Production of Oil Under Unitization in Wertz Dome Field, Wyoming

Abstract

Abstract The unit agreement for the Wertz Dome field, Wyoming, was approved by theActing Secretary of the United States Department of the Interior on November 4,1937, effective on December 1, 1937. The stated objectives of the agreement areto conserve and put to beneficial use all oil and gas produced; to makepossible a uniform withdrawal of oil and gas in order to maintain equalizedreservoir pressures; to provide for an orderly determination of the structuralfeatures of the productive horizons; and to permit the injection of gas forpressure maintenance. The purpose of this paper is to show by a discussion ofthe problems involved and the engineering practices employed by the unitoperator, how well the objectives of the unit agreement have been accomplishedin the development and production of oil and gas from the field. History and Development The Wertz Dome oil and gas field is located 88 miles southwest of Casper and 38miles north and westerly from Rawlins, Wyoming. It is served by a statesecondary oiled road connecting with U. S. Highway No. 220 at Lamont, adistance of 3 miles from the field. It has been a producing field for 27 years, first as an important producer of gas and more recently of oil. The Producers and Refiners Corp. completed Well No.1, NE?SW? sec. 7, T. 26 N., R. 89 W., the first productive well in the field, in September, 1921, in theMuddy sandstone of Upper Cretaceous age, at a depth of 3435 feet for an initialproduction of 42,000,000 cu. ft. of gas per day. In 1922 pipe lines were laidto Casper, Wyoming, for supplying fuel to the Standard of Indiana refinery, theadjoining town of Mills, and the Producers and Refiners Corp. pump station No.6in Mills; and to Parco (now Sinclair), Wyoming, for supplying that refinerywith fuel. The gasoline content of the gas was extracted in an absorption plantlocated near the town of Mills. No compressors were used as the line pressurewas sufficiently high to flow the gas through the absorbers. As high as30,000,000 cu. ft. of gas per day were treated in the plant extracting 6000gallons of gasoline. In September 1937, the pipe line was discontinued and theplant was dismantled at which time 61,000,000,000 cu. ft. of gas had beenproduced from the seven Muddy, Cloverly, and Sundance gas wells drilled in thefield. Of this volume of gas 800,000,000 cu. ft. were produced from theFrontier formation, 34,200,000,000 cu. ft. from the Muddy sandstone,24,000,000,000 cu. ft. from the Cloverly, locally called Dakota, and2,000,000,000 cu. ft. from the Sun dance formation. The pipe line wasdiscontinued because of the near depletion of the gas reserves in Wertz andnearby fields, and because of the local field requirements demanding theretention of the remaining gas reserves. T.P. 2588