Cement slurry and preparation method and application thereof

Abstract

The present invention relates to a cement slurry and a preparation method and application thereof, wherein the cement slurry includes the following components in parts by weight of 65 to 75 parts of cement, 20 to 30 parts of reducing agent, 3 to 6 parts of reinforcing agent, 0.3 to 1 parts of filtrate reducer, 2 to 4 parts of early strength agent, 0.6 to 1.0 parts of retarder, 60 to 80 parts of water, wherein the reducing agent is the hollow microsphere containing main components of silicon dioxide, aluminum oxide, lime, magnesium oxide and ferric oxide, with particle size of between 56 and 360Mum and density of 0.80g / cm3; the reinforcing agent powder has specific surface area of between 15 and 20m2 / g and particle size range of between 0.1 and 200 Mum with particle size distribution of 0.1 Mum: 15%; 0.1-0.5 Mum: 45-50%; 0.5-1.0 Mum: 10-20%; 1.0-3.0 Mum: 5-10%; 3.0-10.0 Mum: 5%; 10.0-200 Mum: 7-12%. The cement slurry can adequate return the slurry to the top position and improve the cementing quality of low-pressure leaky well section. The cement slurry has small initial consistency, which is beneficial for on-the-site mixing, flow resistance reducing, and the high-temperature performance is table and the thickening time is adjustable.

Description

technical field [0001] The invention relates to a well cementing cement slurry, its preparation method and application. Background technique [0002] At present, my country's undeveloped reserves total 3.5 billion tons, 70% of which are low-pressure reservoirs, which are prone to leakage during drilling. In the process of underbalanced drilling, the proportion of mud is below 1.0, and the proportion of cement slurry is required to be 0.95-1.10g / cm 3 , some low-permeability (0.025-15.6md), low-porosity, low-abundance, and low-yield oil and gas reservoirs have multiple pressure layers. In order to improve the success rate of exploration, prevent leakage and formation pollution, reduce costs, and achieve one-time sealing , requires the use of ultra-low density cement slurry for effective isolation. Cementing in low-pressure and leaky formations is a difficult problem for drilling technology. Due to the low pressure bearing capacity and high cementing slurry density in low-pres...

AI Technical Summary

Problems solved by technology

[0004] Due to the incorporation of a large amount of external admixtures in low-density cement slurry, the density of the cement slurry is reduced, the stability of the cement slurry system is poor, and the system is delaminated and segregated; the water loss of the cement slurry is difficult to control; the rheological properties of the cement slurry are poor and pumping is difficult; Slow strength development, low strength, high permeability of cement slurry, easy to cause corrosion of corrosive media

[0005] At present, the ultra-low density lightening materials that can be provided in China cannot meet the requirements of ultra-low density cement slurry in terms of strength, activity, and slurry mixing performance; it is possible to use foam cement slurry to achieve ultra-low density cement slurry However, due to the influence of downhole temperature and pressure, the conventional foam cement slurry has a large difference between the actual density and the ground density, and the strength is low at low temperature. Due to the shortcomings of comprehensive performance requirements, it is difficult for a single ultra-low density foam cement slurry to meet the requirements of high strength, low permeability and downhole cement slurry density, so the low density high strength cement slurry system is studied on the basis of existing technologies

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