特超稠油油藏蒸汽吞吐筛选标准的探讨

Discussion on Screening Conditions for Steam Huff and Puff in Super Heavy Oil Reservoirs

蒸汽吞吐是目前开采稠油油藏最主要的技术,但对原油粘度远大于5×104mPa·s的特超稠油油藏仍存在着筛选条件不明确的问题。根据目前油价,基于投入与产出平衡原理,研究确定了单井周期极限油汽比、单井极限产油量等经济指标。在此基础上,应用数值模拟技术,对特超稠油油藏吞吐的筛选标准进行了探讨,确定了油藏条件下原油粘度不超过50×104mPa·s,油层有效厚度大于8.5m,净总厚比大于0.4,含油饱和度大于50%,孔隙度大于20%,渗透率大于500×10-3μm2,最佳的垂向与水平渗透率比值为0.1～0.5.该筛选条件的确定对特超稠油油藏蒸汽吞吐开采具有重要的指导意义。

Steam huff and puff is the major technology for the development of heavy oil reservoirs now. But for the super heavy oil reservoirs whose oil viscosity is far larger than 5×10^4 mPa· s, the screening conditions are still unclear. According to the present oil price, the periodic ultimate oil-steam ratio of single well, the ultimate oil production of single well and other economic indices are studied based on input and output balance principle. Then screening criteria for steam huff and puff are discussed by simulation. The simulation results show that the super heavy oil reservoir is suitable for steam huff and puff when the oil viscosity is less than 50×10^4 mPa.s, the effective thickness is lager than 8.5 m, the net-gross thickness ratio is larger than 0.4, oil saturation is lager than 50%, porosity is larger than 20%, permeability is larger than 500×10^-3μm2, and the Kv/Kh ranges from 0.1 to 0.5. The determination of these screening conditions will be an important guiding significance for steam huff and puff in super heavy oil reservoirs.