Harvey J. Fitzpatrick

Fracpack Completion of Gas-Storage Wells for Enhanced Deliverability

This case-history paper presents results of installing fracpack (one-step tip screenout fracture stimulation and gravel-pack operations) completions in gas-storage wells in the West Clear Lake Field of Harris County, Texas. Using the fracpack technique, operators have fracture-stimulated six wells (new drills and workovers) in the past 3 years as part of an overall facility upgrade. Gas is injected daily into the Frio formation (5,500 ft) of the field and withdrawn at high rates during peak demand periods. A strong waterdrive can water-out production at the end of peak-season gas withdrawal, and water recedes when withdrawal is ended and gas volume and pressure in the reservoir are restored by injection. The paper presents (1) fracpack installation techniques, (2) performance comparison of conventional methods and fracpacks, and (3) completion technique selection to achieve high production efficiency. New wells completed with fracpacks in 1994 have yielded rates up to 100 MMcf/D each with about 500 psi drawdown pressure. In 1995, a well capable of producing at 25 MMcf/D with a gravel pack was recompleted with a fracpack, which increased its rate capacity to 49 MMcf/D. Because of the performance of the first three wells, three more wells were completed with fracpacks in 1997. The fracpack completion has proven superior to other sand-control methods in providing high-rate deliverability in the West Clear Lake Field. Fracpack completions have, in general, provided a two-fold increase in daily production rate. Fracpack completions and recompletions can be applied in gas-storage wells where high production rates are needed and sand-control measures are necessary for the life of the well. This paper provides guidelines and results associated with fracpacking by ○ demonstrating the importance of selecting completion techniques that will provide high-efficiency production from gas-storage wells ○ presenting case histories of fracpack-stimulated gas-storage well performance over a relatively long time period ○ comparing well performance of conventionally completed and fracpack-completed gas-storage wells producing at high rates ○ providing insight into operational aspects of fracpack completions.