PETE 689 - UBD

1. PETE 689 - UBD Lesson 16 Risk Management and Downhole Problems

2. Risk Management and Downhole Problems Risk Management Risk Identification Quantitative Risk Analysis Risk Mitigation Planning

3. Downhole Problems and Troubleshooting Wellbore Instability Excessive Vibration Fluid Influxes Stuck Pipe and Fishing Corrosion Risk Management and Downhole Problems

4. Risk Management A major success factor in UBD is how effectively the designers and implementers identify risks and develop an effective plan to deal with the risks.

5. Risk Management Before implementing the final design, the selected equipment and operating procedures should be subjected to an exacting risk analysis.

6. Risk Identification Quantitative Risk Analysis Risk Mitigation Planning Risk Response Risk Management

7. Risk Identification Quantitative Risk Analysis Risk Mitigation Planning Risk Management

8. Source of Risk. Probability of Occurrence. Potential Impact. Action to Mitigate. Cost to Mitigate. Probability Mitigation Succeeds. Risk Identification

9. Source of Risk Internal: risks that the designer can control. External: risks that the designer cannot control.

10. Probability of Occurrence Can be on a scale of: 1 to 10 or High, Medium, and Low

11. Potential Impact High, Medium, or Low. May be referred to as �Consequence� Can be defined by dollar amounts or other criteria, such as severity of injuries or death, or any combination of dollar amount and injury. Probability * Consequence = Risk

12. Action to Mitigate Next, the decision whether to live with the risk or if risk mitigation is in order. Mitigation involves reducing the probability of occurrence or the potential impact of a given risk.

13. Risks can be mitigated by: Choose substitute equipment types. Upgrade specifications such as materials strength, ratings, etc. Modify the basic design. Transpose steps in the procedure. Change mud systems, completion options, etc. Include backup equipment.

14. Cost to Mitigate The relative cost to mitigate must be estimated, based on rough approximations, in order to evaluate the viability of the mitigation actions.

15. Probability Mitigation Succeeds Estimate the probability will succeed.

16. Risk Mitigation Table

17. Risk Identification Quantitative Risk Analysis Risk Mitigation Planning Risk Management

18. Quantitative Risk Analysis What is Uncertainty? Risk Analysis and Decision-Making. What is Quantitative Risk Analysis? When should I use Quantitative Risk Analysis? Why should I use Quantitative risk Analysis?

19. What is Uncertainty? Dictionary definition: �the estimated amount or percentage by which an observed or calculated value may differ from the true value� Benjamin Franklin pointed out: �In this world nothing can be said to be certain, except death and taxes�

20. Risk Analysis and Decision-Making Risk analysis and decision making are fundamentally related. A key component of Risk Analysis is to provide support for a particular decision. In our industry, the decision that requires risk analysis is usually subject to acceptance by a team of technical professionals and approval by management.

21. What is Quantitative Risk Analysis? Any technique for analyzing uncertainty and quantifying the effects of that uncertainty on factors that will significantly effect decision making.

22. A method of quantifying the consequences of the risks identified by intuition through a structured approach to decision making based on: what you think you know and don�t know. What you can do. What you want the outcome to be. What is Quantitative Risk Analysis?

23. When should I use Quantitative Risk Analysis? Risk analysis can be used throughout an UB project to improve the quality of technical evaluations and improve risk mitigation techniques.

24. Technical professionals overrate their ability to predict specific variables and even a simplistic approach to risk analysis will lead to superior forecasting and decision making. Why should I use Quantitative Risk Analysis?

25. Probabilistic methods provide better decisions than deterministic methods because a full range of potential outcomes is examined. Why should I use Quantitative Risk Analysis?

26. Quantitative Risk Analysis The Process Problem Identification. Deterministic Analysis. Probabilistic Analysis. Evaluation and Communication. Decision and Action.

27. Problem Identification Identify the problem, the reason that a solution is required, and project desires. Collect and review data. Verify accuracy of data, and ensure it is pertinent to the issue at hand.

28. Deterministic Analysis Construct a model relating inputs and possible outcomes. Perform a sensitivity analysis and present the results in graphs and tables. Identify key variables and examine them in more detail.

29. Probabilistic Analysis Assign key variables a range and probability distribution. Conduct an assessment using Monte Carlo simulation.

30. Evaluation and Communication Check if the results make sense, determine if additional information is needed, and create graphs and tables to communicate the results of the analysis.

31. Decision and Action Recommend the best alternative consistent with the analysis and project desires.

32. HAZOP

33. Essential Elements

38. Small Group

39. Recorder

40. Co-ordinator

41. �What-If� for Hazards

42. With a Hazard Named:

46. With Risks Assessed

47. Now What?

48. Final Steps

50. Problem with Quantitative Risk Analysis Determining the probabilities. Mis-understanding of the inner workings of the model. Lack of reality checks. Ignoring relationships between variables. Use of subjective judgments.

