关键词: 海相碳酸盐岩, 油气特征, 主控因素, 四川叠合盆地

Abstract:

The heavy oil reservoir of the first member of Shahejie Formation in Jinjia Oilfield has strong water sensitivity. In the process of steam stimulation, minerals are easy to change at high temperatures, which makes pore structure change and affects reservoir physical properties. In order to understand the characteristics of mineral changes and their effects on reservoir physical properties, an autoclave physics simulation was conducted. Experiment results show that the changes of minerals in the reservoir at high temperatures were reflected in the following three aspects：the expansion caused by the changes of crystal spacing of montmorillonite, mineral dissolution and transformation, as well as dissolved pores. From 200 ℃ to 300 ℃, the expansion of montmorillonite weakened and was gradually near to disappear, and the dissolution further strengthened, which makes the pores large and medium, and then reservoir connectivity and physical properties further changed better. In the steam stimulation process of strong water sensitivity heavy oil reservoirs, it need to ensure the temperature and dryness of injecting steam to make the reservoir temperature higher than 200 ℃ , so as to reduce reservoir water sensitivity, and improve reservoir physical properties and enhance development effect.

Key words: marine carbonate, hydrocarbon features, controlling factors, Sichuan superimposed basin