超临界二氧化碳和水交替注入井储层内流体的吸附特征研究

Adsorption Characteristics of Fluid in the Reservoir of Wells Injected Alternately by Supercritical Carbon Dioxide and Water

白玉杰 蔚浩东 南晓函

BAI Yujie WEI Haodong NAN Xiaohan

东北石油大学提高油气采收率教育部重点实验室, 黑龙江 大庆 163318

MOE Key Laboratory for Oil and Gas Recovery Improvement, Northeast Petroleum University, Daqing, Heilongjiang 163318, China

为了研究水和二氧化碳交替驱地层内不同流体的竞争吸附特征，分析了储层岩石的微观结构及矿物成分，建立了地层岩石结构的分子模型，研究不同黏土矿物对流体吸附特征，分析了不同流体在岩石表面的竞争吸附及影响因素。结果表明，大庆榆树林油田的致密岩石主要由二氧化硅基质以及高岭石和蒙脱石等黏土矿物构成；储层矿物对轻烃的吸附能力大于对重烃类的吸附能力，对水和二氧化碳的吸附能力大于对烃类的吸附能力；二氧化硅对水和二氧化碳的吸附能力最强，说明采用超临界二氧化碳和水交替注入驱，以二氧化硅为主的储层采收率更高。采用水和二氧化碳交替驱替采收率更高，间歇性地停止注入可以使二氧化碳更容易进入到岩石样品当中，使原油更容易排出；较高的温度会加速原油、水和二氧化碳分子的物质交换，高压下二氧化碳会与岩石表面的原油作用改变原油性质，进而提高除油率。

In order to study the adsorption characteristics of fluid in the reservoir of wells injected alternately by supercritical carbon dioxide and water, the microstructure and mineral composition of reservoir rocks were analyzed. The molecular model of stratum rock structure was established to study the fluid adsorption characteristics of different clay minerals, and the competitive adsorption and influencing factors of different fluids on the rock surface were analyzed. The results showed that the compact rocks of Yushulin oil layer in Daqing Oilfield are composed of silica matrix and clay minerals such as kaolinite and montmorillonite. The adsorption capacity of reservoir minerals for light hydrocarbons was greater than that for heavy hydrocarbons, and adsorption capacity for water and carbon dioxide was greater than that for hydrocarbons. Silicon dioxide had the strongest adsorption capacity for water and carbon dioxide, indicating that the oil recovery of the reservoir dominated by silicon dioxide was higher by using alternate injection flooding of supercritical carbon dioxide and water. Intermittent stop injection could make carbon dioxide easier to enter into rock samples and make crude oil easier to discharge. The higher temperatures accelerate the exchange of crude oil, water and carbon dioxide molecules. Under high pressure, carbon dioxide reacts with crude oil on the rock surface to change the properties of crude oil, thereby increasing the oil removal rate.

10.11885/j.issn.1674-5086.2022.06.21.02