SU891890A1 - Apparatus for treating mud in well - Google Patents

Description

(54) DEVICE FOR TREATMENT OF SOLUTION 8 WELL

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The invention relates to the drilling of oil and gas wells, in particular, to devices for carrying out insulation works, for example, at eliminating absorption, by pumping a cement slurry with an increase in its viscosity at the outlet of the casting column.

A well-known deep jet hydrodisperser is known, comprising a casing with a nozzle and a Cl screen mounted in it.

A disadvantage of the known device is the impossibility of using inert fillers and distorting the results of hydrodynamic studies. With the dispersant bounded in the composition of the casting column, which requires additional tripping. This leads to an increase in the cost of time and funds to combat absorption.

Closest to the present invention is a device for treating .. a solution in a well, including a hollow body with a saddle and a hollow plug with a nozzle and a G23 filter.

The disadvantage of the device is that its use affects the hydrostatic pressure of the medium, which does not allow the potential of increasing the insulating properties, such as the plastic strength of the cement slurry, to be maximized. In addition, the presence of a screen in the middle of the channel limits the possibility of large-scale and long-fiber fillers being washed over due to the danger of their clogging of the channel. All this reduces the efficiency of insulation works.

The purpose of the invention is to increase the efficiency of the device operation by eliminating the influence of the hydrostatic pressure in the well on the operation of the device.

The goal is achieved by THAT: the device is equipped with a connecting pipe connected to the lower part of the tube with a through-passage made in the form of successively arranged confuser, a cylindrical part and a diffuser, and the inner diameter D of the cylindrical part is determined as D g dGHT d - output diameter holes nozzle, mm; P is the injection pressure at the wellhead 9 — the density of the liquid network in the well; q is the acceleration of free fall H — the depth of installation of the device Such an embodiment of the device provides. creating a vacuum in the cavity of the nozzle when pumping through the dispersant of the cement slurry in the design mode, which reduces the energy consumption of the dispersion of the solid phase and increases the plugging capacity of the cement slurry. Vacuum in the nozzle cavity increases the pressure drop across the nozzle by the amount of hydrostatic pressure of the liquid column in the pipes without changing the pressure at the wellhead, which intensifies the dispersion of the solid phase. The absence of a screen allows large and long fiber fillers to be inserted through the pipes into the well before the tube is dropped. All this increases the efficiency of insulation works. The drawing shows the device, the overall appearance. The device contains a hollow body 1 with a saddle 2, a hollow tube 3 with a nozzle k and a filter 5 To the bottom of the tube 3 is attached a nozzle 6, the passage channel of which is made in the form of successively located along the confuser 7 in the cylindrical part 8 and the diffuser 9 and the inner diameter 8 is found from the relation where d is the diameter of the nozzle orifice, mm; P is the discharge pressure at the mouth of kPa; 9 is the density of the fluid in the well, q is the acceleration of free fall, H is the depth of the device, m. The length of the cylindrical part of the displacement and the distance from it to the nozzle should be respectively 8-10 and 2-4 of its diameter. The implementation of the outer diameter of the nozzle 6 should ensure that it passes through the saddle 2. The device is lowered into the well on the pipes 1.0. The device works as follows. When isolating the absorbing formation, the body 1 with the saddle 2 on the drill pipe 10 is lowered into the well. At the same time, the plug 3 with the nozzle 1, the filter 5 and the nozzle 6 is left on the surface. . f Proerd hydrodynamic studies and, if necessary, alluvium fillers. Then a cork 3 is thrown into the pipes, which is pushed down before it is seated on the saddle 2 adjoining it. The grouting mixture is pumped into the well with cementing ci-fagates. The initial pressure of the supercharger, taking into account the design of the device and the working conditions, is found by the formula, where P is the initial discharge pressure at the wellhead, kPa; 5 is the fluid density in the well, O, is the acceleration of gravity, m / s; - depth of descent of the device, m; d U D diameters respectively. cage and cylindrical mixing chamber, mm. According to the hydraulic characteristic, the QL -f (P) nozzle, taking into account the density of the cement slurry, the corresponding flow rate of the fluid is found to determine the required number of units and the mode of their operation. The prepared cement slurry is pumped into the well with the flow rate found. In this case, the pressure of the injection will first increase to the calculated PH, and then fall on the value equal to the hydraulic pressure of the liquid column in the pipes, and will be equal to ()

The discharge pressure drop by an amount equal to the pressure of the liquid column in the pipes at a constant flow rate is associated with the removal of fluid from the cavity of the nozzle 6 by a stream from the nozzle 4 with the formation of a vacuum in the space between the nozzle k and the cylindrical part .8.

Despite the drop in injection pressure in the wellhead, the pressure drop across the nozzle k will remain and be equal to the sum of the pressures created by the unit and the fluid column in the pipes, and will be the calculated P at a constant flow rate. For example, with a pressure of ai-gregata at the mouth of 10 MPa (10,000 kgf / s and a dispersant descent depth of 1000 m, the pressure drop across the nozzle in the presence of water in the well will be 20 MPa V200 kgf / cm). Having exhausted from the nozzle k, a jet of cement slurry, practically did not lose energy in the evacuated cavity of the nozzle, it hits the liquid filling the cylindrical mixing chamber 8 under the pressure of the liquid column in the annular space, where dispersion takes place and displaces the resulting mixture 1 through the cylindrical part 8 into the well.

The inevitable presence of liquid countercurrents in the cylindrical part 8, moving towards the jet and being carried back by it, provides for multiple dispersion of the cement slurry, which enhances the plugging properties of the cement slurry ...

The evacuation of the jet and the fluid in the upper part of the cylindrical part 8 reduces the energy consumption of dispersion.

After the extrusion of the cement slurry has been completed, the device is lifted to the surface.

The proposed device provides an increase in the efficiency of insulation works, which will reduce the time and cost involved in carrying out insulation works. The expected economic effect from the use of a single dispersant is 20.3 thousand rubles. The estimated annual need for dispersants only by the Ministry of Oil Industry exceeds 25 pcs. that it will isolate more than 500 zones of acquisitions. The expected annual economic effect from the maximum use of the invention will be about 509 thousand rubles.

Claims (2)

1.Krylov V.I. et al. A method for isolating absorption zones using deep hydrodispersion .- Works VNIIKrneft, Issue 15, Krasnodar, 1976, p. 123-127. 2.Assignment of the USSR on the application, No. 05/03, cl. E 21 B-33/13, 1979 (prototype).