高性能弹浮式套管浮箍的研制及在页岩气井的应用

在页岩气水平井固井中，现有套管浮箍可靠性低，常因浮箍失效对固井质量造成不良影响。为解决该问题，分析了浮箍失效的具体原因，确定了提高浮箍可靠性的结构改进技术方案，通过仿真模拟分析了该方案的可行性，并在室内模拟试验和分析其综合性能的基础上，研制了高性能弹浮式套管浮箍。室内试验表明，研制的浮箍可耐压60 MPa，耐温180℃，在2.0 m3/min排量下冲蚀72 h无损伤。该套管浮箍在涪陵页岩气田焦石坝区块的200多口页岩气水平井中进行了应用，应用结果表明，弹浮式浮箍耐高压、耐高温、耐冲蚀、可靠性高（一次坐封可靠率达100%）。研究认为，该浮箍可广泛应用于各类套管外大压差井、水平井、高温深井和复杂井的固井作业。 

The Development of High-Performance Elastic-Floating Float Collars and Their Applications in Shale Gas Wells

Existing float collars exhibit low reliability in cementing operations of horizontal wells for shale gas development. Consequently, the failure of floating collars for casing may frequently induce negative impacts on quality of cementing operations. To solve these problems, a review was conducted of the root causes for failures of float collars together with technical solutions to enhance reliability of such collars. The feasibility of such solutions had been analyzed through simulation tests. On bases of combination of lab test results and assessments of overall performances, high-performance elastic-floating type float collars were developed. Laboratory test results showed that the newly developed float collar might endure pressures up to 60 MPa with resistance to temperature 180℃. In addition, these collars might experience no damage for 72 h under displacement erosion rate of 2.0 m3/min. High performance elastic floating float collars were applied in more than 200 shale gas horizontal wells in the Jiaoshiba Block of the Fuling Shale Gas Field with outstanding resistance to high pressures, high temperatures, erosion and excellent reliability,with a one-time setting success rate up to 100%. Research results suggested that these float collars may be widely used in cementing operations in wells with significant differential pressures, horizontal wells, high-temperature deep wells and wells under complicated conditions.