RU1776301C - Method for development of wells - Google Patents

Abstract

A pipe column (CT) 2 is lowered into the well with a hole 10 in the lower part. Below the hole 10 in CT 2, a saddle 8 is installed under the waste shut-off element 9. To lower the liquid level in the well, a gaseous agent (HA) 13 is pumped into the annulus 3 and squeezed by squeezing liquid to the calculated depth. After that, the discharge of the pump unit is opened, the elastic energy of the compressed pack GA 13 throws the injected fluid out of the well. The increased volume of free space 3 is re-filled with GA 13 and pushed it to a new calculated depth until a productive horizon 11 is reached. At the time of stopping the well for inflow, drilling fluid 12 located in the pipe channel 7 of CT 2 will begin to flow into the annulus 3 through a hole 10. The dimensions of the latter are selected in accordance with the expression given in the text of the description. 5 ill. In capacity Ј

Description

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The invention relates to mining, and in particular to well development.

A well-known method for well development is provided, which includes creating a depression in a well equipped with a string of pipes filled with drilling fluid by lowering the level by squeezing gas cushions and squeezing fluid, and then releasing part of the latter and filling the vacated volume with a gaseous agent.

The presence of a packer reduces the effectiveness of the method. The method also cannot be applied in oil and gas wells, since maneuvering the tubing string can only be done if there is no pressure on the wellhead.

The aim of the invention is to increase the efficiency of the method. .

The goal is achieved in that in the known method of well development, which includes creating in a well equipped with a pipe string filled with drilling fluid, depression on the productive horizon by lowering the level by squeezing gas packs and squeezing fluid and then releasing part of the latter and filling the vacated volume with a gaseous agent , part of the displacement fluid is discharged through the annulus with the pipe channel blocked in the lower part, and after the level is completely lowered into the annulus In this space, the drilling fluid located in the pipe channel through the hole in the lower part of the pipe string is sized, the size of which is selected in accordance with the expression:

 q (10 Rpl - Un L)

12

L-born -10 P

pl

gu

where F is the cross-sectional area of the hole, cm

Rpl - reservoir pressure, kgf / cm;

L is the depth of the hole in the pipe string, m;

UN - the specific gravity of the reservoir fluid, g / cm;

Zh. - the specific gravity of the drilling fluid filling the pipe string, g / cm.

Figures 1-5 schematically show the principle of the method: Figure 1 shows the moment of filling the annular space of the well with a gaseous agent during the first cycle of lowering the liquid level; in Fig.2 - the same moment of completion

gas packs with squeezing liquid; Fig. 3 - the same moment of release of the squeezing fluid from the annulus and filling of the increasing volume of the annulus with a gaseous agent; Fig. 4 is the same, the moment of completion of the bursting of the gas pack during the second cycle of lowering the level in the annulus; figure 5 - the same moment of release

squeezing fluid from the annulus and filling the increased emptying volume with a gaseous agent for a third cycle of lowering the fluid level.

Figures 1-5 show the well into which the production string 1, the tubing string 2 (tubing) are lowered, forming an annular space 3 between them, from which the manifold lines A and 5. and the manifold lines 6 from the pipe channel 7 .

At the lower end of the tubing 2, a socket 8 is installed under the waste shutoff member 9, which acts as a check valve,

providing circulation in only one direction - from the bottom up the pipe channel 7. In the lower part of the tubing 2 there is a drain hole 10. A variant with a hole 10 in the shut-off1 is possible

body 9. This option is preferable since the casing 1 will not be washed out by the jet exiting the hole 10. The drain hole 10 must satisfy the following requirements. Its dimensions

must ensure that the fluid from the tubing 2 is drained in such a time that the formation fluid coming from the productive horizon 11 has time to carry out the fluid draining from the hole 10 from the well. Well

filled with drilling fluid 12. Lowering the level of fluid in the well is carried out using a gaseous agent 13, and its punching is done with a squeezing fluid 14. As the most appropriate use of water.

