The Investigation Of Waterflooding Well Location Optimizations For Block S74 In Tahe Oilfield With Physical Model Experiments

Well location incompletion is one of most key problems in the middle and later periods of water flooding development for fractured-cavity reservoir in Tahe Oilfield.However,there is an obvious difference between fractured cavity reservoir and conventional reservoir in geological characteristics,reservoir storage space and flow relationship and so on.At the same time,the flow type hardly does obey Darcy law in fractured reservoirs,which contributes to the fact that well location incompletion is not to be solved well with conventional well nets improved strategies and consequently has a negative influence on the effect of water flooding development.Hence,the fractured cavity reservoir of block S74 in Tahe Oilfield has been chosen as a subject,and some physical model experiments apply to studying the well location incompletion deeply,and some achievements have been gained from those researches being followed.(1)Based on important aspects including karst geological background,reservoir storage space and flow pattern,crops on the earth,dominant flow path,residual oil distribution and connectivity styles in oil wells,the fractured cavity body of block S74 for Tahe Oilfield is classified as big sized vugs,fractured-cavity and fractured-pore,and the connectivity style of it is regarded as the key to analyze the fractured cavity combination.(2)Physical models combination has been adopted to perform investigations,and twelve typical fractured-cavity bodies are designed and processed.The 45 styles of fractured-cavity combination and three methods used to connect the physical models also have been achieved.(3)The sigle fillings model in cavities has been treated as a key point,and two types of fillings model are investigated from karst geological background.(4)The general laws to help select well locations of water flooding development for fractured reservoirs have been investigated with 54 trials according to three following factors:reservoir types,injection and production property,and high and low locations.(5)Three typical residual distribution model of water flooding have been concluded with 22 expriments for water flooding in combination models,and some relative methods are worked out from changing injection and production property,improving flow path and adding or reducing the entrance of in-let and out-let.(6)The effective measures have been evaluated with 17 combined models including two ones,and five multi-models are to study the well location optimizations from two perspectives:flow path accommodations and increasing or decreasing numbers of inlets and outlets.The effect of some measures has been studied with some applications in block S74.