Sawan Gas Wells De-Liquification
Research output: Research › Master's Thesis
OMV (Pakistan) is the Operator of Sawan Field, Located in District Sukkur, Sindh. The field is a dry gas reservoir, discovered in 2003 through exploration well, Sawan-1, which encountered hydrocarbon bearing Lower Goru C sand. Sawan is a depletion drive gas reservoir with the initial reservoir pressure of ~5350 psi & 350oF bottomhole temperature & has produced ~1.43 TCF. Sawan Gas Field has been producing since June 2003 and onwards from February 2010 the field is producing through front end compression (FEC). Up to date 16 wells (15 vertical & 1 horizontal) have been drilled and currently 14 wells are producing with 115 MMscfd gas & 5322 bbls/d water. Sawan field is divided into two distinct parts, Sawan North and Sawan South, separated by a North West – South East trending strike slip fault. Sawan North is a high permeability good quality sandstone reservoir, with maximum net pay in excess of 100 meters. To achieve high gas rates the wells in Sawan North (Sawan-2 ST, 3, 7, 8, 9) were completed with big bore during development phase. Sawan South, however, consists of low permeability reservoir due to deposition of poor facies in this part of the field. So far 4 wells (Sawan-4, 5, 6 & 12) have been drilled and completed in Sawan South area with 4-1/2” completion followed by hydraulically fracturing; a huge amount of water was produced after fracturing Sawan-6 and Sawan-12 which are more prone to hydraulics problem. Currently Sawan has declined to ~600 psi reservoir pressure in Sawan North area which resulted in increased WGR value (condensed) that may cause wellbore hydraulics issues or early natural abandonment due to plant backpressure in near future; similarly Sawan South wells may observe wellbore hydraulics issues due to high post fracture water production. This thesis work evaluates the well current and future potential in order to increase well life and ultimate recovery based on technical and economic considerations by considering various applicable artificial lift strategies.