Well Control in Alaska Arctic Waters Spill Prevention Workshop Wainwright, AK July 9, 2009

Transcription

1 Well Control in Alaska Arctic Waters Spill Prevention Workshop Wainwright, AK July 9, 2009 Les Skinner Shell E&P

2 Prevention Preparation & Planning Training Risk Identification and Mitigation Drill Well on Paper (DWOP) Contingency Planning Execution Real Time Operations Center (RTOC)

3 Layers of Prevention No single incident leads to the worst case blowout scenario Phase IV Loss of Control Relief Well Operations Contingency plans in place for the worst case scenario Phase III Mechanical Barriers (including special arctic barriers) Testing and inspection criteria in place to ensure competency Phase II Early Kick Detection and Kick Response Procedures. Continuous Monitoring (including use of RTOC) Response shut down pumps flow check shut in kill well Phase I Proper Planning (DWOP), Risk Identification, Training, Routine Drills on Rig (BOP Tests, Pit Drills, Trip Drills) Phase I is used to build a strong foundation

4 Proactive Measures to Maintain Well Control Shell s approach to reducing the risk of a well control incident includes the implementation of the following safeguards: PREPARATION Training Key Rig Site Personnel Risk Identification and Mitigation (Drill Well on Paper - DWOP) Contingency Planning Flexible well design to accommodate range of uncertainty in subsurface data EXECUTION Real Time Influx Assessment Well Control Equipment Maintenance, Inspection, and Testing Procedures

5 Training Onsite Shell and contractor supervisors will maintain up-to-date well control certification Prospect-specific well control scenarios and kill techniques modeled and simulated at Shell s Robert Training & Conference Center Shell foreman, Shell engineers, contract supervisors, and rig skilled positions (drillers, assistant drillers) trained for prospect-specific well control situations Pit Drills, Trip Drills, BOP Tests, H 2 S Operations and Rescue, and Secure Well Drills (when applicable) Training on Critical Operations Curtailment Plan (including daily status reporting)

6 IADC WellCAP Training MMS commends IADC for the WellCAP program and acknowledges the value WellCAP could bring in providing minimum well control training requirements to leassees and contractors worldwide. Federal Register, 14 AUG 2000

7 IADC WellCAP Topics List Pressure Basics Kick Theory Causes of Kicks Complications Shut-in Procedures Fluids Kick Warning Signs Killsheets BOP Equipment Constant Bottomhole Pressure Methods Regulations Subsea Stripping Snubbing Wireline Operations Workovers Simulations Certification isrequired for Shell Drilling Foreman, Engineers, Drilling Superintendent, Wells Delivery Manager and for Frontier Toolpushers, Drillers, Assistant Drillers

8 Risk Identification and Mitigation Site-specific HAZOP conducted for each prospect Drill Well On Paper (DWOP) exercise for each prospect Site Specific Well Control Modeling for anticipated hydrocarbon intervals Site specific dynamic well control modeling for prospects with possible shallow gas or hydrate accumulations Virtual ice management using shipboard marine radar combined with satellite RADARSAT ice imagery to permit advanced and accurate warning of ice hazards

9 Risks - Causes of Well Control Problems Pressure Aquifer outcrop elevation Thick zone of oil or gas above a normal pressure aquifer Up-lifted and sealed fault zones Biogenetic methane from shallow bacterial action Compaction over sealed reservoirs Conditions Formation must have permeability and contain fractures or channels Formation pressure must be greater than wellbore pressure at the point of influx

10 Primary Causes for Loss of Well Control Insufficient Mud Weight Fluid Losses Swabbing Hole not kept full of mud Charged formation Rapidly Drilling a Gas Sand Dissociation of Gas Hydrates Mitigation plans included via operation-specific Shell Drilling Prognosis to avoid these potential causes of loss of well control.

11 Risk Mitigation - Well Control Bow-Tie

12 Site Specific Well Control Modeling Updated models in place to provide guidance on well kill parameters

13 Contingency Planning Blowout Contingency Plan updated and kept available in Anchorage office and on drillship Additional casing & wellhead equipment sourced & carried with the fleet for relief well if required Contingency plans to replace or augment existing rig and drilling equipment (drillpipe, mud materials, etc.) and services, in place with sources identified if a relief well is required Spare BOP refurbished, tested and accessible to the rig if required Relief well drilling plan prepared and approved by the MMS before spudding exploration well

14 Real Time Influx Assessment Use of Shell s Real Time Operations Center (RTOC) to assist in monitoring operations, analyzing penetrated formations, and analyzing pressure trends from Houston or New Orleans. This service augments mud logging capabilities at the rig site. Latest generation MWD and PWD tools to identify the onset of abnormal pore pressures, swabbing, or the influx of hydrocarbons near the bit.

