Evaluation Of Remaining Oil Of Es1 And Es2 Reservoirs In Wen-119 Fault Block

Es1 and Es2 reservoirs in Wen-119 fault block belong to typical complex fault block reservoir,whose oil-bearing area is controlled by the master fault,and forming a narrow oil-bearing distribution in the fault line;the fault block belongs to fluvial deposit in delta front zone,and the river is mostly distributed like "finger" with narrow channel,which is approximately orthogonal to the fault.So that the oil distribution is not continuous and the connectivity between the wells is poor.It is typical complex fault block reservoir controlled by lithology and tectonism.The fault block was formally put into development in January 1999,and since then,it has experienced totally five times of development and adjustments,and entered the end of the development now.Based on the geological characteristics and the problems existing in development of Wen-119 fault block,this paper analyzes and evaluates the structural features,sedimentary characteristics and reservoir characteristics of the work area,and then from the view of development characteristics of research,this paper divides the development stage and analyze the development characteristics and problems in detailed.At the same time,after a lot of researches and applications,this paper further improves the cumulative yield curve for predicting recoverable reserves and dynamic analysis methods;furthermore,the recoverable curve method and water drive curve method and other reservoir engineering methods are used to predict the recoverable reserves and recovery rate,as well as to evaluate the development effect.Then,the yield splitting is calculated by using the product profile data or the stratum coefficient KH value,and recoverable reserves of remaining oil in the single well are calculated and predicted based on the single well cumulative yield curve analysis method;furthermore,combining with the degree of water content and recovery percent of recoverable reserves,the potential coefficient of remaining oil in single well are calculated;finally,the potential coefficient distribution of remaining oil in each layer is shown through using the three-dimensional reservoir modeling method,and the potential spatial distribution of remaining oil in the reservoir is displayed in the form of three dimensions as well.It is found that,after long-term waterflooding and edge water intrusion,the remaining oil distribution is highly dispersed,the narrow and long original oil distribution has been instead of the remaining oil distribution in the shape of "toothbrush",which is distributed in the downthrown side of master fault and the transfer area of its branch faults;the analysis shows that it is caused by the approximate orthogonality of "finger shape" channel and the master fault.In this paper,referring to the methods of dividing remaining oil at home and abroad,as well as combining with the remaining oil characteristics in this region,the remaining oil in Es1 and Es2 reservoirs of Wen-119 fault block is divided into 5 types: the remaining oil with imperfect well pattern caused by the shelter of master fault,dense lithology cutting and dispersing type of blocky remaining oil,cutting type of remaining oil in cross fault,retention type of remaining oil balanced in well and remaining oil without controlled well.Based on the comprehensive evaluation of tectonic characteristics,sedimentary microfacies,reservoir heterogeneity and development effect,the main controlling factors of remaining oil are summarized,and the favorable regions for mining the remaining oil are predicted as well with static and dynamic methods.Finally,based on the research and understanding of this paper,some water-control and oil-stablize technical measures of reducing the contradiction between the layers,coordinating the production and injection profile as well as improving the water driving degree are studied;furthermore,combining the adaptability analysis of injection and production well pattern,this paper studies the development and adjustment of treatment plan,puts forward the measures to adjust the well position and potential tapping,and provides the reference ideas for further development and adjustment of reservoirs.