Zhang Bojian, Liu Youquan, Xiong Ying, Fu Cheng, Wang Xianbing
Southwest Oil and Gasfield Company Research Institute of Natural Gas Technology, Chengdu, 610213, Sichuan, China.
Southwest Oil and Gasfield Company Engineering Technology Department, Chengdu, 610017, Sichuan, China.
Sci Rep. 2025 May 7;15(1):15923. doi: 10.1038/s41598-025-99968-9.
In this study, based on the escalating demand for thermally stable scale inhibitors in high-pressure/high-temperature (HPHT) water-gas reservoirs, an organic-inorganic composite scale inhibitor (CT-5) was successfully synthesized via solution polymerization-mediated in situ intercalation using acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and diallyldimethylammonium chloride (DMDAAC) as monomers, with surface-modified montmorillonite (MMT) as reactive filler. Orthogonal optimization established ideal synthesis parameters, which including a reaction temperature of 75 °C, an initiator dosage of 0.6%, a solution pH of 7, a reaction time of 12 h, and a monomer ratio of m (AMPS): m (AA): m (DMDAAC): m (MMT) = 48:25:23:4. Moreover, the molecular structure and thermal stability of CT-5 were characterized by FTIR, XRD, and TG-DTG, as a result, the polymer intercalated MMT was successful, and CT-5 had a composite intercalation structure of organic polymer/inorganic montmorillonite, with a thermal decomposition temperature of 235.24 °C. Salt tolerance evaluation demonstrated robust performance under saline conditions. The scale inhibition mechanism of CT-5 was explored through scale inhibition rate testing, interlayer spacing testing at different temperatures, characterization of CaCO scale crystal structure and morphology, and chemical binding energy testing of CaCO scale crystals. The CT-5 can release effective chelating groups in the intercalation layer at high temperature, which inhibits the formation of CaCO scale by chelating Ca to form chelates, and also forms an adsorption layer on the surface of CaCO scale crystals to interfere with the normal growth of CaCO scale crystals and change the lattice structure of CaCO scale crystals, thereby achieving the scale inhibition effect.
在本研究中，基于高压/高温（HPHT）水气藏对热稳定防垢剂不断增长的需求，以丙烯酸（AA）、2-丙烯酰胺基-2-甲基丙烷磺酸（AMPS）和二烯丙基二甲基氯化铵（DMDAAC）为单体，采用溶液聚合介导的原位插层法，成功合成了一种有机-无机复合防垢剂（CT-5），并以表面改性蒙脱土（MMT）作为反应性填料。通过正交优化确定了理想的合成参数，包括反应温度75℃、引发剂用量0.6%、溶液pH值7、反应时间12h以及单体配比m（AMPS）：m（AA）：m（DMDAAC）：m（MMT）=48:25:23:4。此外，通过傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）和热重-微商热重（TG-DTG）对CT-5的分子结构和热稳定性进行了表征，结果表明聚合物插层MMT成功，CT-5具有有机聚合物/无机蒙脱土的复合插层结构，热分解温度为235.24℃。耐盐性评价表明其在盐水条件下具有良好性能。通过防垢率测试、不同温度下的层间距测试、碳酸钙垢晶体结构和形貌表征以及碳酸钙垢晶体的化学结合能测试，探索了CT-5的防垢机理。CT-5在高温下可在插层层中释放有效的螯合基团，通过螯合钙离子形成螯合物来抑制碳酸钙垢的形成，还可在碳酸钙垢晶体表面形成吸附层，干扰碳酸钙垢晶体的正常生长并改变碳酸钙垢晶体的晶格结构，从而实现防垢效果。
