Cyclic Water-flooding Technique Research On Sub-sea Distributary Channel Sands

Basic well pattern in Sanan developing area has been in the ultra-high water-cut period after many years developments, on the bases of applying numerical simulation technique and refined geologic research results, this paper discusses a cyclic water-flooding technique on Basic well pattern, optimizes the cyclic parameters, designs and establishes a concrete cyclic water-flooding plan by applying cyclic water-flooding experiments in this pattern. This paper achieves the purposes of further tapping the potentials of remaining oil, controlling the water-cut ascending velocity, reducing the low-efficiency water flood cycling, slowing down the production declining, and improving the basic pattern developing effects. Also the experiences and acknowledges gaining in this experiment have effects on nearby area.We have acquired these achievements through the research:1,By using the plan of cyclic water-flooding on line well pattern of southern 6-8 area, developing effect has been improved, product of basic well pattern has been improved, product declining and water-cut ascending velocity have been effectively slowed down. It provides an economical and effective way for remaining oil potential tapping of thick oil layer of line well pattern in extra high water-cut stage.2,To achieve the best effect of cyclic water-flooding,we should base on different tectonic specialty,deposition characteristic and distribution way of different area,should compositely use numerical simulation,refine geological researching accomplishment,combine dynamic changing law,choose and assemble parameters like the best way of cyclic water flooding,half cycle and water flooding intensity and so on to carry out cyclic water flooding development.3,As the numerical simulation technique used now confuses in-layer heterogeneity longitudinally,it's difficult to reflect the effect of cyclic water flooding development.We can correct the model equally according to historical dynamic changing law of the area,so that numerical simulation can be applied effectively to the optimizing of cyclic water flooding.4,The additional channeling caused by cyclic water flooding can adjust in-layer and interlayer contradiction,make the in-layer flooded degree more even,and can increase area recovery efficiency by 0.2 to 0.5 percent.But it's capability of improving well pattern developing effect is not persistent,it reduces as time goes by.According to the forecast of numerical simulation, the period of line well pattern cyclic water-flooding should be about 3 years.