The Severe Loss of Well Productivity in an Iranian Gas Condensate Carbonate Reservoir: Problem Identification and Remedy

Abstract

Khami reservoir of Marun field is a gas condensate carbonate reservoir with initial pressure and temperature of 12,556 psia and 285°F, respectively, at a specified reference depth. The high pressure and high temperature condition along with carbonate lithology make this reservoir a matchless gas condensate reservoir worldwide. This article, as a field case study work, discusses a comprehensive work to identify the source of severe loss of productivity and find the best remedial technique for one of the wells in this reservoir. Pressure buildup test data were used and well test diagnostic, interpretation, and analysis was performed using pressure transient analysis software. Extreme buildup of condensate bank around the wellbore, due to bottomhole pressure below the dew point pressure, was observed. The buildup of condensate bank causes a composite reservoir behavior with two mobility zones, a high condensate saturation region followed by a region of gas with initial condensate saturation. Then, to analyze well inflow and outflow performance of production system, a multiphase flow simulator software was used. Deficiency and sensitivity of well inflow performance was concluded; therefore, effect of hydraulic fracturing on improving inflow performance and recovering well productivity was investigated. Considerable improvement in productivity could be gained as a result of hydraulic fracturing. As recommended, a practical way for improving the well productivity of the studied well, with respect to reservoir characteristic and existing operational condition, is use of fracturing methods. In general, the understudy well is a good example to being familiar with the most prevailing cause of well productivity loss in gas condensate reservoirs.