In Situ Combustion Tests On Eyehill Cummings Reservoir

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Abstract In early 1984, a series of four combustion tube tests were performed at The University of Calgary on restored cores from the Eyehill Cummings heavy oil pool, located near Lloydminster, Saskatchewan. The tests provided a useful comparison of normal vs enriched air in situ combustion. Important observations arising from this test series were:water injection decreased the oxygen requirements;increased oxygen enrichment resulted in increased oxygen storage in the swept zone behind the combustion/ rant; andwater injection resulted in an increase in (swept zone) oxygen storage. The dry enriched air test showed some oxgyen breakthrough near the end of the test which resulted in an increase in viscosity of the produced oil. Increased sulphate levels in the produced water during that test also reflected the oxygen breakthrough. Introduction In recent years, laboratory combustion tube tests have become the customary method of determining the feasibility and the design parameters of an in situ combustion project. These tests, which utilize oil and homogenized core from the proposed reservoir, provide a relatively inexpensive method of predicting the type of problems which will be encountered in the field. They also give a qualitative indication of the "burn" performance of a specific reservoir, because it has been found that the results from one reservoir are rarely applicable to another. In addition to providing the air or oxygen and fuel requirements for an in situ combustion project, combustion tube tests also determine the properties and compositions of the produced fluids (oil, water and gas). Moore, el at. (1984) showed that the burning mode (low or high temperature oxidation) and the location of the burn front could, to some degree, be inferred from the composition of the produced gases, as well as by the viscosity and asphaltenes content of the produced oil and the pH and sulphate ion concentration of the produced water. In 1984, Murphy Oil Company and the Canadian Government's Department of Energy, Mines and Resources (EMR) contracted with the In Situ Combustion Research Laboratory at The University of Calgary to perform four combustion tube tests using core,oil and brine from the Eyehill Cummings heavy oil pool. This research group, located in the university's Department of Chemical and Petroleum Engineering has conducted over 230 such tests on over 50 different reservoirs world wide. This paper summarizes the results of the series of four combustion tube tests and compares the combustion process characteristics in various operating modes. Experimental Equipment The core holder used for this test series was a 10 cm (4 in.) diameter, 1.83 m (6 ft) long thin walled (1 mm) Type 600 Inconel tube. The tube was wound with twelve 1000 W heaters, forming twelve heating zones, each 15 cm (6 in.) in length, thus allowing for near adiabatic operation of the combustion test. A thirteenth heater was wound around the injection end of the tube to aid the ignition process.