Abstract: Evolution of Completion and Fracture Stimulation Practices in the Jonah Field, Sublette County, WY
R. W. FINCH, J. L. SKEES, and J. T. HANSEN
This case history discusses the evolution of the completion strategies and fracture stimulation techniques that have turned a large marginal gas resource at the Jonah field into a commercially viable field. Completion practices have evolved from single zone, high-quality nitrogen foam fracture stimulations to multiple zone completions utilizing crosslinked borate fluid systems.
A reservoir/stimulation description was developed to establish a baseline and to begin developing an optimal economic completion and stimulation approach. An integrated strategy was created and implemented to 1 ) complete more pay intervals with pseudo-point source perforated, multiple-staged treatments; 2) modify the borate fluid chemistry to address complicated fracture geometry and improve far-field proppant placement; 3) reduce multiple fracture initiation; and 4) eliminate screen-out problems.
Initial results using these approaches indicates significant improvement in field economics. Both the average production and the normalized productivity (q/(delta)P) per foot of gross clean sand are higher using the new approaches than the previous foam completions. The decline rates are shallower suggesting better lateral and vertical proppant placement. Previously uncompleted reserves in uphole Lance pay sections were proven economic. Reserve recovery from these shallow intervals has been accelerated by commingling all the Lance pay intervals in the initial completion phase. Completion costs per pound of proppant placed were reduced 35% compared to an offset foam treatment.
AAPG Search and Discovery Article #90946©1997 AAPG Rocky Mountain Section Meeting, Denver, Colorado