Cano Limon Field, Colombia: The Latest Giant Oil Reservoir in South America
Authors: Rivero Ramon T. , Dominguez J. Guimer , Slater James A. , Hearn Charles L. 
Published: December 2007

Summary
The recent discovery of the giant Cairo Limon field in the northern Colombian Los Llanos basin is the most successful result of the Association-type contracts instituted by the Colombian government 15 years ago. A major construction and development drilling effort resulted in production startup in Dec. 1985, 2 1/2 years after discovery. As of production startup in Dec. 1985, 2 1/2 years after discovery. As of publication date, the field oil production rate is about 200,000 STB/D publication date, the field oil production rate is about 200,000 STB/D [31.8 × 10(3) stock-tank m3/d]. With optimum reservoir management, oil recovery is expected to reach 109 bbl [1.59 × 10(9) m3].

Introduction
In June 1980, the Colombian Natl. Oil Co. (Ecopetrol) and Occidental de Colombia signed the Cravo Norte Assn. Contract for exploration of the northern Los Llanos basin. After 3 years of intense exploratory activity, oil was discovered in the Cano Limon area (Fig. 1). Cano Limon (CL)-1, completed in July 1983, flowed at 10,900 STB/D [1733 stock-tank m3/d].
Discovery and development of the Cano Limon field are of major importance--it has made Colombia self-sufficient in oil. Occidental, with a 25 % participation in the association contract, is the field operator. Other participants are Ecopetrol (50 %) and Royal Dutch Shell (25 %).
The field (Fig. 1) produces primarily from the Lower Carbonera/ Mirador sandstone formation at an average depth of 7,600 ft [2315 m]. Smaller but significant producing formations are the overlying Upper Carbonera and the underlying Cretaceous sands. Original oil in place (OOIP) is about 2 × 10(9) STB [318 × 10(6) stock-tank m3]. The 29 degrees API [0.88-g/cm3] oil has a bubblepoint pressure less than 100 psia [0.7 MPa] and a solution GOR less than 10 scf/STB [1.8 std m3/stock-tank m3], making the accumulation one of the more rare in the world. The producing mechanism is edgewater drive from an extensive freshwater aquifer.
A major construction effort resulted in production startup in Dec. 1985, only 2 1/2 years after discovery. In addition to development drilling and construction of surface facilities, a 467-mile [752-km] pipeline was built through the Andes Mountains to an offshore pipeline was built through the Andes Mountains to an offshore terminal in the Caribbean Sea. Present production rate is 200,000 STB/D [31.8 × 10(3) stock-tank m3/d] from 35 wells. Artificial lift with electrical submersible pumps is needed to produce at this rate.
The objectives of this paper areto describe the association contract leading to discovery of the Cano Limon field;to present the geology and reservoir properties of the field;discuss the field development, early production history, and reservoir management plan.

Association Contract
Laws allowing Ecopetrol the right to grant association contracts started in 1969 and were firmly in place by 1974. It is estimated that from 1976 to 1984 they have attracted enough foreign capital to Colombia to drill more than 75 % of its exploration wells (306 out of 405).