油井水泥宽温带缓凝剂SD_(210L)的研制与应用

Development and application of the well cement retarder SD210L with a wide high temperature range

四川和新疆地区的部分钻井深度已达7000m,长度2 500～3 600m的技术套管悬挂固井井段已很常见,水泥浆柱顶部和底部温度差大(已达120℃),60～180℃宽温带缓凝剂成为解决大温差固井难题的瓶颈。为此,研制了由含磺酸基、双羧基以及酰胺等功能基团的两种单体共聚物——宽温带缓凝剂SD210L。实验测评其综合性能:SD210L缓凝剂稠化时间可调、稠化曲线平稳、呈直角稠化;与不同类型的降失水剂复配均可有效降低水泥浆滤失量;高温浆体在中低温条件下水泥石早期强度高;抗盐能力强。先后20井次成功应用到四川盆地龙岗气田礁滩、安岳震旦系等气藏的Ф177.8mm或Ф168.3mm长封固段大温差尾管固井作业中。结果表明,SD210L克服了大温差对高温水泥浆体系带来的"超缓凝"问题,与现有高温缓凝剂相比,SD210L适应的井下温度更宽更高且不含磷酸酯因而更环保。

The depths of some wells in Sichuan and Xinjiang even reach up to 7000 m so it is very common to cement the intermediate casing which is 2500 - 3600 m long, thus, a retarder with the operating temperature range of 60 - 180℃ is extremely necessary to be applied when there is a big temperature difference （some reaching 120℃） between the top and the bottom of cement slurry column. To this end, the cement retarder SD210L with a wide temperature range is thus developed. It is a copolymer of two monomers containing functional groups such as sulfonic group, diearbonxyl group, acy[amides, etc. The test evaluation indicates that this retarder is featured by adjustable thickening time, smooth thickening curve and right angle thickening; it can not only effectively reduce slurry filtration if compounded with different types of fluid loss agents, but improve the early stage strength of the set cement made from high temperature slurry under middle and low temperature; besides, this retarder has a high salt-resistance ability. This retarder has been applied in 20 different wells located in Longgang reef, Anyue Sinian geological structures, etc. for their liner （Ф 177.8 or Ф168.3 mm） cementing operations troubled by great lengths and a big temperature variation. These on-site applications demonstrate that the SD210L solves the problem of ＂extra retarded set＂ of high temperature cement slurry caused by a big temperature difference; and compared with the existing high temperature retarders, is fitted for a wider downhole temperature range and is also more environmentally friendly due to being free of phosphate ester.