一种新型含沥青质储层解堵液体系的研究——以四川盆地龙女寺龙王庙储层为例

Study on a new plugging removal fluid system for asphaltene reservoir:Taking Longwangmiao reservoir of Longnusi in Sichuan Basin as an example

四川盆地龙女寺龙王庙储层沥青充填较为普遍,储层的渗流能力与品质相当但沥青质充填程度相对较低的储层相比,该类储层测试产量明显偏低。常规碳酸盐岩储层的酸化改造一般以胶凝酸酸液体系为主,然而室内试验表明,常规酸液对沥青质溶解分散性差,酸化解堵效果不理想。基于相似相溶原理以及表面活性剂增溶原理,优选设计了一种以醚为主体,辅以溶剂油、两性表面活性剂和稳定剂的沥青溶解分散剂,并以胶凝酸为基础,结合储层特点优化配方,开发了一种适用于含沥青质储层的解堵液体系。该体系在高温下性能稳定,150℃下剪切100min后黏度超过15mPa·s,150℃动态腐蚀速率小于70g/(m^(2)·h),耐温耐剪切性能好,达到了含沥青质储层的酸压施工工艺要求。含沥青质储层岩心流动试验结果表明,该体系对岩心渗透率改善倍数达到4~6倍,相比常规胶凝酸,对含沥青质储层岩心渗透率改善效果更为显著。

Asphalt filling is common in Longwangmiao reservoir of Longnusi in Sichuan Basin,and the seepage capacity of the reservoir is weak.Compared with the reservoirs with similar quality but relatively low asphaltene filling degree in this area,the test production of this kind of reservoir is obviously lower.The acidizing transformation of conventional carbonate reservoir is generally based on gelled acid system.However,the laboratory tests show that the dissolution and dispersion of asphaltene by conventional acid is poor,and the effect of acidizing and plugging removal is not ideal.Based on the similar phase solubility principle and the solubilization principle of surfactant,a kind of asphalt dissolution dispersant with ether as the main body,supplemented by solvent oil,amphoteric surfactant and stabilizer was optimally designed.Based on gelling acid and combined with reservoir characteristics,the formula was optimized to develop a kind of plugging fluid system suitable for asphaltene reservoir.The system has stable performance at high temperature,the viscosity is≥15mPa·s after shearing for 100min at 150℃,and the dynamic corrosion rate is less than 70g/(m^(2)·h)at 150℃.The system also has good temperature and shear resistance and meets the requirements of the acid fracturing construction technology for asphaltene reservoir.The core flow test results of asphaltene reservoir show that the core permeability of the system is increased by 4~6 times,and the improvement effect on core permeability of asphaltene reservoirs is more obvious than that of conventional gelling acid.