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岩石可压裂性的判定大多以脆性指数的方法来评价,但脆性指数概念混杂,地质依据不足,大多停留在半定量估算的水平,没有从岩石破裂机理出发定量评价其可压裂性大小,适用性及准确度均存在较大的局限性。基于低渗透油藏砂岩储层可压裂性缺乏可靠判据的实际,对大庆外围某油田压裂先导试验区块储层开展精细地质建模。采取有限元定量模拟手段,改善固有裂缝预测模式,将原先局限于垂直地层剖面的裂缝预测导向转变为“水平方向预测”。首次提出“平面逐层累积”压裂缝预测方法,对压裂目的层段每小层开展平面裂缝模拟,实现了在三维空间中开展压裂缝定量预测的目的。建立起“实际压裂指数(AFI)”、“潜在压裂指数(PFI)”、“总压裂指数(FI)”、“测井压裂指数(LFI)”4个新判据。结论与现场井下微地震检测结果吻合良好,这将为低渗透油藏提高采收率提供重要的科学依据。
However, the concept of brittleness index is mixed and the geologic basis is not enough, most of them stay at the level of semi-quantitative estimation. The fracability of rock is not evaluated quantitatively based on the rock fracture mechanism. Applicability and accuracy are larger limitations. Based on the fact that there is no reliable criterion for the fracturing of sandstone reservoirs in low permeability reservoirs, a detailed geologic modeling of fractured pilot reservoirs in an oil field in the periphery of Daqing Oilfield is carried out. Finite element simulation method is adopted to improve the prediction model of natural fractures, and the fracture prediction direction originally confined to the vertical stratigraphic section is changed into “horizontal prediction”. For the first time, the method of plane-by-plane cumulation fracturing prediction is put forward to simulate the plane fracture of each layer in the fracturing target interval and achieve the purpose of quantitative prediction of fracturing fractures in the three-dimensional space. Established the “Actual Fracturing Index (AFI)”, “Potential Fracturing Index (PFI)”, “Total Fracturing Index”, "Well Logging Fracture Index (LFI) 4 new criteria. The conclusion is in good agreement with the on-site downhole micro-seismic test results, which will provide an important scientific basis for enhancing oil recovery in low-permeability reservoirs.