珠江口盆地古近系低渗透储层具有孔隙度低、孔隙结构复杂、喉道细小等特点,探井钻杆测试(DST)测试产能低.对比分析模块式地层动态测试器(MDT)取样分析结果及关井压力恢复资料,发现储层在测试前浸泡时间长,产生较为严重的水锁效应.剖析低渗透储层产生水锁效应的机理,推导出泥浆滤液侵入储层深度的公式,结果表明泥浆滤液侵入储层深度与浸泡时间呈正相关关系,针对区域深层低渗透油藏因水锁效应而导致的风险,提出措施建议.
The low-permeability reservoir of the Paleogene Wenchang Formation in Nanhai East has the characteristics of low porosity,low permeability,complex pore structure,developed secondary pores,small throats,and high capillary pressure,and the DST test productivity of exploration wells is low.By comparing and analyzing the MDT sampling analysis results and shut-in pressure recovery data,it was found that the reservoir was soaked for a long time before testing,resulting in serious water locking effect.On this basis,the mechanism of water locking effect in low-permeability reservoirs was analyzed,and the formula for the invasion depth of mud filtrate into the reservoir was derived.The results showed that the depth of mud filtrate intrusion into the reservoir was positively correlated with the soaking time,and for the risks caused by water locking effect in deep low-permeability oil reservoirs in Nanhai East,corresponding technical countermeasures have been proposed.