The Gunn Graben: Geology, engineering, and the missing key, Geomechanics
Abstract
A deep drill test took place in 1989 which discovered an extensive gas charged Pennsylvanian clastic interval on the Matador Arch in north Texas. Unknown at the time, this exploration well
stepped off into an elongate, left-lateral, asymmetric graben, where the eventual total vertical depths of these wells reached over 15,000 feet. Rotated fault blocks with several thousand feet of throw to the adjacent fault block, resulted in the development of both positive and negative flower structures where bedding planes dipped upwards to seventy degrees. These fault planes act as the compartmentalization mechanism trapping tight gas within these clastic reservoirs, and therefore reaching the targeted total depth a true
drilling
challenge. However, by not reaching the targeted total depths, this project left unknown numerous clastic packages undrilled within the Pennsylvanian Bend interval because of mechanical failures within the
well
bore.
In 2014, Schlumberger proposed a drilling
geomechanics solution which involved integrating Schlumberger's Petrel and Stonefish software and Schlumberger's geomechanics expertise from their Petro-Technical Services along with K&M Technology
drilling
expertise coupled with K&M's torque and drag software to manage these
drilling
engineering issues. To understand the effect of geomechanics on the
well
bore, a mechanical earth model (MEM) was constructed via Stonefish which provided a coherent view of the earth stresses and mechanical properties of the rock within the
well
bore. The MEM was then complimented with a
drilling
engineering analysis performed by K&M Technology to more fully understand how the
well
bore was behaving while
drilling
. By applying these data sets and
drilling
practices, identifying parameters to increase
drilling
efficiency, the likelihood of obtaining success within this deep dynamic graben and reaching the targeted total depth becomes greater.
AAPG Datapages/Search and Discovery Article #90292 © 2017 AAPG Southwest Section, Midland, Texas, April 29 - May 2, 2017