Composite flocculant, water-based drilling fluid and application of water-based drilling fluid

Abstract

The invention relates to the technical field of petroleum drilling fluids, in particular to a composite flocculant, a water-based drilling fluid and application of the water-based drilling fluid. The composite flocculant disclosed by the invention is prepared from the following components in parts by weight: 0.05-0.3 parts of polyacrylamide, 2-20 parts of inorganic salt and 1-10 parts of a polyamine inhibitor. According to the composite flocculant disclosed by the invention, the flocculation effect of the composite flocculant is improved by mainly utilizing the synergistic effect of the macromolecular polyacrylamide and the polyamine inhibitor. The composite flocculant can reduce clay hydration and accelerate solid-phase particle flocculation and sedimentation, is used for rapid drilling of an upper stratum, improves the flocculation degree and realizes effective solid-phase control.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling fluid, in particular to a composite flocculant, water-based drilling fluid and applications thereof. Background technique [0002] Polyamine shale inhibitors are one of the important components of amine-based drilling fluids, which play a key role in inhibiting wellbore instability caused by shale hydration expansion and dispersion, bit balling and wellbore purification. role. The high-molecular-weight polyamine shale inhibitor is adsorbed by the polar group on the molecular chain with the clay, thereby forming an adsorption layer, which has the function of retarding the penetration of water molecules into the shale; low-molecular-weight amines Polymer-like shale inhibitors can enter the middle of the clay layer, and rely on the electrostatic adsorption of protonated amines and hydrogen bonds to bind the clay layers together, thereby reducing the crystal layer spacing of clay minerals ...

AI Technical Summary

Problems solved by technology

[0009] At present, due to the strong slurrying during the drilling process, the flow velocity of the cuttings slows down when they pass through the settling tank during conventional large-scale circulation operations. After being separated by coagulation and sedimentation under the action of flocculants, the supernatant liquid returns to the circulation system, thus realizing normal drilling. It solves the problems that the rheology of the drilling fluid is difficult to control and the wellbore is not smooth, but it also brings problems such as the large circulation pool occupies a large area and is easy to pollute the environment.

In addition, some high-deflection point wells and the second well of the cluster well group or its subsequent construction wells cannot carry out large-scale circulation, which makes it difficult to control the rheology of the drilling fluid and the problems of unsmooth boreholes are prominent, causing some wells to trip Complicated accidents such as blockage, electrical resistance stuck, new holes drawn out, and even drilling tools buried

However, during the small circulation drilling process, due to the extrusion and grinding of the drill string, as well as the hydration and dispersion, the surface of the clay particles is negatively charged, and they repel each other, are not easy to coalesce and sink, and are difficult to remove

[0010] However, the problem of low solid control efficiency of solid control equipment during the rapid drilling of upper formations has not yet been resolved

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