低毒油包水钻井液用耐高温有机土的研制

Development of a High Temperature Low Toxicity W/O Organophilic Clay

通过用十八烷基二甲基苄基氯化铵对提纯钠基蒙脱石改性,制备出了1#有机土,在此基础上再用妥尔油基聚羧酸聚合物ENVAMOD-595与1#有机土复合,制备出2#有机土。采用X射线衍射仪和DSC-TGA同步热分析仪对制备的1#和2#有机土样品进行了测试,并测定了用其配制的油包水钻井液在热滚后的流变性能。结果表明:十八烷基二甲基苄基氯化铵和ENVAMOD-595均能插层进入蒙脱石层间,与蒙脱石复合形成有机土,且ENVAMOD-595的加入能提高有机土的热稳定性;适当升温可以促进有机土的分散,使钻井液黏度升高,高温会破坏有机土的结构,使得钻井液的流变性能降低;1#有机土抗温达170℃,而2#有机土抗温达210℃,好于矿物油基钻井液用有机土B155。用2#有机土配制的现场油包水钻井液经150℃热滚后具有较高的稳定性,证明该有机土适用于高温钻井液的配制。

An organophilic clay was developed using octadecyl benzyl dimethyl ammonium chloride, a polymer ENVAMOD-95 and a purified sodium montmorillonite, and analyzed with X-ray and simultaneous thermal analyzer DSC-TGA. A water in oil mud was prepared with the organophilic clay, and was tested for its properties against a mud sample taken from a well. The analyses showed that octadecyl benzyl dimethyl ammonium chloride and ENVAMOD-95 can both enter into the space between the layers of montmorillonite to form organophilic clay. ENVAMOD-95 actually enhanced the thermal stability of the organophilic clay. In laboratory experiment, the viscosity and gel strength of the mud first increased and then decreased with temperature. The preparedwater in oil mud retained its properties after hot-rolling 16 hours at 210 ℃, showing that organophilic clay made from ENVAMOD-95 had better thermal stability than other two polymer samples tested. Water in oil mud prepared with this organophilic clay at rig-site retained good properties after hot-rolling at 150 ℃, showing its potential for field use in HTHP wells.