D.J. White, Dowell Schlumberger
This paper discusses a case history of a hydraulic fracture optimization and evaluation process conducted on four Dean formation wells in the Spraberry Trend Field of Midland County, Texas. The first topic of discussion focuses on the basic steps of the optimization process. This systematic process review will show how the fracture stimulation treatments were designed to provide an optimum economic return based on simulated production results. These designs used reservoir data that was carefully collected by the most up to date technological tools and methods available. Present economic factors including a best estimate on the time value of money, were also used. A state-of-the-art fracturing simulator combined these parameters to formulate the optimized fracture treatments. These resulting Dean treatments were designed to yield optimum economic value over a targeted time period. The second major discussion will focus on the evaluation of these treatments. This evaluation study will be based upon the actual average production history of these four Dean wells versus the simulated production obtained from the design model. This evaluation comparison clearly shows that actual production to date is very close to the production simulated by the model. The study also reveals that production from this fracture stimulated Dean reservoir can be accurately modeled and, therefore, successfully optimized on an economic value basis. These four optimized Dean wells will also be compared on a production history basis to six previously completed Dean/Wolfcamp wells. The optimized Dean wells are completed only in one relatively small section of the Dean formation. The Dean/Wolfcamp wells are completed over much-larger intervals of the Dean formation and in extensive portions of the Wolfcamp formation. Fracturing stimulation treatments were done in these Dean/Wolfcamp wells but an optimization attempt has not been made. Most of fhe wells were completed with two separate fracture treatments per well. The comparison study of these four Dean and six Dean/Wolfcamp wells shows that the average cumulative production of these two differently completed well types is very similar. Although the cumulative production is similar, this study shows that the four optimized Dean wells are clearly more efficient on a production per perforated foot basis. They are also shallower and were each completed with only one fracturing stimulation treatment. All of these factors indicate that the four optimized Dean wells are providing a better value to date than their six Dean/Wolfcamp predecessors.