复合硅酸盐钻井液体系室内研究

Laboratory Studies on Mixed Silicate Drilling Fluids

对复合硅酸盐钻井液作了详细的室内实验研究 ,包括 :与常用钻井液和钻井液处理剂的配伍性 ,配方研究 (膨润土含量 ,护胶剂PTV加量 ,pH值 ,降粘手段 ,加药顺序 )和应用性能评定 (阻止压力传递 ,滤液中SiO2 含量 ,硅酸盐模数 ,硅酸盐加量与岩屑回收率 ,与其他体系钻井液抑制性比较 ,抗温、抗盐、抗钙性能 ,抗膨润土污染性能 ,加重钻井液 ,润滑剂的使用 ,电稳定性 ,岩心伤害 )。主要结论如下 :①硅酸盐对膨润土浆有降粘作用 ,与含有铵、钙等离子的处理剂如NH4 HPAN ,PMHC ,PAC141等不配伍 ;②硅酸盐必须与护胶剂一起加入淡水钻井液中 ;③pH值是影响哇酸盐钻井液性能特别是粘度的主要因素 (pH值应 >12 ) ,此外 ,护胶剂PTV含量、膨润土含量、硅酸盐模数及加量等对硅酸盐钻井液的流变性和滤失量有较大影响 ,聚合醇防塌润滑剂和表面活性剂ABS共用在改善硅酸盐钻井液润滑性能的同时 ,还能提高钻井液的高温稳定性 ;④配方适当的硅酸盐钻井液抗温、抗盐、抗钙、抗钻屑污染能力和封堵能力强 ,抑制性好 ,润滑性能好 ,稳定性好 ,保护储层的效果明显。报道了性能优良的硅酸盐钻井液的配方。

A detail laboratory investigation for silicate drilling/completion fluids is performed on compatibility with commonly used drilling fluids and additives, formulations (bentonite and colloid protector PTV use levels, pH value, viscosity reducing measures, and ingredient introducing order), and performance properteis (resistance to pressure transfer in relation to SiO 2 content in filtrate, moduli and use level of silicate, cuttings recovery, inhibiting ability in comparison with other fluids, thermal resistance and tolerencies to salts, clay contamination, weighted fluids, lubricants, electric stability, and core damage). The main results are as follows: ① silicates can reduce the viscosity of bentonite mud and are incompatible with NH 4- and Ca-salts containing additives such as NH 4HPAN, PMHC, PAC141, etc.; ②silicates must be introduced into fresh water clay mud together with a colloid protector; ③pH value is the main factor influencing behavior and viscosity, in particular, of silicate fluids (pH value of the fluid must be >12) and the use levels of colloid protector, bentonite, and silicate and its module have significant effects on fluid rheology and filtrate loss, polyglycol as anti-caving agent/lubricant and surfactant ABS in combination improve thermal resistance as well as lubricity of silicate fluids; ④well formulated silicate fluids are thermally resistant, tolerent to salt and Ca, proof to clay contamination, lubricious, stable, highly inhibitory and possess strong sealing and shielding ability thus provide good protection to reservoir formation from being damaged. Formulas of silicate drilling/completion fluids of excellent performance properties are recommended.