Evaluation of EOR potential of energized fluid fracturing – From an energy perspective
蓄能流体压裂利用了流体的高压缩性及其与地层的配伍性。压裂后，流体中储存的能量有助于促进返排，并将油气驱出。一些论文和专利提出了相关想法，现场试验很少。一些论文预测，CO2压裂扩大了裂缝缝网提高了原油采收率（EOR）。但文献中并没有从能量角度给出提高采收率潜力的量化分析。
本文分析了CO2压裂的现场试验，并探讨了提高采收率的潜力。采用现场测试数据拟合数值模拟模型并用于定量分析提高采收率潜力。据分析，蓄能压裂用CO2的注入量非常有限，因此提高采收率的潜力并不大。这种CO2压裂过程类似于压裂后为提高采收率而进行的一次CO2吞吐注入。
ABSTRACT
Energized fluid fracturing utilizes the high compressibility of fluids and their compatibility with the formation. After the fracturing, the energy stored in these fluids helps to facilitate flow back and to drive oil and gas out. Some papers and patents propose the ideas but with few field tests. Some papers predict the enhanced oil recovery (EOR) potential assuming a fracture network is enhanced from CO2 fracturing. No quantitative analysis has been performed to analyze the EOR potential from an energy perspective in the literature.
In this paper, a field test of CO2 fracturing was analyzed to discuss the EOR potential. The test data are used to calibrate a simulation model to quantitatively analyze the potential to improve or enhance oil recovery. The EOR potential of energized fracturing fluids is discussed. It is observed that the volume from the CO2 injection for fracturing is very limited so that the potential to enhance oil recovery is not significant. Such CO2 fracturing process is analog to one cycle of huff-n-puff CO2 injection for the EOR purpose after fracturing. 