The Harrisville Gas Field, Randolph County Indiana: Basement Geology, Reactivated Faulting, Geophysics, Trenton Gas Reservoirs and Economics (or not)

Kevin L. Strunk
Wabash Resources & Consulting, Indianapolis, IN, [email protected]

The Harrisville Gas Field is a satellite field close to the main Trenton Field located in eastern Randolph County, Indiana just four miles from the Ohio border. The 3000-acre field was discovered in 1967 when an magnetic and gravity high shown on public domain maps was drilled during the regional Knox (Trempealeau) play, with natural gas found in a partially dolomitized-fractured limestone portion of the upper Trenton. According to landowners, original exploration was supposedly aided by some sort of now lost geophysical data and resulted in commercial production of at least 125,000 MCF of largely unprocessed gas over a 13-year period into a nearby local gas distribution line, prior to the field being abandoned in the early 1980’s due to operational difficulties.

A few plugged step-out tests were drilled in 1989, but the presence of several “orphan” wells reportedly of high volume, a gas line tap and high gas prices led to the four older wells being worked over and five new wells being drilled during 2004-2007. All wells were flow tested and had gas chemistry determined. Unfortunately, this activity led to the current shut-in gas field status due to high costs of nitrogen removal, iron sulfide control, and field infrastructure installation, and the sustained multi-year slide in gas prices from the higher prices ($6-13/MCF) which originally enabled the project, to the current $2/MCF.

The Harrisville Field is located over an apparent tilted or horsted basement block related to reactivation movement along a prominent regional gravity and magnetic basement lineament interpreted to be an intrusive dike. The feature was studied and modeled by Andreasen and Zietz (1962). The most recent drilling was guided by acquisition of seven miles of modern intersecting 2-D seismic lines run in the center of the structure. The outcome of drilling and well testing and the nature of the reservoir, and local dolomitization are reviewed from older and newer log suites and other data.

Conclusions include: (1) features seen on public domain magnetic and gravity maps are often related to Trenton gas and oil reservoirs, but an understanding of the local geology is key to using these maps in context; (2) researching past field history, including speaking with landowners is important; (3) acquisition of seismic data, magnetics and gravity data can greatly enhance geologic understanding and resulting drilling location selection; (4) air-drilling and open hole completions are suggested while acknowledging certain limitations on well operations and stimulation; and; (5) running a Pe-curve on TBR logs can better provide an important understanding of the nature and extent of dolomitization and porosity.

AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012