An integrated method for estimating recoverable reserves of Jurassic continental shale oil in Fuxing area,Sichuan Basin
The Fuxing area is located in the northern part of the Fuling block,situated within the territory of Chongqing.It features a low mountain and hilly topography with a ground elevation of 300～600 m.Tectonically,it is located in the Wanzhou synclinorium of the high steep fold belt in the eastern Sichuan Basin.The Jurassic continental shale reservoirs in the Fuxing area are characterized by high clay content,multiple interlayers,medium-low organic matter abundance,and medium-high thermal evolution.Reservoir stim-ulation by volume fracturing,and production dynamic adjustment by means such as constant-pressure/rate production and changing working systems realize short-term high production or long-term stable production,but result in extremely complex seepage behaviors of shale oil in the area,which makes the dynamic analysis and productivity prediction more challenging.Considering the geological and production dynamic characteristics of the continental shales in the lower submember of the second member of the Lower Jurassic Lianggaoshan Formation in the Fuxing area,an integrated method for estimating recoverable reserves of continental shale oil in the Formation was established on the basis of three popular production calculation methods:the elastic yield,the traditional production decline,and the advanced production decline.Application case shows that,(ⅰ)the integrated method enables history matching of pro-duction data,and prediction of post-frac fractures and formation parameters;(ⅱ)the estimated recoverable reserves of 2.1×104-2.3×104 t per well have an average error of only 1.96% in contrast to the value(2.14×104 t)estimated by numerical simulation method;and(ⅲ)a single method estimating recoverable reserves has a certain limitation in application,but this integrated method can provide a more accurate estimation.The proposed method for estimating recoverable reserves of continental shale oil is adaptable to matching and es-timating recoverable reserves at different development stages and under different production systems.It facilitates a systematic,quick,and accurate evaluation for well productivity,and provides a new idea and reference for estimating recoverable reserves of similar res-ervoirs.
万方数据
维普
