Abstract

Ahmedabad field in the Cambay Basin has vertically stacked, multilayered reservoirs. All pay sands are low permeable and produce after hydrofracturing (HF) and installation of artificial lift. Additional recovery from a low permeable reservoir depends on effective reservoir management, viz., optimum well placement, zone transfer (ZT), zone addition (ZA), HF and proper surveillance. Optimum well placement is the most important factor to improve the recovery in such reservoirs. The placement of the new wells as well as the SIMultaneous EXploration (SIMEX), was the key factor in achieving the highest-ever production. It provides an additional zone along with the objective sand for exploitation. Additional zones were identified based on the integrated approach, viz., incorporating field knowledge, understanding of channel deposition and interpretation of Reservoir Description Tool (RDT) samples. 1-D Mechanical Earth Model (MEM) was developed using the core data and advanced logs, such as sonic logs for pore pressure variation, principal stress variation. These data were incorporated into the seismic data for stress variation throughout the field to build a 3-D MEM for better planning of HF. Production from existing wells was also enhanced by targeting missed opportunities and identifying the low-resistivity zone, through improved geological understanding. Integration and execution of key initiativesSIMEX approach, 3-D MEM, ZT, ZA, low resistivity zone identification and reservoir surveillance boosted oil production from 210 m3 /d in May 2020 to 541 m3 /d in July 2024, the highest ever peak production after four decades Since 1981 and has paid rich dividends to the organization