Abstract
VICO Indonesia is an Oil and Gas company which has operated the Sanga-Sanga Production Sharing Contract (PSC) in East Kalimantan, Indonesia, since 1968. More than 750 development wells have been drilled to date in the harsh swampy environment of the Mahakam Delta in East Kalimantan. Today, the mature reservoirs are predominantly gas, extremely depleted, and have an average recovery factor of 70%.
The flowing tubing head pressure (FTHP) for wells in these developments are typically 50 to 60 psi, allowing for a potential reservoir abandonment pressure of approximately 300 psi. The reservoirs are depletion drive gas reservoirs. Through the installation of wellhead compression, further lowering the FTHP, a lower abandonment pressure was obtained and consequently reserves recovery increased through well life extension.
In 2008, VICO installed 19 wellhead compressors, achieving FTHP’s as low as 5 psi. This resulted in increased productivity, individual well production stability and an expected improvement in overall recovery volumes from the reservoirs. The compressors installed have a small footprint (3.4 × 8.5 m), low fuel consumption and minimal operating costs. Each unit has a nominal capacity of 1 MMscfd. Through the careful well selection process and the ability to quickly relocate the compressors to different wells has enabled Vico to maximize the benefit of this technology.
The paper will present the benefits of wellhead compression in mature gas fields, the selection process for the wells and the compressors, and the operational challenges faced by the project.
