Screening of Oils for In-Situ Combustion at Reservoir Conditions by Accelerating-Rate Calorimetry
SPE Reservoir Engineering, 1995
Summary This paper introduces a new method to screen crude oils for applicability of the air-inje... more Summary This paper introduces a new method to screen crude oils for applicability of the air-injection/in-situ combustion process. Testing is performed at reservoir conditions, up to 41.4 MPa, with a specially modified accelerating-rate calorimeter (ARC™). ARC results are shown for four medium- and high-gravity oils, combustion-tube data is presented, and air-injection field data are discussed and compared. We interpret that the continuity of the ARC trace ties in kinetics, combustion-tube, and field air-injection results. Thus, a method is available to delimit the envelope of applicability of air-injection/in-situ combustion to those oil reservoirs where the probability of technical and economic success is greatest.
Keys to Increasing Production Via Air Injection in Gulf Coast Light Oil Reservoirs
Proceedings of SPE Annual Technical Conference and Exhibition, 1997
Following the long-term commercial success of air injection as a secondary light oil recovery pro... more Following the long-term commercial success of air injection as a secondary light oil recovery process in the Williston Basin (documented in SPE 27792, 28733, & 35393), Amoco, with the support of the U.S. Department of Energy, is piloting the use of air injection for tertiary light oil recovery at West Hackberry Field in Southwestern Louisiana. Air injection is ongoing at West Hackberry under the following two operating conditions:In a watered out oil reservoir, air is injected to generate incremental oil recovery through the Double Displacement Process (DDP, SPE 28603). DDP is the gas displacement of a water invaded oil column to recover additional oil through gravity drainage. West Hackberry possesses steeply dipping high permeability light oil reservoirs that exhibit water drive recoveries of 50%-60% of the OOIP versus gravity drainage recoveries of 90% of the OOIP. Although insufficient air has been injected to see production response, reservoir pressure has increased by 500 psi and air injection is continuing.In a low pressure reservoir with a gas cap and a thin oil rim, air is injected into the gas cap to push the oil rim to downstructure wells, to repressure the reservoir, and to gain the improved recovery benefit derived from DDP. As of May of 1997, the first two low pressure reservoirs to undergo air injection have increased production by a combined total of 150 BOPD (or 60%) above the normal decline. To build upon these results, air injection will be extended to similar reservoirs in the field. Key project aspects discussed in detail include:valuable field experience gained from injection and production operations,the use of laboratory tests in the selection process for target reservoirs,the interpretation of laboratory results obtained from the combustion tube and the accelerating rate calorimeter, andthe numerical reservoir simulation employed to forecast tertiary oil bank development and movement, recovery profiles, and tie-in experimental and field data. P. 65
Proceedings of SPE/DOE Improved Oil Recovery Symposium, 1996
Several papers have been recently published1,2,3,4,5 discussing the process of air injection for ... more Several papers have been recently published1,2,3,4,5 discussing the process of air injection for light oil recovery and describing the criteria for a successful project. The performance of some light oil air injection field projects has also been discussed in these papers.2,5 However, the economics of this process have never been fully addressed before. This paper discusses the economics of a successful on-going project, the Medicine Pole Hills Unit (MPHU, ND), and a new project underway at West Hackberry, LA. The economics of air injection in low pressure fault blocks for repositioning and producing the oil rim are discussed as well.
Laboratory Testing and Simulation Results for High Pressure Air Injection in a Waterflooded North Sea Oil Reservoir
All Days, 1997
The Maureen field, a light oil reservoir in the North Sea which has achieved waterflood oil recov... more The Maureen field, a light oil reservoir in the North Sea which has achieved waterflood oil recovery close to 53 percent of the OOIP is nearing the end of its producing life under waterflooding operations. This field was evaluated as to the feasibility of improved oil recovery through high pressure air injection as an inexpensive substitute for other unavailable or costly gases. Six accelerating rate calorimeter (ARC) tests and five combustion tube tests were conducted to determine the oxidation characteristics of Maureen crude oil while injecting air in the presence of reservoir rock and brine. These tests showed that Maureen oil will reliably autoignite, generate flue gas (85 % N2 and 15 % CO2) and propagate a stable combustion front. In addition with air enrichment, a first contact miscible displacement process can be maintained. High pressure air injection was then modeled as a miscible process using the history matched Maureen waterflood model: the results showed incremental oi...
Summary The Medicine Pole Hills Unit (MPHU) EOR project is the deepest air-injection/in-situ-comb... more Summary The Medicine Pole Hills Unit (MPHU) EOR project is the deepest air-injection/in-situ-combustion project in the Williston basin. A unit comprising 9,600 acres with 13 producing wells was formed in July 1985, and air-injection operations began in Oct. 1987. Laboratory combustion tests and detailed feasibility studies were completed before starting the full scale project. The combination of light oil (39°API), carbonate formation, hot reservoir (230°F), and low permeability (1 to 30 md) makes this a unique air-injection project. Cumulative air injection as of Dec. 1993 was 12 Bscf. This paper reviews production performance of the MPHU to date. Oil production from the unit has shown a significant increase over its historical decline, and a processing plant has been installed to recover the liquids stripped from the oil by the produced flue gas. Although well workovers, acid fracturing, and pump changes in some producers complicate the determination of the oil response to air inj...
Summary In deep, high-pressure light-oil reservoirs, air injection provides several advantages co... more Summary In deep, high-pressure light-oil reservoirs, air injection provides several advantages compared with other improved recovery injection processes. The combination of rapid pressurization, spontaneous ignition, complete oxygen utilization, stripping of the light hydrocarbons [natural gas liquids (NGL's)], and near miscibility of the in-situ-generated combustion gases with the reservoir oil results in improved recovery. The availability of the injectant should allow wide application of air injection. Estimation of the recovery factor for this process is subject to uncertainties and requires history matching. To date, computer models have shown limited predictive capability owing to the complexity of the process. Also, an estimate of the fuel laydown at high pressure is not available. In this paper, a method is proposed for estimating the recovery factor on the basis of the producing gas/oil ratio (GOR) of the field. The field results of two ongoing air-injection projects, M...
Field Tests Assess Novel Air-Injection Eor Processes
Oil & Gas Journal, 1996
Two ongoing field tests are assessing novel air-injection processes, in situ combustion, for enha... more Two ongoing field tests are assessing novel air-injection processes, in situ combustion, for enhancing oil recovery from light and heavy oil fields. Amoco Producing Co. operates the light oil test in the West Hackberry field in Cameron Parish, La. This test combines air injection with the double-displacement process. The other test is Amoco Canada Petroleum Co.`s air-injection project that involves a variation on steam-assisted gravity drainage in horizontal wells. The test is in a thin pay zone containing heavy oil in the Wabasca area, about 250 km north of Edmonton. Also in its research facility in Tulsa, Amoco is conducting laboratory tests to develop ways for mitigating the risks of air injection.
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Papers by D. Yannimaras