Calcium carbonate isolation solution for large-porosity easy-to-leak oil gas layer well cementation

Abstract

The invention discloses a calcium carbonate isolation solution for large-porosity easy-to-leak oil gas layer well cementation. The calcium carbonate isolation solution is prepared from the following components in parts by weight: 100 parts of clean water, 2.4 to 2.8 parts of a washing agent, 0.13 to 0.21 part of a diluting agent, 1.1 to 5.6 parts of a suspension stabilizing agent, 0.24 to 3.36 parts of a drag reducing agent, 18 to 205 parts of a calcium carbonate increasing agent and 0.05 to 0.12 part of a de-foaming agent, wherein the calcium carbonate increasing agent is prepared from the following components in percentage by mass: 6 to 10 percent of light calcium carbonate with the grain diameter of 80 to 120 meshes, 10 to 15 percent of light calcium carbonate with the grain diameter of120 to 160 meshes and 74 to 84 percent of light calcium carbonate with the grain diameter of 160 to 200 meshes; the calcium carbonate isolation solution has a good oil gas leakage layer blocking capability and acid solubility; a blocked oil gas layer leakage channel can be unblocked through an acidification yield-increasing measure and the oil gas yield is recovered; meanwhile, the calcium carbonate isolation solution has good flowability and a washing effect of a large grain diameter on a well wall mud cake; the interface cleanliness can be improved and the interface crossing strength of cement is improved. Meanwhile, the calcium carbonate isolation solution has a wide density applicable range and good suspension stability.

Description

technical field [0001] The invention relates to the technical field of downhole operations in oil and gas fields, in particular to a calcium carbonate spacer fluid used for well cementing in oil and gas layers with large porosity and easy leakage. Background technique [0002] The existing cementing spacer fluid is prepared from suspending agent, barite and related performance regulators. The density of barite is 4.3g / cm3, the usual fineness is 325 mesh, and the chemical composition is BaSO 4 , strong chemical stability, is a non-water-soluble, oil-soluble and acid-soluble inert material, used to prepare cementing spacer fluid, although it has good density adjustment, slurry stability and compatibility. But because of its small particle size, it has no plugging effect on the formation with large porosity and loss. Once the spacer fluid is lost in the oil and gas layer during the cementing process, its insolubility will lead to the permanent plugging of the oil and gas chan...

AI Technical Summary

Problems solved by technology

Once the spacer fluid is lost in the oil and gas layer during the cementing process, its insolubility will lead to the permanent plugging of the oil and gas pores, causing irreversible pollution damage to the oil and gas layer

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