基于活性泥岩的聚合物-聚胺钻井液室内研究

Laboratory Study on Polymer-polyamine Drilling Fluid Based Reservoir Protection

KL 9-1油田明化镇组发育大套泥岩,黏土矿物以高混层比的伊蒙混层为主,造浆性强,常规聚合物-氯化钾钻井液因抑制性不足而出现起下钻遇阻、井径缩径等现象。为提高钻井液抑制性,通过流变性试验、离心法膨胀试验、滚动回收率试验及高温高压膨胀试验优选出聚胺抑制剂SAC和大分子包被剂PAM,进而优化出一套聚合物-聚胺钻井液体系,其配方为:3%海水土浆+0.1%Na_2CO_3+0.3%PAM+0.5%降失水剂PANS+0.5%CMS+2%SMP-1+0.5%聚胺抑制剂SAC+0.5%石墨粉。性能测试结果表明,该钻井液泥岩滚动回收率高达93.3%,高温高压膨胀率仅为5.72%,抑制性能良好;高温高压滤失量为11.7mL,失水造壁性较好;流变性良好;污染后岩心渗透率恢复值大于80%,储层保护效果较好;其抑制性较前期使用的常规聚合物-氯化钾钻井液有显著提高,可以满足大套活性泥岩钻井作业需要。

The Minghuazhen Formation of KL 9-1 Oilfield developes a large set of mudstone,and the main component of clay mineral is illite-smectite mixed-layer,then mud yield ability was strong.Conventional polymer-potassium chloride drilling fluid was insufficiently inhibited,which induced drilling instability such as tripping difficulty and well diameter shrinkage.In order to improve the inhibition of drilling fluid,the polyamine inhibitor SAC and the macromolecule coating agent PAM are optimized by rheological experiment,the experiment of centrifugal expansion,the rolling recovery experiment and the high temperature and high pressure expansion experiment,and then a polymerpolyamine drilling fluid system is optimized.The formula is:3% seawater slurry+ 0.1% Na_2CO_3+0.3% PAM+0.5% Fluid loss additives PANS+0.5% CMS+2 % SMP-1+0.5% polyamine inhibitor SAC+0.5% graphite powder.The results show that the rolling recovery rate of mudstone is 93.3%,the high temperature and high pressure expansion rate is only 5.72%,and it has good inhibition.The high temperature and high pressure filtration loss is 11.7ml,and it has good wall building properties and good rheological property.The recovery value of the core permeability after pollution is more than 80%,the effect of formation protection is better.Its inhibition is significantly higher than that of the conventional polymer potassium chloride drilling fluid and can meet the needs of large sets of active mudstone drilling operations.