Simultaneous Underground Combustion and Water Injection In the Carlyle Pool, Iola Field, Kansas

Abstract

Abstract This progress report presents results to April 1, 1965, of an underground combustion project initiated in Feb., 1963, in the Carlyle pool of the Iola field in Allen County, Kans. The initial pilot pattern consisted of one inverted 2.5-acre five-spot which was expanded in Aug., 1963, to include an adjacent 1.7-acre inverted five-spot. Four additional wells were drilled in and adjacent to the test area for experimental and evaluation purposes. Simultaneous injection of water with air required for combustion was initiated in April, 1964.Production rate of the project was increased from a total of 10 to a peak of 125 B/D. Technical and projected economic aspects of this pilot project have ben favorable. Another year's operation will be required before complete evaluation of the economics of full-scale development can be made. Introduction After extensive theoretical evaluations which indicated that in situ combustion operations would be feasible in the Carlyle pool of the Iola field in Allen County, Kans., the Layton Oil Co. began a field test of the process in Feb., 1963, on leases owned by Layton and Texas Pacific Oil CO.Purposes of the test were to develop operating techniques for completion and ignition of injection wells; develop techniques for optimum completion and operation of producing wells; train operators for these operations; determine possible adverse effects and possible remedies of reservoir conditions on the process; determine actual operating costs; and prepare for expansion to full scale commercial operations as soon as the process proved economical. Efforts and plans were made to develop the maximum amount of practical information without elaborate expenditures for academic data. In general, most techniques used were similar to those employed in other combustion projects from which data have been published. Information on the physical plant layout and some early history of the project have already been published Included are field results of two interesting techniques that were used: combustion stimulation of producing wells. and water injection combined with combustion air injection. Testing of the simultaneous combustion-water injection technique was initiated to verify if water injection would result in a substantial transfer of heat from the burned out area through the combustion front by steam convection. Use of this heat to reduce viscosity of the oil bank ahead of the combustion front could result in earlier productivity increases at the producing wells. The combustion stimulation techniques were attempted to evaluate the idea that by initiating short periods of combustion in a producing well, heat would be generated to stimulate oil producing rates in a manner similar to steam injection stimulation. In addition to the favorable short term effects of temperature on the oil viscosity, it is also possible that combustion temperatures in the formation can result in permanent permeability increases because of thermal alteration of the rock properties. It is expected that these two techniques may help overcome the problem of extremely poor natural productivity in this reservoir. Results of the project's first two years of operations are discussed in this report. Field History and Reservoir Characteristics The Carlyle pool of the Iola field, located three miles north of Iola, Kans., was discovered in the early 1900's with most of the original development occurring in the 1919 to 1925 period. The field was extensively developed over an area of about 2,000 acres. Sporadic drilling has continued from discovery to date. The reservoir is Bartlesville sand lying at a depth of 860 ft. Gas sand is found in the upper part of some areas of the section; however, it is usually separated from oil sand by shale barriers. The oil zone averages 30 ft in thickness and is underlain by a water zone 100 to 125 ft thick, which maintains the reservoir pressure at about 230 psi (Table I details reservoir characteristics in the combustion pilot area).While old information indicates that some wells had initial productivities of up to 100 B/D of 19 deg. API gravity oil, run data from leases with available production histories indicate that well rates rapidly declined to 1 to 2 B/D. These low rates were apparently maintained for periods of up to 45 years. JPT