Integrated Approach to Formation-Water Management: From Reservoir Management to Protection of the Environment

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 116218, "The Integrated Approach to Formation-Water Man agement: From Reservoir Management to Protection of the Environment," by Jose G. Flores, SPE, and Jon Elphick, SPE, Schlumberger, and Francisco Lopez and Pablo Espinel, Agip Oil Ecuador, prepared for the 2008 SPE Annual Technical Conference and Exhibition, Denver, 21-24 September. The paper has not been peer reviewed. Most fields in the Oriente basin of Ecuador and neighboring Marañón and Putumayo basins in Peru and Colombia, respectively, produce large volumes of water. In most cases, as the water cut increases, oil production is restricted, which creates production problems including scale deposition, corrosion, and sand production. An integrated approach to formation-water management begins with an understanding of the water-flow mechanisms in the reservoir and identifying the water-breakthrough mechanism at the producer well, followed by the detection of production bottlenecks in the wellbore and surface facilities, and then finishing with analysis of water disposal or reinjection. Introduction Villano is a heavy-oil field in a tropical rainforest area in the Province of Pastaza in the Oriente basin of Ecuador. Discovered in 1950, it began producing in 1999. Because of concern for the environment and native communities in the area, development was performed in an offshore-type fashion. With no road access, all transport was provided by helicopter. The drilling and production facilities are limited to two well pads, V-A and V-B of approximately 4 and 2 hectares, respectively. Pad V-A hosts a drilling and a workover rig, drilling warehouses, well pads, living quarters, production facilities to dehydrate the oil, and transfer pumps to transport the oil through a 12-in.-diameter 44-km-long pipeline to the central processing facility (CPF). Formation water is disposed of at Pad V-A into two water-disposal wells (WDWs). Pad V-B is a remote wellsite with limited facilities. Particularly relevant in the effort was construction of the aerial 12-in. pipeline, built without road support and with a minimum effect to the rain forest environment. The Villano structure was developed primarily with horizontal wells. Sixteen wells have been drilled in Villano—13 producers, all fitted with electrical submersible pumps (ESPs); two WDWs; and one discovery well (V-1), which has been abandoned. There are two additional WDWs at the CPF. All the production is from and water disposal is into the Hollín formation, of Cretaceous age.