苏里格致密气田丛式井组连续油管一体化压裂技术

苏里格致密砂岩气藏大井组多井型的丛式井组机械分层压裂工艺不能满足多层、高排量压裂技术发展需求。为此，根据体积压裂理论进行了致密气田高排量混合水压裂工艺设计，采用滑溜水+基液+交联液的注入模式，低黏液占比40%~75%，排量6~8 m3/min；研发了连续油管底封分层压裂工具串:导向扶正器+机械式接箍定位器+机械锚定器+Y211封隔器+平衡阀+喷射器+机械式安全丢手接头+连续油管外卡瓦式连接头+连续油管，满足了连续解封和坐封的需求；为确保安全施工，研发了连续油管井口保护器，结合全过程防砂工艺制定了标准地面作业流程，形成了安全作业配套技术，并研发了压裂返排液处理装置，实现了压裂返排液再利用，最终形成苏里格致密气田丛式井组连续油管一体化压裂技术。截至2018年12月底现场试验32个井组201口井，压后单井产量较对比井提高15%，平均单井压裂作业周期由常规模式的19.5 d缩短至11.0 d，提产提速效果显著。

Coiled-tubing integrated fracturing technology of multiwell cluster in Sulige tight gasfield

In recent years, the multiwell cluster development mode of large well group with multiple well types is the main development mode of tight sandstone gas reservoirs in Sulige Gas Field. However, the mechanical separate layer fracturing technology cannot satisfy the technical development requirements of multilayer high displacement fracturing. For this regard, high-displacement mixed water fracturing technology suitable for tight gas fields was designed according to the theory of volumetric fracturing and the injection mode of slick water+base fluid+crosslinked fluid with low viscous fluid ratio of 40%?75% and displacement of 6?8 m3/min was adopted. Then, to satisfy the requirements of continuous unsetting and setting, the coiled tubing and undersealing differential pressure tool string was developed i.e., guide centralizer & mechanical collar locator & mechanical anchor & Y211 packer & balance valve & ejector & mechanical safety release sub & slip type connector outside the coiled tubing & coiled tubing. In order to ensure the construction safety, the wellhead protector of coiled tubing was developed. Based on the whole-process sand control technology, the standard flow of ground operation was formulated. Thus, the support technologies for safe operation were developed. In addition, the flowback fracturing fluid treatment device was developed, so that the recycle of flowback fracturing fluid was realized. In this way, the coiled-tubing integrated fracturing technology of multiwell cluster is ultimately formed in Sulige tight gas field. By December 2018, this technology had been tested on site in 201 wells of 32 well groups. It is shown that the post-fracturing production rate per well is 15% higher than the reference well and the average fracturing cycle per well is shortened to 11.0 d from 19.5 d (conventional model). It is indicated that this technology is remarkable in production and ROP improvement.