高性能、低成本化学泡沫水泥浆在青海油田低压易漏井的应用

针对青海花土沟油田、油砂山油田低压油气井地层承压能力低，固井时易发生漏失的特点，固井时采用在漂珠水泥浆中加入FC系列发气剂配制成的化学泡沫超低密度水泥浆。试验结果表明，化学泡沫超低密度水泥浆强度高、稠化时间易于控制，并具有低污染和一定的堵漏性能，能使水泥浆井下密度降低至1.30-1.35g/cm^3，井口密度降低至0.90-0.95g/cm^3,提高低压易漏地层的封固质量，降低对产层的污染。在青海油田6口中、浅层低压易漏失油气井进行了应用，这6口井的漏失非常严重，但是固井质量为3口优质、3口合格，固井质量达到了原先的预想，表明该泡沫水泥浆较好地解决了青海油田浅、中层低易漏失井的固井问题。化学泡沫超低密度水泥浆避免了固井补救措施造成的费用，而且节约了大量的机构设备购置资金和维修费用，具有较好的经济效益。

The application of better properties and lower costs chemical foam cement in the iow-pressure and lost-circulation wells of Qinghai Oilfield

The formations of low-pressure oil and gas wells have low pressure-bearing capacity and are easy to leak during cementing in Huatugou and Youshashan oilfields of Qinghai. In order to solve this problem, a ultra-low density chemical foam cement slurry which made from a slurry containing micro-spheres adding FC series gas generating agents were applied. Experimental results showed that ultra-low density chemical foam cement slurry has characters of high compressive strength, thickening time easy of adjusting, low pollution and plugging. It can reduce respectively density of 1. 30-1. 35 g/cm3 in bottom hole and 1. 30-1. 35 g/cm3 in wellhead and improve cementing quality on low-pressure and lost circulation formations and remove contamination out of production zones. The cement slurry has been used in six relative shallow wells of low-pressure and lost circulation formation in Qinghai oil field. Even though severe lost circulation can be encountered in the wells, cementing quality of three wells are excellent and the others are eligible. This result shows that such cement slurry can preferably solve the cementing problems in relative shallow wells of low-pressure and lost circulation formation in the oil field. Ultra-low density chemical foam cement slurry reduced the costs of cementing remediation and saved a lot of money for equipment purchase and maintenance.