SU1357559A1 - Apparatus for locating absorption zones in wells - Google Patents

Abstract

This invention relates to well testing devices. The purpose of the invention is to increase the reliability of work. The device contains a perforated tube 1 with a hydraulic packer 2, the upper 3 and the lower 4 nipples with throttling holes 5 and 6, the large and malleable discharge valves (K) 7.8, the overflow channels 9, the shift of the glass 10 with Retaining the cuffs 11 and gT jack 12 are for D 7. The nipple 3 is made with bypass channels 9. The latter are flush with the holes 5 and 6, and the outlets from them are filled under the shear cup 10 in its lower position. Dump through the column of pipes first K 8 and then K 7, while K 8 passes through the glass 10 and closes the central opening in it. When applying the flush Ci SS about: SL h 01 Oi

Description

liquid in the column occurs pressure drop over the glass 10 and below it. By the action of this pressure, the cup 10 moves downward and opens the holes 5 and the channels 9. Through the latter, the liquid enters the packer 2, inflating it and pressing it against the walls

15

20

.one

The invention relates to the field of well studies, namely to the field of determining the absorption zones of the drilling fluid in the wells.

The purpose of the invention is to increase the reliability of the device.

FIG. 1 shows the device section; in fig. 2 and 3 - position of the device in the well when determining the lower boundary of the absorption zone; in fig. 4 and 5 show the position of the device in the well when determining the upper boundary of the absorption zone.

The device for determining the absorption zones in the wells contains a perforated tube 1 with a hydraulic packer 2, upper and lower nipples 3 and 4 with throttling holes 5 and 6, large and small reset valves 7 and 8, bypass channels 9, shear cup 10 s retaining cuffs 11 and a 12 liter socket of a large valve 7, while the upper nipple 3 is complete with the bypass channels 9, and the inlets to the bypass channels 9 are flush with the throttling holes 5, and the outlets from them are made under the sliding glass 10 m its position.

In the lower nipple 4, a socket 13 is made for a small ejection valve 8. In the upper nipple 3, a bypass channel 9 is made. The device is placed in a well with a channel 14 in the wall 35 of the well.

The throttling orifices 5 and 6 are designed in such a way as to create the pressure differential required to open the hydraulic packer 2 and close the gap between the walls of the well and the packer. The amount of flushing fluid supplied to the device25

thirty

40

wells, through the holes 5, the fluid enters the well. Then the supply of liquid is stopped, the pressure in the system is released, under the action of elastic forces, the packer is compressed and the liquid is pushed through the channels 9 into the pipe string. 5 il.

five

0

five

35

five

thirty

40

2

The ability to create the required pressure drop across the throttling holes 5 and 6 is determined by the formula

Q F / if,

where / and, is the coefficient of flow resistance, depending on the shape of the edges of the throttling hole, for simple drilled holes / 6 0.62-0.64; F is the cross-sectional area of throttling holes, g is the acceleration of gravity, g

 9.81 m / s2;

H is the pressure drop required to inflate the packer, m water. pillar.

The device works as follows.

When assembled, with throttling holes 5 blocked by means of a cup 10 and bypass channels 9, the device is attached to a string of drill pipes (not shown) and lowered into the well into the assumed absorption zone (Fig. 2). A pump begins to feed a flushing fluid into the pipe string, which passes through the tumbler and enters the hydraulic packer 2. The latter, under the action of the differential pressure of the flushing fluid at the throttling orifice. Step 6 is inflated and closes the gap between the walls of the well and the packer. If the device is in the absorption zone or above it, the flushing fluid leaving the throttling orifice 6 goes into the channels 14 in the borehole walls and the pressure gauge on the pump will show only the pressure drop needed to inflate the packer. The fluid supply is stopped, the rubber packer is compressed, the device is moved down 3-5 m down the wellbore and the fluid is pumped again. If the device has not left the absorption zone, then the pressure gauge will show the same pressure. The device is lowered even lower and the cycle is repeated. When the absorption zone is above the packer of the device (Fig. 3), the liquid escaping from the throttling orifice 6 cannot escape into the absorption channels and the pressure in the system rises sharply, which will be indicated by a pump gauge. Consequently, the lower boundary of the absorption zone will be between the measurement points with normal and increased pressure on the pump gauge.

-After this, proceed to the determination of the upper boundary of the absorption zone. To do this, through the string of drill pipes, the mally 8 is dropped, and then the large 7 ball valves. Mally valve 8 passes through the cup 10, sits in the socket 13 and closes the throttling hole 6. The large valve 7 sits in the socket 12 of the cup 10 and closes the central hole in it. When the flushing fluid is supplied to the pipe string, a pressure drop occurs above and below the beaker 10. Under the action of this pressure drop, the cup 10 moves down and opens the throttling holes 5 and the bypass channels 9. Through the bypass channels 9, the liquid enters the hydraulic packer 2 and inflates it, pressing it to the walls of the well through the throttling holes 5, the liquid flows into the well. If the device is in the absorption zone or below it (Fig. 4), then the liquid exiting the hole 5 goes into the absorption channels 14, not the exit to the surface. The liquid supply is stopped, the pressure in the system is released (for example, into the discharge hose of the pump); under the action of elasticity, the rubber packer 2 is compressed, pushing the fluid into the drill pipe string through the open bypass channels 9. After compressing the packer, the device is raised higher by a measuring step, for example, 3-5 m, and the cycle is repeated. If mouth

If the device is again in the absorption zone, it is raised even higher. The number of cycles is not limited. When the device is above the absorption zone (Fig. 5), the fluid emerging from the openings 5 fills the well bore and flows out through its mouth.

The movable cup 10 is moved from the upper position to the lower one only once, after the small 8 and large 7 ball valves are discharged through the drill pipe string and the flushing fluid is supplied. All cycles, by definition, the upper boundary of the absorption zone are carried out with the open bypass channels 9, and the cup 10 is no longer returned to the upper position.

The time required to fill the wellbore depends on the performance of the pump Q, the fluid level in the well h (the groundwater level), the diameters of the well D and the drill pipes d, and is determined by the formula

t

I () 4Q

Thus, the lower and upper boundaries of the absorption zone are determined in a single descent of the device, after which they proceed to the elimination of absorption by known methods.

Claims (1)

Invention Formula A device for determining absorption zones in wells, comprising a perforated tube with a hydraulic packer, an upper and lower nipple with throttling openings, a large and malleable discharge valves, bypass channels and a sliding glass with retaining cuffs and a seat for a large valve, characterized in that In order to improve the reliability of operation, the upper nipple is made with bypass channels, the inlets to the bypass channels are filled at one level with throttling holes, and the outlets from them are the sliding glass in the lower position.