基于数值模拟的致密油油藏注气开发技术研究

致密油将是缓解我国能源紧缺局面的重要非常规资源,美国利用注气开发致密油已取得显著进展,因此我国开展致密油注气开发研究是十分必要的。利用数值模拟技术,评价不同注气方式对致密油油藏开发效果的影响,从提高采出程度、压力保持水平以及气窜等角度分析了不同混相程度、不同井型及不同注入方式对致密油油藏生产的影响。研究结果表明,近混相和混相注气都能高效开发致密油,以0.5%PV注气量生产20年后,混相和近混相注气下的采出程度能在衰竭式开发基础上提高9.56%以上;在近混相下,水平井注气比直井注气更能提高波及系数和采出程度,循环注气能有效减缓气窜的发生。因此,采取水平井近混相循环注气将是高效开发致密油藏的重要技术。

A Simulation Research on Evaluation of Development in Tight Oil Reservoirs by Near-Miscible Gas Injection

Tight oil can be one key resource to relive the energy shortage in the future. Although the tight oil is abundant in China, the relevant research is still in the preparatory stage. The development of tight oil in America has achieved remarkable success by gas injection. Therefore, it is necessary to study the mechanics of gas injection in tight oil reservoirs. This paper evaluates the development efficiency of gas injection in tight oil reservoirs by simulation. The results show that both near-miscible and miscible injection can develop tight oil effectively. After 20 years, the recovery percentage can improve 9.56% on the basis of depletion development in the condition of near-miscible and miscible injection on the speed of 0.5%PV gas injection. Horizontal well injection is better than vertical well injection with respect of sweep efficiency and recovery. Cyclic gas injection is superior to continuous gas injection, for the former can relieve gas channeling. Consequently, the method of horizontal well, miscible, cyclic gas injection can be a potential way to develop tight oil reservoirs effectively.