Efficient Evaluation of a Fractured Reservoir in the Syria Kurrachine Dolomite—A Case Study

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractEfficiently identifying and evaluating the producibility of fractures after drilling through potential reservoirs remains a challenge to both the oilfield operator and explorationist. Timely identification of features crossing the drilled borehole, indication of feature permeability, and testing of the well at the most promising depths with the drilling rig still on location are the keys to cost-effective development of tight and fractured reservoirs.The Kurrachine Dolomite formation in central Syria is of Middle Triassic age and has low primary porosity. Economical production from Kurrachine reservoirs is therefore highly dependent on the drilled wells encountering zones of permeable secondary porosity. This paper presents a field example demonstrating the success of wireline-conveyed services in evaluating the producibility of the Kurrachine Dolomite. The services involve the latest technology sensors for petrophysical formation evaluation, electrical imaging of the borehole to evaluate the depths of electrically conductive features crossing the hole, acoustic measurements to evaluate the relative permeability of the conductive features, and testing of the depths of interest by sampling, pressure measurement, and real-time formation fluid analysis. Analysis is presented to show which wireline measurements are particularly important to the operator in this environment. The paper presents techniques successfully implemented to overcome the challenges in formation pressure evaluation and fluid sampling of the Kurrachine formation.Because the formation is accurately evaluated in real time with the drilling rig on location, the combination of services permits efficient, cost-effective decision making for development of Kurrachine Dolomite reservoirs.