致密油气窜波及控制体系适用性评价

Applicability Evaluation of Tight Oil Reservoir Gas Channeling and Sweep Control System

我国致密油藏分布广泛,储量占比大,开发潜力巨大。此类油藏目前注气开发较多,基质渗透率、孔隙度均较低,油气流动通道主要为裂缝。但油藏裂缝跨尺度发育,受储层非均质性和黏性指进的影响,注气提高采收率技术受限,在裂缝及高渗条带存在时易形成气窜,对地层能量补充带来了诸多问题。选择泡沫和CO_(2)响应性凝胶配制气窜波及控制体系,并通过物理实验模拟评价其性能和在致密油藏的适用性;利用商业数值模拟软件表征CO_(2)注气吞吐及地下成胶反应。经过对国内某致密油藏的数值模拟研究,证明CO_(2)响应性凝胶对注气吞吐有明显的增产效果,采收率增加3.1%,验证了CO_(2)响应性凝胶体系在致密油藏开发中具有良好的应用前景。

Tight oil reservoirs are widely distributed in China,with a large proportion of reserves and great development potential.These reservoirs have low matrix permeability and porosity,with fractures acting as main oil and gas flow channels,and gas injection is often used to recover such reservoirs.However,due to the cross-scale development of reservoir fractures and the influence of reservoir heterogeneity and viscous fingering,the technology of gas injection to improve oil recovery has limits.Gas channeling can easily occur in the presence of fractures and high permeability bands,causing many issues related to the energy supplement of formation.In this pa-per,foam and CO_(2)-responsive gel were selected to prepare the gas channeling and sweep control system,and their performance and ap-plicability in tight oil reservoirs were evaluated by physical experiment simulation.Commercial numerical simulation software was used to characterize CO_(2) huff-n-puff and underground gelling reaction.Through the numerical simulation of a tight oil reservoir in China,it is proved that the CO_(2)-responsive gel has an obvious stimulation effect during huff-n-puff treatment,resulting in an increase in recov-ery rate by 3.1%.This research validates the promising application prospects of the CO_(2)-responsive gel system in the development of tight oil reservoirs.