疏水缔合聚合物AP-P4在SZ36-1油田油藏储层条件下静吸附和解吸附规律研究

Research on Static Adsorption and Desorption of Hydrophobic Associating Polymer AP-P4 under the Formation Condition of SZ36-1 Reservoir

为进一步研究疏水缔合聚合物提高原油采收率的机理,以SZ36-1油田储层油砂、注入水和疏水缔合聚合物AP-P4为研究对象,开展了聚合物浓度、聚合物类型、调节剂浓度和油砂粒径对吸附和解吸附规律影响研究。研究结果表明,疏水缔合聚合物静吸附和解吸附量与聚合物分子间缔合程度、聚合物分子吸附方式以及油砂比表面积密切相关。当AP-P4浓度在500数2500 mg/L时,吸附量为0.758数1.278 mg/g,解吸附量为0.122数0.653mg/g,其中,当聚合物浓度高于1200 mg/L时,"多分子层"吸附量增加。与"单分子层"吸附相比,"多分子层"吸附时聚合物分子聚集体与油砂表面间结合力较弱,吸附稳定性较差,更容易发生脱附。加入β-环糊精可以抑制疏水缔合聚合物疏水基团间的缔合作用,导致聚合物分子聚集体尺寸减小。随着聚合物分子聚集体尺寸和油砂粒径减小,聚合物分子吸附量增大,以"单分子层"吸附方式附着于油砂颗粒表面的聚合物分子数增多,吸附稳定性增强。

To understand the oil incremental mechanism of hydrophobic associating polymer flooding further, the influence of polymer concentration, polymer type, conditioning agent concentration and sand grain size on adsorption and desorption was studied with oil sand grains of SZ36-I reservoir formation, injected water and hydrophobic associating polymer as the research object. Results showed that the static adsorption and desorption of hydrophobic associating polymer was closely related with intermolecular association degree, adsorption mode and sand grains specific surface area. When the AP-P4 concentration was at the range of 500--- 2500 mg/L, the range of the adsorption quantity and the desorption quantity was 0.758--1.278 mg/g and 0.122--0.653 mg/g, respectively. When the polymer concentration was higher than 1200 mg/L, the proportion of the multilayer adsorption increased. Compared with monolayer adsorption, when multilayer adsorption happened, the binding force between polymer molecular aggregate and sand grains surface was weaker, and adsorption stability was worse, hence, the polymer molecule was easier to be desorbed. The addition of the β-cyclodextrin could inhibit the association action happened among the hydrophobic groups, as a result, the polymer aggregate size became smaller. When polymer aggregate size and sand grains got smaller, the adsorption of polymer molecule increased, at the same time, the amount of polymer molecules attached to sand grains surface by means of monolayer adsorption increased, and the adsorption stability enhanced.