摘要
水锁损害广泛存在于低渗透致密砂岩油气藏,是低渗透致密砂岩油气藏的主要损害类型之一,这严重地影响着油气藏的勘探开发效果。文章在改进现有水锁损害室内评价方法的基础上,以川西致密砂岩气藏为研究对象,采用模拟地层水对致密砂岩气藏由于自吸作用造成的水锁损害,以及作用压力对水锁损害的影响进行了实验研究。结果表明,与水敏损害不同,即使是采用与地层配伍的模拟地层水与岩心接触,水锁损害仍然存在,且水锁损害程度可以超过80%。对于低渗透气藏,即使不存在压差,或采用负压作业,只要作业流体中包含有水相,那么在自吸作用下,水溶液都将进入地层,造成水锁损害,且损害程度随接触时间及作用压力增加而增加。因此,对低渗透致密砂岩油气藏应尽可能采用负压作业,尽可能减少与水相作业流体接触的机会。
Water locking damage happens widely in tight sand gas reservoirs with low permeability, and is one of the main damage types for tight sand gas reservoirs with low permeability, which influences the results of oil/gas reservoir exploration and exploitation severely. Based on the improvement of the existing in-house evaluation method for water locking damage, taking the west Sichuan tight sand gas reservoirs as the research object, it is investigated the water locking damage caused by self-sucking action of tight sand gas reservoirs when simulating the formation water effecting to the reservoirs, and the influence of the effecting pressure on the water locking damage. The results show differing from the water sensitivity, the water locking damage still exists even when the core contact the simulating formation water that is compatible with the formation. And the scale of the damage can reach 80% and more. For low-permeable gas reservoirs, the water locking damage will happen even without pressure difference or with operating under balance because the water solution will enter the reservoir under the self-sucking action and cause water locking damage only if water phase exists in the operating fluid. The damage level will increase as the contacting time and the effecting pressure increase. So, it is better to do operation under balance and reduce the chance to contact the operating fluid with water phase as much as possible for tight sand gas reservoirs with low permeability.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2005年第4期125-127,共3页
Natural Gas Industry
