A New Dynamic Reserve Prediction Model of Fractured Horizontal Well in Tight Gas Reservoir Considering Stress Sensitivity

Abstract

AbstractSince the stress sensitivity and other characteristics of tight gas reservoirs make their seepage mechanism more complex, the accurate calculation of dynamic reserves of fractured horizontal wells in tight gas reservoirs has always been a difficulty in the dynamic evaluation of gas reservoir development. To resolve the calculation problem of dynamic reserves in tight gas reservoirs, a dynamic reserves prediction model of fractured horizontal well which bases on the seepage mechanism of tight gas reservoirs is established by considering stress sensitivity and finite fracture conductivity. Meanwhile, Laplace transformation and Bessel function are used to solve the model of seepage equation. Secondly, Duhamel production transformation is carried out after the superposition of bottom hole pressure which obtains the typical production decline curve of fractured horizontal well and the seepage characteristics of fractured horizontal well are analyzed. Finally, the number of fractures, fracture length, fracture conductivity and stress sensitivity factor of the dynamic reserve calculation model are analyzed. And the production of model is compared with the actual well production to verify the accuracy of the model. The results show that the seepage characteristics of fractured horizontal well can be divided into five stages: early linear flow, mid-term radial flow, mid-term linear flow, systematic radial flow and boundary control flow. The model's production prediction curve is in good agreement with the production curve of actual production well, which verifies the accuracy of the model. The dynamic reserve prediction model innovatively considers the stress sensitivity and the obtained model and method play a certain practical role in the development plan of fractured horizontal well in tight gas reservoir. It has certain guiding significance for forecasting the dynamic reserves fractured horizontal well in tight gas reservoir, deploying well pattern and developing efficiently the tight gas reservoir. KeywordsLow permeabilityStress sensitivityFractured horizontal wellDynamic reservePrediction modelHigh-efficient development