The Use of Air Injection To Improve the Double Displacement Processes

Abstract

SPE Members Abstract The Double Displacement Process (DDP) has been defined as the gas displacement of a water invaded oil column. The purpose of injecting gas into a watered out oil reservoir is to recover more oil by creating a gas cap and thereby allowing gravity drainage of the liquids to occur. During 1994, Amoco Production Company, in partnership with the United States Department of Energy, will initiate the first project to combine air injection with the DDP. Due to the relatively low cost and potential for accelerated recovery, this unique IOR process may prove to be economically viable in low price environment. This report introduces the project by describing:the initial project design,core and fluid property tests,details of the scoping reservoir models,projected production performance andsafety considerations. Modeling of the DDP with air indicated that injection/production rates are predominant factors on the performance of the DDP and need to be optimized. Also, gravity drainage is enhanced due to mobilization of oil by the thermal front. It is shown that the in situ generated flue gas strips the light hydrocarbon components. These appear as natural gas liquids (NGL) in the producing stream. Experimental results indicate that the oxygen in the injected air will spontaneously combust with the residual oil saturation in the reservoir. Compared to nitrogen injection, air injection should yield the same cumulative oil at a lower cost. The use of air injection with the DDP will be applicable in watered out oil reservoirs which have both:sufficient reservoir temperature to accelerate oxygen consumption, andlow oil viscosity in conjunction with sufficient bed dip and permeability for gravity drainage to occur. Introduction During 1994, Amoco Production Company in partnership with the United States Department of Energy will initiate an air injection project in die West Hackberry Field, located in the Cameron Parish, Louisiana near Lake Charles (see Fig. 1). The goals of this project are to:displace the oil by gravity drainagepush the encroached aquifer toward its original water-oil contact The Amoco/DOE partnership comes through die DOEs Class 1 mid-term program for development of advanced recovery technologies for fluvial-dominated deltaic oil reservoirs. Through this partnership, DOE will pay 50% of the project costs in return for transferring this technology to the outside companies. Figure 1: Amoco Production Company, West Hackberry Field Air injection for oil recovery from deep light oil reservoirs has been recommended for the following reasons. P. 81^