HSE Challenges While Testing and Completion of High Sour HPHT Exploratory Wells

Abstract

Abstract Kuwait Oil Company (KOC) is fully committed to protect the health and safety of its people and the environment. Strict adherence to the KOC HSE policies and procedures helped safe execution of critical well testing and completion operations of sour High Pressure High Temperature (HPHT) exploratory wells. This paper describes safety challenges, H2S related risks, and methodology adopted to achieve safe and successful well-testing operations with deep drilling rigs in extreme sour HPHT environmental conditions. Critical operational equipment and safety precautions to be followed prior to and during well testing will also be discussed in detail. Deep HPHT wells with sour environment continue to challenge the execution of well testing and completion operations, especially when wells are of exploratory nature. Wells drilled in deep Jurassic section (14,000'-17,500') having bottom hole pressure more than 10,000 psi, bottom hole temperature higher than 280°F and high sour content(up to 35% H2S) are considered for this case study. Almost 30 exploratory wells under similar environmental conditions have been drilled and tested with deep drilling rigs in different fields in the state of Kuwait. Drill Stem Testing (DST) technique is being used to test the targeted formations. Well related production testing operations like Perforation, Coiled Tubing, and acid stimulation warrant high HSE standards and technical precautions. Every HPHT well is unique and demands special attention when it comes to the selection of critical safety equipment and other safety requirements such as Personal Protective Equipment (PPE), H2S monitors, wellhead equipment, sealing material, flow control equipment and surface safety valves (SSV) with emergency shutdown switches. Even in such hostile environment, with meticulous planning and testing strategies, KOC could overcome all the challenges and all HPHT sour wells were safely tested without any incident. Commitment to HSE was given the highest priority during testing of sour HPHT wells with great emphasis on personnel safety.