Water plugging agent and preparation method thereof

Abstract

The invention relates to a water plugging agent, containing 66 to 70 parts of slag powder, 3 to 7 parts of kaolin, 3 to 7 parts of calcium oxide, 8 to 12 parts of calcium carbonate superfine powder, 6 to 10 parts of calcium silicate, 1 to 3 parts of sodium silicate, 0.5 to 1.5 parts of polyanionic cellulose and 0.5 to 2 parts of short linter; when the plugging agent is extruded to a target layer,the plugging agent is changed from a suspension state which is easily mobile to an uncured viscous state after a pump is stopped, so that the plugging agent can be effectively resided on the plugged part without missing, thereby raising the successful rate of plugging; and after entering the formation, the plugging agent enters a highly permeable water layer, the short linter is combined with gelsubstance, i.e. the sodium silicate, a grid structure is formed to reduce the permeation rate of the highly permeable water layer, thereby the difference of interlayer permeation rates of the water layer can be better solved to ensure that the plugging radii of the entire water layer are consistent, and the defect of the conventional water plugging agent that short effective period is caused by large difference of the plugging radii of the water layers with different permeation rates is overcome; besides, the water plugging agent reacts with the formation under borehole temperature and pressure in order to be tightly glued with the formation as a whole, and the water plugging agent has high compressive strength and is capable of plugging the water layer effectively.

Description

technical field [0001] The invention relates to a water blocking agent and a preparation method thereof, belonging to the technical field of oil field chemistry. Background technique [0002] In the process of oil field development, strong production and strong injection have resulted in the formation of many secondary large pores after long-term water injection in the formation, which seriously affects the separate production of oil wells and the separate injection of water wells. At the same time, due to many years of development, oil and water well casing leakage caused by casing corrosion and perforation is very common, especially casing broken wells above the cement return height, which are not easy to plug, and the number of such wells is large, which affects the oil and water wells. Work normally. [0003] At present, the cement extrusion sealing method is commonly used in oilfields for plugging. This plugging method has a low one-time success rate, especially for ca...

AI Technical Summary

Problems solved by technology

At the same time, due to many years of development, oil and water well casing leakage caused by casing corrosion and perforation is very common, especially casing broken wells above the cement return height, which are not easy to plug, and the number of such wells is large, which affects the oil and water wells. Normal operation

[0003] At present, the cement extrusion sealing method is commonly used in oilfields for plugging. This plugging method has a low one-time success rate, especially for cased wells without effective plugging agents.

After analysis, the reason why oil-water well casing leakage and large pores are not easy to plug is that the plugging agent has been squeezed into the target layer and lost before solidification; in addition, in view of the serious water flooding of oil wells in the late stage of oilfield development, the validity period after plugging with the current plugging agent is relatively short. short