单56块蒸汽驱热敏凝胶调驱影响因素分析

注蒸汽热力采油是开采稠油油藏的主要技术手段,但由于长期的热力作用和地层本身的非均质性,蒸汽吞吐或蒸汽驱过程中极易发生汽窜,严重影响开采效果。热敏凝胶的黏度随着温度的升高而增高,在一定范围内可逆变化,正适于注蒸汽开采油藏的深度调驱。以单56块先导试验区的地层性质数据建立地质模型,分析了热敏凝胶的调驱机理;根据数模结果研究了纵向窜流、有效厚度等地质参数以及操作参数对开采效果的影响。数值模拟结果表明:纵向渗透率、净毛比、初始含油饱和度、埋深等均在一定程度上影响采收率和深部调驱效果;考虑到经济因素,热敏凝胶调堵注入孔隙体积倍数可取0.1 PV;热敏凝胶注入时机越晚,开发效果越差,而当吞吐+汽驱的总采出程度超过30%以后,开发效果大幅降低,因此当吞吐与汽驱的总采出程度低于30%前实施注热敏凝胶调驱开发效果较好。

Analysis of Factors Affecting Gel Displacement Control in Steam Flooding Based on Shan 56

Steam injection is an essential method in exploiting heavy oil reservoir. Because of the thermal effects in a long time and high heterogeneity in the stratum itself, steam channeling always happens, which affects production seriously in the steam stimulation and steam flooding process. The viscosity of heat sensitive gel increases with the temperature and then changes reversibly within a certain range, which is suitable for depth displacing adjustment in steam injection .Based on the geological data in pilot area of Shan 56, a geological model was established. Mechanism of displacing control was analyzed; meanwhile the effect of geological parameters such as vertical channeling, net thickness and operating parameters on production was studied according to simulation results. The numerical simulation results are as follows: Parameters such as vertical permeability,net-to-gross, initial oil saturation and depth will certainly affect recovery and displacing. Taking economy into account, 0.1PV gel injection is chosen. The later gel is injected, the worse the development results. After the total recovery displaced by stimulation and gas flooding reaches 30%, the development effect is reduced significantly, therefore. Only before recovery reaches 30%, the gel injection is more effective.