Deep Drilling and Completion Practices Uinta Basin

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Drilling and completion costs in the Uinta Basin have been high for several reasons, mainly, 1) tough, abrasive formations, 2) long rig moves into the Basin, 3) weather, and 4) high inflationary rate. Other author have discussed these problems in detail. This report discusses some of the cost reducing practices which Gulf has used. The objective practices which Gulf has used. The objective has been to develop efficient, safe, drilling and completion practices. Savings of approximately 10 per cent have resulted even though the inflationary rate has been at a record high during this period. Introduction The Uinta Basin, located in Northeast Utah (Figure 1), came into recent drilling prominence in May, 1970, with the field prominence in May, 1970, with the field discovery, Shell-Miles No. 1. This well flowed, initially, at a rate of 1100 barrels of oil per day from an interval near 12,900 feet. Subsequently, 210 wells have been drilled and completed (Figure 2), by a drilling force varying from 25 to 40 rigs. Production has been principally from the Wasatch formation with a small amount being produced from the Green River formation. produced from the Green River formation. The producing trend stretches 40 miles northeast-southwest and is 10 to 15 miles in width. Daily production from this area has risen to approximately 62,000 barrels oil per day (Figure 3). DEPTH DIFFERENCES An earlier report by Findley in 1972 described drilling and other difficulties associated with operations in the Uinta Basin. At that time only two Gulf development wells had been completed. Currently, 37 development wells have been completed, with 6 of the 37 wells reaching depths ranging from 16,200–19,500 feet. The other 31 wells were drilled to depths ranging from 10,000 to 14,800 feet. Figure 4 indicates the reason for the differences in depth. This northwest-southeast cross-section, covering approximately 16 miles, shows Duchesne River, Uinta, Green River, Basal Green River, Wasatch and Cretaceous formations dipping northwest toward the axis of the Basin, while surface ground level is rising northwest, toward the Uinta Mountains. This combination provides more interval to penetrate to the provides more interval to penetrate to the northwest, accounting for increased depth across the field.