Best Practice of Data Integration in Developing Naturally Fractured Tight Carbonate Reservoirs: Kuwait Case Study

Al-Anzi, Ealian¹; Pattnaik, Chinmaya¹; Srinivasa Rao, Narhari¹; Al-Ashwak, Samar¹; Hussain Al-Ajmi, Neema¹; Hussain Al-Mayyas, Rawan¹; Kidambi, Vijaya Kumar¹; Al-Qadeeri, Bashar¹; Motar Al-Anzi, Abdullah¹; Acharya, Mihira Narayan¹; Darous, Christophe²
¹Field Developement Gas Studies, Kuwait Oil Company, Ahmadi, Kuwait.
²Field Developement Gas, Schumberger kuwait, Ahmadi, Kuwait.

Fracture characterization is vital for efficient field development of naturally fractured Carbonate reservoirs. This assumes further prominence in tight reservoirs wherein fractures play primary role in flow behavior. This paper is a case study presenting the best practice in integrating disparate dataset ranging from static to dynamic in understanding and characterizing the fractures in a deep tight carbonate reservoir of North Kuwait inspite of the lack of analog outcrop data for calibration .

Seismic attribute data, in particular the seismic volume curvature, was used for qualitative estimate of fracture intensity in development well location selection process. Extensive core and image log data was acquired and integrated in the data analysis stage. This reorientation of the core data also helped in establishing a number of quantitative fractures attributes such as frequency, spacing, dip-azimuth and aperture. These quantitative measures were further segregated based on fracture families, in this case three families, and standard fracture classification of open, partially open, closed and induced fracture sets. This detailed integration also helped in accurately mapping the local and regional present day stress and the variations of the same laterally and vertically. Regional structural analysis was carried out to link the fracture families with the major structural elements. These detailed fracture attribute data has been integrated in populating the geocellular models with soft constraint from seismic attributes, and subsequently the dynamic model.

A comparison of these static fracture properties with flowmeter logs showed an excellent match between maximum fracture porosity and permeability and the zone of maximum fluid contribution. This analysis also established a strong relation between present-day maximum horizontal stress, open fractures and the flowing zones. Successful fracture characterization has been possible through early recognition of fracture play and careful execution of relevant data acquisition campaign.

This study has directly contributed in taking crucial field development decisions such as selecting the zones of perforation intervals, design of well trajectories, and orientation of highly deviated and horizontal wells. Drilling and testing results have been extremely encouraging through enhanced reservoir performance in these tight carbonate reservoirs.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012