An option without a hole 10 is possible. In this case, the locking member 9 is made of a material that is destructible for a predetermined time (by dissolving it, melting it, etc.).

To ensure that the above condition is met, the size of the hole 1p should be selected in the following way.

The size of the hole 10 can be determined from the known formula

F-./1.2Xft.p. g- / rhsg

(1)

where Q is the flow rate of the drilling fluid flowing into the well through the hole 10 in l / s;

kill - specific gravity of the drilling fluid filling the pipe channel 7 of the tubing 2, g / cm3;

P is the pressure of the column of drilling fluid 12 in the tubing 2 at the level of the hole 10, kgf / cm2.

Since the tubing string 2 descends into the roof of the productive horizon 11 and the hole 10 is at the lower end of the tubing 2, it can be assumed that their depth is the same. Let this depth be L Then, after filling the annulus 3 to the entire height with a mixture of reservoir fluid with a specific gravity yy and drilling fluid flowing from the hole 10, we can compose the following equality:

(L-X) -un X-Ub. 10h 10 Rg

where X is the total height of the drilling fluid 12 in the annulus 3 at the time of its removal by the formation fluid to the surface;

  formation fluid height at this point.

After simple transformations we get

X - 10 rpl -L -un Ub.r. -Un

From the condition of operability of the proposed system (i.e., the formation fluid coming from horizon 11 carries drilling fluid 12 from the bottom of the well), we can write the following equality:

X

L-x

0 q

where q is the flow rate of the reservoir fluid in l / s.

After substituting the values of all terms included in formula (1) from formulas (3) and (4) we obtain:

q (10 Rpl - Un-L) AT L-kill -10 Rpl Y L

Well development is as follows.

PRI me R. A metering tank (not shown) is connected to the manifold lines 6 of the pipe channel 7, and a gaseous agent screen 13 (for example, the UKP-80 compressor) is connected to line 4, and a CAA-320 pump unit is connected to line 5.

First, backwash is carried out and leak tightness is checked by the waste organ 9 of socket 8. First, before the tubing 2 is lowered into the well, size 5 of the drain hole 10 is selected by calculation.

We give a calculation for the following conditions:

The reservoir pressure in the productive horizon is 10 Rpl 11 500 kgf / cm2.

Hole depth 10 L 5000m.

The tubing string 2 is filled with drilling mud 12c 1.2 g / cm3. 15 The specific gravity of the reservoir fluid is 0.8 g / cm3.

Well production q 1 l / s.

After substituting all the data in the formula (5), we obtain F 0.05 cm2 or 5 mmg. 20 Then the diameter of the drain hole 10 is 2.5 mm.

After checking the quality of the sealing by the waste organ 9 of the socket 8, they started lowering the liquid level in the annular 25 space 3 (see Fig. 1-5). For this, an air pack 13 (i.e., a gaseous agent) was pumped through line 4 into the annulus. Under air pressure 13, the drilling fluid 12, located in the annulus 30, is expelled into the pipe channel 7. and from it through the manifold line 6 into the metering tank. The volume of displaced solution 12 is judged on the amount of injected air 13 and the depth of its lower boundary. 35 After reaching a predetermined pressure value P at the wellhead (in this case, P 80 kgf / cm2), air supply 13 was stopped. In this case, the level of drilling fluid 12 in the annulus 3 decreases to a depth H equal to

N-10P

Ub.

(6)

45 where P is the air pressure 13 at the end of the displacement cycle of the drilling fluid 12 (see Fig. 1) from the annulus 3.

