SU1506068A1 - Method of controlling equivalent density of flushing fluid in the annulus in direct drilling and flushing of borehole - Google Patents

Abstract

The invention relates to the drilling of wells. The goal is to reduce the likelihood of complications and to save consumption of the gel by increasing the accuracy of regulation. The density of the drilling fluid entering the well, the density of the rock, the radii of the well and the drill string, and the mechanical drilling rate are determined. In addition, the continuous drilling time, the density of the drilling fluid exiting the annulus, and the depth of the well are determined. In the course of continuous drilling, the increase in the density of the fluid in the annular space over time is taken into account due to the introduction into the fluid of the particles of cuttings into the fluid. During the well flushing process, after the cessation of drilling, a decrease in density is observed due to the cleaning of the flushing fluid from drill cuttings, compensated for by the desire of the fluid to the equivalent density, which occurs at the end of drilling in the annular space. The equivalent density value is calculated by the formula.

Description

The invention relates to drilling a well, in particular to drilling, and can be used in drilling and flushing a well in a straightforward manner without back pressure at the wellhead.

The purpose of the invention is to reduce the likelihood of complications and to save consumption of the emulator by increasing the control accuracy.

The method is carried out as follows.

In the process of drilling with a direct circulation scheme of the flushing fluid without backpressure at the wellhead, the density of the fluid flowing in and out of the well, the time of continuous drilling, and the mechanical drilling rate are monitored. In addition, with the well-known radius of the well and drill string, respectively, the density of the drilled rock for a specific depth of the well in

31506068

oh point in time determine the magnitude of the equivalent density by the formula

one

l about -, GK1 -E)

ciCRcK-R)

de p - - shyutnost flushing liquid

bone coming out of the annular space (well), rg - rock density, kg / m; , R is the radius of the well and the drill string, respectively,

m;

y - mechanical speed of storm-15

ki, m / h;

t - time of continuous drilling, h:

ck

about

  - the proportionality coefficient characterizing the probability of the removal of rsham to the day surface per unit of time, where the flow of fluid flowing into the well, kg / m;

H is the depth of the well, m. In the course of continuous drilling, an increase in the density of the drilling fluid in the annulus is observed in time due to the introduction of suspended cutting particles into the washing fluid, and in the washing process of the well after the drilling stops, the density decreases due to cleaning of the washing fluid liquids from particles of drill cuttings, which leads to a decrease in hydro

dynamic pressure in the well and is taken into account when selecting the required equivalent density of flushing fluid. In order to compensate for the decrease in hydrodynamic pressure, the washing liquid is desired to the equivalent density occurring at the end of drilling in the annulus.

Claims (1)

Invention Formula The method of adjusting the equivalent density of drilling fluid in the annular space while drilling and flushing the well according to a direct scheme, including determining the density of pro0 five 0 five about five 0 five washing fluid entering the well and the density of the rock, the radii of the well and the drill string, respectively, the mechanical drilling speed, characterized in that, in order to reduce the likelihood of complications and save the amount of zheletel due to increased control accuracy, the continuous drilling time, the density of the drilling fluid leaving the annulus, the depth of the well, and during continuous drilling the increase in the density of the industrial fluid in the ring is taken into account space in time due to particles of drill cutting in the washing liquid, and in the process of washing the well after stopping drilling - decrease in density due to cleaning the washing liquid of drill cutting particles, compensated by loosening the washing liquid to the value of equivalent density place at the end of drilling in the annular space, and the value of the equivalent density p, is determined by the formula 0-l + -iL-Blf-VjAlS. 1 o6 (Rl, -R) -H where is the density of the flushing fluid leaving the annular space (well), kg / m; Pr - rock density, kg / m; si to radii respectively wells and buripny column, m; v — mechanical drilling rate, m / h; t - time of continuous drilling, h: | .1-1 " H is the proportionality coefficient characterizing the likelihood of sludge being carried to the day surface per unit of time, where PPX is the density of the drilling fluid entering the well, kg / m; well depth, m