A kind of mud cake cleaning fluid for deepwater synthetic base drilling fluid and its application

Abstract

The invention provides mud cake cleaning liquid for deep water synthetic base drilling fluid, and belongs to the field of petroleum natural deep water drilling engineering oil field chemistry. The mudcake cleaning liquid is prepared from the following ingredients in parts by weight: 100 parts of water phase, 30 to 100 parts of emulsifying agents, 0.1 to 1 part of low surface tension agents, 10 to20 parts of solvents, 10 to 30 parts of penetrant and 50 to 200 parts of mutual solvents. The cleaning and emulsification effects are achieved on the synthetic base liquid contained in the syntheticbase drilling fluid through the clean washing and emulsification function of the emulsifying agents, the solvents and the mutual solvents, so that the synthetic base liquid can be separated from the mud cake, and the adhesion of the mud cake can be reduced; through the joint action of the seeping agents, the low surface tension agents and the mutual solvents, the whole of the mud cake cleaning liquid can seep into a combination part of the deep part of the mud cake and the well wall; the ultralow surface tension is used; under the turbulence flow flushing effect of cleaning liquid, the mud cake of the synthetic base drilling fluid is peeled from the well wall; the wettability reversal is realized.

Description

technical field [0001] The invention relates to the technical field of petroleum natural deep-water drilling engineering oil field chemistry, in particular to a mud cake cleaning liquid used for deep-water synthetic-based drilling fluid. Background technique [0002] Cementing construction is an essential link in the process of oil and gas field development, and in the process of cementing construction, a certain amount of pre-fluid is often replaced before the cement slurry. The pre-fluid is flushing fluid, cleaning fluid, and spacer fluid. It is used to remove and isolate drilling fluid, reduce the risk of early solidification of cement slurry, and improve the quality of cementing. However, when operating with oil-based drilling fluid, special pre-fluid, namely cleaning fluid, is often required to remove oil. The mud cake and oil film of the base drilling fluid can be eliminated, and the wetting reversal effect can be provided to improve the cementing quality. [0003] At...

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Problems solved by technology

[0003] At present, oil and gas exploration and development are gradually developing towards deep water and ultra-deep water. In order to solve the problem of seawater low-temperature cooling and well wall stability, deep-water (ultra-deep water) drilling fluid often uses synthetic-based drilling fluid technology. Synthetic-based drilling fluid is a safe, environmentally friendly, Non-toxic emulsified drilling fluid, the base fluid used is a synthetic base fluid with a single component, which is essentially different from diesel oil and mineral white oil used in traditional oil-based drilling fluids, which brings great challenges to cementing construction. Certain difficulties and challenges, and may even cause cementing quality problems due to poor cleaning and wetting reversal effects on synthetic-based drilling fluid mud cakes

Many different types of oil-based drilling fluid cleaning fluids, flushing and preparation methods are disclosed in the prior art, but they are all only applicable to oil-based drilling fluids, and there is no mention of whether they are suitable for synthetic-based drilling fluids, and synthetic-based drilling fluids Because the synthetic base fluid used in it is essentially different from the diesel and mineral white oil used in oil-based drilling fluids, especially the aromatic hydrocarbons contained in diesel and mineral white oil are easier to be cleaned by surfactants, while synthetic The components of the base fluid basically belong to straight chain or branched chain alkanes, the components are more single, and it is more difficult to be cleaned by surfactants

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