致密油充注过程中储层润湿性变化对含油性影响——以川中侏罗系致密油为例

Influence of reservoir wettability changes on oil-bearing features during tight oil accumulation: A case study of Jurassic tight oils in Sichuan Basin

公言杰 柳少波 刘可禹 姜林 袁选俊 陶士振

Gong Yanjie Liu Shaobo Liu Keyu Jiang Lin Yuan Xuanjun Tao Shizhen

中国石油 勘探开发研究院, 北京 100083 2. 提高石油采收率国家重点实验室, 北京 100083 3. CSIRO Earth Science and Resource Engineering, Perth WA 6000, Australia

Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China 2. State Key Laboratory of Oil Recovery, Beijing 100083, China 3. CSIRO Earth Science and Resource Engineering, Perth, WA 6000, Australia

以四川盆地川中侏罗系致密油储层岩心样品为例,开展了致密油微观充注物理模拟实验。实验模型采用砂岩薄片模型(尺寸为2.5 cm×2.5 cm,厚度约0.6 mm),将实验用油注入模型引槽中,压力由小到大逐步增加至每个模型出口端只出油不出水为止,观测渗流特征并计算含油饱和度。实验结果显示,充注前样品束缚水饱和度与充注后含油饱和度总和大于100%,基于核磁共振法对储层束缚水等流体饱和度与储层润湿性的分析,提出了充注前后储层润湿性的改变(水润湿转变为油润湿)使得最终含油饱和度高于被驱替的动水饱和度。致密油运聚过程中储层润湿性改变抵消了致密油储层高束缚水饱和度对致密油含油性的抑制作用,利于致密油运聚,是致密油成藏含油饱和度提高的重要原因。

A physical simulation of tight oil microcosmic filling was carried out with core samples from the Jurassic tight oil reservoirs in the central Sichuan Basin. A sandstone thin section model (2.5 cm×2.5 cm×0.6 mm) was adopted. Oil for the experiment was filled through a chute, and the pressure gradually increased until oil instead of water flowed out of each outlet end. Percolation characteristics were observed and oil saturation was calculated. Experiment results showed that the sum of irreducible water saturation before filling plus oil saturation after filling was more than 100%. Reservoir wettability changed from water wet to oil wet after filling, so the final oil saturation degree is higher than the displaced moveable water saturation according to magnetic resonance analyses. The change of reservoir wettability during tight oil migration and accumulation counteracted the inhibition function of irreducible water saturation of a tight oil reservoir on the saturation of tight oil, and was favorable for tight oil migration and accumulation, which explained the high oil saturation of tight oil reservoirs.

国家重点基础研究发展计划"973计划"项目(2014CB239000)、国家科技重大专项(2011ZX05001)和中国石油天然气股份有限公司科学研究与技术开发项目(11.2011A-02.x.01)资助。

https://doi.org/10.11781/sysydz201504423