Bangko Shaly Sand is the Key for The Future To Be Main Reservoir and Increase Oil Production with The Fracturing Stimulation in Beruk Field Coastal Plan Pekanbaru Block Central

Abstract

Beruk field is located in the western part of Bengkalis Graben, Central Sumatra Basin, Coastal Plain Pekanbaru (CPP) Block. Started production since 1980, Beruk is mature field that has entered the waterflood phase in 1996 with recovery factor (RF) 45.5%. Production of Beruk Field continues to decline with an annual decline of 25%, average water cut 98% which is produced from clean sand reservoir from Bekasap and Bangko Formation, but shaly sand reservoir not yet optimized. This study explains shaly sand become main reservoir with the detail stratigraphy analysis and precise stimulation method, based on well dan production data.
In lithology, shaly sand reservoir included in Bangko Formation indicated not tight, thin thickness, low resistivity, high shale content, limited lateral distribution and low of liquid rate. This reservoir interpreted as sand flat and tidal mud flat in the estuarine to marine environment system, characterized with lenticular and flaser sediment structure. Based on ultraviolet light, isolated sand on the lenticular dan flaser sandstone show oil indication from core data. Fracturing stimulation using carbolite combined with water shutoff stimulation made non connected oil sand become connected and stimulated flow to the well. This method can
increase production index shaly sand reservoir while water shut off is used to restricted flow of water. Fracturing have been implemented at well BRK-25, increased production from 20 BOPD become 160 BOPD and stayed above the baseline production for almost two years, with incremental cumulative reaching 58.42 MSTB. Stimulation works have successfully raised oil production from shaly sand and has brought profit for company. Based on this condition, shaly sand reservoir needs to be considered for more advanced develop at others well in Beruk fields.