煤层气水平对接井钻井技术研究

Study on Techniques for Drilling CBM SIS

水平对接井 ( SIS) 由水平井与垂直井对接组成,并可根据地质条件和需要,设计成多口水平井与 1 口直井对接的多 "U"型组合; 其井身结构简单,尤其是完井后可下入一根高强度PVC 筛管,克服因煤体坍塌、煤粉沉淀等原因可能造成的水平井段堵塞,还可对水平段井眼进行双向冲洗,保证采气阶段井眼的畅通。煤层气开发实践证明水平井可有效地导通煤储层的裂隙系统,增加气、水导流能力,大幅度提高单井产量和采收率,是开发低压、低渗地区煤层气资源的有效手段,而水平对接井以其合理的井身结构和独特的完井方式,更适宜于中国大多数煤储层条件的煤层气开发。

SIS consists of a horizontal well and a vertical well. Based on the requirements of the geolog- ical conditions and requirements, the author may design the well grouping as a ＂U＂ type assembly, con- sisting of a multiple of horizontal wells and a vertical well. The structure of wellbore is simple. Especially after well completion a high strength perforated PVC pipe can be lowered into the well to prevent the hori- zontal section from plugging due to collapsing of coal solid, or deposition of fine coal. Bidirectional flush- ing can also be carried out in the horizontal section of the borehole, so as to ensure smooth flow of gas in the production section of the borehole. Practical experiences obtained from development of CBM have proved that horizontal well can effectively connect the fracture system in coal reservoir. It can increase the diversion capacity of gas and water, and enhance to a great extent the production of a single well and re- covery rate. It is an effective means to exploit CBM resources in low pressure, low permeability areas. SIS well due to its rational wellbore structure and unique completion method is more suitable for develop- ment of CBM in most coal reservoir conditions in China.