Experimental results on the oxidation reaction kinetics in the forward combustion oil recovery process are presented. A total of 48 runs were made wherein a stationary thin layer of coked, unconsolidated sand was burned isothermally in a combustion cell. Individual runs were made at various temperature levels to permit determination of the effect of temperature upon the reaction. An expression was obtained for the burning rate of carbon as a function of carbon concentration, combustion temperature and oxygen partial pressure. The carbon burning rate for two types of crude oil indicated a first order reaction with respect to both carbon concentration and oxygen partial pressure. The effect of combustion temperature on the reaction rate constant matched the Arrhenius equation. The activation energy was similar for the two crude oils examined. The activation energy decreased for a porous media containing clay. The rate of oxidation of crude oil at reservoir temperature was found to be significant. Other significant findings included information on hydrogen-carbon content of fuel residues, fuel reactivity and the products of combustion. Introduction The production of crude oil by underground combustion has been studied in the laboratory by many investigators. Results of laboratory and field experiments have been reported in the literature describing the forward combustion process. But as yet, no qualitative or quantitative study of the kinetics of fuel combustion involved in this process has been reported. The fuel concentration and the rate at which fuel is burned at the front are important factors governing the air requirement in a forward combustion operation. Although the fuel is essentially unrecoverable crude, the air required to burn the fuel is an important economic factor in this process. Because fuel is burned, the heat transport associated with forward combustion is a key and unique feature of this new oil recovery method. Many investigators have presented information on the heat transmission and fluid mechanics involved in forward combustion. Berry and Parrish demonstrated the utility of considering reaction kinetics in reverse burning. From differential thermal analysis, Tadema presented a qualitative discussion of the nature of reactions between oil and oxygen in combustion oil recovery. Although little quantitative work has been done on be reaction kinetics involved in forward combustion oil recovery, an extensive literature does exist on combustion of carbons and oils, and carbonaceous residues from cracking catalyst pellets. Dart, et al., studied the combustion rate for oxidation of carbonaceous residues on clay catalyst pellets, and found the reaction to be second-order with respect to carbon concentration, and first-order with respect to oxygen partial pressure for carbon concentrations less than 2 weight percent of the catalyst weight. The reaction appeared to be first-order with respect to carbon concentration for concentrations greater than 2 percent. Metcalfe noted that other workers had found that aging of the fuel during the combustion process was responsible for changing coke properties, and A accounted for the apparent second-order carbon concentration effect found by Dart, et al. It appears that burning of residues from cracking pellets is first-order with respect to both carbon concentration and oxygen partial pressure. Dart, et al., also observed that hydrogen in the hydrocarbon residue appeared to react faster than the carbon. Lewis, et al., studied oxidation of charcoal, coke and graphite in a fluidized bed. Gas velocities were high enough to partially lift and circulate the carbon particles. Their results indicated first-order reaction dependency with respect to both carbon concentration and oxygen partial pressure. SPEJ P. 137ˆ

An in-situ combustion project was initiated in the Caddo Pine Island field in a thin oil column underlain by a water zone. An inverted five-spot well pattern was selected for the project, and the formation was ignited in Sept. 1980 to evaluate the potential of enhanced oil recovery by a combustion process. This paper presents engineering and laboratory procedures used in evaluating the reservoir for in-situ combustion. The program used to monitor the project performance, including both surface and subsurface measurements, is discussed. The paper reviews the design and installation procedures for the project wells and surface facilities, and presents project results.

This paper presents the results of hot-water and steamfloods conducted in a five-foot linear cell. The effect of injection rate of 240°F water and steam was studied for the Kern River viscous oil (13°API) using a fine graded silica sand. Temperature profiles along the sandpack were used to relate changes in oil saturation with temperature effects. An increase in the water rate resulted in higher temperature profile and minimum Sorw values obtained near the sandface. The results were used for determining the optimum temperature for mobilizing and effectively banking Kern River oil by hot-water floods. A correlation was obtained relating final Sorw values to the oil/water viscosity ratio, thus removing the temperature dependency for the viscous oil (6800 cp @ 80°F). The steam rate was varied between tests to observe its effect on the steamflood recovery process. The oil and temperature response at the production end was related to the steam fronted advance along the sandpack. The oil response and recovery at steam breakthrough increased with increase in the steam rate. The opposite effect was obtained after breakthrough. The frontal velocity to steam and gas saturation in the steam zone varied with the steam rate. The study evaluates the effect of steam rate on frontal advance, oil banking process, oil recovery, and production to injection ratio as a function of a dimensionless time factor based on steam breakthrough.

Described is a simple glass apparatus for rapidly obtaining gas porosities of porous rocks. The method consists of fast volume measurements of samples at atmospheric and lower pressures. This method applies basically the same principle as Boyle's law, P1V1 = P2V2, however, volume measurements are obtained at atmospheric pressure and lower in one simple operation. The apparatus is easily built from readily available glass components. A diagram of the glass porosimeter is shown in Fig. 1. The porosimeter has five basic components: two 500-cc glass burettes, a glass sample holder, a three-way glass valve, a 1/4-in. glass tube next to a meter stick and a 500-cc glass leveling bulb containing about 200 cc of mercury. The sample holder can be designed to contain samples of any dimensions; in this case, cores of 1 in. diameter X 3.0 in. long are used. The samples initially were placed in a perforated plastic holder that reduced direct handling of the samples and easily allowed their insertion in and removal from the glass sample holder. A relationship was obtained between the volume drop in cc of Hg and the height drop in cm for the right-hand burette. The value of this slope m is shown in Table 1. The method consists of measuring a new gas volume at a pressure below atmospheric. Briefly, the operational procedure consists of two steps for obtaining the grain volume measurements and a third step for obtaining the bulk volume.The sample is placed inside the glass sample holder with the lid firmly secured (Fig. 1). Initially, the leveling bulb is brought to Position 1 where the mercury level is adjusted to the zero mark on the right burette.The valve to the atmosphere is closed and the leveling bulb is lowered a distance L equal to the room pressure in cm of Hg (read on the meter stick). The new mercury level on the right burette is obtained directly and corresponds to the increase in gas volume in cc at the lower pressure p2. The bulk volume of the sample can be measured from the following step.The leveling bulb is adjusted to Position 3 and the valve to the atmosphere is opened gradually, allowing the mercury to rise slowly and submerge the sample up to the reference mark. The three-way valve is turned slowly to the position connecting the left burette to the right burette. Mercury is drained from the sample holder until the level reaches the zero mark on the right burette. The volume on the left burette v, is obtained directly. Caution must be exercised to prevent any air bubbles from being trapped in the system. All samples are dried TABLE 1-DESCRIPTION AND OPERATIONOF POROSIMETER Calibration Data of Porosimeter Volume of sample holder 79.6 cc Volume of plastic holder 2.6 cc Net volume of sample holder:For grain volume measurements 77.0 ccFor bulk volume measurements 76.2 cc Average value of slope m in cm of Hg per cc of Hg drop1.137 + 0002 Sample Measurements and Calculations True volume of aluminum rod = 36.63 cc Volume increase at p2, = 35.5 cc Atmospheric pressure p1 = 75.88 cm Hg Grain volume of rod = 77.0 P. 335ˆ