Loose sand oil accumulation replacement sand prevention method

Abstract

The invention provides a sand control technology for loose sandstone. Before sand control, by foam huff and negative-pressure mixed arrangement, the foam is used to discharge reservoir sand and clay particle fully, which are distributed unevenly near borehole zone; than high-pressure gravel is filled to sand control, even gravels are filled in the deficit stratum near borehole to improve the seepage behavior near borehole zone. The invention changes the seepage behavior of uneven stratum near borehole zone in basic, improves the well production rate, reduces the plugging near borehole zone by solid particles such as fine-silt sand, clay particle and so on in effect, and prolongs the valid period of sand control.

Description

Technical field: [0001] The invention relates to an oil reservoir sand control technology. Background technique: [0002] In the development process of unconsolidated sandstone reservoirs, sand control is generally required to ensure the normal production of oil wells. Commonly used sand control technologies mainly include gravel packing sand control with wire screen, sand control with fracturing, sand control with sand filter tube and chemical sand control. These sand control methods have their advantages, disadvantages and applicability, but for oil layers with high content of fine silt and clay, the above sand control methods all have the problem of serious plugging near the wellbore, that is, during the production process of the oil well, some Fine silt and clay particles will migrate to the vicinity of the wellbore with the produced fluid, causing blockage, resulting in a decrease in permeability near the wellbore, a decline in oil well production, and a shortened effe...

AI Technical Summary

Problems solved by technology

These sand control methods have their advantages, disadvantages and applicability, but for oil layers with high content of fine silt and clay, the above sand control methods all have the problem of serious plugging near the wellbore, that is, during the production process of the oil well, some Fine silt and clay particles will migrate to the vicinity of the wellbore with the produced fluid, causing blockage, resulting in a decrease in permeability near the wellbore, a decrease in oil well production, and a shortened sand control period

[0003] The root cause of this problem is that the formation sand is not uniformly sorted, the particle size is different, and it contains a large amount of fine silt and clay. In this way, during the production process of the oil well, the fine silt and clay will fill the formation pores. Reduce formation permeability

In the near-wellbore area, due to the fast flow of formation fluid, the migration and accumulation of solid particles such as fine silt and clay are relatively fast, and the colloid and asphaltenes in crude oil are also easy to precipitate and precipitate on the surface of these fine solid particles. Exacerbate the blockage near the wellbore, resulting in a decrease in the permeability near the wellbore, a decrease in oil well production and a shortened effective period of sand control