Study On Remaining Oil Distribution At High Water-cut Stage Of Kumkol Oilfield

Kumkol oilfield has entered into the high water-cut stage through the exploitation and development of more than20years, facing many problems such as the water cut continued to increase, the efficiency of stimulation and the production rate has gone into a rapid decline phase. In that situation, to accurately determine the distribution of residual oil is to ensure that oil reserves and production by the material foundation and an important basis for enhanced oil recovery.This paper focuses on remaining oil saturation of producing formation in high water-cut stage, aiming at studying the remaining oil distribution rules, on the basis of logging data, core data, well test, logging and rich dynamic data, the geologic characteristics such as sedimentary microfacies and microstructure, development characteristics, water out behavior have been systemieally studied. The remaining oil saturation of new wells in recent two years are established with conventional logging data and carbon-oxygen ratio spectral logging data. In combination with the method for evaluating remaining oil saturation of payzone with production logging data, the remaining oil saturation of single wells are obtained and the plane distribution charts of remaining oil saturation are plotted. Then the remaining oil distribution rules are studied, which suggests that the water-flooding degree of Object Ⅱ layer is relatively low and the residual oil is relatively rich. Combined with the research on geological and development factors controlling remaining oil distribution, this paper concludes that sedimentary facies, sedimentary rhythm, interlayer, microstructure, fault and injection-production pattern are the main factors controlling residual oil distribution. According to the above research, the plane patterns of remaining oil distribution are concluded.At last, the potential area of residual oil is established. The residual oil is mainly distributed in structural high part, the fault sheltered, areas of low-degree well control and imperfect injection-production pattern on the plane. And in vertical, the residual oil is mainly distributed in the thick reservoir with poor physical property, the upper section of positive rhythm and homogeneous rhythm reservoir and the layers with poor physical property of composite rhythm reservoir.