After that, the air pack 13 was squeezed with water 14 (see figure 2) to a depth of h + A h,

50, the pump unit was stopped and the unit was opened on line 5. With the elastic energy of compressed air 13, the injected water 14 was displaced from the annulus 3 into the unit’s meter (not counting water leaks through air pack 13, which did not exceed 10%). Since the bottom of the tubing 2 is blocked by a check valve 8-9, the drilling fluid 12 located in the pipe channel 7 almost does not flow out of the tubing 2 (not counting leaks through

hole 10, which are negligible). Therefore, the level of drilling fluid in the annulus 3 obtained during the first lowering cycle (see Figs. 1-3) remains almost unchanged and is at a depth HI equal to

 + Ah,

where h is the injection depth of the squeezing liquid 14 during the first lowering cycle, m;

DP - the height of the compressed pack 13, pumped to a depth of Hi, in m.

Thus, a new level of drilling fluid 12 in the annulus 3 will be at a depth of Hi. If no inflow is obtained at this depth of the level decrease, this means that the level in the annulus 3 is not lowered enough. In this case, a second liquid level lowering cycle is started (see Figs. 4 and 5). For this purpose, air 13 is again fed into the annulus 3 and filled with it the entire increasing volume from emptying during the first lowering cycle to the depth Hi. When the air pressure 13 is equal to P at the mouth, it is forced through with water 14 to the next calculated depth hi. After that, the discharge of the pumping unit, which pumped water 14, is again opened, and the pumped water 14 is discharged from the eatrub space 3. After this fluid is completely displaced, the level of drilling fluid 12 in the annulus 3 will be lowered to a depth of H2. Thus, after each new cycle, the level of drilling fluid 12 in the annulus 3 decreases to a greater depth than in the previous cycle. This makes it possible to pump a larger volume of air 13 into the annulus 3 at each subsequent cycle, although the pressure in all cycles is the same and equal to P (in this case, P 80 kgf / cm). The reduction is carried out until the productive horizon 11 begins to work or until the annular space 3 is completely drained.

After the horizon 11 has begun to work, the well is worked out for 4-5 hours, so that at least half of the volume of the tube space 7 is passed through the hole 10, after which the well is switched from the annulus 3 to the tube 7. With the available pressure in the well ( it is close to the reservoir) the remains of the drilling fluid 12 located in the pipe channel 7 of the tubing 2, you

throws out of the well and normal production begins - through the pipe channel 7.

Since the method allows

Since a multi-cycle decrease in the level, up to the complete drainage of the well, this makes it possible to use it to develop both deep and shallow wells, from abnormally high pressures to depleted productive horizons.

The method allows both a sharp and smooth decrease in the level of fluid in the well. If necessary, it is possible to dynamically influence the test horizon by abruptly releasing gaseous agent 13. This ensures fluid inflow even from those wells that were considered dry by known development methods. Way

20 accelerates well bottom hole cleaning, which helps to increase well production.

The method eliminates the multi-cycle fluid replacement in the well (i.e., a switch to water, then oil, etc.). As a result, precipitation of the solid phase present in the drilling fluid is reduced. This prevents the formation of slurry plugs in the perforation zone, which reduce the effective area of the working horizon of the productive horizon.

Claims (1)

The claims of the Well development, including 35 creating depression in the well equipped with a pipe string filled with drilling fluid by lowering the level by squeezing gas packs and squeezing liquid, followed by releasing part of the latter and filling the vacated volume with a gaseous agent, characterized in that, for the purpose of To increase the efficiency of the method, a part of the intermediate fluid is discharged through the annulus with the pipe channel blocked in the lower part, and after the level in the annulus is completely reduced Drilling Rig 50 of the solution located in the pipe channel through an opening in the lower part of the pipe string, the size of which is selected in accordance with the expression: F d (YuRpl-un-r.LG LyB.p. -YUR ™ U L where F is the hole cross-sectional area, cm2: Rpl is the reservoir pressure, kgf / cm2 L is the depth of the hole. - the specific gravity of the drilling fluid, pipe bore, m; pipe filling column, g / cm. y is the specific gravity of the formation fluid, g / cm3; FIG. g ShchigZ fie. 5