De-Watering of Hunton Reservoirs

Author: Mohan Kelkar, University of Tulsa, Tulsa, OK.

Venue: Tulsa Association of Petroleum Landmen meeting in Tulsa, OK, April 19, 2007 (http://www.landman.org [external site]).

Abstract: The Hunton reservoir in Oklahoma represents one of the largest discoveries in Oklahoma in recent history. Since 1995, several Hunton reservoir fields have been exploited by various operators. The principle behind this exploitation remains the same: The wells produce large quantities of water, and along with it, significant quantities of natural gas and sometimes oil. Examination of various fields producing from the Hunton reservoir indicates that the economic success from these fields is not uniform. Some fields produce significant quantities of oil, whereas some fields only produce gas. In some fields, horizontal wells work best, whereas in some other fields, vertical wells do a good job. The water production from the fields ranges from as low as few hundred barrels per day to several thousand barrels per day. In this paper, we present the results from various fields to indicate the parameters needed in a Hunton field to make it economically successful. We restrict our evaluation to parameters that can be easily measured or are readily available. These include log data (gamma ray, resistivity, neutron, and density), initial potential data, production data (oil, gas, and water—if available) and well configuration (vertical or horizontal). By analyzing the recovery of oil and gas according to various reservoir parameters, we developed a methodology for predicting the future success of the field. For example, a clear relationship exists between porosity of the rock and initial hydrocarbon saturation: The higher the oil saturation, the better the recovery factor. Initial potential is critical in determining possible recovery. Horizontal wells cost 1.5 to 2 times more than vertical wells and may not provide the additional recovery to justify the costs. The Hunton formation is extensive in Oklahoma. If we want to extend the success of some of the fields to other areas, we need clear guidelines in terms of what is needed to exploit those fields. This paper provides some of those guidelines based on the examination of the currently producing fields.

Related NETL Project: The overall goal of the related NETL project entitled “Exploitation and Optimization of Reservoir Performance in Hunton Formation, Oklahoma” (DE-FC26-00NT15125) is to understand the mechanism of gas and oil production from the Hunton Formation in Oklahoma so that similar reservoirs in other areas can be efficiently exploited. An additional goal is to develop methodologies to improve oil recovery using secondary recovery techniques.

NETL Project Contacts
NETL - Purna Halder (purna.halder@netl.doe.gov or 918-699-2084)
U. of Tulsa - Mohan Kelkar (mohan@utulsa.edu or 918-631-3036)