mud pump drilling pdf quotation

The article presents selected technical issues relating to drilling performed by a drillship, one type of drilling rigs. Basic problems encountered in the main function of such rigs − drilling a well − are failures of mud pumps. The authors investigate these pumps in operational conditions, aiming at development of a system for monitoring the technical condition of these pumps. Work on a diagnostic system is in progress that will permit to predict the condition of mud pump valves well in…Expand

The complexity of today’s drilling projects, especially the need for sufficient pressure and flow rate for wellbore cleaning, challenge mud pumps manufacturers. Their efforts focus on the improvement of pump running time and efficient maintenance management to reduce or eliminate nonproductive time and HSE risks. Drilling rigs rely on mud pumps to efficiently circulate the mud, and synchronized pumps are employed to minimize mud pulsation effects. The mud circulation system is of major interest…Expand

GDEP is the original creator of the drilling pump and continues to set the standard for durable, high-quality drilling pumps that can withstand the world’s toughest drilling environments. Starting with our PZ7 and rounding out with the market"s most popular pump, the PZ1600, our PZ Series of pumps are the perfect choice for today"s high-pressure drilling applications.

The Hex Pump is an axial piston mud pump with six vertical pistons driven by two AC motors via a gear and a specially profiled cam. In contrast to crankshaft-driven triplex pumps, the Hex pump delivers a nearly pulsation free flow. Consequently, there is no need for pulsation dampeners on either the suction or discharge side when running this pump. Other major advantages are compactness (reduced weight and footprint) and no need for replacing liner sizes to achieve high pressure or flow. The Hex 240 version with 4 1/2" liners has a rated capacity of 2540 HP, a maximum rated pressure of 7500 PSI and a maximum flow capacity of 1034 GPM.

The Hex Pump has substantially less weight than a comparable Triplex pump, and this results in increased variable deck load capacity on drilling units. The potential cost savings related to increased variable deck load capacity both on new builds and on existing rigs will be discussed in this paper. Also, the potential steel weight reduction in the substructure on drilling units will be discussed.

The Hex Pump creates a clean standpipe pressure with much lower pressure fluctuation levels than triplex pumps. Due to this, there are no need for pulsation dampeners when running the Hex Pump. This additionally leads to much better and cleaner MWD-signals for the directional driller. As a consequence, this will contribute to faster and more accurate drilling in long and complicated directional wells.

The design and development of the Hex Pump is described in SPE paper 79831, ref /1/; "Development and Performance Testing of the Hex Mud Pump", but for the understanding of this paper it is important to understand the functionality of the Hex Pump design. Some of the main items are therefore repeated in this paper. SPE paper 92507, ref. /2/, "Operational experience with use of a Hex Pump on a land rig" focuses on the improved MWD-measurements related to use of Hex Pump compared to triplex pumps. Some of the main items discussed there will also be repeated in this paper.

Mud pump liner selection in today"s drilling operations seldom (at best) considers electrical implications. Perhaps, with more available useful information about the relationships between mud pump liner size and operational effects on the electrical system, certain potential problems can be avoided. The intent of this paper is to develop those relationships and show how they affect an electrical system on example SCR rigs.Introduction

There, seems to be little consideration for the relationships between liner size and demand on a rig"s engine/generator set(s). Yet, consideration for this relationship can prove to be very helpful to drillers and operators in efficiency of a rig"s electrical system. In order to develop the relationships and help drillers and operators understand the importance of each, relationships between liner size, pump speed, pump pressure, and electrical power will be developed. Only basic physical laws will be used to develop the relationships; and, once developed, the relationships are readily applied to realistic examples utilizing a mud pump manufacturer"s pump data. Finally, conclusions will be drawn from the examples.DEVELOPMENT OF RELATIONSHIPS BASIC RELATIONSHIPS

where HHP= Hydraulic horsepower, GPM = Mud pump volumetric flow rate in gallons per minute, and PST Mud pump output pressure in pounds peer square inch.

Hydraulic horsepower is reflected to the mud pump motor via a multiplier for mechanical efficiency. it follows that motor horsepower is then represented by

Manufactured to withstand the toughest drilling and environmental conditions, our K-Series triplex mud pumps are ideal for all drilling applications. This legacy product features a balanced forged-steel crankshaft and Southwest Oilfield Products ‘L” Shaped modules which is essential to minimize wear, noise, and operating vibrations. These attributes are essential when drilling deeper high pressure formations, long laterals and when handling corrosive or abrasive fluids and slurries.