15 Containment Early Kick Detection Well Control Barriers Special Arctic Requirements Critical Operations and Curtailment Plan Relief Well Definition, Strategy, and Procedures

16 Early Kick Detection Training - Crew Training leading to Rapid Response Time Drillers, Drill Crews, Mud Engineers, Mud Loggers, Logging Engineers Continuous Monitoring of all Operations - 100% of the time Downhole Monitoring MWD/ LWD / PWD Tools Surface Monitoring Accurate Flow In / Flow Out Monitoring Equipment Sensitive Trip Tank Level Indication Equipment Thorough Flow Checks Sensitive Pit Volume Totalizer Equipment (Flow Show) Drilling Breaks Treated as Potential Kick Situations

17 Barriers to Maintain Well Control Fluid Barriers Weighted Drilling Mud Brines (seawater) Mechanical Barriers Blowout Preventer Casing Cemented Casing w/ Floats Cement Plugs (pressure tested) Mechanical Isolation Plugs Storm / Ice Isolation Packers High Pressure Cement Unit Pump

18 Special Arctic Requirements Mud Line Cellars excavated to maintain BOP competency despite ice conditions Critical Operations Curtailment Plan (COCP) in place and strictly followed to mitigate ice or other hazards forcing the rig off location in an emergency situation

19 Critical Operations and Curtailment Plan What is a Critical Operation? Any operation that would increase the risk of a well control incident if something should go wrong.

20 Examples of Planned Critical Operations Drilling into a formation containing oil or gas Conducting certain procedures with an oil or gas zone exposed in the wellbore such as: Continuing to drill after a kick has been taken Coring Pulling the drillstring out of the hole Wireline logging Running casing and cementing Certain well control operations (circulating a kick out of the hole) Refueling

21 Examples of Unplanned Critical Operations Fishing for lost items in the well Cutting and pulling casing/milling casing window Open hole sidetracking Perforating Well completion work Remedial well work Formation stimulation

22 Curtailment Stopping or not starting an operation until it is safe to continue. Suspending the Well Making the well safe (i.e., leak-free and secure) while waiting for a hazardous condition to be mitigated.

23 Methods of Suspending the Well Pump and fill the wellbore with heavy mud Pump and set cement plugs in the wellbore Set mechanical plugs in the casing Close the BOP rams and lock them, leave bottom section of BOP over the well Kulluk Emergency Disconnect.exe

24 Even More Definitions Suspend Time (ST) - the time it takes to make the well secure Move out Time (MT) - the time it takes to make the drillship ready to move Total Time (T-Time) - the total of ST + MT Hazard Time (HT) - the predicted time until the arrival of the hazard or hazardous condition Mathematically: T-Time < HT

25 ALERT LEVEL TIME CALCULATION ACTION Green (HT T-Time) greater than 24 hrs Normal operations Yellow (HT T-Time) greater than 12 hrs but less than 24 hrs Heightened awareness Orange Red (HT T-Time) is greater than 6 hrs but less than 12 hrs (HT MT) is less than 6 hrs Limit well operations in line with COCP, possibly commence securing well Secure well, disconnect riser and commence mooring recovery operations Black HT is less than 1 hr Move drilling vessel to a safe location Time calculations are minimums.

26 Relief Well The name - where did it come from? Originally A well drilled into a reservoir to relieve pressure and stop a blowout. Relief Wells Blowout

27 Relief Well Strategy Procedure Drill and intersect the blowout Pump fluid at sufficient rates to kill the well Circulate kill weight mud in both wells Plug and abandon both wells

28 Relief Well Strategy 1. Oil or gas influx into the original well has led to loss of control of the original wellbore 2. Relief well has been drilled and has intersected the original wellbore 3. Circulation is established from relief well to original wellbore 4. Kill weight fluid is then circulated from the relief well to the original wellbore to bring the well back under control

29 Relief Well Characteristics No Mud Line Cellar No additional formation evaluation at casing points Permits in place prior to spud Well design in place Wellhead, casing, other tangible equipment in place Kill fluid available

30 Advances in Industry Technology, 2009 Evolution of MWD Wellbore evaluation tools permits real time assessment of hydrocarbons/pressures near bit Improved drilling efficiency reduces trips Anticipated locations in the Chukchi Sea have relatively benign drilling environments (normal pressures, shallow formation dips, and ample formation strength/pore pressure separation) Satellite imagery improves timeliness and accuracy of ice forecasting

31 Questions?