基于季戊四醇的超支化降滤失剂的合成及性能评价

The Synthesis and Evaluation of a Pentaerythritol-Based Hyperbranched Polymer Filter Loss Reducer

针对现有的降滤失剂在使用过程中存在对钻井液流变性影响大、抗温和抗盐能力不足的问题,以季戊四醇为核心结构的多烯基单体四烯丙基醚(PPTE),与2-丙烯酰胺-2-甲基丙磺酸(AMPS)、N-乙烯基吡咯烷酮(NVP)、丙烯酰胺(AM)为原料,通过自由基聚合反应合成一种基于季戊四醇的超支化降滤失剂PPAAN-1。在正交实验的基础上,进一步考虑四烯丙基醚加量对降滤失剂的表观黏度的影响,最终确认了降滤失剂PPAAN-1的最佳合成条件:PPTE加量为17%、AMPS∶AM∶NVP=2∶6∶1、反应温度为55℃、引发剂(AIBN)为0.2%。在室内评价其降滤失效果、流变性能、热稳定性能以及其对滤饼质量的影响。实验结果表明,与国外降滤失剂Driscal D和DrisTemp相比,降滤失剂PPAAN-1对钻井液流变性能影响小,同时拥有良好的热稳定性能以及降滤失效果,其热降解温度高达302.29℃,在30%氯化钠盐水浆(1%PPAAN-1)中的API滤失量(220℃老化后)为9.8 mL、高温高压滤失量(150℃)为18.5 mL;在高温高矿化度的条件下降滤失剂PPAAN-1可形成网状结构,并吸附在黏土表面,提高钻井液中黏土颗粒粒径的分布范围,从而形成致密的泥饼,以达到降滤失的目的。

Filter loss reducers presently in use have some deficiencies such as great negative impact on mud rheology,poor high temperature resistance and poor salt contamination resistance etc.To overcome these deficiencies,a pentaerythritol-based hyperbranched polymer filter loss reducer PPAAN-1 was developed through radical polymerization with tetraallyl ether(PPTE,a polyene monomer with pentaerythritol as its core molecular structure),2-acrylamido-2-methylpropanesulfonic acid(AMPS),N-vinyl pyrrolidone(NVP)and acrylamide(AM)as raw material.Based on orthogonal experiment results,the effects of the concentration of the tetraallyl ether on the apparent viscosity of the filter loss reducer PPAAN-1 was also studied.The optimum synthesis condition of PPAAN-1 was finally determined as follows:concentration of PPTE=17%,AMPS∶AM∶NVP=2∶6∶1,reaction temperature=55℃,initiator(AIBN)concentration=0.2%.In laboratory evaluation,the properties of PPAAN-1 were compared with Driscal and DrisTemp.PPAAN-1 has little effect on mud rheology,good thermal stability and good filtration control capacity.The thermal decomposition temperature of PPAAN-1 is 302.29℃.A 30%NaCl drilling fluid treated with 1%PPAAN-1 had API filtration rate(220℃)of 9.8 mL and HTHP(150℃)filtration rate of 18.5 mL.In high temperature high salinity conditions,PPAAN-1 can form a network structure and adsorb on the surfaces of the clay particles,thereby widening the range of the particle size distribution of clays in a drilling fluid,helping the drilling fluid form dense mud cakes,and reducing the filtration rate of the drilling fluid.