SU1754886A1 - Drilling-in method - Google Patents

Description

glushek. The chemical is injected through a tubing string that is lowered into the well by injecting and then opening the cement wall with counterpressure both by depression and repression after removing the plugs to the plug.

However, since traditional methods of zero perforation due to the danger of open spouting, emissions and fires, people poisoning, environmental degradation are unacceptable, it is unacceptable in conditions of deposits with a high content of hydrogen sulfide more than 25% vol. pumping into wells containing hydrogen sulfide, which itself is aggressive and dangerous, especially at high pressures and costs, a large amount of acid, the latter will lead to the eroding of glands, threaded pipe joints, residual gaskets and cuffs that will cause depressurization of wellhead and well equipment with possible leaks, poisoning of people, etc.

Under abnormal conditions, with a reservoir thickness of 600 m and more, its base may not be reached and the reservoir will not be completely covered by running pipes. A large interval of opening the holes in the casing will lead to the need for repeated repetition of acid injection, which will worsen the complexity and create dangerous situations fraught with open emissions.

Only to fill the b of a casing with a length of 600 m will require 10 fti3 acids and its losses will be multiples higher because of the difficulties indicated. At the same time, powerful aggregates are needed to provide acid treatment of the wells, as well as equipment, the reliability of which under the action of the acid decreases sharply.

Thus, it is not possible to dissolve all the plugs at once at the height of the column corresponding to the depth of the reservoir. At the same time, the process of acid exposure to the plugs is not the same and, in general, it may be absent especially on the plugs far from the end of the column and in the absence of control over the eroding of the plugs, which can lead to the shutdown of many interlayers.

In addition, through the lower holes, the acid will begin to leave the reservoir, which will multiply its need and will require multiple lifting and lifting operations.

Injection of acid from top to bottom through a specially emptied column cannot be

combined with oil production from the well s, produced from the bottom up.

The aim of the invention is to increase the efficiency at the opening of productive layers of high power of hydrogen sulfide-containing fields with high pressure and deep wells with a simultaneous increase in the reliability and safety of operations.

0 The goal is achieved by the fact that the material of the plugs is chosen chemically degradable under the action of hydrogen sulfide, and after cementing the wells, the cement stone is drilled under

5 with a tubular body with a chisel opening on the bottom of the productive formation and equip the lower end of the tubular body with a check valve, after which the fluid inflow of the reservoir is made through the return

0 valve until the plugs are completely destroyed by the action of hydrogen sulfide contained in the fluid, while simultaneously operating the well itself.

Fig. 1 shows a part of a column of about 5 garden pipes with a tubular body with couplings and openings freed from plugs, with a valve lowered to the bottom to destroy the cement plug, depression pressure, longitudinal section; on

0 FIG. 2 — a connecting sleeve of a tubular body with openings plugged with plugs of their chemically destructible material under the action of hydrogen sulfide, a longitudinal section; on FIG. 5, section A-A in FIG. 2; Fig. 4 shows a valve combined with a packer mounted on the bottom of a well to destroy a cement plug with a formation pressure (depression).

0 EXAMPLE 1. The implementation of the method is provided by a device that consists of reservoir 1, a well.

2 lowered into the well casing

3, the tubular body 4, which is composed of 5 of individual pipes interconnected by couplings 5, having holes 6 plugged with stoppers-plugs.

Position 7 shows the hole drilled by a chisel in the cement plug for

0 outlet into the reservoir 1. There is a non-return valve 8. The lateral ducts in the cylindrical part of the cement crust, formed after repression, are indicated by the position 9.

5 A check valve 8 consists of a body 10 in which a seat with a ball 11 is located and is attached by washers 12 with bolts 13 of a rubber cuff 14.

The movement of the ball 11 is limited to the rod 15, the outer surface of which has inclined tracks 16, on which wedges 18 are spring loaded 17. The openings 6 of the sleeves 5 are threaded and the plugs 19 made of material (copper, steel H18N12MZT, steel EI432) are screwed into them, easily susceptible to corrosion from exposure to a chemical, in particular hydrogen sulfide.

The plugs 19 are sealed with gaskets 20. After the plugs 19 are installed, the last 19 are blackened outside and scalded around the perimeter. The internal surface of the plug is radially machined.

The method is carried out in the following sequence.

A borehole 2 is lowered into the well 2 drilled into the reservoir 1 so that the tubular body 4 with perforated holes on the side surface blocked by plugs 19 of the material destroyed by hydrogen sulfide is located opposite the reservoir 1.

Cementing the well. Then the cement stone is drilled (hole 7) under the tubular body 4 with bits and the productive base of the reservoir 1 is opened.

Down in the lower part of the tubular column 4 check valve 8, pre-cleaning the inner surface of the casing string from the remnant of cement. When this valve 8 under the action of its own weight, and if necessary, and under pressure, first down through the casing 3. And then through the tubular body 4 to the bottom. In so doing, thanks to the spring-loaded wedge, it is ensured that its pass is down, but its rise is not allowed. Then 2 tubings are lowered into the well, sealing the cross section and reducing the density of the solution inside the well. Causes the flow of hydrogen sulfide from the reservoir into the tubular body 4. Hydrogen sulfide liquids act on the material of the plugs 19, corrode them, open the openings 6 in the sleeves 5 of the tubular body 4.

