FRACTURE ANALYSIS OF EOCENE CARBONATE RESERVOIRS, NORTH POTWAR DEFORMED ZONE, PUNJAB, PAKISTAN

Abstract

The purpose of this research is to conduct fracture analysis of Eocene carbonate reservoirs (Chorgali and Sakesar) exposed in the Chorgali Pass, Potwar Basin, Pakistan. The fracture analysis is done in terms of trend of open fractures. The main idea of this research is to quantify the orientation of open set of fractures at different inventory circle, to identify the most dominant fracture set produced as a result of regional stress; so that the same can be used to propose a well trajectory which could encounter maximum number of these regionally distributed fractures. The data gathered from the field which was plotted on rose plots via Geo-Rose software, indicated the presence of three dominant fracture sets namely A, B and C sets of fracture. A set of fracture was found on every inventory circle with West North West (WNW) to East South East (ESE) direction almost perpendicular to the direction of Indian-Eurasian plate collision, the major source of deformation and stress build up in Indian Plate. Therefore, A set of fractures have been concluded as regionally distributed fractures and deemed essential for designing of any well trajectory targeted at these Eocene carbonate rocks, which mostly lack the primary porosity. It is recommended that a horizontal well drilled perpendicular to A set of fracture must be drilled in these hard and compact Eocene carbonate rocks so as to encounter maximum number of open fractures, as these carbonate rocks generally lack the primary porosity and much of the permeability comes from open fractures.