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Home > JOGMEC's Activities > Technology Development and Technical Support (Oil and Natural Gas) > Maximizing Oil Recovery : Air Injection for Enhanced Oil Recovery

Air Injection for Enhanced Oil Recovery

Air injection is a technique to enhance oil recovery that surged in popularity in the second half of the 1980s. JOGMEC has conducted a series of sophisticated experimental studies and numerical simulation works to establish the evaluation method for the applicability of air injection to light oil reservoirs. We plan to conduct field pilot tests to expand our understanding of this technology.

Air Injection Technology

Overview and Applications

Air injection is a technique for enhanced oil recovery (EOR) with several advantages. The injection gas source is air, which can be supplied anywhere, and the main facility required is simply an air compressor. Initial investment and operating costs are therefore lower than for other EOR methods. The main oil recovery mechanisms are the flue gas sweeping and thermal effect generated from oxidation and combustion reactions. Moreover, air can be applied even in low permeable reservoirs where water cannot be injected. However, the evaluation method for this technology is difficult, because oxidation and combustion reactions are complicated.

Overseas, the pioneering application of air injection in the United States from the middle of 1980s to the beginning of 1990s yielded successes, and the popularity of air injection surged. This technology has been deployed at 20 oil fields, including exploratory projects. However, Japan and its companies have not used it.

JOGMEC's Experimental Studies

A series of experiments is essential in air injection study. An Accelerating Rate Calorimeter (ARC) test, Thermo Gravimetric Pressurized Differential Scanning Calorimeter (TG/PDSC) test and Combustion Tube (CT) test are generally conducted to evaluate the potential of air injection in fields. JOGMEC's Petroleum Engineering Research Team started experimental studies in fiscal 1999. Specifically, in fiscal 1999 the JOGMEC Technology and Research Center (TRC) consigned the implementation of oxidization and combustion experiments using accelerating rate calorimetry (ARC) tests on three kinds of domestic and overseas oil samples to University of Calgary. In fiscal 2000, JOGMEC also consigned thermal gravity and pressurized differential scanning calorimeter (TG/PDSC) tests to evaluate the details of the oxidization and combustion reaction to the University of Calgary. The results of these studies suggested a sufficient extent and continuity of reactions in the low and high temperature range.

The purposes of the CT test are (1) to assess the overall burning characteristics of oil, (2) to measure incremental oil production, air and fuel requirements and other parameters and (3) to measure the composition of gas produced and oil and water production to provide benchmarks for monitoring future field operations. JOGMEC conducted combustion tube tests in cases of low water saturation and high water saturation after waterflooding from fiscal 2002 through fiscal 2004 using domestic oil samples to estimate the applicability of air injection, including in the tertiary mode. The results showed stable combustion performance in terms of temperature, pressure response, composition of gas produced and incremental oil production.

JOGMEC's Numerical Simulation Studies

Numerical simulation is important to predict field production performance. The appropriate reaction kinetics for the combustion must be used in the numerical simulation. History matching with CT tests is the only way to obtain the kinetics. JOGMEC TRC has conducted history matching studies with two CT tests using the "STARS" thermal simulator. Reaction kinetics was defined as oxidation reactions and combustion reaction. Good matching results were achieved using the same reaction kinetics in both cases. In addition, TRC has conducted a field-scale simulation using the reaction kinetics constructed in the history matching.

JOGMEC's Future Plans

JOGMEC is now planning field pilot tests of air injection at domestic oil fields in fiscal 2008 at the earliest. Activities to prepare for these tests include site evaluation and selection using simulation studies, engineering surveys and field surveys. We plan to execute the tests from fiscal 2008 though fiscal 2012 with the objective of acquiring air injection technology to enhance oil recovery in the future.

TRC has designated enhanced oil recovery as a key technology. We will contribute to Japan's oil development technological capabilities by acquiring enhanced oil recovery technology as represented by the air injection method and by implementing sophisticated basic and applied research and development. JOGMEC will also support private-sector oil development in ways such as applying EOR technologies and cooperating with oil-producing countries.