苏里格气田致密砂岩气藏水平井开发技术及展望

Horizontal well development technology for tight sandstone gas reservoirs in the Sulige Gas Field,Ordos Basin

鄂尔多斯盆地苏里格气田具有"低渗透率、低压力、低丰度、薄储层、强非均质性"的特征,单井产量低、压力下降快、稳产难度大、开发难度大。为了实现该气田的有效开发,中国石油长庆油田公司从2001年开始持续攻关,逐渐掌握了该气田致密砂岩气藏储层地质特征精细描述的方法,形成了针对该气田薄层强非均质性致密砂岩储层的水平井开发地质、快速钻井、多段改造等技术系列。水平井有效储层钻遇率已由初期的23%提高到目前的60%以上,单井日产气量超过5×104 m3,是邻近直井的3～5倍,已规模建成水平井整体开发区,实现了气田开发方式的转变,开发水平和开发效益显著提升。苏里格气田低渗透强非均质性致密砂岩气藏水平井开发技术的成功应用,说明了水平井是致密砂岩气有效开发的重要技术,也展示了该气田致密砂岩气藏良好的开发前景。

Typical tight gas reservoirs in the Sulige Gas Field, Ordos Basin, are characterized by low permeability, low pressure, low abundance, thin layer and strong heterogeneity, so it is tough to efficiently and economically develop this field due to a quick drop in formation pressure and a rather low singlewell production. In view of this, the PetroChina Changqing Oilfield Company has tackled with many technical problems since 2001, among which the fine description method was developed for characterizing the geological properties of such typical tight sand gas reservoirs in the Sulige Gas Field. Besides, aimed at thin layers with strong heterogeneous sandstone reservoirs, a series of technologies has been established, such as horizontal well development geology, rapid drilling techniques, reservoir stimulation by multifractured horizontal wells, etc. The application results of horizontal wells show that the drilling rate reaching target zones increased from initial 23% to current above 60%; single well production reached more than 5×104 m3/d, which is 3 - 5 times that of adjacent vertical wells. Thus, an integrated horizontal well development zone was built, and the development mode was then successfully transformed, as a result, an obvious rise was seen either in the development level or the development profit in this field. This successful case not only proves that the horizontal well development technology is an important technical way for the efficient and costeffective exploitation of tight sand gas reservoirs, but reveals that tight sand gas reservoirs are prospective in the future with the aid of appropriate development technologies.