Protecting People and the Environment during Stimulation Treatments in Offshore Settings NASEM Workshop: Offshore Well Completion and Stimulation using Hydraulic Fracturing and Other Technologies Paul Hebert October 2, 2017 Washington D.C.
Key Points Industry has an excellent 20-year offshore safety track record for offshore hydraulic fracturing and acid pumping operations. Offshore hydraulic fracturing operations are different than onshore operations not a traditional unconventional (shale) resource. Offshore hydraulic fracturing has multiple hydraulic and mechanical barriers with procedures in place to protect people and the environment. Industry uses comprehensive Risk Management processes for planning and pumping operations, with Management of Change Process when required.
Onshore Wellsite View Safety Focus on Location of Pumps of Tanks for Emergency Access Highly coordinated pumping operations from a remote control cabin removes people from close proximity of operations. Operational procedures, Risk Assessments, and Job Site Safety Analysis are routinely performed. Multiple layers of physical barriers, valves, over pressure release, and line containment in place.
Offshore Wellsite View Integrated procedures and communications between pumping vessel and rig maintain safe operations Photo with permission from Baker Hughes Close proximity, dynamic positioned vessels requires an integrated Simultaneous Operations Plan to maintain vessel position. Requires purpose-built, high pressure pumping vessel that holds fluids and proppant material. Vessel connects to rig via 15,000 psi pressure rated flexible pipe with built in emergency disconnect feature. Personnel are removed from dedicated high pressure piping routes / areas.
Integrated Approach for Safe Operations of Offshore Hydraulic Fracturing / Acidizing Safety Processes : Simultaneous Vessel Operations -Integrated vessel station keeping plan with emergency disconnect and vessel management plans. DP3 positioning, Reference positioning, and redundant electrical power management systems. Jobsite Safety Analysis, Stop Work Authority, Barrier off HP areas of vessels during pumping ops. Remote Operation controls all mitigate personnel exposure to HP areas. Physical Barriers for Pumping Operations: Use of inspected and pressure tested mechanical barriers in flow path. Wellbore kill weight fluid in well annulus while pumping. Subsea BOP stack with multiple seal points for pressure isolation capability.
Effective Risk Management Processes in Place Consistent with Safety Environmental Management System (SEMS) Bow Tie Model Causes Event Outcomes Barriers A 1. X B 2. Y C 3. Z Identify the inputs Develop effective barriers / mitigations Lower Outcome Impact Matrix Assessment Model Probability Identify procedure steps Identify Probability & Impacts Develop Barriers / Mitigations to move from red to green Consequences Management of Change for both processes to stop and reassess risks when situation changes
Offshore HF Conducted Safely for 20 years 2007 2016 Safety Data from Combined Pumping Contractors TRIR data bases ( ~ 80 % of actual jobs pumped ) Average number of Significant Safety Events / Yr. 1.1 ( 214 jobs ) Total Average Probability of Occurrence of Significant Safety Event : 0.52 % per well operation. Average Total Recordable Incident Rate / Yr. is 0.83 ( OSHA 200K MH ) Note : OSHA 2015 TRIR data for all industries and government is 1.7. Per OHSA 2015 Industry Injury and Illness statistics report, Table SNRO2
Conclusions Industry has an excellent safety track record for offshore Hydraulic Fracturing and acid pumping operations. Industry utilizes both hydraulic and mechanical barriers with procedures in place to protect the people and the environment. Industry uses comprehensive Risk Management processes for planning and pumping operations, with Management of Change Process when required. Offshore HF / Acidizing processes results in fewer wells drilled, and thus reduced safety risk and potential environmental impact.
Back up information
Examples of Barriers and Mitigations Pressure Flow Path equipment is inspected and pressure tested prior to job. Wellbore kill weight fluid in well annulus while pumping. Subsea BOP stack with multiple seal points for pressure isolation capability. Surface injection flow head with two independent closure valves one valve is remote operated.
OSHA 2015 Industry Injury Illness, DAFW Statistics -Table SNR02 ( TRIR data )