This paper presents various techniques/ tools used to demonstrate the major Health, Safety and Environment (HSE) risks involved in the tight gas appraisal program, especially in designing the surface facility for the Trial Production Operation (TPO), has been reduced to As Low As Reasonably Practicable (ALARP). In the challenging environment of central Sichuan basin i.e. local hilly terrain and densely populated farm land, the paper looks at the local requirement and importance of the analysis right from the design phase for a safe and efficient operation of the TPO facility. The techniques covered include Hazard Identification (HAZID) Study, Hazard and Operability Study (HAZOP), Safety Integrity Level (SIL)/Instrumented Protective Function (IPF) study, Fire and Explosive Risk Analysis (FERA) and Fire Protection Analysis (FIREPRAN) study.
The paper covers the documentation of ALARP demonstration into a Design HSE Case. Major Accidents Hazards (MAH) in the TPO facility are identified using the Risk Assessment Matrix (RAM). A systematic and structured Hazards and Effects Management Process (HEMP) is applied in the design of the TPO facility and the risks associated with MAHs are actively and systematically reduced to ALARP. The effectiveness of all barriers and controls for each MAH are evaluated and complied with the set criteria (Bow-tie assessment). If the HEMP assessment determines that a barrier or risk management of a MAH is only partially effective, further remedial action and effort is done to close the gap. Besides, Safety Critical Elements (SCE) and their performance standards are identified and developed as a key input to the Asset Integrity Process Safety Management (AIPSM) in the operations phase.
Finally, the TPO facility design on a plot size of 70m x 70m pad was accepted for construction and trial production. Further improvement study and optimization has been ongoing including taking other unconventional gas (UCG) best practices and learning into the development planning.