Improved oil recovery by in-fill drilling in a mature field; a success story

Proposal: North Kadi oil field in North Cambay Basin, India has been under production since 1969. The hydrocarbon accumulation in the field is mainly in Middle Miocene sandstone of Kalol Formation having high permeability and strong aquifer support. The development plan of the reservoir had been drawn on the basis of simulation studies carried out at various stages. Recently, remodeling of the field has been done for rational exploitation of the reservoirs. Improved Oil Recovery (IOR) Scheme was formulated after updating the geological model. In-fill drilling of 33 locations were firmed up to achieve the optimal recovery. It envisaged 1.7% additional recovery of in-place oil in 20 years over the primary component of 31.23%. At the time of implementation of the scheme, the field had already produced 20% of 67.0 MMt OIIP. Thirty two IOR locations have been drilled during last three years. As of now, the incremental production from IOR wells is 26% higher than envisaged production profile. The in-fill wells have shown no interference on the performance of nearby wells within their past two years of production history. The drilling and completion cost of the wells break-evened in 20 months. The IOR Scheme involving in-fill drilling rejuvenated the declining trend of a mature oil field.