Abstract

Hydraulic fracturing (HF) is a reservoir stimulation technique used to enhance permeability and improve hydrocarbon production, especially in low-permeability formations. In an offshore X field, the Basal Sands reservoir exhibits variable porosity and permeability. Well BS-8z was drilled targeting Basal Sands showed favorable reservoir characteristics, with MDT pressure measuring 2800 psi. However, despite several stimulation efforts, the well failed to produce. A substantial discrepancy between MDT and SBHP suggested poor reservoir–wellbore connectivity and planned for hydraulic fracturing operation. In absence of sonic logs in the well, nearby offset well data was used for fracture gradient and sensitivity studies at 30MT, 40MT and 50MT of job size were conducted, and in all the cases, fracture height of around 42m was indicated, suggesting vertical confinement within the Basal Sands, a 50MT job was planned. A Cased Hole Sonic Log was recorded before the job, and a 1D Mechanical Earth Model (1DMEM) was revised to enhance the job design and precision. Revised simulation results revealed that a 50MT job could cause the fracture to extend upto the Basement, and risk water ingression. Consequently, the job size was revised to 40MT, and finally, a 37MT HF job was carried out. Post-job evaluation using updated pressure responses and real-time pumping data confirmed that the actual fracture geometry aligned closely with the design predictions. This refined approach ensured effective stimulation while maintaining fracture containment within the target reservoir, thus avoiding water encroachment and improving operational success.