Study Of Evaluation System And Methods For Oilfield Development In High Watercut Stage

By the end of 2002, the Shengli oildom has developed 67 oilfields with 89.9 percent watercut and 76.3 percent of recoverable reserve. Furthermore, watercut of 19 oilfields including Shengtuo, Gudao, and Gudong and so on has exceeded 90 percent. There are 339 reservoirs in especially high watercut stage with 1.52 billion tons of OOIP which accounts for 43.1 percent of the Shengli oildom. Development status and character of these oilfields has changed a lot. The paper has demonstrated the trend of development indexes.47 indexes, which are normally used in development effect evaluation, are classified into 3 catalogs, including technology index, production management index and economic index. Moreover, the technology index is divided into well pattern status index, injection status index and development status index. Furthermore, production management index is classified into stimulation measures representation index and management status index. Using logistic analysis method to analyze relations among these indexes and delete some casual and alternative indexes. Then using Gray Correlation Analysis Method to analyze effect on development status of such indexes, and determine the evaluation indexes on the basis of practical statistics.On the basis of oil and gas industry criterion, evaluation criterion of every index is determined by reservoir engineering calculation methods, such as practical statistics, theoretical calculation and limit forecast. Oilfield development effect evaluation is very complex, because there are more indexes and important degree of every index is different. By confirming Weighted Coefficient of all indexes, fuzzy comprehensive assessment method is used to evaluate reservoir development effect in especially high watercut stage.The evaluation software is made to execute the assignment. It is not only used to development effect evaluation, but also analyze the majority reasons which infect the result and point out proper adjustment measures.Through this project, the evaluation system is established. It can be used in objectively evaluating the development standard and effect of oilfields. Furthermore, it is worthwhile to apply the system to the other oilfields which are in especially high watercut stage.