稠油蒸汽驱过程中储集层伤害模式分析——以辽河盆地西部凹陷齐40区块为例

Research on Reservoir Damage Model during the Heavy Oil Steam Flooding——An Example from Qi40 Block in Western Sags,Liaohe Basin

蒸汽注采过程中的储集层伤害是导致稠油开发后期产量下降的重要因素之一,其伤害机理与伤害模式一直是油藏开发过程中的研究难点。以辽河油田齐40区块莲花油层为例,采用物理模拟实验的方法,分析了蒸汽驱过程中储集层的伤害机理,建立了研究区块蒸汽驱过程中储集层伤害模式。研究结果表明,高温强碱性蒸汽注入后,高温溶蚀区中的矿物溶解量增加,储集层物性明显变好;而中温低溶膨胀区至低温膨胀区中,蒸汽对储集层物性逐渐转为破坏作用,岩石颗粒的溶解量降低,生成的钠基蒙脱石等黏土矿物发生水化膨胀并堵塞孔隙喉道,致使储集层受到伤害。

The reservoir damage during steam-injection process is one of the important factors that lead to the decline of production in the late stage of heavy oil thermal recovery, and its damage mechanism and damage model have been difficult problem during the development of oil reservoir. Taking the Lianhua reservoir of Qi40 block in Liaohe oilfield as an example, damage mechanism of the heavy oil reservoir during the steam-injection process was analyzed by using physical simulation experiment, and established the damage model of Qi40 block during the steam flooding. The results show that when high temperature and strong alkaline steam injects, the dissolution of minerals increases, and reservoir properties are significantly better in dissolved region of high temperature. Where-as ,in dissolved and expansive region of middle temperature and expansive area of low temperature, steam gradually transforms into katogene, and the dissolution of mineral gradually decreases. At this time, the pore throat fills with the expansive clay such as sodium montmorillonite. Ultimately, the reservoir is subject to severe damage.