Research On Profile Modification Result Evaluation Of Ansai Oilfield

After years of production, Ansai oilfield yields sever conflicts between layers and as aresult profile modification has become one of the most important stimulation methods. Butnow most sites only employ two indexes for profile modification result evaluation that isincreasing oil rate and decreasing water rate. In this manner, the result usually is unreal forusing different index there may be different comment. So it is necessary to take full account ofthe inlfuence of the measure to build the evaluation standard and facor system, and theneventually deliver the evaluation result.Employing several methods like logic analysis, data statistics and expert advice, thisdissertation picked ten indexes for evaluation which can be categorized as four aspects:production well, injection well，reservoir and economy. Before calculation, considering thewell interference and the fact that the reservoir should be viewed as a whole, this measurerequires all well experienced profile control be divided into block and well group. This methodincludes two steps. The first step which is called the first-stage evaluation has a clearevaluation standard and so it could get a qualiifed result. While the second step which isaccordingly called the second-stage evaluation could provide a quantified result. Based onfuzzy mathematics, the second-stage evaluation needs first to build an evaluation matirx foreach index and then ascertain their weight coefficient using analytic hierarchy process. Last,multi-stage fiizzy evaluation is employed for the ifnal result calculation, which will be a score.Furthermore, a set of software based on the above theory is established for better applicationin site.Ansai oilfield has used this approach for profile modiifcation result evaluation of29injection wells and190related production wells. Result shows that among the ten blocks andwell groups, the stimulation measure is invalid to two well groups, which only scored2point.Other blocks and well groups all prove to be valid to the profile modification and they all got acore around6point. This profile modification result evaluation approach with easy calculationand clear result has a great application value.