抗高温强封堵防塌钻井液体系研究与应用

Study and Application of a High Temperature Drilling Fluid with Strong Plugging Capacity

针对高温深部复杂地层的钻探需求,通过分子设计研发出一种抗温达200℃、具有刚性结构和高温形变能力的抗高温封堵防塌剂SMNA-1。该剂在140~200℃广谱温度范围内,能够通过其变形性和黏结性有效地堆积填充黏结滤饼,同时利用其自身的疏水性能在滤饼表面形成封堵膜,束缚自由水,增强滤饼的韧性和致密性、降低高温高压滤失量,提高钻井液的封堵防塌能力。以抗高温封堵防塌处理剂为主剂SMNA-1,优选抗高温降滤失剂SMPFL-L、SML-4和高效润滑剂SMJH-1等抗高温处理剂,构建出抗高温强封堵钻井液体系。抗高温聚合物降滤失剂SMPFL-L以丙烯酰胺、2-丙烯酰胺基长链烷基磺酸、双烯磺酸等单体采用自由基聚合制得,分子量较低,且分子量分布具有多分散性,饱和盐水基浆中加入2%SMPFL-L后可使高温高压滤失量降低至54 m L,该剂还具有良好的解絮凝作用,耐温达210℃。抗高温抗盐降滤失剂SML-4是针对高密度钻井液固相加重材料含量高对降滤失剂要求,研发的一种降滤失剂,其能够部分改变加重材料表面性质,提高加重材料的分散性,降低水化膜厚度,4%SML-4可使高密度盐水浆的API滤失量由164 m L降至5.8 m L,且不增加钻井液的黏度。在密度为2.0 g/cm^3钻井液中加入2%高效润滑剂SMJH-1,极压润滑系数降低率为24%。该体系在新疆顺北1-1H井三开井段现场应用近1 300 m,施工顺利,未出现任何复杂情况,试验井段平均井径扩大率仅6.88%,井身质量好,取得了良好的应用效果。

A high temperature borehole wall stabilizing agent SMNA-1 was developed to resolve problems encountered in high temperature deep well drilling. SMNA-1 functions at high temperature to above 200℃. It has a rigid molecular structure and is deformable at high temperature. SMNA-1 is able to enhance the strength of mud cake through its deformability and cohesion capacity. SMNA-1, through its hydrophobicity, also forms a sealing membrane on the surface of mud cake to bind free water and enhance the toughness and consistence of the mud cake, thereby reducing HTHP flter loss and enhancing the capacity of drilling fluid to plugging and stabilizing borehole wall. A high temperature polymer flter loss reducer, SMPFL-L, was synthesized with acrylamide, 2-acrylamide long carbon chain sulfonic acid and diene sulfonic acid through free radical polymerization. SMPFL-L has low widely distributed molecular weight. A saturated saltwater drilling fluid treated with 2%SMPFL-L had its HTHP flter loss reduced to 54 mL. The property of SMPFL-L remained stable at 210℃, and had good deflocculating ability. SML-4, a high temperature salt-resistant flter loss reducer, has been developed for use in high density muds weighted with weighting materials that will result in high solids content. SML-4 is able to alter the surface behavior, enhance the dispersity, and thin the hydration flm of weighting material. A high density saltwater drilling fluid treated with 4% SML-4 had its API flter loss reduced from 164 mL to 5.8 mL, without increasing the viscosity of the drilling fluid. A drilling fluid of 2.0 g/cm3 treated with 2% SMJH-1 had its extreme pressure friction coeffcient reduced by 24%. A high temperature drilling fluid with strong plugging capacity has been developed with SMNA-1 as the main additive, SMPFL-L and SML-4 as flter loss reduces, SMJH-1 as high effciency lubricant. This drilling fluid formulation was successfully used in drilling the third interval （1,300 m） of the well Shunbei-1-1H located in Xinjiang, and no downhole troubles were encountered. The average percent hole enlargement was only 6.88%, and good application results were achieved.