A Successful HSE Management Process Implementation During Drilling and Well Testing Operation in Sour Gas Wells

Abstract

ADNOC took up the challenge to drill, test and produce the highly sour HPHT gas reservoirs with +30% H2S and 10 % CO2 in brown field. The objective of the appraisal program was to gain valuable reservoir data by drilling and then testing the highly sour wells in order to finalize the facilities design and full field development plans. Before drilling the wells in the high sour environment, an extensive safety review of the area, emergency H2S zones, rigs technical capabilities, equipment required for safe operation, testing equipment design and its layout, crew competencies and SIMPOS protocol was prepared. The HSE requirements checklists were developed, reviewed and agreed based on the scope of work both for the drilling and testing phases in a highly congested brown field. The aim was to complete entire operation expanding over 2-3 years without jeopardizing the nearby activities and production. Due to the critically and strategically importance of the project, all the available best practices and technical competencies were applied in this project which allowed to overcome all the SAFETY challenges during drilling, tie-in and testing of these crucial wells. All objectives were successfully achieved with no HSE incidents and failures. Findings and lessons learned are being used to tailor next stage of the project to ensure most efficient scenario of Field development to support country’s increasing gas demand. All existing HSE assurance measures, procedures and programs were reviewed and implemented to suit the condition of sour wells including:Fire & Gas detection, Emergency Shutdown Systems and their layoutsEnvironmental Impact Studies focusing on the potential effects of flaring from sour wells including Zero spill and safe disposal of produced fluids into dedicated disposal wells drilledEstablishing and aligning all communications for imposition of EPZ (emergency planning Zone) and Site Specific Safety Plan with emergency response/evacuation procedures including SIMPOS with multiple evacuation route maps preparedEmergency communication protocol was developed considering the nearby population/towns in case of any gas release.Civil defense, Police and other governmental agencies were informed and ensured their participation during the large scale exercises carried out This paper provides an insight of steps taken to achieve the target of drilling/testing highly sour gas wells safely in brown field. Successful implementation and close follow up of all measures/controls identified in SIMOPS thru multiple audits; resulted in drilling, tie-in and testing of Sour gas wells with no safety incidents or injuries. All routine rig and rigless activities in the vicinity were performed safely complying fully with SIMOPS and no operation was stopped. This paper emphasis importance of following all rules and regulation set by HSE to achieve the objective safety and efficiently. A typical brown field having operational challenges while drilling and testing highly sour gas well