51. Risk Identification Quantitative Risk Analysis Risk Mitigation Planning Risk Management

52. Risk Mitigation Planning Risk Mitigation Plan Risk Response

53. Risk Mitigation Plan Should be incorporated into the individual well program for each well. Should include a brief description of the operations� risks identified and analyzed in the previous phases and suggested mitigation measures that were derived. Keep is simple.

54. The plan should include: Emergency phone numbers. Engineering drawings and sketches. Risk mitigation procedures. Risk Mitigation Plan

55. Risk Response Field personnel must be ready to implement emergency responses. Inspections, audits and field visits will assist in ascertaining the ability of operations personnel to respond to a particular risk.

56. Downhole Problems and Troubleshooting Wellbore Instability Excessive Vibration Fluid Influxes Stuck Pipe and Fishing Corrosion

57. Wellbore Instability Causes of Instability Symptoms Prevention Solutions and Treatments

58. Causes of Instability Mechanical - Most are related to mud weight, more specifically, to mud weight reduction while attempting to get underbalanced. Abnormal pressure, tectonic stress, and unconsolidated formations are all causes of mechanical wellbore instability.

59. Chemical - related to reactivity of shale and/or clay that may be present in other formations. Most causes by exposure to fresh water. Causes of Instability

60. Symptoms Most symptoms are due to rock failure and excessive amounts of formation in the wellbore. Include: increased torque/drag. increase fill on bottom during connections/trips. increased annular pressure. excessive cuttings at the surface.

61. Prevention Determine the cause. Adequate mud density. Proper chemical make-up of the drilling fluid.

62. Solutions and Treatments Increase circulation rate. Keep pipe moving at all times. Use inhibitive fluids.

63. Downhole Problems and Troubleshooting Wellbore Instability Excessive Vibration Fluid Influxes Stuck Pipe and Fishing Corrosion

64. Excessive Vibration Causes of Excess Vibration. Symptoms of Vibration. Prevention and Solution to Excessive Vibration.

65. Causes of Excess Vibration Drilling rough, highly fractured or abrasive rocks. Hard rocks. Improper handling of percussion tools. Gas drilling does not dampen vibrations as much as liquids.

66. Symptoms of Vibration Drillstring damage noticed through inspection. High incidence of downhole tool failure.

67. Prevention and Solution to Excessive Vibration Keep the drillpipe in tension. All compressive forces should be contained in the BHA. Calculate the neutral point so that when the maximum WOB is applied, the neutral point is in the BHA.

68. Wellbore Instability Excessive Vibration Fluid Influxes Stuck Pipe and Fishing Corrosion Downhole Problems and Troubleshooting

69. Fluid Influxes Causes Symptoms of Unwanted Influxes Prevention of Influxes Solutions to Unwanted Influxes

70. Causes Major cause is UBD. Three requirements for influx. some measurable porosity. Permeability. wellbore pressure < formation pressure.

71. Symptoms of Unwanted Influxes Fluids being returned to the surface that are not pumped into the wellbore. Damp cuttings when drilling with dry gas. Reduction in the number of cuttings at the surface. Increased injection pressure. Loss of returns.

72. Prevention of Influxes Only real prevention is to drill overbalanced. But this is not possible if our goal is to purposefully drill underbalanced.

73. Solutions to Unwanted Influxes Control influx rate. When drilling with gas or air, attempt to unload the liquids from the hole. May require a switch to mist drilling. Increase EMW in stages. Carefully weighting up the system.

74. Wellbore Instability Excessive Vibration Fluid Influxes Stuck Pipe and Fishing Corrosion Downhole Problems and Troubleshooting

75. Stuck Pipe and Fishing Causes Symptoms Prevention Solutions

76. Causes All causes of stuck pipe can occur during UBD except differential sticking. Keyseating. Excessive cuttings due to wellbore instability. Mud rings.

77. Symptoms Cannot pick up the drillstring.

78. Prevention Proper design of the drillstring. Adequate hole cleaning.

79. Solutions Fishing.

80. Wellbore Instability Excessive Vibration Fluid Influxes Stuck Pipe and Fishing Corrosion Downhole Problems and Troubleshooting

81. Corrosion Requirements for Corrosion. Causes and Factors Effecting Corrosion. Symptoms. Prevention. Solution.

82. Requirements for Corrosion Requires the presence of four components: an anode (component that corrodes). a cathode. an electrolyte. an external connection.

83. Simple Corrosion Cell

84. Causes and Factors Effecting Corrosion Fluid utilized is the single largest source of corrosion. The fluid becomes the electrolyte.

85. Corrosion Rate Factors Oil content. Conductivity of electrolyte. pH of the fluid. Temperature and Pressure. Fluid velocity. Bacteria. Internal and External stress concentrations. Presence of dissimilar metals.

86. Symptoms Generalized corrosion. Pitting.

87. Prevention Corrosion cannot be stopped, but it can be slowed.

88. Solution Avoidance Inhibition