摘要:
为了解决以往成井工艺存在的新近系储层回灌堵塞问题,根据热储条件,滨海新区西部25#地热回灌井采用大口径管外填砾的成井工艺。在施工重点工序上,一方面为了减小热储层的水流阻力,提高回灌量,25#回灌井采用下管前的破壁洗井和填砾前的正循环管外洗井,破坏井壁泥皮和清除渗入热储层中的稠泥浆,使过滤器周围形成一个良好的人工过滤层;另一方面总结以前填砾经验和教训,25#回灌井采用动水填砾,有效避免了填砾过程中的砾料膨胀与搭桥现象,保证了填砾安全到位。25#回灌井成井后进行了科研性回灌试验和生产性回灌试验,最大稳定灌量达66 m3/h,稳定动水位埋深71.37 m,回灌效果良好,而且后期回灌运行稳定,进一步验证了填砾成井工艺有利于回灌。
Abstract:
In order to solve the clogging problems of reinjection well in Neogene geothermal reservoir, the drill-ing technology of gravel-packed completion technology outside the casing in large diameter well is taken in 25# reinjection well according to geothermal reservoir conditions in the Binhai New Area. For reducing flow resis-tance of the thermal reservoir and improving recharge amount, the well flushing for broken the mud wall before casing installed and direct well flushing outside the casing before gravel-packed method was adopted, which can damage the mud wall and clean out the viscous mud that have got into reservoir, so that the filter is formed a good artificial filter layer. And the dynamic water filling gravel was taken into the drilling of 25#, based on the ex-periences before, which can avoid gravel expansion and bridging phenomenon to ensure the gravel-packed in place. The reinjection and production tests have carried out separately. It indicates that the maximum recharge amount is 66 m3/h and the stable water level is 71.37 m. The test achieves a good reinjection effect. The operation of the system is running steady. This is a good verification that gravel-packed completion technology could make geothermal reinjection in sandstone reservoir easier.
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