Abstract: Additional Potential for Older, Antrim Shale Wells

Joseph H. Frantz Jr., Christopher W. Hopkins, David G. Hill

The Gas Research institute (GRI) has been performing evaluations to estimate the recompletion and restimulation potential in older, Antrim Shale wells. The recompletion potential is two-fold: (1) wells that can be deepened to the productive Norwood interval, and (2) wells with Upper Antrim potential. There arc also numerous restimulation candidates due to sand flowback and or other problems.

The Antrim Shale is an organic-rich, naturally fractured formation which produces both gas and water. Operators today typically complete the Lachine and Norwood intervals but many older wells were not drilled deep enough to encounter the Norwood We performed an evaluation to determine the optimal deepening method using actual and simulated data We estimate there are over 500 deepening candidates with total potential reserve additions of 50 Bscf.

The Upper Antrim formation can be added in approximately 1,500 existing wells throughout several counties. This interval is uphole from the Lachine and Norwood. In this phase of the project, we collected production and reservoir data from several Upper Antrim tests across the basin. We estimate the Upper Antrim could add total new reserves of 100 to 200 Bscf from all the recompletion candidates across the basin.

In the restimulation evaluation, we developed a novel injection test unit to help operators identify the best restimulation candidates in a cost effective manner. The injection test determines if an effective hydraulic fracture is connected to the wellbore. Based on 60 test wells, we estimate the restimulations could add 50 to 200 Bscf of future reserves from the 500 to 1,000 candidate wells.

AAPG Search and Discovery Article #90954©1995 AAPG Eastern Section, Schenectady, New York