Study On Remaining Oil Distribution And Potential - Tapping In Oilfield

Residual oil distribution and potential tapping are important and difficult problems for reservoirs in the late period of development. After the exploitation for nearly40years, reservoir B has entered the late stage of development. So far, recovery percent of the block is not high, and there is still a lot of residual oil in the formation. Finding out the distribution law of remaining oil and put forward effective ways and measures to tap the potential is the central task of this block. Based on the theories of the development geology, reservoir engineering, numerical simulation and so on, combined with static and dynamic information of the reservoir, distribution law of residual oil in reservoir was studied and comprehensive treatment plan was put forward.First of all, the characteristics of the reservoir were re-understood through logging and drilling data. In this foundation, the three-dimensional geological model of reservoir was set up based on stochastic modeling.Secondly, through the analysis production data, oil and water producing, response characteristics of water injection and incremental rules of water cut were studied; the ultimate recovery of reservoir was predicted; present well pattern adaptability was analyzed, which could provide a basis for later potential tapping measures.Lastly, by the using numerical simulation method, remaining oil distribution was identified; different projects for potential tapping were brought up and predicted by simulation; prediction results were compared, and the best scheme to further tapping was selected, which could provide technical support for the potential tapping of remaining oil.Through this research, the distribution law of residual oil in reservoir B is:(1) There is lots of remaining oil in main layer.(2) The heterogeneity of the region is severe, which results in a lot of residual oil existing in layers and interlayer.(3) The well pattern is not perfect which causes that there is a lot of remaining oil among wells. Based on the understanding remaining oil distribution, ideas for potential tapping of residual oil are:(1) Drill new or side-tracking wells in plane to address the poor control of well pattern;(2) improve the shooting layer of water injection and production wells in vertical aspects to address the injection-recovery problems. The final design for potential tapping measure is implementing well pattern infilling in the foundation of adjusting layers which can increase by3.54percent for oil recovery based on current development mode.