Enhancing Acid Fracturing Performance Through Deeper Penetration and Innovative Leak-Off Control: First Application of Self-Degradable Particulates in Mumbai Offshore
Abstract
Abstract Acid fracturing is a key stimulation technique in tight carbonate reservoirs, relying on the differential etching of fracture faces by acids such as hydrochloric acid (HCl) to generate conductive flow paths. A critical challenge in this process is managing fluid leak-off, especially in formations with high temperature where the acid rock reactions are rapid resulting in higher leak off and compromised frac geometry. This study evaluates the use of Self-Degradable Particulates (SDPs) as a leak-off control additive to impart far-field acid diversion and improve frac geometry. Laboratory testing demonstrated over 50% reduction in the wall-building leak-off coefficient with SDP of appropriate concentration, while maintaining low spurt loss. These particulates degrade fully into water-soluble products, minimizing the risk of formation damage post treatment. Fracture modeling using FieldPro software, calibrated with laboratory-derived parameters, showed that integrating SDP stages between pad and acid slugs increased fracture half-lengths by up to 30%. An optimization workflow was employed to determine the optimal SDP concentration, balancing performance with operational cost. Field implementation was conducted in three wells targeting tight limestone formations in the Mumbai Offshore region. In all cases, SDP-assisted acid fracturing resulted in marked productivity improvements. One oil well saw a 21-fold production increase, while a previously non-productive gas well achieved commercial flow rates. Post-fracture production monitoring over eight months confirmed the sustained effectiveness of the stimulation. This work highlights the operational feasibility and performance improvement of acid frac operation with SDP-based leak-off control. The study provides a validated workflow – from lab to field – for enhancing acid placement and improving stimulation outcomes in carbonate reservoirs.
