Abstract
The Khuff formation is a late Permian age heterogeneous carbonate sequence that underlies the massive Ghawar field in eastern Saudi Arabia. The Khuff is subdivided into four separate intervals (A through D), though production is primarily from the B and C intervals. Since its initial appraisal in the late 1970s, the majority of Khuff development activity has been focused in the Khuff-C reservoir, where single and multistage matrix acidizing treatments have been the predominant stimulation technique.
As domestic gas demand in Saudi Arabia continues to rise, unrelenting efforts are underway to develop the tighter Khuff-B areas while sustaining production levels from Khuff-C wells. As a result, an increasing number of wells have been drilled and completed in the Khuff-B reservoir. The latest trends in the development of these tight gas Khuff wells include multistage acid fracturing to optimize the stimulation treatments.
Various drilling, completion, and stimulation techniques have been utilized in the Khuff development since its inception. Some of the variants analyzed to determine impact on production include: type of stimulation treatment, hole azimuth, completion isolation system, and number of stimulation stages per well. In addition, treatment design parameters were analyzed. Particular attention was paid to performance trends from Khuff-B wells where improved technical solutions were required to address challenging reservoir characteristics.
The results of this analysis demonstrate that multistage fracturing (MSF) technologies made a positive impact on Khuff development—with improved production results over time. Trends also highlight an increase in stimulation stage count and a wider range of stimulation treatments with the application of new technologies. The analysis identified the key production drivers in the Khuff and ways to improve production of future wells drilled in the formation. Continued use of multistage fracturing has proven very successful in Khuff reservoir providing substantially higher rates and sustained production.
