High-temperature resistance base fluid for well cementing of oil gas well, preparation method and application thereof

Abstract

The invention relates to a high-temperature resistance base fluid for well cementing of an oil gas well, which belongs to the filed of oil drilling. The base fluid comprises the following ingredients in parts by weight: 100 parts of water, 6 to 20 parts of high molecular tackifiers, 1 to 8 parts of surface active agents, 1 to 8 parts of shale stabilizing agents and 2 to 15 parts of high-temperature stabilizing agents, wherein the high molecular tackifiers are selected from at least one material of biogum and high molecular fiber polymers, the surface active agents are negative ion surface active agents, the shale stabilizing agents are alkaline earth metal salt, and the high-temperature stabilizing agents are clay minerals. A preparation method comprises the following steps: heating the water; adding each ingredient at the same time of agitation; and then carrying out heat preservation and agitation to obtain the base fluid with the pH value between 6 and 9 and the viscosity between 40 and 180 mPa.s. A flushing fluid can be obtained through diluting the base fluid by water according to a weight ratio of 1/ (5 to 10), and an isolation fluid can be obtained through adding weighting agents into the flushing fluid. The isolation fluid obtained by the method has the advantages of high temperature resistance, good salt resistance performance and freely adjustable density, and has wide application ranges and application prospects.

Description

technical field [0001] The invention relates to an oil well admixture for oil and gas well cementing, and more specifically relates to a high temperature resistant oil and gas well cementing base fluid and its preparation method and application. Background technique [0002] Most drilling fluids, whether water-based or oil-based, are incompatible with cement slurries. In cementing construction, if the cement slurry is in direct contact with the drilling fluid, the drilling fluid will have cement invasion, and the cement slurry phase will be polluted by the drilling fluid to produce viscous agglomerated flocculation substances. Therefore, in the oil field cementing operation, the spacer fluid is mainly used to isolate the drilling fluid and cement slurry, so as to avoid the early thickening or flocculation thickening of the cement slurry due to the contact pollution of the drilling fluid; Drilling fluid and filter cake gelled on the casing wall and well wall; effectively con...

AI Technical Summary

Problems solved by technology

There are relatively few types of isolation fluid systems in China, and most of them are flushing fluids, which cannot be aggravated, have no isolation effect, and cannot maintain pressure balance in the well

The spacer fluid that can be weighted is also mainly used in shallow well cementing. The application temperature range generally does not exceed 90°C. No matter how high the temperature is, the spacer fluid will lose its stability, and the weighting agent will precipitate, unable to maintain its density, plastic viscosity and dynamic shear force. , can not ensure the effective isolation of drilling fluid and cement slurry, affecting the displacement efficiency of drilling flui

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