Fractured Well: A Case Study of a Tight Silt Reservoir in Cambay Basin

Sanat Mohanty and Mohit Srivastava
University of Petroleum and Energy Studies

Hydraulic fracturing is one of the stimulation technique where in, the productivity is increased by generating fractures of high conductivity, thus increasing the formation conductivity for the flow of oil and gas. Fracture treatment acts effectively for low permeability formations, of the order of 1-5 mD (in case of oil reservoirs).The stimulation ratio acquired after a fracture treatment, has been traditionally dealt with - Prats method, Tinsley et al. charts , Mc Guire Sikora charts etc. These correlations and type curves assume the wells to be at steady state or pseudo steady state. However, low permeabililty formations require years of constant rate production for achieving steady or pseudo steady state, post fracturing. In contrast to this, Jacques Hagoort ( ‘Stabilized productivity of a hydraulically fractured well producing at constant pressure’, SPE, March 2006), discussed a numerical model for calculation of stabilized productivity of a hydraulically fractured well producing at a constant well pressure. In this paper an analysis of the productivity change in the semi steady state flow regime of a hydraulically fractured well in a marginal oil field, in Cambay Basin has been done. The basis for the selection of the above numerical model as a tool for analysis is the pressure- production data of the well post-fracturing that indicates a semi steady state flow regime. The well also adheres to the basic assumption of the model i.e. production at a constant pressure with a square drainage pattern. The pressure production data (post fracturing), well testing data & fracture operation data are integrated with the above mentioned numerical model to study the productivity change in the semi steady state.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery