Fracture Characterization and Their Impact on the Field Development

Abstract

 Fracture characterization is a biggest challenge for the geoscientists in clastic and nonclastic reservoirs. With the advancement of all technical capabilities, in the acquisition of surface and subsurface geological data, still it is extremely difficult to understand, characterize, and predict the distribution of fractures in a field. Image logs can successfully be used to locate and to provide directional trends of fractures near the wellbore. However, capturing all the fractures in one well and to predict their flow behavior can still be a challenge. In this paper, a case study of a fractured carbonate reservoir will be presented. The field is currently producing about 500 bbl of oil per day through fractures. Four wells have been drilled on the structure to drain the oil reserves. Water flooding is being carried out in the field for the last 9 years for pressure maintenance and now 80 % water is being produced. The reservoir has very low primary porosity and permeability, and the flow is through fractures only. Based on the fracture data of three wells, a new well was drilled, located ideally at a structurally higher position, in crestal area of the field. Image data showed abundance of fractures with different orientation in the well bore but the well didn’t flow and that led to its suspension. In this study, fracture data from image logs is compared with outcrop analogs and seismic reflection and interpretation data. In this paper, limitation of the available information, importance of understanding the stress regime, integration of geological and geophysical data and lesson learned from the current evaluation of the fracture system and their impact on development of a field in Powar basin will be presented.