Every American Block triplex mud pump is manufactured and fully load tested before leaving our manufacturing campus, and is available in sizes ranging from 800 HP to 2200 HP. The American Block K1600 HP Mud Pump is also available in a 2000 HP up-grade version, when more HP is needed in the same 1600 HP footprint.

Our pump stroke counter systems (CPS101 Series) measure the stroke rate and number of strokes on mud pumps. The oilfield pump stroke system is user-friendly and reliable and is configurable to measure up to three mud pumps at once. Our digital pump stroke counter systems are manufactured here in the U.S. by Crown Oilfield Instrumentation, and Crown’s Pump Stroke Counter provides easy monitoring of strokes per minute on multiple mud pumps. Each mud pumps’s stroke rate can be selected individually and the display is updated regularly for accurate monitoring. LCD displays indicate both pumps strokes per minute and the total number of strokes. Located at the bottom of the panel, push buttons provide easy operation and reseting of each pump. When you need to accurately monitor and maintain the amount of mud being pumped, you can trust Crown’s oilfield stroke counters.

The circulation system on the rig is the system that allows for circulation of the Drilling Fluid or Mud down through the hollow drill string and up through the annular space between the drill string and wellbore. It is a continuous system of pumps, distribution lines, storage tanks, storage pits, and cleansing units that allows the drilling fluid to fulfill its primary objectives (these will be discussed later in this lesson). The mud pumps of the circulation system and the drawworks of the hoisting systems are the two largest draws on the power from the power system

Drilling fluid is mixed in the mud pits and pumped by the mud pumps through the swivel, through the blow out preventer (not part of the circulation system) down the hollow drill pipe, through holes (Jet Nozzles) in the bit, up the annular space between drill pipe and wellbore (where it lifts the rock cuttings), to the surface, through the Solids Control Equipment (Shale Shaker, Desander, and Desilter), and back to the mud pits. A schematic of the circulation system is shown in Figure 9.05.

In this figure, fresh water-based drilling fluid (mud) is mixed with water from the Water Tank (not shown in Figure 9.05) and components from the Bulk Mud Components Storage (not shown in Figure 9.05) in the Mud Pit. The Mud Pumps then pump the mud through the swivel, kelly, kelly bushing, and rotary table down to the drill string.

The mud pumps on a typical drilling rig are either single-action or double-action Reciprocating (Positive Displacement) Pumps which may contain two pistons-cylinders (duplex pump) or three pistons-cylinders (triplex pump). Figure 9.06 shows schematics of a single piston-cylinder in (A) a single-action and (B) a double-action reciprocating pump.

In these pumps, the positive pressure and negative pressure (suction) in the cylinder cause the valves to open and close (note: the valves in the schematic are simple representations of the actual valves). Due to the high viscosity of the drilling fluid, the inlet side of the pump may require a Charge Pump to keep fluids moving into the cylinders at high pressures and to prevent Cavitation in the pump.

From the mud pumps, the drilling fluid goes to the swivel, through the blow out preventer, and down the hollow drill string and bottom-hole assembly. The drilling fluid then goes through jet nozzles in the drill bit; at which point, it begins its return to the surface. The drilling fluid travels up the annular space between the drill pipe and the wellbore, picking up and carrying the drill cuttings up the hole.

Once the drilling fluid reaches the surface, it goes through the mud return line to the gas-mud separator and the solids control equipment. The shale shaker is where the large cuttings from the returning drilling fluid are removed. The shale shaker is a set of vibrating mesh screens that allow the mud to pass through while filtering out cuttings of different size at screen screen mesh sizes. A Mudlogger or a Well-Site Geologist may be stationed at the shale shaker to analyze the cuttings to determine the lithology of the rock and the depth within the Stratigraphic Column at which the well is currently being drilled.

The drilling fluid then passes through the Desander and Desilter. These are hydrocyclones which use centrifugal forces to separate the smaller solids from the drilling fluid. The desander typically removes solids with a diameter in the range of 45 – 74 μm, while the desilter removes solids with a diameter in the range of 15 – 44 μm.

The drilling fluid is then sent through a degasser to remove any gas bubbles that have been picked up during the circulation. These gasses may include natural gas from the subsurface or air acquired during the solids control. Typically, the degasser is a piece of equipment that subjects the drilling fluid to slight vacuum to cause the gas to expand for extraction. The drilling fluid is then returned to the mud pit to start the circulation process over again.

