致密砂岩气藏多层系水平井立体开发技术——以鄂尔多斯盆地致密气示范区为例

Multi-layer horizontal wells development for tight sandstone gas reservoir:Case study of tight gas reservoir model zone in Ordos Basin

中国致密砂岩气资源丰富、分布广泛,但储层非均质性强,单井产量低,有效开发难度大。为提高致密砂岩气单井产量和储量动用程度,探索致密砂岩气藏多层系高效立体开发模式,以鄂尔多斯盆地苏里格气田致密气示范区盒8段、山1段等多套含气层系为例开展了研究,提出了一套致密砂岩气藏多层系水平井立体开发技术体系。首先,针对致密储层特征,通过利用三维地质建模与三维地震资料对各小层砂体空间展布进行精细刻画和含气有利区评价;其次,优选水平井开发主力层位和落实水平井部署有利区,整体部署盒8段、山1段2套水平井井网,进行多层系立体水平井开发;第三,应用地质—地震综合水平井地质导向技术,有效提高了气层钻遇率。基于该技术开发体系,完钻的多层系水平井气层钻遇率较邻近区块提高了10%以上,试气平均无阻流量达到87.3×10~4m^(3)/d,实现了致密气藏的高效开发。

There are more tight gas sandstone reservoirs in China.However,tight gas reservoirs are characterized by strong heterogeneous,low well productivity and it’s difficult to develop efficiently.Tight gas reservoir model zone in Ordos Basin with He 8 and Shan 1 multi-layer is studied as an example for enhancing well productivity,improving reserves producing degree and exploring efficient development model.Multi-layer horizontal wells development technologies are proposed.Firstly,feature of every layer is characterized finely and sweet point evaluation is done by 3 D geologic and seismic model;Secondly,He 8 and Shan 1 layers are nominated and laid out in model zone for horizontal well development by formation optimized.Thirdly,length of gas-bearing sand to horizontal section ratio increased efficiently via geo-seismic steering.Length of gas-bearing sand to horizontal section ratio is 10%higher compared to adjacent field.The average AOF of horizontal wells is 0.873 million cube meters per day based on these technologies.Efficient development of tight gas reservoir is achieved.