Modified biological rubber particle water shutoff agent for precision screen of heavy oil horizontal well

Abstract

The invention provides a modified biogel particles blocking agent used for a precision screen pipe of a thick oil horizontal well as well as a preparation method thereof. The blocking agent is composed of a main body material, an additive and water, the main body material is composed of 60-90% of G grade cement and 40-10% of fly ash with weight ratio; the additive is composed of 0.5-5% of plant polysaccharide, 1-8% of modified biogel and 10-20% of inorganic salt with weight ratio; and the main body material and the water are blended by weight ratio of 1:6-10. The preparation method of the blocking agent comprises the following steps: weighing the modified biogel and inorganic salt, uniformly mixing, placing in a reaction vessel filled with clear water, uniformly stirring; then adding a reinforcing agent plant polysaccharide in the reaction vessel, stirring while adding, adding the G grade cement and fly ash after uniformly stirring, and then uniformly stirring. The blocking agent has the characteristics of good dispersibility, no gel breaking, fast dissolving speed, easy pumping and environmental protection.

Description

Technical field [0001] The invention relates to a water shutoff agent used in the field of water shutoff with precision screens for heavy oil horizontal wells, in particular to an environmentally friendly modified biological glue particle with good dispersion performance, strong penetrability of precision screens, gel formation without gel breaking, and high sealing strength Water shutoff agent. Background technique [0002] At present, gel particle water shutoff agents for heavy oil horizontal wells have disadvantages such as low degree of cross-linking, poor dispersibility, shallow plugging depth, poor acid and alkali resistance, poor salinity, insoluble in water, and contaminated formations. In the heavy oil horizontal well section, due to the poor dispersion performance of the water shutoff agent, the effect of gravity causes the water shutoff agent to stratify and cannot pass through the precision screen uniformly, resulting in insufficient plugging depth and strength. In a...

AI Technical Summary

Problems solved by technology

[0002] At present, gel particle water shutoff agents for heavy oil horizontal wells have disadvantages such as low cross-linking degree, poor dispersion, shallow plugging depth, poor acid and alkali resistance and salinity, not easy to dissolve in water, and pollute the formation.

In the horizontal well section of heavy oil, due to the poor dispersibility of the water blocking agent, the gravity makes the water blocking agent layered and cannot pass through the precision screen evenly, resulting in insufficient plugging depth and strength

In addition, polyacrylamide is generally used as a dispersant for gel-type granular water blocking agents. This dispersant is not tolerant to high salinity and pH, and is easily converted into strong carcinogens in the formation, polluting formation water, and causing pollution to the formation.