Online control device for drilling fluid density

Abstract

The invention relates to an online control device for drilling fluid density. The online control device comprises an outer tube and a plurality of hollow balls with density lower than the drilling fluid density. The outer tube is provided with a central hole; the central hole comprises a backflow cavity, the bottom of the backflow cavity is communicated with a drilling fluid via hole, a layering filter structure is inserted in the central hole, allows the hollow balls to enter the backflow cavity in a layering manner, comprises a filter cartridge structure which is capable of sliding, layeringand filtering the hollow balls, the side wall, at the bottom of the backflow cavity, of the outer tube, is provided with a plurality of radially-running-through drain holes arranged circumferentially, and the diameter of the drain holes is greater than the outer diameter of the hollow balls; the bottom of the layering filter structure can run through the drilling fluid via hole in a hermetical sliding manner. With application of the online control device, variable-gradient drilling in deep water can be realized, and problems of complex layering in running of casings during single-gradient drilling, needing large-size equipment during double-gradient drilling and the narrow window of density in deep water drilling are all solved while drilling cost is reduced.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling, in particular to an online regulating device for drilling fluid density. Background technique [0002] In recent years, 50% of the world's major oil and gas exploration and development has come from the ocean, mainly in deep water areas. Deep water areas have become an important replacement area for oil and gas exploration and development in the world. Deepwater oil and gas exploration and development are becoming the main growth point of world oil and the frontier of technological innovation, and deepwater will become the main battlefield for oil and gas resources in the future. [0003] Drilling is a key link in deepwater oil and gas exploration and development, and deepwater drilling faces many challenges and risks: (1) Challenges brought about by water depth. With the increase of water depth, higher requirements are put forward for drilling tools, drilling fluid, riser, platform b...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide an on-line control device for drilling fluid density, through which deep water variable gradient drilling can be realized, which solves the problem of too many casing layers in single gradient drilling, and also solves the problem of double gradient drilling. The problem of large-scale equipment is needed in the middle, the cost of drilling is reduced, and the problem of narrow density window in deepwater drilling is finally solved

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