Evaluation and Application of the Extended Cyclic Steam Injection as a New Concept for Bachaquero-01 Reservoir in West Venezuela.

Abstract

The thermal recovery method has been applied in to the heavy oil reservoirs in Venezuela for more than 50 years. The cyclic steam injection is the principal thermal technique in Venezuelan heavy oil reservoirs, which has an oil viscosity at reservoir conditions between 600 to 5000 cp. Steam flood has been applied in Venezuela as a pilot project in the Tia Juana reservoir (Formation C3-C4 and M-6) and East Venezuela in the Oficina Formation. The Bachaquero-01 heavy oil reservoir has been producing with cyclic steam injection since 1965. Due to the high number of steam cycles (more than 6 steam cycles per well), cyclic steam injection is not economical in a lot of wells. Therefore an extensive work has been done to improve the economics of steam injection in Bachaquero-01 reservoir. In this paper we present the application and the results of the extended cyclic steam injection, which is a combination of cyclic steam injection and continues steam injection. For the evaluation of this thermal process for Bachaquero-01 reservoir, we used an available history matched full field thermal model of the Bachaquero-01 (Area 95 Km², OOIP 6621 MMSTB, Recoverable Reserves 1072 MMSTB, Number of perforated wells 776, number of steam cycles 1600). Within the Bachaquero-01 reservoir we defined a representative area with 7 inverted seven-spot patterns. We discuss the results of the application of the extended cyclic steam injection and make a comparison with the results of the traditional steam flood and conventional cyclic steam injection. The field application of the extended cyclic steam injection for the Bachaquero-01 reservoir has been approved by the PDVSA management. The field site has been selected and the project will start at the beginning of 2012.