Downhole rotational flow shearing generator

Abstract

The invention discloses a downhole rotational flow shearing generator, comprising a coupling, an outer barrel and a guide holder and relating to the cementing technical field in the petroleum engineering. The downhole rotational flow shearing generator is characterized in that a shearing rotor is arranged in the outer barrel, the shearing rotor is provided with a blade grid, a locking screw is used for fixing a guide stator, the guide stator plays a flow guiding role, the guide stator is provided with a plurality of guide oblique holes, the flowing direction of the fluid is changed by the guide oblique holes, the fluid hits on the rotational flow rotor vertically, the energy conversion efficiency is increased, the rotational flow rotor generates the high-speed rotation, the spiral fluid continues to be under a shearing and stirring action and finally flows out through the guide seat arranged at the end part of the outer barrel in the shape of a large-intensity spiral flow. The downhole rotational flow shearing generator has the beneficial effects of reasonable structure and high intensity, after the downhole rotational flow shearing generator is arranged in the well cementing process, the peripheral shearing drive force of the well wall can be increased through the spiral flow of the downhole rotational flow shearing generator, the rock debris can be effectively carried, and the well wall can be washed more effectively, the interface cementing strength can be increased, the displacement effect of the cement paste to the drilling fluid can be increased by 5%-7%; the initial jelling time of the cement paste is shorted by 10%-15%, the cementing strength of the well cementing bi-interface is increased by 20%-30%, the compressive strength of the cement stone is increased by 15%-22%, and the cementing quality of the second interface is obviously better than the conventional cementing.

Description

Technical field [0001] The invention relates to the technical field of well cementing in petroleum engineering, in particular to a downhole swirl shear generator in the swirl displacement cementing technology. Background technique [0002] In the helical movement of the displacement fluid in the swirl displacement technology, the base circumferential flow velocity increases the circumferential shear driving force on the well wall, forming the axial displacement linkage effect of circumferential flow carrying, flushing and axial flow. Displacement can effectively remove cuttings and improve cement displacement efficiency and interface cementation strength. [0003] The existing swirl displacement technologies mainly include the following types: 1. Swirl flow displacement cementing with movable sleeves. The spiral flow of cementing fluid is realized by rotating the casing during the displacement process. The defect is that the rotation speed cannot be too fast due to the exces...

AI Technical Summary

Problems solved by technology

[0003] The existing swirl displacement technologies mainly include the following types: 1. Swirl flow displacement cementing with movable sleeves. The spiral flow of cementing fluid is realized by rotating the casing during the displacement process. The defect is that the rotation speed cannot be too fast due to the excessive rotation torque. , leading to unsatisfactory results; increasing the speed will increase the risk of operation, especially for highly deviated wells and horizontal wells, and this technology is even more limited

2. The swirling casing technology adopts the method of winding stainless steel wire on the outer layer of the drilling casing, and the casing is lowered into the well. When cementing, the entire cementing section generates swirling flow, which improves the displacement efficiency of the drilling fluid and at the same time It can improve the bonding quality of cement and casing to a certain extent. The disadvantage of swirling casing is that the frictional resistance generated by the cementing fluid when passing through the flow channel will be much larger than normal. The degree of swirl flow is not high when passing through; if the degree of flow channel rotation is high, the frictional resistance of the cementing fluid will also increase, and the degree of swirl flow will be greatly limited. Generally speaking, this kind of cement swirl casing The swirl intensity generated will not be very high, and the effect is not obvious

This kind of cementing cyclone can improve the displacement effect of cement slurry to a certain extent. The disadvantage of the cementing cyclone is that the cementing fluid needs to pass through the inner pipe to enter the outer pipe before it can be swirled. This process will consume a lot of cement. The kinetic energy of the well fluid reduces the flow capacity of the cementing fluid and also limits the swirl intensity generated

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