Research On Potential Evaluation And Measures For Potential Tapping Of High Efficient Wells In51~#Fault Region

Lamadian Oilfield is in a complex geological condition with discontinuous sand bodydevelopment caused by fault development. Due to the shielding effect of the faults, it ischaracterized by scattered distribution of remaining oil, poor response of water flooding andworse recovery efficiency.51#fault is one of the largest faults in Lamadian Oilfield，extending4.25km with the maximal fault throw of184.0m, area of2.60km2and geologicreserve of1641.87×104t. At the early stage of oilfield development, lower well spacingdensity along faults result in remaining oil accumulated. Therefore, it is vital to research thepotential distribution of remaining oil and further put forward corresponding measures forenhancing oil recovery.The paper studied the potential evaluation and measures for potential tapping of highefficient wells in51#fault region, and more details are as follows.Firstly, remaining reserves distribution of fault region can be quantitatively analyzedthrough setting up a triangulation network model for51#fault region. By potential analysis, itcan be concluded that remaining reserves of fault region are mainly distributed in the edge offault. The remaining oil is enriched along the fault by imperfect injection-production patterndue to lacking of production wells. The main potential layers can be determined by drawingremaining oil saturation distribution maps for each layer.Secondly, according to the potential evaluation of the fault region, the measures forpotential tapping of high efficient wells can be conducted. By formulating the principle ofwell spacing and optimizing well spacing pattern and location, directional wells are selectedfor potential tapping. Based on49breakpoint regions, utilizing fuzzy comprehensiveevaluation method to comprehensively evaluate the indicators, three optimal high efficientwell regions can be optimized, namely d43、d41、d19, and corresponding high efficient wellsarrangement plans can be set out.Finally, based on optimal high efficient well regions and corresponding high efficientwells arrangement plans, the effect of potential tapping the remaining oil of3high efficientwells can be predicted. Utilizing multivariate stepwise regression method, major parameterswhich make great influence on production of high efficient wells can be optimized, in order toestablish production prediction models of the fault region. By correcting the regressioncoefficient, it can be concluded that the models have high fitting accuracy.The mean absoluteerror of the model is1.02t and the mean relative error is22.1%. By multivariate stepwise regression method and analogy method, the mean daily oil production of the three wellsrespectively are W112.287t，W211.210t，W315.095t. The completion production of thethree high efficient wells is0.93×104t and the cumulativeoil production is4.2×104t.The analysis results in this paper indicate that through research on potential evaluationand potential tapping of high efficient wells in this fault region, injection-production relationcan be further improved and potential along the fault can be effectively tapped in order toretrieve the production decline of the fault region.