深井抗高温钻井液体系的研究与应用

Study and application of high temperature drilling fluid for deep wells.

深井钻井液的热稳定性一直是国内外研究的关键问题。室内试验在优选抗高温处理剂的基础上,通过引入新型的硅氟共聚物降粘剂GF260,开发出了一种新型抗高温硅氟聚合物钻井液,即4%钠膨润土+3%MMH+5%MF1(复合降滤失剂)+2%Na2SO4(抗高温稳定剂)+2%RH1+2%GF260+1%ZHⅢ(缓蚀剂)+其它辅剂。室内对该钻井液的抗温性、页岩膨胀性和悬浮稳定性进行了评价。结果表明,抗高温硅氟聚合物钻井液具有优良的抗高温悬浮稳定性、抑制防塌能力和很高的热稳定性(抗温可达220℃)。在和参1井和莱深1井应用中,抗高温硅氟聚合物钻井液性能稳定,钻井施工顺利,电测和下套管一次成功,未发生井壁垮塌现象,钻井周期比该地区同类井缩短了1/3,综合钻探效果显著。

Thermal stability of deep well drilling fluid has been a key point at home and abroad for a long time. Based on optimizing drilling fluid additives for high temperature condition, and by introducing new silicofluoric polymer GF-260 as a viscosity reducer, a new silicofluoric polymer drilling fluid for high temperature was developed. Its composition includes 4% sodium bentonite, 3%MMH, 5%compounded fluid loss additive, 2%high temperature stabilizing agent Na2SO4, 2%RH-1, 2%GF-260, 1%retarding agent ZH-Ⅲ and other auxiliary agents. In lab, thermal stability, hole swelling inhibition and suspension stability of this fluid were evaluated. Results showed that, this fluid provides excellent suspension and hole swelling prevention at high temperature up to 220 ℃. Application in Hecan1 well and Laishen1 well verified the fluid characteristics. No problems occurred in drilling, logging and casing operations, and the drilling period was shortened by 1/3 comparing with same wells in this area.