amplitudes of -20 dB or higher are seen, with the largest peak of about -5 dB at 5 Hz. The pressure signal obtained after utilizing the calibration and noise cancellation steps of FIGS. 7 and 10 in order to substantially cancel mud pump noise from the signal of FIG. 10a is seen in FIG. 10b. As seen in FIG. 10b, the remaining noise is substantially reduced relative to the noise of FIG. 10a, with the largest peak of about -18 dB occurring at approximately 18 Hz.

There have been described and illustrated herein methods and apparatus for canceling mud pump noise in order to recover a logging while drilling signal. While particular embodiments of the invention have been described it is not intended that the the invention be limited exactly thereto, as it is intended that the invention be as broad in scope as the art will allow. Thus, while particular pressure transducers, position sensors, pump-types, computers, FFT programs, and the like have been disclosed, it will be appreciated that other equipment and programs can be utilized effectively. Similarly, while certain preferred data gathering time periods were disclosed prior to running the LWD or MWD tool, it will be appreciated that other time frames could be utilized. Also, while the invention was described with reference to LWD and MWD procedures, it will be appreciated that the terms LWD and MWD are intended to include any other data signaling procedure where data is transmitted in drilling mud in the presence of mud pump noise. Further, while the invention was disclosed with reference to systems utilizing one or two mud pumps, it will be appreciated that the teachings equally apply to systems utilizing additional mud pumps. All that is required is that the pressure signature of each mud pump relative to its piston position be obtained via transforming the total signal into the Fourier domain, dividing the Fourier response among the various mud pumps based on their fundamental and harmonic frequencies, and converting the responses back into respective pressure signatures. It will be understood, of course, that where two mud pumps are working in unison (i.e. at the same frequency), their signatures can be treated together. Therefore, it will be apparent to those skilled in the art that other changes and modifications may be made to the invention as described in the specification without departing from the spirit and scope of the invention as so claimed.

Plumber with minimum 3 years commercial new construction experience with cast iron, PVC, copper, carriers. No digging, No Ladders, No Port A Jons, No mud, No…

Maintain valid driver"s license and must be able to travel throughout United States. Perform mud checks and maintain properties within the scope of customer mud…

Scope of work includes water district (MUD) project oversight, attending board meetings, contract administration, reviewing construction plans, construction…

Operate winch truck to haul and mobilize/demobilize surface rental equipment. Tanks, pumps, mud mix plants, containment, flare lines & igniters, light towers,…

Use trowels to spread mud. Fill joints in-between panels with mud. Prepare panels for painting by taping or finishing joints. Screw panels to wood framework.

Black gold is truly the best description to sum up the value of oil. One of the most important contributors to change and industrialization, it drives the wheels of progress. ShalePumps is headquartered in Houston, the global oil capital. Headed by experts, it has a vision to support the industry with superior completion equipment. Frac operators, drilling contractors and well service companies source rely on ShalePumps for superior quality.

The key personnel of ShalePumps have a combined experience of more than a hundred years. This experience is reflected in the quality of our equipment. The fracking pumps, components and all services are much sought after for reliability and long life. This is because of the processes we follow. The design, materials, precision engineering and expertise contribute to an advanced assembly line.

After many years of thought and conscientious engineering, the team at ShalePumps is proud to add the Q5K™ 5000 HP Frac Pump to their list of many product offerings. Perfectly capable and suited for the next generation of hydraulic fracking market demands and technology. The Q5K is the only frac pump that has been designed and developed from the ground up to be capable of accepting true 5000 HP in a continuous duty frac application.

ShalePumps has consistently delivered high quality completion equipment to all stakeholders. The mission is to develop faster, rugged and efficient equipment to help the Oil and Exploration Industry. The vision is to continue leading the race with the best quality in completion equipment.

The stakes, though, are no less significant to the companies involved. This week, a state district judge granted a temporary restraining order against Houston-based Mud King Products, which sells replacement parts for the oilfield services industry.

A Mud King rival, National Oilwell Varco, also based in Houston, sued on Friday, claiming Mud King employees engaged in an espionage scheme to steal designs for mud pumps - motors that are used to pump special chemicals known as drilling mud into and out of wells. Mud King then sold the pump designs to a Chinese company that made cheap knockoffs from them, the lawsuit contends.

In National Oilwell"s case, it was tipped off to the alleged scheme last month by an anonymous letter from a Mud King employee who felt the company"s tactics crossed the line.

National Oilwell investigated and said it discovered suspicious emails between one of its employees and Freddy Rubiano, Mud King"s quality manager. Rubiano had worked at National Oilwell for four years before being fired in 2010, the lawsuit said.

Mud King and Rubiano denied National Oilwell"s claims in court documents filed Tuesday. "We intend to vigorously defend Mr. Rubiano," said John Neese, Rubiano"s attorney.

Mud King"s attorney was unavailable for comment. National Oilwell"s general counsel, Dwight Rettig, said the company doesn"t comment on pending litigation.

Last summer, Rubiano called the Inside Woman and asked her for some details of a mud pump component. After she provided the information, he then asked her to get a copy of a secret blueprint, which she emailed to him.

Then, the scheme intensified. Rubiano would send the Inside Woman text messages requesting plans for specific mud pump parts using National Oilwell"s internal identification numbers. The woman would then print copies "and leave them on Rubiano"s kitchen table in exchange for cash compensation," the lawsuit said.

When Rubiano needed more cash to pay the woman, he turned to Mud King"s chief operating office, Nigel Brassington, who authorized the payments, the lawsuit said.

In issuing a temporary restraining order Friday, State District Judge Alexandra Smoots-Hogan told Mud King to stop selling any mud pumps or parts derived from National Oilwell"s designs and return all design documents to National Oilwell. A hearing on a temporary injunction is set for Monday.

Mud pumps may not be the stuff of Hollywood spy movies, but the case underscores the high stakes involved in almost every aspect of the world"s relentless quest for oil.