Understanding Fractures Through Seismic Data: North Kuwait Case Study

Summary: Understanding fracture corridors is the primary driver for successful development of fractured carbonate reservoirs. This assumes further significance if the carbonate reservoir is characterized by very low porosity and permeability; producibility of the reservoir is purely dependent on the presence of natural fractures. Distribution and type of natural fractures is a function of palaeo & present day stress, structural elements, regional tectonics and diagenetic history. Direct detection of fractures is below the resolution of conventional seismic data. However, through a combination of seismic derived attributes integrated with well data, it is possible to better understand the distribution of fracture swarms. Kuwait Oil Company (KOC) is currently engaged in an early phase of development of a tight fractured carbonate North Kuwait Jurassic gas play. Considering the limited well control, field development is heavily reliant on seismic data for fracture characterization. This paper presents our current understanding of the relationship between fractures observed in the well data and structures, faults and lineaments interpreted on seismic data. In addition to conventional seismic analysis a suite of seismic attributes including Dip, Coherence, Edge and 3D Volume curvature were used for mapping structures, faults and minor lineaments. Well-wise and field-wise analysis of relationships between seismic derived attribute-pattern and fracture orientation was established. The understanding between these two different sets of data has helped in locating potential zones of sweet spots for placing successful delineation and development wells. These seismic attribute volumes were also used as soft constraint for building the Discrete Fracture Network (DFN) model for populating the fracture network in the reservoir model. The data presented in this paper are from the Raudhatain, Sabriyah and North West Raudhatain (NWRA) fields for the Najmah-Sarjelu part of the Jurassic section.