鄂尔多斯盆地侏罗系延安组小油藏剩余油区水平井开发研究

Research of Horizontal Well Development of Micro-reservoir Remaining Oil in Jurassic Yanan Formation in Ordos Basin

鄂尔多斯盆地中生代侏罗系延安组油藏具有含油面积小、构造起伏小、分布零散、储层物性好和单井产能较高的特点,历来都是勘探和开发的主要目的层。正226井区是西区油田一个典型延安组小油藏,根据鄂尔多斯盆地侏罗系延安组油藏特征,正226井区还存在较大的开发潜力,同时也说明目前的开发井网不能满足区块提高采收率的要求,进行开发调整势在必行。通过对正226井区加强地质研究和动态分析,分析了正226井区延安组的剩余油分布状况,并根据剩余油分布特征在正226井区部署了3口水平井进行开发。3口水平井完井方式均为油层段下筛管完井。投产初期日产液均大于15m3,平均日产油10.4t,含水率与区块老井初期平均含水率一致。根据预测,西平3井、西平4井最终累积产量分别为1×104t和2.1×104t,延92层最终采收率提高3.1%,西平8井最终产油量1.3×104t,延81最终采收率提高5%,开发效果良好。

The reservoir of Mesozoic Jurassic Yanan Formation in Ordos Basin is a small oil-bearing area,small fluctuation of structure,scattered distribution,good reservoir properties,and high productivity of single well,it is the main reservoir of exploration and development.The Area Zheng 226 is a typical Yanan Formation micro-reservoir in Xiqu Oilfield.According to the reservoir characteristics of Jurassic Yanan Formation,there also has great development potential in Zheng 226 Area,simultaneously it also explains the development well pattern that can't meet the requirements of improving oil recovery,therefore development adjustment is imperative.By strengthening the geological research and dynamic analysis of Zheng 226 Area,residual oil distribution in Zheng 226 Area of Yanan Formation,the deployment of3 horizontal wells is analyzed according to the remaining oil distribution in the area.All of the completion methods are screen completion under the reservoir condition.More than 15m3 daily fluid production per well is obtained at the early stage,the daily oil production is 10.4t,and the water content is the same as the average of old wells at the early stage.According to the forecast,the final cumulative production of Well Xiping 3and Xiping4 is 1×104t and 2.1×104t respectively,3.1%of the ultimate recovery of Yan92 layer is improved,the final cumulative production of Xiping8is1.3×104t,5%of the ultimate recovery of Yan81 layer is improved,the effect of development is good.