Evaluation of the Potential of High Angle Wells for the Najmah-Sargelu Reservoirs in Kuwait

Abstract

Abstract The Najmah-Sargelu reservoirs are fractured carbonates and have been penetrated by several vertical wells. Productivity from these wells depends on chance intersection with vertical fracture clusters and as a result has varied from zero to quite productive wells. The chances of intersecting major fracture clusters will be improved if high angle wells are used. This paper investigates and compares the expected performance of vertical and high angle wells based on assumptions about the density of major vertical fracture clusters also, the azimuth, length, width, and rock matrix properties. The analysis tool developed incorporates uncertainty in these parameters using the algorithm below and Monte Carlo Simulation. Define vertical or HAW well locations. Then, for each Monte Carlo trial: Select fracture density. 2 Select fraction of fractures in primary and secondary azimuth. Randomly map fractures in reservoir area, sampling length and width distribution for each fracture cluster location. Count intersections of fixed location high angle or vertical wells with fracture clusters. Use cluster intersection statistics to determine the number of multiple fracture clusters connected to each well. Calculate average matrix volume associated with each fracture cluster and compute matrix fracture feed. Calculate OIP and recovery for each well. Sample well costs and perform economics. The analysis allows the comparison not only of vertical and high angle wells, but also high angle wells with different completion lengths. The method provides a quick and simple method of screening and prioritizing fractured reservoir opportunities for more-detailed analyses.