RU1822901C - Formation fluid back pressure control device for well tests - Google Patents

Abstract

Purpose: improving the reliability of the device in use when using it in the process of testing unstable reservoirs. SUMMARY OF THE INVENTION: the device consists of a hollow body 1. in which over-packer openings 2 and under-packer openings are made 3. The device has a bushing 4. spring 5 and a hollow plunger rod 6. In the plunger stock 6 there are under-packer openings 7, a protrusion 8 and flushing openings 9. A packer 10 is installed on the housing 1 of the device, the housing 1 and the stem-plunger 6 can be made of several separate parts. When the pressure in the eatrub space increases until the sub-packer hole 7 of the plunger rod 6 is lower than the sub-packer holes 3, the formation fluid will be blocked from entering the hollow space of the plunger rod 6. Therefore, holes 3 and 9 will be combined through them. will fill the plunger rod 6 and tubing. In this case, drilling fluid is pumped into the annulus. A second option is possible in which the pressure in the annulus decreases, the packer 10 is torn off and the drilling fluid fills the bottomhole zone of the well. In this case, drilling fluid is pumped into the annulus. 1 ill. Ј

Description

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Yu Oh

The invention relates to the oil and gas industry, in particular to devices for controlling back pressure on unstable reservoirs during well testing.

The purpose of the invention is to increase the reliability of the device in use when used in testing unstable reservoirs.

The drawing shows the proposed device.

It consists of a hollow body 1, in which over-packer holes 2 and under-packer holes 3, bushings 4, springs 5, and a hollow plunger rod 6 are made. In the plunger rod 6, there are sub-packer holes 7, a protrusion 8, and flushing holes 9. A packer 10 is installed on the housing 1 of the device. The housing 1 and the stem-plunger 6 can be made of several separate parts.

The device is lowered into the well on the tubing. A straight valve can be installed in the tubing string and then part of the tubing is filled with drilling fluid or a special solution, including water, which facilitates the descent of the tubing string into the well, and also prevents the possibility of a hydraulic or gas-hydraulic shock on wellhead equipment.

The device operates as follows.

Packer 10 is sealed with the annulus (annulus above the top of the reservoir), then the drilling fluid is injected under pressure into the annulus (annulus), which presses through the openings 2 onto the ledge 8 of the plunger rod 6, as a result of which the plunger 8 moves downward, compressing the spring 5. When the spring 5 is compressed, the under-packer openings 7 of the plunger rod 6 and the under-packer openings 3 of the body begin to combine, forming a downhole fitting, through which the drilling fluid with the bottomhole (zone under-pack) and formation fluid with formation begin to flow first into the empty hollow space of the plunger rod, and then into the pump and compressor pipes and fountain fittings.

The cross-sectional area (diameter) of the slots (nozzle) is controlled by the amount of injected fluid into the annulus or by pressure on the discharge line of the cementing unit. A certain back pressure on unstable reservoirs is maintained by the cross-sectional area (diameter) of the slots (nozzle) in the sub-packer zone. The optimal back pressure on unstable formations is

then back pressure, and therefore, that volume of drilling fluid pumped into the annulus (annulus) space, or that annulus (annulus) pressure at which rock is not removed from the well

productive formation. After the optimal backpressure on the formation has been established, the well is examined in regimes, then plugged.

Well killing is carried out

in two ways.

According to the first method, the pressure in the annular (annular) space is increased until the sub-packer hole 7 of the plunger rod 6 is lower than the sub-packer holes 3 of the housing 1, as a result of which the access of the formation fluid to the hollow space of the plunger rod 6 is completely blocked. the combination of the through holes 2 of the housing 1 and the flushing holes 9 of the plunger rod b, through which the drilling fluid fills the hollow space of the plunger rod 6 and tubing. At the same time, drilling fluid is pumped into

annular (annular) space.

According to the second method, the pressure in the annular (annular) space is reduced, as a result of which the spring 5 returns the plunger rod 6 to its original position, with

this interrupts the access of the formation fluid to the hollow space of the plunger rod 6, equalizes the bottomhole and formation pressure and stops the access of the formation fluid to the well. After the pressure in the annular (annular) space is reduced, the packer 10 is torn off, the drilling fluid fills the bottomhole zone of the well, and the drilling fluid is pumped into the annular (annular) space.

After jamming in the second way, when raising the tubing, the wells are constantly replenished

Thus, the proposed device allows you to control the back pressure on unstable reservoirs when testing wells, which improves the quality and reduces the time of testing wells by preventing the destruction of unstable reservoirs and the resulting complications of the technology of well testing

Claims (1)

SUMMARY OF THE INVENTION Device for controlling backpressure of formation fluid during testing wells, including a hollow body, lowered into the well on pump and compressor pipes, a packer installed on it and a fitting assembly located in the body, characterized in that, in order to increase the reliability of the device when used in the process of testing unstable reservoirs, the casing is made with radial channels located above and below the packer, and the fitting unit is in the form of a plunger spring-loaded relative to the casing in its lower part with an axial channel muffled from below, through radial channels in the upper and lower parts and the annular groove between the latter, the plunger and its axial channel are stepped. The housing has a sleeve concentrically mounted in it at the level of the step of the smaller diameter of the plunger, which forms an annular ring with its lower end and plunger a chamber communicating the nadlaker space behind the body with the axial channel of the plunger when moving it down and placing the radial channels in a step of smaller diameter at a level not lower than the radial channels of the coopus.