A kind of elastic fluid for well cementing and its preparation method and application

Abstract

The invention provides an elastic fluid for well cementation. The elastic fluid comprises two parts of an elastic fluid A section and an elastic fluid B section, the elastic fluid A section is prepared from, by weight, 100 parts of water, 0.3-0.6 part of shear strength-improving agent, 5-15 parts of activator and 10-100 pats of aggravating agent; the elastic fluid B section is prepared from, by weight, 50 parts of water, 0.3-0.6 part of shear strength-improving agent, 20-40 parts of elastomer, 4-8 parts of emulsifying dispersant and 5-100 parts of aggravating agent. The elastic fluid can heatup in an airtight environment, the growth trend of expansion pressure is much lower than that of conventional liquid expansion pressure; the elastic fluid can meet the heating up temperature range of0-150 DEG C in an airtight environment, the range of temperature difference between applicable mud line temperature and bottom hole temperature is wider, the elastic fluid can be used for casing annulus at all levels, moreover, it is also ensured that the annulus pressure increases less than the maximum collapse strength of the casing at all levels.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling, in particular to an elastic fluid for well cementing and its preparation method and application. Background technique [0002] In the production wells of oil and gas development, the channel to open up the oil and gas flow is composed of multiple pipe strings. During the cementing of land oil and gas wells, the cement can be returned to the wellhead, and the annulus between each pipe string is sealed by cement. In offshore oil and gas fields, most of them are For subsea wellheads, the cement slurry usually does not return to the wellhead during cementing operations, leaving a trap annulus between each pipe string and filling with drilling fluid. In the production test operation in the later stage of well completion, when the formation fluid is produced, the temperature of the fluid in the trapped annulus will rise, resulting in the phenomenon of pressure in the annulus. [0003] The b...

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Problems solved by technology

However, this elastic liquid has certain shortcomings and deficiencies: (1) The weighted density is not suitable for high specific gravity annular spaces. Since the core material of the elastic agent is floating beads, the added amount is 40-80 parts, which is relatively large, and the density is 0.4 ~0.6g / cm 3 , the design is only suitable for conventional density annulus (1.30g / cm 3 ), for the use of high specific gravity annulus, the density cannot meet the requirement (the density required for high specific gravity annulus is 1.5~1.9g / cm 3 ); (2) The applicable temperature has limitations. If the temperature of the high-temperature section at the bottom of the well exceeds 120°C or even higher, the heat conduction will increase significantly, and the temperature range of the elastic spacer fluid involved has certain limitations.

However, this device is not suitable for offshore oil and gas wells. The inert gas storage tank device needs to be installed at the wellhead and connected to the annulus. The operability of the device at the subsea wellhead is poor

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