Well Interference Analysis Of Fractured Wells In Ultra-low Permeability Reservoir And Asymmetric Evaluation Of Fractures

After several small-scale refracturing and large-scale volume fracturing,there is Interference caused by artificial fracture interaction between production wells of ultra-low permeability reservoir in Y block.The characteristics of asymmetric fractures propagation is one of the reasons for the intensification of interference.Therefore,it is particularly important for development adjustment to carry out inter-well interference diagnosis and asymmetric fractures evaluation.Firstly,it is determined that the interwell interference type in Y block is mainly artificial fracture interference.According to the microseismic monitoring results in Y block,the asymmetric fracture propagation characteristics are found.Based on the actual parameters of Y block,the mathematical model is established by using t Navigator numerical simulation software.In this paper,the production losses caused by asymmetric fractures relative to symmetric fractures in single well and multi-well production is compared and analyzed.At the same time,the influence of asymmetric fractures with different reservoir permeability,different geometry shape and different distance between wells on the interference between wells is studied.It is found that when the reservoir permeability is 0.3×10^-3μm²,the inter-well interference is the strongest and the production loss is greater.When the length of fractures and the distance between fracturing wells are constant,the geometry shape of asymmetric fracture has little effect on interference.Whereas,the distance between fracturing wells has a greater influence on the interference degree.Then,taking the single well pressure drop curve of fractured horizontal well as the benchmark curve and comparing the pressure drop curve under interference,the inter-well interference diagnosis method is established.Besides,the reliability of the method was verified by the dynamic history matching results of RTA production and the influencing factors of the interference diagnosis curve were analyzed.Based on the principle of interference similarity response,a method to determine the asymmetric degree of fracture network is proposed.In this paper,MATLAB programming is used to calculate the inter-well connectivity coefficient and depict the asymmetric fracture geometry.The reliability of the results is verified by the microseismic monitoring data of the actual block.Finally,results of asymmetric fractures are used to adjust the historical fitting of typical well groups in Y block.The research results of this paper have certain guiding significance for inter-well interference analysis and development countermeasures adjustment of ultra-low permeability reservoir in Y block.