水平裂缝-蒸汽辅助重力泄油物理模拟试验研究

通过自行研制的三维高压模型本体 ,利用原有蒸汽驱三维物理模拟试验系统 ,进行了超稠油油藏的水平裂缝蒸汽辅助重力泄油 (FSAGD)室内物理模拟试验。试验表明 ,FSAGD具有和水平井蒸汽重力泄油 (SAGD)相类似的渗流及传热机理。与常规蒸汽驱和SAGD相比 ,FSAGD可以明显提高蒸汽波及系数和最终采收率。根据试验结果可将FSAGD过程分为 3个阶段 :预热阶段、稳定泄油阶段和降压开采阶段。为实现稳定泄油 ,应保证一定的注汽速度和较高的注汽干度。对射孔、蒸汽附加氮气、储层纵向非均质性等因素对FSAGD开采效果的影响进行了模拟试验。结果表明 ,生产井适当补孔和蒸汽附加氮气均有助于提高采油速度和累积油汽比 ,但不能提高原油最终采收率 ;5倍级差以内的储层纵向非均质性对蒸汽波及系数和最终采收率影响不大

Simulation experiment on horizontal fracture-steam assisted gravity drainage

The self designed three dimensional high pressure scaled model and the former 3 D physical experimental system for steam flooding was used to simulate the horizontal fracture steam assisted gravity drainage (FSAGD) in super heavy oil reservoir. The experimental result shows that FSAGD has very similar flow and heat exchange mechanism to the steam assisted gravity drainage (SAGD) in two horizontal wells. Compared with the general steam flooding and SAGD process, FSAGD can obviously enhance the volumetric sweep efficiency of steam and the ultimate oil recovery efficiency. FSAGD process can be divided into three stages of pre heat, steady drainage and pressure declined production. For maintaining steady drainage, certain high quality steam and adequate steam injection rate are required. Both reperforation in production wells and simultaneously adding nitrogen with steam injection in the FSAGD process can increase drainage speed and cumulative oil steam ratio, but hardly increase the cumulative oil recovery. Relatively slight vertical heterogeneous formation has little influence on steam zone and oil recovery.