Impact of Formation Properties and Well Design on Cumulative Gas Production from Devonian Shale.

摘要

Devonian Shale refers to all the shale strata sandwiched between two different formations; the younger Berea sandstone above it and the older limestone termed Onondaga or Coniferous below it. Devonian Shale consists of exceptionally rich source rocks; were it not for their low porosity and permeability, the shales would represent one of the greatest oil and gas producing provinces of the world. It is estimated that up to 90 TCF of natural gas could be recovered from Devonian Shale. However, production potential of Devonian Shale is difficult and expensive to determine with production being variable because shale is a very complex sedimentary rock that is difficult to characterize on a particular basis. Additionally, a lot of hole stability problems are encountered when drilling in shale formations. The key therefore in improving production of gas from Devonian Shale lies in studying and analyzing the properties of shale and developing technologies that would eventually overcome shale's undesirable problems and ultimately enhance production.;The objective of the proposed work is to understand the behavior of shales by examining its internal stratigraphy, structure, reservoir characteristic, production controls, drilling and development history and using this knowledge to model the effect of the various properties (fracture length, lateral wellbore length, fracture half length and shale permeability and porosity) on the production of gas from a Devonian shale bearing reservoir. A sensitivity analysis was then performed to identify which parameter has the most influence on cumulative gas production.