Challenges and Modeling Results of a Mature Rich Gas Condensate Field Redevelopment Study Applying Depletion and Multiple EOR Methods to Unlock Field Potential

Abstract

A large rich gas condensate field in The Sultanate of Oman has been studied. 30 gas wells were drilled in the field producing 3 MMm3/d of gas and 450 m3/d of condensate from the Barik formation. Water production is negligible. A redevelopment study was initiated with value drivers focused on maximizing the gas and condensate development. New wide azimuth seismic (WAZ) was interpreted and integrated with new petrophysical realizations and geological concepts. This has resulted in a 20% drop in both the GIIP and the CIIP. Earlier wells results and cores when fully re-evaluated support this conclusion. Petrophysical reinterpretation combined with production testing (PLTs) and sampling (MDTs) showed two potential contact scenarios. The field can either be interpreted as having one GWC or it can be interpreted as having an oil rim with a GOC and an OWC. Both of these interpretations result in very different predictions regarding volumetric recoveries, future well locations, and number of wells to be drilled. Static and dynamic models based on these two broad realizations were then generated that capture all the known uncertainties. For the Gas development value driver, a depletion case scenario was studied. For the condensate development value driver, a study of IOR and EOR methods was initiated covering water injection and water alternating gas, nitrogen injection, huff and buff, produced gas injection, and CO2 injection. Wells and surface development concepts were also assessed for each of the development scenarios and the best option was then used in the economics evaluation.