聚合醇硅基防塌钻井液在王101井的应用

王101井是大港油田小集区块王27断块下降盘官106井断鼻高部位构造上的一口评价井,完钻井深3773m.大港油田沙河街组大段泥岩、泥质粉砂岩和生物灰岩易造成井壁坍塌、划眼、井漏;孔店组石膏层易污染钻井液,泥页岩吸水膨胀,导致粘度和切力增大、流动性变差、产生剥落掉块,钻井过程中易发生井壁坍塌等事故.针对不同的地层特点,采取相应的施工方案.即一开采用膨润土浆钻至井深103 m;二开采用聚合物钻井液钻至井深1743 m;三开地层复杂,在1743～2733 m井段采用硅基防塌钻井液,2733～3774 m井段采用聚合醇硅基防塌钻井液.钻至井深2837 m,进入油层时,在聚合醇硅基防塌钻井液中加入0.25%单封、1%细目碳酸钙、0.25%酚醛树脂、0.5%润滑防塌剂.现场应用表明,聚合醇硅基防塌钻井液润滑、防卡效果好,抗岩屑污染能力强,流变性能好,阻止了泥页岩水化分散,井壁稳定,井眼规则,井径扩大率为4.16%.该钻井液体系保证了王101井钻井施工的顺利进行.

Application of polyol silicate anti-sloughing drilling fluid in well Wang-101

Well Wang-101 is an evaluation well on the Xiaji Block of Dagang Oilfield, with a total depth of 3773 m. As large sections of shale, silty shale and biostromal limestone exists in the Shahejie group of this area, sloughing, filling and lost circulation is likely to happen. The gypsum in Kongdian Group may cause contamination to the drilling fluid, and the hydration of shale can cause the rise of viscosity and shearing force, which leads to the poor rheological property and slamming. Such trouble as hole collapse frequently occurs during drilling. In accordance with the different formation characteristics. the corresponding field plans are adopted respectively. Specifically, for the 103 m surface hole, bentonite mud is used; in the second section, i.e. , 103- 1743 m, polymer mud is used. More complicated formations exist in the third section, thus silicon based anti-sloughing drilling fluid is used between 1743 - 2733 m, and polyol silicate anti-sloughing drilling fluid between 2733 - 3774 m. When it is drilled to 2837 m and before hitting the payzone, 0. 25% of one-direction plugging agent, 1 % of fine calcium, 0. 25% of phenolic resin, 0. 5% of lubricating anti-sloughing agent are added into the system for reservoir protection. Field using shows its advantages over good lubricity and anti-sticking property, free of cuttings contamination and good rheological property. It inhibits the hydration and dispersion of the shale, which results good wellbore stability and regular hole, with the hole enlargement of only 4. 16%.