腰英台特低渗透油藏C02驱油井见气规律研究

机理研究和国外矿场实践表明，C02驱油可以大幅度提高低渗透油藏的采收率。在腰英台油田进行7注30采的CO2驱油试验，注气1a后，16口油井不同程度见气。针对试验区低孔、特低渗透、储层非均质性强、油水关系复杂的地质特征，结合油井见气前、CO2前缘突破到井口、气量稳定与上升、接近气窜前后和严重气窜等阶段的生产动态特征，系统分析了CO2驱油井的见气规律。研究认为裂缝发育方向上的油井优先见气，快速气窜；沉积微相是控制C02平面运移方向与速度的主要因素；同一沉积微相上，储层物性好的高渗带是C02黏性指进的重要影响因素。另外，紧密跟踪动态，建立腰英台地区油井的气窜标准，剖析了不同见气阶段生产特征的内在原因，给出气窜井与气窜井组的监测生产建议。

Law of gas breakthrough on C02 flooding well in ultra-lower permeability reservoir of Yao Yingtai Oilfield

Mechanism research and foreign oilfield practice indicate that CO2 flooding can greatly improve the recovery of low permeability reservoir. Sixteen oil wells of CO2 flooding test area have shown the gas breakthrough to different extents after one year of gas injection with seven water injection wells and thirty oil production wells in Yaoyingtai Oilfield. Aiming at the geological features of low porosity and ultra-low permeability, strong reservoir heterogeneity, complex oil-water relation, combined with production performances of before gas breakthrough of oil well, breakthrough of CO2 front to well head, stability and rising of gas production rate, before and after gas breakthrough and at the different stages of serious gas breakthrough, gas breakthrough law of CO2 flooding well is analyzed. It is believed that the oil in the direction of fracture development shows the gas breakthrough and rapid gas channeling preferentially. Sedimentary microfacies are the main factors of controlling the CO2 plane migration direction and speed. The high permeability zone with good reservoir property is the important influential factor of viscous fingering in same sedimentary microfacies. The gas breakthrough standard of oil well of Yaoyingtai Oilfield is set up through tracing the production performance. Inherent reasons of production performance at different gas breakthrough stages are analyzed, and monitoring production proposal of gas breakthrough well and gas breakthrough well groups are given.