An integrated study of the reservoir performance in the Area Central Norte (ACN) region of the Tordillo Field (Argentina)

Abstract

The Tordillo Field is located within the San Jorge Basin of southern Argentina. The field is located within a small, dominantly extension basin, and is operated by Tecpetrol S.A., a domestic private oil company. The field produces from the El TreboL Comodoro Rivadavia, and Mina El Carmen Formations and is estimated to contain approximately 1,800 MMSTB of in-place oil. The Area Central Norte (ACN) region is a designated portion of the TordiHo Field in which a pilot waterflood was initiated in September 1993. There are immediate plans for expanding the pilot waterflood, and therefore, it is imperative that we evaluate the reservoir properties, as well as the reservoir production potential in order to design the most effective field development plan. Our integrated study of reservoir performance in the ACN pilot area, combining the geological, engineering, and reservoir performance data, is utilized to characterize the reservoir and to develop an appropriate reservoir management plan. This study win be used to determine the feasibility of expanding secondary recovery efforts throughout the Tordiflo Field by developing a reservoir description that includes the reservoir structure, rock and fluid properties, and the performance potential of the reservoir. The main focus of this work is to evaluate primary and secondary well performance in a highly stratified sequence of oil producing sands. In this study, we use rigorous methods to analyze and interpret production rate, injection rate, and pressure data from oil and water injection wells using decline type curves and estimated ultimate recovery (EUR) analysis. These methods are shown to yield excellent results for a variety of field conditions, without regard to the structure of the reservoir (shape and size), or the reservoir drive mechanism(s). Results of these analyses include the following: eservo rties: 0 Fonnation permeability, k ³Skin factor, s, for near-well damage or stimulation In-pplace fluid volumes: ³Original oil-in-place, N ³ Reservoir drainage area, A ³Movable oil at current conditions, Np,,,,,, We examined the available core and modem well log data to develop an understanding for the petrophysical (k and 0) properties of the reservoir. These results will help us determine if reservoir performance is directly influenced by the geologic structure and flow characteristics of the reservoir. By combing the geological, petrophysical, and reservoir performance data in this manner, we are able to develop an integrated reservoir description for future developments as well as production optimization.