深层-超深层页岩气全域支撑压裂技术及矿场应用OA

The Qiongzhusi Formation shale in the Ziyang area of the Sichuan Basin is currently one of the primary exploration zones,but its typical reservoir characteristics such as abnormally high pressure,high felsic content,low porosity,ultra-low permeability and strong reservoir heterogeneity pose challenges to fracturing operations,including ineffective utilization of matrix reservoirs,low complexity of fracture networks,limited effective stimulated reservoir volume,and difficulty in lateral proppant migration and vertical proppant placement.Based on the geological and engineering characteristics of the shale reservoirs in the study area,this paper reviews the technical challenges for the efficient stimulation in this area,and proposes a core technical concept,namely whole-domain support fracturing,which integrates"point desorption,line communication,plane fracture promotion,and solid proppant support".Then,the whole-domain support fracturing technology is applied in the field through the processes such as matrix modification,fracture propagation control,and proppant system optimization.The following results are obtained.First,the wells adopting the whole-domain support fracturing technology in the Qiongzhusi Formation shale reservoirs in the Ziyang area of the Sichuan Basin exhibit remarkable effectiveness of volume fracture promotion.The coefficient of variation among clusters decreases significantly,and the proportion of clusters with a coefficient of variation greater than 0.2 decreases from 78%before temporary plugging to only 19%afterward,indicating greatly improved uniformity in cluster opening.Second,the average fracture length in the whole-domain support fractured wells is 2.68 times that of adjacent conventional fractured wells,the equivalent reservoir permeability is 1.44 times,and the average fracture conductivity is 35.1%higher.Third,both fracturing efficiency and long-term production rates are superior in the wells using whole-domain support fracturing technology compared to those stimulated with conventional fracturing methods,indicating that whole-domain support fracturing technology enables more effective support of artificial fractures and sustained conductivity.In conclusion,the matrix modification,fracture propagation control,and proppant system optimization based on the technical concept of whole-domain support fracturing can effectively improve fracturing outcomes.This technology has achieved notable success in deep shale gas development within the Qiongzhusi Formation and can ensure effective exploitation of deep and ultra-deep shale gas in the area.