A Drilling Fluid Circulation System for Reducing the Suction Pressure of Drilling and Tripping

Abstract

The invention provides a drilling fluid circulation system for reducing the suction pressure of drilling and tripping, which includes a drilling tool assembly, a normal drilling circulation channel and a tripping circulation channel. The drilling tool assembly includes a drill string and a drill bit. The normal drilling circulation channel includes a first swirl valve, a solid phase control device, a mud tank and a mud pump that are connected in sequence, and the tripping circulation channel includes a second swirl flow that is connected in sequence. valve, tripping pump, tripping mud tank and the third swirl valve, the method of reducing the drilling and tripping suction pressure through the drilling fluid circulation system is: before tripping, close the first swirl valve and mud pump , open the second swirl valve and the third swirl valve, determine the displacement of the tripping pump according to relevant parameters, and start the tripping pump to make its displacement reach the displacement value of the tripping pump. The beneficial effect of the technical solution proposed by the present invention is: adding a tripping mud circulation circuit to the conventional mud circulation circuit, and using the mud circulation circuit when tripping to reduce the tripping suction pressure.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of drilling engineering, in particular to a drilling fluid circulation system for reducing suction pressure during drilling and tripping. Background technique [0002] With the development of oil and gas production in the direction of deep strata and deep water, drilling encounters more and more narrow safe density windows. In the narrow safe density window environment, because the pore pressure of the formation is close to the fracture pressure, the bottom hole pressure caused by the tripping operation of the well Fluctuations make the bottom hole pressure easily exceed the window range, resulting in complex downhole accidents such as overflow and lost circulation. [0003] Bottomhole pressure fluctuations are affected by factors such as tripping speed, well depth, drilling fluid density, drilling fluid viscosity, drilling fluid rheology, and tripping depth. The higher the drillin...

AI Technical Summary

Problems solved by technology

This results in a long tripping time for deep wells, ultra-deep wells, and extended-reach horizontal wells, which not only increases the time cost of drilling, but also prolongs the exposure time of the open hole section and increases the risk of wellbore instability

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