SU1484904A1 - Borehole flushing method - Google Patents

Description

The invention relates to the drilling of wells. The goal is to increase the efficiency of drilling by reducing the dynamic pressure on

the battle. In the drill string serves the drilling fluid and output it through the washing holes in the bit in the annular space. In the zone of reducing the cross-sectional area of the latter, the flow of the solution is divided into two parts. One of the parts is guided along the drill pipe, and the other into the annular space. While the flow rate of the solution is directed into the annular space, determined by F-Le taking into account the flow rate before the separation and the cross-sectional area of the annular space to and below the separation zone of the stream in the column. I il.

The invention relates to the drilling of wells, in particular to the technology of washing wells.

The purpose of the invention is to improve the efficiency of drilling by reducing the hydrodynamic pressure at the bottom.

The drawing shows a diagram of the device for implementing the method of washing wells.

The device for carrying out the method comprises drilling pumps 1, a swivel 2, a drill string 3 with a bit 4, lowered into the well 5, and a node 6 for bypassing part of the drilling fluid, made as an element of the drill string (for example, in the form of a sub) with a hole in the side the wall inside which the nozzle is installed with the required diameter of the output section.

Node 6 is installed in the area of reducing the cross-sectional area of the annular space in the direction from the mouth to the bottom of the well. The flow rate of the drilling fluid directed into the annular space is determined from the expression

(1 where <) ₍ - the flow rate of the drilling fluid before the separation of the stream in the drill-bit column;

G is the cross-sectional area of the annular space to the flow separation zone in the drill string;

G 2 - the cross-sectional area of the annular space below the flow separation zone in the drill string.

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1484904

The method of flushing wells carried out as follows.

Drilling pumps 1 drilling fluid through the swivel 2 is fed into the drill string 3 "Node 6 divides the flow of drilling fluid in the zone of abyssing of the cross-sectional area of the annular space into two parts, one of which with a flow rate <3 _{2 is} sent to the annular space, and the other continues to move inside the drill string and through the flushing holes of the bit 4 also enters the annular space. The cost ratio 15 of both parts of the flow O _g = O (1 "P _g / P _A ) ensures the equality of the speeds of the ascending flow in areas of the annular space with different cross-sectional areas, which leads to a decrease in pressure loss in areas of the annular space with a smaller cross-sectional area and thereby to a decrease in hydrodynamic pressure at the bottomhole, accompanied by an increase in mechanical sk-25 growth of penetration.

Claims (1)

Claim Method of flushing wells, including 30 supplying drilling mud into the drill string and leaving it through the flushing holes of the bit and the annular space to the surface, characterized in that, in order to increase the efficiency of drilling by reducing the hydrodynamic pressure on the bottom, moving inside the drill string The flow of drilling mud in the zone of reduction of the cross-sectional area of the annular space is divided into two parts, one of which is directed along the drill pipes and the other into the annular space, and the quantities the flow directed into the annulus drilling fluid is determined from the expression R where 0, is the flow rate of the drilling fluid before the flow is separated in the drill string; the cross-sectional area of the annular space to the flow separation zone in the drill string; the cross-sectional area of the annular space below the flow separation zone in the drill string.