Cycle Optimization Of Heavy Oil Steam Injection Production Based On Well-testing

Heavy oil is an important resource in China.The way to efficiently utilize the heavy oil is very important for reliving the current shortage of resource in our country.Cyclic steam stimulation is a major way for heavy oil recovering,and the production of heavy oil could be increased by reasonable period of steam stimulation.But the present study on reasonable period of steam stimulation is less.Instead of considering both of the actual situation and the theoretical terms,most of current researches are only considering the theoretical terms.Based on the above issues,as example by an oilfield of Xinjiang,first of all,the suitable model is established by the method which considering the relationship among all factors in period of steam stimulation.The method also consists of the following three ways: applying well test auto-matching,numerical well testing and sensitivity analysis of each factor in steam stimulation.Meanwhile,the heating radius is contained through well test auto-matching.Then on the base of this,the previous heating radius is corrected and a new concept called oil-fluid radius is proposed based on the changing of crude oil flow range.The formula of oil-fluid radius has also been derived.Meanwhile,the formula of soak time has also been derived based on the formula of oil-fluid radius by considering the relationship between oil-fluid radius,soak time and cyclic steam injection.Then the steam injection time can be optimized by the method of analyzing historical production performance data aimed to study the relationship between each key parameter of steam stimulation in practical production.And the production time can be optimized by the method of economic maximum analyzing.In these ways,this paper provides a well-test-based method to optimize steam stimulation period.At last,this paper compare between the two results,one is the example calculation which using the data from oil-fluid radius calculation by well test auto-matching and the parameters optimization by historical production performance analyzing,the other is the multi-targeting optimization.The comparing result indicated that the mentioned method needs a small amount of parameters,shorter time,and the calculation precision satisfies the actual requirement.In conclusion,this paper has practical value on the heavy oil development.