Book Description

A joint study between USDOE/METC and GRI was initiated to evaluate the application of horizontal wells for improving production from Clinton Sandstone reservoirs in eastern Ohio. A contract was awarded by USDOE/METC to Belden & Blake Inc. for drilling a horizontal well on their lease holdings in Mahoning Co., Ohio. Through a site evaluation study, reservoir and in situ stress characteristics were determined and well geometry designed. GRI contracted CER Corp. to drill a preliminary vertical well near the proposed horizontal well site to collect reservoir information and perform stress profile tests in the Clinton Sand reservoir and adjacent formations. USDOE and EG & G personnel worked with Belden and Blake, Inc. personnel to develop a 3-D geologic reservoir model. The geological model will be used as input parameters to reservoir simulation and production economic models to predict horizontal well effectiveness versus a conventional vertical well production at the selected site. This integrated effort is an example of the methodology that should be applied to the evaluation of a site prior to locating and designing a horizontal well. Realistically, an operator does not have the time nor money to drill a vertical well in an area for coring and stress testing the reservoir to determine natural fracture orientations and stress directions. Often these data can be obtained through published geologic literature on an area. However, natural and induced fracture orientations, reservoir properties (i.e. pressure, thickness, potential reserves) and the geologic environment are all key parameters for a successfully designed and oriented horizontal well.