After that, the fluid is pressurized inside the casing of the column 3 and its tubular body 4, which destroys the cement crust in the places between the holes 6 and the reservoir 1, forming ducts 9 in it. Then, the production of the reservoir 1 is injected into the well 2 in the usual way and proceed to well operation,

EXAMPLE 2. The implementation of the method is ensured by its device in the same way as in the device of example 1. only, instead of valve 8, a valve of the following construction is used.

The valve consists of a housing 21. In which a stem 22 is mounted inside the housing is a spring-loaded cam 24 spring-loaded 23. The carriage is pressed by the nut 25, has a lock nut 26 and a seat 27, closed by a ball 28 moving in the direction of the guides 29. The carriage is sealed by rings 30.

The valve is attached to the packer left at the bottom. A packer „« “is from a cylindrical body 31, an internal thrust thread terminating on one side, onto which a pressure 32 is screwed on top. A pressure bearing is clamped through the thrust bearing 33 on the outer surface of the body 31 through the thrust outer end 31.

sleeves 34-36, as well as wedge-joints 37 s

a gap around the perimeter of the inner surface of the tubular body 4, interconnected by a spring 38 with a corrugated surface, and the cuff 39. The bottom of the conical sleeve 36 abuts against the protrusion 40, in the notches

which is spring-loaded rollers 41 with a corrugated surface on the levers 42. The clamp 32 has two diametrically spaced groove 43 with bevels. At the end of the pipe string 44 there is a grip base 45 The base has a longitudinal groove, into which the plates 46, spring-loaded plate springs, pivoting stops 47 are inserted. The housing 31 has internal longitudinal grooves 48, and

32 povoootnye levers 49, located in the grooves 50, the shanks 51 which by weight is much more than the opposite end of the lever 52.

The method is carried out in the following sequence.

At the beginning of the operation, the same as in example 1, and after the destruction of the cement stone (hole 7) on the pipes 44, a packer with a valve is lowered into the well (Fig. 4),

the pre-spring-loaded stops 47 are inserted into the grooves 43, thereby keeping the packer with the valve on the pipes 44, since the weight of the valve and the packer is insufficient to overcome the force of the springs 46.

When the grip base 45 enters the packer, the levers 49 are turned in and out of the grooves 48.

After descending to the required depth, the pipes 44 are rotated clockwise, the rollers 41 abut with their pointed ends into the inner surface of the tubular body 4, and create a reactive moment, preventing the body 31 from rotating. Next, the clamp 32 is screwed onto the body 31. The cuff 39 is expanded. and

resting it against the inner surface of the tubular body 4. creating a tightness. As in Example 1, fluid flow from the formation is caused.

Due to the fact that the difference in pressure forces acting from below and above the valve is not sufficient to lift the carriage 24, the valve is not closed and the fluid from the reservoir 1 easily passes through the valve seat 27.

The pipes 44 are lifted, and the packer is disconnected from the pivoting stops 47 due to the fact that the ends of the pivoting stops 47 are compressed as they slide along the bevels of the grooves 43. At the same time, the levers 49 fix the pressure 32 on the casing 31 due to the levers 49 falling into grooves 48.

The liquid inside the pipe string is replaced with a liquid with a lower specific weight, on the order of 1.0 kg / dm3 (water, oil), with the result that at a well depth of 4500 m, the pressure inside it will be about 450 kg / cm, and outside 900 kg / cm2. Thus, the cement crust will collapse when exposed to a pressure difference outside 900 kg / cm2, and inside - 450 kg / cm2, i.e. at 450 kg / cm2.

In this case, the lower valve is closed, as they create pressure differences between the productive formation 1 and the well above the valve, sufficient to compress the springs 23 and thereby lift the carriage 24, abut the ball 28 between the seat 27 and the stem 22, and close the valve. After that, raise the density of the fluid in the well 2, open the valve and restore the normal operation of the well 2.

Claims (1)

Invention Formula A method of opening the productive formation of a well including a descent in the composition of the casing and placing a tubular body opposite the productive formation with holes on the lateral surface, blocked with plugs of chemically destructible material, cementing introduction of a chemical substance to destroy the plugs into the well in the interval of the productive formation and placing it at the time of the destruction of the plugs, destruction of the cement stone in the interval of the productive formation and creating a hydrodynamic connection of the productive formation with the well differential pressure between the annulus and the borehole spaces, characterized in that , with the purpose of increasing its efficiency when opening productive layers of high power of hydrogen-sulphoniferous fields with high pressure and deep wells to increase reliability and safety of work, the material of the plugs is chosen chemically destructible under the action of hydrogen sulfide, and after cementing the well, the cement stone is drilled under the tubular body with a bit opening of the reservoir bottom and the lower end of the tubular body is equipped with a check valve, then the inflow is called fluid reservoir with hydrogen sulfide through a check valve until the plugs are completely destroyed by the action of hydrogen sulfide. Ј Matt . i 988fr91t fef /