库车山前深层高温高压气井多封隔器分层压裂工艺

库车山前区域深层高温高压低孔低渗气藏多封隔器分层压裂作业易发生封隔器失效、钢球堵塞管柱及射孔段下部替液不干净等问题，成为影响储层改造作业成功的关键问题。为解决上述问题，在完井管柱上加装了伸缩短节并延伸管柱至射孔段底界；研发了一种高强度铝合金可溶球，以三聚氰胺为过渡层的复合有机硅树脂涂层为其特殊保护膜，其承压强度在69 MPa以上且溶解速度先慢后快；研发了一种全通径压裂阀，采用棘爪式结构和投球打压方式，滑套打开侧孔时扩径通过球，使球移动至管柱底部，其通径可与下部封隔器保持一致，形成了适用于深层高温高压气井的多封隔器分层压裂工艺。现场累计应用14井次，未出现封隔器压裂时失效、管柱堵塞和替液不净等问题。分析表明:伸缩短节能够缓解温度效应和管内外压差产生的轴向力；可溶球满足压裂施工需求的同时，避免了滞留堵塞现象的出现；延伸管柱配合全通径压裂阀为射孔段替液和压裂液有效注入提供了通道，解决了射孔段钻井液沉淀堵塞和支撑剂沉积在井底的问题。多封隔器分层压裂工艺能够为深层高温高压气井储层压裂改造提供可靠技术支撑。

Multi-packer separate layer fracturing technology for deep,high temperature and high pressure gas wells in Kuqa piedmont

The multi-packer separate layer fracturing operation in the deep, high temperature, high pressure, low porosity and low permeability gas reservoirs of Kuqa piedmont area tends to suffer packer failure, steel ball blocking pipe string and incomplete fluid displacement at the lower part of perforation interval, which are the key problems impacting the success of reservoir stimulation operation. In order to solve these problems, the completion string was installed with a slip joint to extend to the bottom boundary of the perforation interval. A kind of high-strength dissoluble ball of aluminum alloy was developed, which takes the composite organosilicon resin coat with the transitional layer of melamine as the special protection film, has pressure bearing strength more than 69 MPa and dissolves slowly first and then fast. In addition, a kind of full-bore fracturing valve was developed, which adopts ratchet-type structure and dropping-to-pressurizing mode. When the side hole is opened by the sliding sleeve, the hole is enlarged to run the ball through it to the bottom of the string, so that the full bore can be kept consistent with the lower packer. Thus, the multi-packer separate layer fracturing technology suitable for deep, high temperature, high pressure deep gas wells was formed. It has been applied on site 14 well times, and no packer failure, string blocking or incomplete fluid displacement occurs during the fracturing. The analysis indicates that slip joints can alleviate the axial force generated by temperature effect and inner-outer pipe pressure difference; dissoluble balls avoid the occurrence of retention blockage while meeting the requirements of fracturing operation; extension string, combined with full-bore fracturing valve provides the channels for the effective injection of fracturing fluid and displacement fluid in the perforation intervals, so as to solve the settling blockage of drilling fluid in perforation intervals and the deposition of proppant at the bottom hole. In conclusion, the multi-packer separate layer fracturing technology can provide reliable technological support for the reservoir fracturing stimulation of deep, high temperature and high pressure gas wells.