Q921 de1 lec 4 v1
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This document provides an overview of key systems used in drilling engineering, including: 1. The hoisting system, specifically the block and tackle system used to lift drill pipe and casing. It discusses mechanical advantage, efficiency, and calculations for hook power, tension in lines, and hoisting speed. 2. The drilling fluid circulation system, including mud pumps, flow lines, and the process of drilling fluid circulating down the drill string and back up to remove cuttings. 3. Components of the drilling fluid system like tanks, pumps, solids removal equipment, and surface piping. Positive displacement pumps are highlighted as the pumps most commonly used.
Q921 de1 lec 4 v1
- 1. Drilling Engineering 1 Course (1st Ed.)
- 2. 1. Power System 2. Hoisting System: A. Introduction B. The Block & Tackle a. Mechanical advantage and Efficiency
- 3. 1. Hoisting System: A. The Block & Tackle a. Hook Power B. Load Applied to the Derrick 2. Drilling Fluid Circulation System A. Mud Pumps
- 5. Input vs. output power For an ideal block–tackle system, the input power (provided by the drawworks) is equal to the output or hook power (available to move the borehole equipments). In this case, the power delivered by the drawworks is equal to the force in the fast line Ff times the velocity of the fast line vf , and the power developed at the hook is equal to the force in the hook W times the velocity of the traveling block vb. That is Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 5
- 6. relationship between the drawworks power and the hook power Since for the ideal case n Ff = W, so that is, the velocity of the block is n times slower than the velocity of the fast line, and this is valid also for the real case. For the real case, Ff=W/nE, and multiplying both sides by vf we obtain which represents the real relationship between the power delivered by the drawworks and the power available in the hook, where E is the overall efficiency of the block–tackle system. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 6
- 7. The Block & Tackle A rig must hoist a load of 300,000 lbf. The drawworks can provide a maximum input power to the block–tackle system of as 500 hp. Eight lines are strung between the crown block and traveling block. Calculate (1) the tension in the fast line when upward motion is impending, (2) the maximum hook horsepower, (3) the maximum hoisting speed. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 7
- 8. The Block & Tackle Using E = 0.841 (average efficiency for n = 8) we have: Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 8
- 10. The total load applied to the derrick The total load applied to the derrick, FD is equal to the load in the hook plus the force acting in the dead line plus the force acting in the fast line for the force in the fast line The worst scenario is that for the real case. For the dead line, however, the worst scenario (largest force) is that of ideal case. Therefore, the total load applied to the derrick is: Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 10
- 11. Derrick floor plan The total load FD, however, is not evenly distributed over all legs of the derrick. In a conventional derrick, the drawworks is usually located between two of the legs The dead line, however must be anchored close to one of the remaining two legs The side of the derrick opposite to the drawworks is called V–gate. This area must be kept free to allow pipe handling. Therefore, the dead line cannot be anchored between legs A and B Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 11
- 12. the load in each leg From this configuration the load in each leg is: Evidently, the less loaded leg is leg B. We can determine under which conditions the load in leg A is greater then the load in legs C and D: Since the efficiency E is usually greater than 0.5, leg A will be the most loaded leg, very likely it will be the first to fail in the event of an excessive load is applied to the hook. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 12
- 13. The equivalent derrick load and The derrick efficiency factor If a derrick is designed to support a maximum nominal load Lmax, each leg can support Lmax 4 . Therefore, the maximum hook load that the derrick can support is The equivalent derrick load, FDE, is defined as four times the load in the most loaded leg. The equivalent derrick load (which depends on the number of lines) must be less than the nominal capacity of the derrick. The derrick efficiency factor, ED is defined as the ratio of the total load applied to the derrick to the equivalent derrick load: Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 13
- 14. derrick load A rig must hoist a load of 300,000 lbf. Eight lines are strung between the crown block and traveling block. calculate (1) the actual derrick load, (2) the equivalent derrick load, and (3) the derrick efficient factor. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 14
- 15. derrick load Solution: Using E = 0.841 (average efficiency for n = 8) we have: (1) The actual derrick load is given by (2) The equivalent derrick load is given by (3) The derrick efficiency factor is Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 15
- 18. drilling fluid roles The drilling fluid plays several functions in the drilling process. The most important are: clean the rock fragments from beneath the bit and carry them to surface, exert sufficient hydrostatic pressure against the formation to prevent formation fluids from flowing into the well, maintain stability of the borehole walls, cool and lubricate the drillstring and bit. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 18
