ABSTRACT

Hua chi block is the southeast broken nose structure, located at the southern tip of the western slope in the western sag of Chang qing oilfield. For a set of sand shale interbed reservoir sedimentation and sedimentary types of alluvial fan, provenance from the south, change of sand body, eastern with western thick thin, the characteristics of the south north of thick thin. From the analysis of fluid distribution and reservoir occurrence as in thick layered edge water reservoirs, district a total of 180 oil wells, comprehensive water cut oil 24.5 × 104 t tired, recovery degree 10.8%, oil recovery rate 1.5%, at present formation pressure is 3.1 MPa. [1-3]

1.1 Reservoir petrology characteristics

Affected by the formation reservoir sedimentary types, reservoir sand body changes greatly. Sand body flat bout point for the south to north thick thin, thick thin east west. Reservoir lithology is mainly for red conglomeratic sandstone and conglomeratic anisometric sandstone, ranging from sand rock, siltstone, etc, which mainly contains gravel anisometric sandstone, reservoir rock grain sorting poor. Rock particles coarser, the median size is about 0.32 mm. Core analysis data, the reservoir porosity of 11.2%∼22.4%. Average porosity was 14.2%, the permeability

2 THE RESERVOIR SENSITIVITY EXPERIMENTS

2.1 Water sensitivity evaluation experiments

Experimental data shows that hua chi block reservoir of strong water sensitive reservoir, index from 0.7 to 0.9, the total reservoir clay mineral is 67.9%, mostly expansive, the effect of montmorillonite mineral with the loss of the experimental fluid salinity, core permeability is decreased. The higher the fluid salinity of reservoir permeability damage.

2.2 Alkali sensitivity evaluation experiments