INTEGRATED COMPLETION STUDY FOR HPHT SOUR GAS WELL DEVELOPMENT IN CARBONATE RESERVOIR X

Abstract

Recently, Indonesia will lead to gas deficits since the increase in domestic gas demand in 2040. The increasing need for energy sources and the decreasing available reserves have encouraged oil and gas companies to explore and manage marginal reservoirs such as sour gas environment to maintain the balance of energy supply and demand. The gap in gas supply-demand will decrease by 20% due to the supply of Natuna Gas Field, as the example of potential sour gas environment (Batubara, 2015). Thus, it is very relevant to develop this potential source immediately. Also, sour gas field approximately shares 40% of Indonesia’s total proven gas reserve with an estimated OGIP of around 222 TSCF, with 75% of gas recovery. Unfortunately, sour gas environment cannot be produced economically since the it has high carbon dioxide (CO2) and hydrogen sulfide (H2S) content, which are toxic and corrosive. The X sour reserves contain 32% carbon dioxide (CO2) and 7072 ppm H2S with fluid gravity of 42 API. This discretionary source of CO2 was recently brought into production from one well with depth of 8400 ft. The well was perforated in a limited interval of 7100 until 7700 ft. The harsh environment presented many challenges to completion design. Unique equipment and material selection were required. This study aims to determine the reservoir fluids and production performance also predict the corrosivity of CO2 dissolved in the natural gas. With the simulation and prediction, it can be obtained the proper material and equipment selection based on the sour service needed. As a result, the wet gas reservoir of X field can produce optimum rate of 19.1063 MMSCFD. For completion design, Nickel Alloy SM2535 or SM2242 is needed as there will be damage in form of corrosion and pitting.