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PETE 411 Well Drilling Lesson 5 Hole Problems.

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Presentation on theme: "PETE 411 Well Drilling Lesson 5 Hole Problems."— Presentation transcript:

1 PETE Well Drilling Lesson 5 Hole Problems

2 Lesson 5 - Hole Problems Lost Circulation Stuck Pipe Junk in Hole
Keyseat- Crooked Hole Differential Sticking Mechanical Sticking Junk in Hole Kicks and Blowouts Crooked Hole

3 Homework Read: * Applied Drilling Engineering, Ch. 1 * Definitions HW #2 ADE 1.12, 1.13, due Friday, Sept

4 Hole Problems - Lost Circulation
Indication: Flow out < Flow in (e.g 400 < 500) Drop in Mud Pit Volume Blowout

5 Hole Problems- Lost Circulation
Causes: High Formation Permeability (e.g. fractures) Low Formation Pore Pressure Poor Drilling Fluid Characteristics Induced Fracturing of Formation From Rapid Pipe Movement

6 Hole Problems- Lost Circulation
Results: Costly Mud Makeup Loss of Production Fire Loss of Permit to Drill

7 Hole Problems- Lost Circulation
Preventive Measures: Crew Education Good Mud Program Study Wells in Area …to be prepared

8 Hole Problems- Lost Circulation
Remedial Measures: Use Lost Circulation Material as Mud Additive (fibrous or granular) Drill Through Troublesome Interval and Case Off Decrease Mud Weight Decrease Circulation Rate

9 Hole Problems - Stuck Pipe (drill pipe, drill collars, casing)
Indication: Cannot Pick Up Pipe (Venezuela case) Causes: Cave - ins Keyseat - Crooked Hole

10 Hole Problems - Stuck Pipe
Causes, cont’d: Differential Pressure Sticking Filter Cake Deposited AFTER Circulation Stops - While Still on Bottom

11 Hole Problems - Stuck Pipe
Results: Fishing Operations Back off, POH, RIG w/fishing string Loss of Hole or at least part of the hole

12 Hole Problems - Stuck Pipe
Preventive Measures: Use Minimum Mud Weight Required to Control Formation Pressures. Use Special Drill Collars (spiral) Use Centralizers on Casing Periodically Establish Circulation while Running Casing or Drillpipe in Deep Hole

13 Hole Problems - Stuck Pipe
Remedial Measures: If Circulation Can Be Established: Erode Mud Filter Cake - at High Fluid Velocity (speed up pumps) Spot Special Fluid; Oil, Acid Reduce Mud Weight as Far as Possible Rotate Pipe - Keep Moving Pipe

14 Hole Problems - Stuck Pipe
Remedial Measures: If Circulation Cannot Be Established: Cut Pipe or Unscrew Joint - and Fish


16 P1 >> P2 P1 P2

17 F = mN N = DP A F = m DP A Thick Filter Cake Thin Filter Cake
How is filter cake formed? Pipe Stuck in Wall Cake

18 Hole Problems - Junk in Hole
Indication: Bit Parts Missing Items from Surface Dropped into Hole Erratic Torque

19 Hole Problems - Junk in Hole
Cause: Negligence of Crew Result: Fishing Operation

20 Hole Problems - Junk in Hole
Preventive Measure: Crew Education Remedial Measures: Run Junk Basket Run Basket with Collapsible Teeth (“Poor Boy” Basket) Run Magnet

21 Hole Problems - Blowout (oil, gas or water)
Indication: Returns to Surface after Circulation is Stopped (KICK!) Well Out of Control - Big Problem! Lost Circulation . . .

22 Hole Problems - Blowout (oil, gas or water) [surface or underground]
Causes: Loss of Hydrostatic Head due to Lost Circulation Poor drilling Fluid Swabbing Effect while Pulling Drillpipe Insufficient Mud Weight

23 Hole Problems - Blowout
Results: Possible Loss of Life and Property Legal and Financial Problems

24 Hole Problems - Blowout
Preventive Measures: Crew Education Be Alert Blowout Control Equipment on RIG including Pit Volume Indicators

25 Hole Problems - Blowout
Remedial Action: If on Bottom: Use proper Mud Weight Add Lost Circulation Materials In Extreme Case of Blowout: May Have to Directionally Drill a Relief Well

26 Hole Problems - Crooked Hole
Indication: Periodic Directional Surveys Stuck Drill String Casing Problems

27 Hole Problems - Crooked Hole
Causes: Too much Weight on Bit Dipping Formation Anisotropic Formation Too Small Drill Collars No Stabilizers

28 Hole Problems - Crooked Hole
Results: Uneven Spacing (on bottom) Legal Problems Production Problems Cementing Problems

29 Hole Problems - Crooked Hole
Preventive Action: Avoid Buckling of Drill Pipe by using sufficient number of drill collars Use “Oversize” Drill Collars Use Reamers and Stabilizers Start the Hole Vertically

30 Hole Problems - Crooked Hole
Remedial Action: Plug Back and Sidetrack Use Whipstock Use Reamers in 3 Locations

31 Lost Circulation Example
This Example shows how to determine the mud weight that can be supported by the formation and also the mud weight that will control the subsurface pressure. Well depth = 16,000 ft Protective casing seat = 12,500 ft Mud Weight = 17.0 lb/gal Drillpipe size = 4.5 in. Hole size, casing I.D. = 8.5 in. Annulus volume = 0.05 bbl/ft Water required to fill hole = 20 bbl

32 Before Water After Water Water bbls 400 ft Mud lb/gal 12,500 ft 16,000 ft BHP = ? BHP = 13,963 psig

33 Example - Solution Determine: The effective hydrostatic head and mud weight in lb/gal. Solution: Water gradient = * 8.33 = psi/ft Mud gradient = * = psi/ft

34 Example 3.1 Pressure imposed at total depth:
400 ft of water x psi/ft = 173 psi 15,600 ft of mud x psi/ft = 13,790 psi Total pressure at 16,000 ft = 13,963 psi

35 Example 3.1 Pressure imposed at the casing seat:
400 ft of water x psi/ft = psi 12,100 ft of mud x psi/ft = 10,696 psi Total pressure at 12,500 ft = 10,869 psi

36 Before Water After Water Water bbls 400 ft Mud lb/gal 12,500 ft EMW = lb/gal 10,869 psig 16,000 ft EMW = lb/gal BHP = 13,963 psig

37 END of Lesson 5 Hole Problems

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