- 19. Drilling fluid circulation Drilling fluid is forced to circulate in the hole at various pressures and flow rates. Drilling fluid is stored in steel tanks located beside the rig. Powerful pumps force the drilling fluid through surface high pressure connections to a set of valves called pump manifold, located at the derrick floor. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 19
- 20. Drilling fluid circulation (Cont.) From the manifold, the fluid goes up the rig within a pipe called standpipe to approximately 1/3 of the height of the mast. From there the drilling fluid flows through a flexible high pressure hose to the top of the drillstring. The flexible hose allows the fluid to flow continuously as the drillstring moves up and down during normal drilling operations. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 20
- 21. swivel The fluid enters in the drillstring through a special piece of equipment called swivel located at the top of the kelly. The swivel permits rotating the drillstring while the fluid is pumped through the drillstring. A swivel Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 21
- 22. drilling fluid in wellbore In wellbore The drilling fluid then flows down the rotating drillstring and jets out through nozzles in the drill bit at the bottom of the hole. The drilling fluid picks the rock cuttings generated by the drill bit action on the formation. The drilling fluid then flows up the borehole through the annular space between the rotating drillstring and borehole wall. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 22
- 23. drilling fluid at surface At surface At the top of the well (and above the tank level), the drilling fluid flows through the flow line to a series of screens called the shale shaker. The shale shaker is designed to separate the cuttings from the drilling mud. Other devices are also used to clean the drilling fluid before it flows back into the drilling fluid pits. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 23
- 24. Process of mud circulation The principal components of the mud circulation system are: pits or tanks, pumps, flow line, solids and contaminants removal equipment, treatment and mixing equipment, surface piping and valves, the drillstring. Rig circulation system Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 24
- 25. The tanks The tanks (3 or 4 – settling tank, mixing tank(s), suction tank) are made of steel sheet. They contain a safe excess (neither to big nor to small) of the total volume of the borehole. In the case of loss of circulation, this excess will provide the well with drilling fluid while the corrective measures are taken. The number of active tanks depends on the current depth of the hole (bypasses allow to isolate one or more tanks.) The tanks will allow enough retaining time so that much of the solids brought from the hole can be removed from the fluid. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 25
- 27. reciprocating positive displacement pumps vs. centrifugal pumps The great majority of the pumps used in drilling operations are reciprocating positive displacement pumps (PDP). Advantages of the reciprocating PDP when compared to centrifugal pumps are: ability to pump fluids with high abrasive solids contents and with large solid particles, easy to operate and maintain, sturdy and reliable, ability to operate in a wide range of pressure and flow rate. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 27
- 28. positive displacement pumps compartments PDP are composed of two major parts, namely: Power end: receives power from engines and transform the rotating movement into reciprocating movement. The efficiency Em of the power end, that is the efficiency with which rotating mechanical power is transformed in reciprocating mechanical power is of the order of 90%. Fluid end: converts the reciprocating power into pressure and flow rate. The efficiency Ev of the fluid end (also called volumetric efficiency), that is, the efficiency that the reciprocating mechanical power is transformed into hydraulic power, can be as high as 100%. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 28
- 29. Pump configurations Rigs normally have two or three PDPs. During drilling of shallow portions of the hole, when the diameter is large, the two PDPs are connected in parallel to provide the highest flow rate necessary to clean the borehole. As the borehole deepens, less flow rate and higher pressure are required. In this case, normally only one PDP is used while the other is in standby or in preventive maintenance. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 29
- 30. Affecting parameters on flow rate The great flexibility in the pressure and flow rate is obtained with the possibility of changing the diameters of the pair piston–liner. The flow rate depends on the following parameters: stroke length LS (normally fixed), liner diameter dL, rod diameter dR (for duplex PDP only), pump speed N (normally given in strokes/minute), volumetric efficiency EV of the pump. In addition, the pump factor Fp is defined as the total volume displaced by the pump in one stroke. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 30
- 31. Types of the positive displacement pumps There are two types of PDP: double-action duplex pump, and single-action triplex pump. Triplex PDPs, due to several advantages, (less bulky, less pressure fluctuation, cheaper to buy and to maintain, etc,) has taking place of the duplex PDPs in both onshore and offshore rigs. Fall 13 H. AlamiNia Drilling Engineering 1 Course (1st Ed.) 31
- 32. 1. Jorge H.B. Sampaio Jr. “Drilling Engineering Fundamentals.” Master of Petroleum Engineering. Curtin University of Technology, 2007. Chapter 2