Low-density cement paste for salt-cavern gas storage well cementation

A gas storage, low-density technology, applied in drilling compositions, chemical instruments and methods, etc., can solve the problems of excessive thickening time, retarded development of early strength, etc., to reduce production costs, reduce free water, The effect of increasing the bulk density

Inactive Publication Date: 2014-06-18
CNPC BOHAI DRILLING ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented technology helps prevent damage caused by excessive hydrations during hardened concrete curings without reducing its durability or improving their properties. It uses near saturaxtures with specific concentrations of calcium sulfoaluminate (CSA), magnesium hydroxide, sodium carbonate, lithite clay mineral, fused aluminum oxysilane gelatin resin, polystyrene microspheres, polyethylene terephthlate plastic particles, etc., along with various chemical agents like citric acid salts, glycerol triacetimidazole, urea formaldehyde polymerization catalyst, ammoniacal nitrogen compounds, iron powder, zinc chlorophyll, pigments, oxygen scavenger materials, activators, antioxic substance, antiwear agents, lubricants, defoamers, nucleators, organic solvents, cellulosics, bacteriostats, enzyme preparative products, and others can improve the performance of these compositions when added together.

Problems solved by technology

This patents discusses different ways how to improve the properties of cured concrete (cement) during drilling operations or other environments where salts are present such as underground oil reservoirs. While traditional methods like adding calcium chloride solution may cause environmental concerns over their disposal, there're technical solutions proposed involving developing an improved method called high density cement(HDCC). HDCC allows for faster setting times without increasing the amount of waste generated from conventional chemical treatments while maintaining excellent resistance against corrosion attacks caused by dissolved gases released through exposures to airborne moisture.

Method used

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  • Low-density cement paste for salt-cavern gas storage well cementation
  • Low-density cement paste for salt-cavern gas storage well cementation
  • Low-density cement paste for salt-cavern gas storage well cementation

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example 1

[0030] Mix 75 parts (parts by weight, the same below) of oil well cement, 25 parts of superfine oil well cement, and 30 parts of floating beads, and put in 3.0 parts of fluid loss reducer Jss, 1.5 parts of dispersant Fss, 61.5 parts of 7wt % NaCl solution in the mixing water was stirred in a corrugated mixer for 60 seconds at a speed of 4000 rpm to obtain a low-density cement slurry with a density of 1.45g / cm3.

[0031] The performance test was carried out in accordance with the national standard GB10238-2005 "Oil Well Cement" at a temperature of 65°C and 25 MPa. The test results are shown in Table 1.

example 2

[0033] Mix 25 parts (parts by weight, the same below) of oil well cement, 75 parts of ultra-fine oil well cement, and 10 parts of floating beads to form ash. Mix 3 parts of Jss, 1.5 parts of Fss, 0.3 parts of defoamer D50, 61.5 parts of 7wt % NaCl solution, stirred for 60 seconds at a speed of 4000 rpm in a corrugated mixer to obtain a density of 1.65g / cm 3 low density cement paste.

[0034] Various performance experiments were carried out according to the API specification, and the test results are shown in Table 1.

[0035] Table 1

[0036]

[0037] It can be seen from Table 1 that the density of the cement slurry system is 1.45-1.65g / cm 3 , API water loss ≤ 50ml, dehydration < 1ml, fluidity 20-23cm, initial consistency < 20Bc, good rheological properties, settlement stability and other comprehensive properties, which meet the construction needs.

[0038] With the increase of the weight ratio of ultra-fine cement and G-grade oil well cement, the thickening time decreas...

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Abstract

The invention discloses a low-density cement paste system for salt-cavern gas storage well cementation. The low-density cement paste system is composed of an oil well cement, a superfine cement, a lightening admixture, a salt resisting and water-loss reducing agent, a defoamer and a saline, and used for gas storage well cementation in a rock salt formation. Due to use of a special salt resisting ingredient, the corrosion of the cement paste to the wall of a salt deposit well is retarded, adverse impact of the salt rock diffusing to the cement paste on the properties of the cement paste is reduced, and such technical problems affecting the quality of sealing and cementation in well cementation as retarded coagulation and extra retarded coagulation of cement paste, and low strength of set cement are well solved.

Description

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Claims

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Application Information

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Owner CNPC BOHAI DRILLING ENG
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