Granny's Creek CO2 Injection Project, Clay County, West Virginia
Authors: Conner William 
Published: December 2007

Columbia Gas Transmission Corporation, in conjunction with the Department of Energy, is conducting a field demonstration of oil recovery by CO2 injection in Clay County, West Virginia. The objective of this test is to evaluate and demonstrate the effectiveness of using CO2 injection to recover high gravity crude oil from shallow watered-out reservoirs.

The reservoir was repressured to approximately 1,000 psi (6.894 × 10(6) Pa) with water prior to CO2 injection. The plant was completed and injection of CO2 began on June 2, 1976. A total of 9,800 tons (8.89 × 10(6) Kg) of CO2 was injected in several stages, alternating with water periodically for mobility control and better sweep efficiency. Injection of the CO2 slug was completed on June 16, 1977. Water injection followed the CO2 slug and continues to the present.

Oil production from the central producer peaked shortly after cessation of CO2 injection and water production increased to about the same as before the project started.

Since it is felt that confinement was lacking in the original test, the current plans call for a "mini-flood" within the confines of the original 5-spot. This paper reviews the project to date and describes the progress to date of the "mini-flood".

Introduction

The Granny's Creek Field is located in western Clay and southeastern Roane Counties, West Virginia, (see Figure 1) approximately 25 miles (40 Km) northeast of the city of Charleston, West Virginia. The field is approximately 5 miles (8 Km) long and 2 miles (3 Km). wide and contains approximately 3,000 acres (12 × 10(6) M). Columbia has under lease approximately 1,200 acres (4.8 × 10(6) M) in the field and has produced approximately 3,000,000 barrels (476 × 10(3) M3) of oil from its leases.

The producing horizon in the Granny's Creek Field is the Upper Pocono Big Injun Sand of Lower Mississippian Age. Production is primarily from three usually separate porous and permeable intervals that have been designated Zones A, B and C (as Illustrated in Figure 2). The A and B horizons are developed in the upper, coarse-grained part of the Injun Sand and generally exhibit low to medium porosities and medium to high permeabilities. The C Zone, on the other hand, is developed in the fine-grained, argillaceous sandstone that characterizes the lower part of the Injun Sand in the Granny's Creek area, and generally shows very high porosity and low permeability. Oil production is controlled by both the structure of the field and by intraformational permeability and porosity pinch-outs.

The field was drilled in the period from 1916 to 1944 and at present is being waterflooded by Columbia on the southern 350 acres (1.4 × 10(6) M) and in a pilot waterflood by Pennzoil in the northern part of the field.

The waterflood was initiated in 1964 by, a then subsidiary of Columbia Gas System, Preston Oil Company, with a 10 acre (40 × 10(6) M) pilot project consisting of 6 water injection wells and 3 producers. Approximately 4,000 barrels (636 M3) per acre of secondary oil was recovered with an approximate response time of 2 1/2 years. (see Figures 3 and 4).

Subsequently, in early 1975, the Columbia Gas System, acting in conjunction with the Morgantown Energy Research Center and the Pennzoil Company, drilled an additional well inside the pilot area as part of the Energy Research and Development Administration's continuing program for furthering the use of fracture systems for secondary recovery., In addition, residual oil saturation was determined and the feasibility of initiating a miscible flood process to recover additional oil was investigated.

Upon completion of the core analysis, log analysis, miscibility studies, fracture orientation determination and other important considerations, the reservoir conditions appeared to be favorable for tertiary recovery project utilizing a miscible flood technique.

Columbia began construction on the project in August 1975, with the resumption of water injection into the 6 original pilot water input wells in an attempt to repressure the reservoir to 1,000 psi (6.894 × 10(6) Pa).