Abstract

Cambay basin is an intra-cratonic, NNW-SSE trending narrow, elongated, rift basin located in the NW margin of Indian Precambrian Shield. North Kadi field is located at southern tip of Mehsana High in the Ahmedabad-Mehsana tectonic block of Cambay Basin and has been under production since 1969. The sands encountered within the Kalol Formation of Middle to Late Eocene age are amongst the most significant producers in the field followed by the Mehsana, Mandhali and Linch Sands of Early Eocene age. The modeling of North Kadi field aimed to capture adequate detail in order to characterize vertical and lateral heterogeneity at the well and the field scale to use as input to simulation and contribute to better reservoir management. Approximately 280 SKM of 3D seismic data in addition to 2D seismic data was interpreted. Six horizon tops were mapped using depth converted seismic interpretation combined with well data. Fault mapping and correlation was done on every 20th Inline and Trace line. A total of 483 wells were taken up for study of the field. Structural model was constructed by inputting fault sticks, well tops and seismic horizons to the relevant Petrel modules. A three dimensional grid was prepared by Pillar gridding. Selected wells were processed to arrive at effective porosity and water saturation values. Effective porosity obtained from ELAN plus processing was propagated to each cell of the three dimensional grid after processed data was scaled up to the grid dimensions and analyzed in detail. Saturation modeling was carried put after relationship between bulk volume of water (BVW) and height above free water level (FWL) was determined for different payzones in different blocks of the field. The effort resulted in a model with 50m X 50m lateral resolution and average cell thickness of 1.2 m with each 3d cell having discrete values for petrophysical parameters.