Method for blocking severely polluted deep well sandstone reservoir

Abstract

The invention discloses a method for blocking a severely polluted deep well sandstone reservoir and belongs to the technical field of oil field blocking. For the severely polluted deep well sandstone reservoir to be blocked, pollution of the immediate wellbore vicinity of the sandstone reservoir is removed firstly; then cement squeezing blocking is carried out on the well section with pollution removed through a packer cement squeezing method; the pollution of the immediate wellbore vicinity of the sandstone reservoir is removed through small acidification; high energy composite perforation is carried out on the sandstone reservoir, and the pollution of the immediate wellbore vicinity of the sandstone reservoir is removed. The method breaks through a conventional blocking thought, pollution of the sandstone reservoir to be blocked is removed firstly, permeability of the reservoir is improved, and then the reservoir is blocked. The blocking success rate is improved, and the period of blocking validity is prolonged. A reference is provided for similar well blocking construction in future.

Description

technical field [0001] The invention relates to a plugging method for heavily polluted deep well sandstone reservoirs, and belongs to the technical field of oil well plugging. Background technique [0002] Oil and gas well plugging is divided into mechanical plugging and chemical plugging. The purpose of plugging is to separate a certain oil and gas layer in the oil and gas well from other oil and gas layers, so as to prevent the oil and gas from the production layer from entering the depleted oil and gas layer. Prevent the brine in the water outlet layer from entering the production layer. Old oil wells are frequently operated, and the killing fluid pollutes sandstone reservoirs. During the frequent operation of oil wells, the reservoir is polluted due to various reasons. In the operation of plugging deeply polluted sandstone reservoirs, the common problems are as follows: 1) When the well fluid is squeezed before plugging, the formation sucks poorly or even does not suck...

AI Technical Summary

Problems solved by technology

4) The plugging period is long and the plugging period is short

5) The cement slurry system cannot meet the plugging requirements of polluted sandstone reservoirs

However, the above two high-pressure cement extrusion methods still cannot solve the problems encountered in plugging polluted sandstone reservoirs, such as short plugging validity period, less formation cement slurry suction, poor test extrusion effect, multiple plugging constructions and long operation period.