Comparison of Reservoir Properties and Development History: Spraberry Trend Field, West Texas and Chicontepec Field, Mexico

Abstract

Abstract The Spraberry and Chicontepec fields are both giant oil fields contained within areally extensive, low porosity and low permeability submarine fan reservoirs. Each field has a gross interval of approximately 1,000–1,500 feet (300–450 m) with multiple reservoirs less than 10,000 feet (3,000 m) deep. Sand-prone intervals are laterally extensive and can be correlated regionally, but do have localized channeling. Both fields produce from solution-gas drive. The Spraberry Trend Field, located in the Midland Basin of West Texas, was discovered in 1948. The field is estimated to contain over 10 billion barrels of original oil in place in a series of stacked Permian-age reservoirs covering over 2,500 square miles (6,475 sq. km). Cumulative production from the Spraberry is approximately 850 million barrels of oil and 3 trillion cubic feet of gas or approximately 8% of the original oil in place. The Chicontepec Field, located in the Sierra Madre Oriental foothills in east-central Mexico, was first drilled in 1931. The field is estimated to contain 140 billion barrels of original oil in place and 35 trillion cubic feet of associated gas in a series of stacked Late Paleocene to Eocene-age reservoirs covering approximately 1,440 square miles (3,731 sq. km). Cumulative production from the Chicontepec Field is just over 140 million barrels of oil-equivalent or 0.1% of the original hydrocarbons in place. However, the fields do differ significantly in their development history. Over 18,000 wells have produced some oil and gas from the Spraberry (over 10,000 currently producing) as compared to less than 1,000 in Chicontepec. Managing drilling costs, fracturing technology and controlling production costs along with economies of scale have allowed the Spraberry, once known as the world's largest uneconomic field, to be developed. Developing the Chicontepec field using similar methods would add significant reserves and production volumes for Mexico. Introduction As we all know, finding new giant accumulations of oil and gas through exploration, especially in areas close to markets and existing infrastructure, is becoming increasingly difficult. An alternative is to look at previously discovered fields in these "mature" areas that are underdeveloped because of their historically low margin economics. Often through the use of new technology and by creative cost-cutting methods significant new production and reserves can be developed to more quickly meet consumer demand even without higher commodity prices. This paper is a high-level comparison of two such fields; discussing the reservoir properties which have caused them to be deemed "uneconomic" and contrasting the development histories to suggest significant new reserves can be economically produced near-term from one that is underdeveloped. The two fields are the Spraberry Trend Field located in the Midland Basin in West Texas and the Chicontepec Field located in east-central Mexico (Fig. 1). Both are located in mature producing regions where numerous other fields, including fields with significantly less original hydrocarbon in place, but with better reservoirs, have produced millions of barrels of oil and billions of cubic feet of gas.