Researches On The Comprehensive Method For Identifying And Characterizing The Thief Zones

At present, the majority of oilfields in our country have entered a period of high watercontent, when the thief zones widely develop. The phenomenon has seriously hampered theimprovement of oil recovery. How to effectively identify the thief zones and select theappropriate process measures to govern the thief zones has become the important issuesessential to be resolved in high water cut stage reservoir development. However, due to theextremely complex problem of the thief zones, it is difficult to cover accurately the thiefzones’ identification and description relying on any kind of information or method solely.Then the qualitative identification system of the the thief zones is not yet complete. The mainidentification indicators are selected from the static data and production performance data,instead of the more important dynamic monitoring data. In addition, most of the quantitativedescription method of the thief zones should be based on monitoring data, but the monitoringdata is not easy to get in every well. Therefore, how to take advantage of the limited oil fielddata to more accurately identify and describe the the thief zones has become an importantproblem in the process of the thief zones’ identification and description.Therefore, this paper first uses the static data, production performance data as well as thedynamic monitoring data ignored in the previous study to build an index system to identifythe thief zones and put forward a more comprehensive fuzzy qualitative identification methodof thief zones. Then a reservoir engineering method to identify and describe the thief zones isproposed. The reservoir problem in the three-dimensional is reduced to one-dimensionalproblem between injection and production wells to get the description results of every well inoilfield according to Berkeley-Lie Weier one-dimensional water flooding theory and thesubstance balance principle. Finally we comprehensively use production performance data,monitoring data, logging data, detailed reservoir description results and integrate the advantages of thief zones identification description method. The quantitative description andthe qualitative identification of the thief zones are integrated as a whole as well as well pointanalysis and the inter-well monitoring analysis are combined as a whole to form acomprehensive methodology to identify and describe thief zones more accurately.