We have discussed the mechanics of how the drilling fluid is circulated during the drilling process, but we have not discussed the role of the drilling fluid. The term “mud” is often used in oil and gas well drilling because historically the most common water-based drilling fluids were mixtures of water and finely ground, bentonite clays which, in fact, are muds.

stabilize the borehole during drilling operations (exert hydrostatic or hydrodynamic pressure on the borehole to prevent rock caving into the wellbore);

allow for pressure signals from Logging While Drilling (LWD) or Measurement While Drilling (MWD) tools to be transmitted to the surface (LWD and MWD data are transmitted to the surface using pressure pulses in the drilling fluid);

As I stated earlier, historically drilling fluids were mixtures of bentonite clay, water, and certain additives to manipulate the properties of the mud (density, viscosity, fluid loss properties, gelling qualities, etc.). Today, there are several different options available for drilling fluids. These include:

Of the listed drilling fluids, the water-based muds and the oil-based muds are the most common; foam drilling and air drilling can only be used under specialized conditions. Of the two liquid based mud systems (water-based muds and oil-based muds), water-based muds are the most common mud system. They are more environmentally friendly and are used almost exclusively to drill the shallow portions of the well where fresh water aquifers exist to minimize any contamination to those aquifers. As this implies, drilling fluids can be – and often are – switched during the course of drilling operations in single well.

In addition, water-based muds are cheaper than oil-based muds, so they are used to reduce drilling costs and commonly represent the “default” selection for a drilling fluid. In other words, water-based muds are often used unless there is a specific reason to switch to an oil-based mud.

Oil-based muds are formulated with diesel oil, mineral oil, or synthetic oils as a continuous phase and water as a dispersed phase in an emulsion. In addition, additives such as emulsifiers and gelling agents are also used. They were specifically developed to address certain drilling problems encountered with water-based muds. The reasons for using an oil-based mud include:

drilling through shales that are susceptible to swelling (in particular, highly smectite-rich shales). Shales contain a large amount of clay material and when these clays come in contact with the water in a water-based mud system, the clays may swell causing the shales to collapse into the hole. Smectite-rich shale formations are often referred to as “Gumbo” or “Gumbo Clays” in the drilling industry;

reducing torque and drag problems in deviated wells. Since oil, a lubricant, is the continuous phase in the mud system, the torque and drag between the drill pipe and the wellbore is reduced with oil-based muds;

achieving greater thermal stability at greater depths. Oil-based muds have been found to retain their stability (retain their desired properties) at greater down hole temperatures;

achieving greater resistance to chemical contamination. Many substances found down-hole (salt, CO2, H2S, etc.) are soluble in water. The introduction of these substances into the water-based mud system may have a deleterious impact on different mud properties (density, viscosity, fluid loss properties, gelling properties, etc.). These substances are not soluble in oil and, therefore, have will not impact oil-based mud properties.

The first three bullet points in this list are becoming more common problems in the oil and gas industry. The shale boom in the U.S. has made long horizontal sections in shale reservoirs targets for drilling. In addition, deviated wells and deeper wells are also becoming more common. For these reasons, the use of oil-based muds is also becoming more common.

high initial costs. Often in an active drilling campaign, if certain depth intervals require an oil-based mud, the mud is stored and reused in different wells;

slow rates of penetration. Historically, the rate of penetration has been statistically slower for oil-based muds than it is for water-based muds. The rate of penetration is the speed at which the drilling process progresses (depth versus time) and is a function of many factors other than mud type, including: weight on bit, RPM, lithologies being drilled through, bit type, bit wear, etc.;

formation evaluation. Some readings from well logs or core analysis may be sensitive to oil entering the formation of interest (for example, if oil from the oil-based mud enters the reservoir in the near-well vicinity, then tools used to detect oil saturation may read artificially high).

Other drilling fluids currently in use that were listed earlier are foams and air. In the context of drilling fluids, foams have the consistency of shaving cream. Both foam and air drilling are used in hard rock regions, such as in the Rocky Mountains, where drill bits render the drill cuttings to dust. Thus, the foam or air only needs to lift this dust to the surface. Air drilling is always an environmentally friendly option if it is applicable because environmental contamination by air is never an issue.