RU2334867C1 - Method of simultaneous-separate operation of several payout beds and installation of well for implementation of this method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas industry and can be used for extraction of fluid or gaseous hydrocarbons, particularly in wells with opening of several payout beds. The invention facilitates reduction of capital investments into development of wells for each of their objects, it also facilitates reduction of operation costs and multipay field completion period, increases hydrocarbon yield for longer period and reduces specific losses during well operation. The essence of the invention is as follows: the method includes running down a tail-piece with packers, well chambers and disconnecting units on a pump-compressor pipe column, installation of the tail-piece in the well and operation of the latter. According to the invention the tail-piece is assembled on the pump-compressor pipes - PCP, further first of all a nipple-funnel with a regulator of pressure or consumption with a reverse valve or plug are lowered into the well. Then PCP is lowered with one or several well chambers or bypass sleeves, then the last one or the top of the last is placed at a distance of 2 internal diameters of operating column below the low holes of perforation intervals of a low payout bed. One or several additional well chambers or bypass sleeves are added to PCP. At that this chamber or the lowest of them is placed 2 internal diameters of operating column above the upper holes of perforation interval of the low payout bed. Then the packer of the lower section of the tail-piece is attached to PCP thus completing the assembly of the latter. After that the second and the following of tail-piece sections are assembled and secured depending on the number of payout beds subject to operation. The packer of each section of the tail-piece is installed at the height of not less than 10 meters from the upper holes of the perforation interval of the developed payout bed. Upon installation of the last packer the disconnecting unit is attached and one or several well chambers are arranged above this disconnecting unit on the PCP. The packers are then run into operation, separating the payout beds one from another. Further the operation of the well commences.

EFFECT: facilitates reduction of capital investments into development of wells for each of their objects, it also facilitates reduction of operation costs and multipay field completion period, increases hydrocarbon yield for longer period and reduces specific losses during well operation.

4 cl, 3 dwg

Description

The invention relates to the oil and gas industry and can be used for the production of liquid or gaseous hydrocarbons, especially in wells that open several productive horizons.

A known method of operating fountain wells using the gas lift effect of associated petroleum gas, in which the rise of the gas-liquid mixture from the bottom to the surface occurs under the action of natural energy of the associated petroleum gas through the layout of the downhole equipment with a packer, downhole chambers and a nipple funnel. With this method of operation, the rise of the gas-liquid mixture is carried out along the tubing string with the layout of the underground equipment, which are lowered into the well before development. Fountain fittings are mounted at the mouth (connection of various tees, crosses and locking devices), designed to suspend tubing strings (tubing) and the direction of the borehole fluid into the oil gathering (see patent RU No. 2129208, class E21B 43/00, 20.04. 1999).

Closest to the invention in technical essence and the achieved result in terms of the method, as an object of the invention, is a method for simultaneous and separate operation of several productive horizons, including descent of a liner with packers, downhole chambers and separation units onto a tubing string, installing a liner in the well , development, research, physico-chemical effects and optimization of well operating modes and operation of the latter (see patent RU No. 2211311, CL ЕВВ 43/14, 08/27/2003).

A well-known downhole installation for regulating and cutting off the medium flow, including a tubing string equipped with packers and well chambers with removable valves and a pump (see patent RU No. 2194152, CL ЕВВ 43/12, 12/10/2002) .

The closest to the invention in terms of technical essence and the achieved result in terms of the device as an object of the invention is a downhole installation containing a jet pump installed in a well on a pipe string and a submersible pump connected to its nozzle, while in the well below the submersible pump with emphasis on the bottom an autonomous pipe string (liner) is installed, the upper end of which is located above the perforation interval of the reservoir, the lower part of the autonomous pipe string is located below the perforation zone th layer and a receiving filter is provided, e.g., in a grid, and the upper part of the tubing string is provided with an autonomous packer (see. the utility model patent RU №45454, Cl. E 21 B 43/00, 10.05.2005).

The well-known methods of operating wells that are mentioned above do not allow the full production of hydrocarbon reserves located in the drainage zone of the well, preserving the filtration properties of rocks in their original form, and well-known well rigs have low productivity, primarily due to the fact that the installation order of the well chambers is not defined or by-pass couplings and no calculation methodology or criteria have been proposed by which the locations of their installation are determined.

The problem to which the present invention is directed, is to increase the profitability of the development of an oil and gas multilayer field due to a more complete extraction of hydrocarbons, which, in turn, will increase the efficiency of use of development objects opened by the well.

The technical result achieved from the implementation of the invention is to reduce capital investment in well construction for each of the development sites, reduce operating costs and development time of a multilayer field, increase hydrocarbon production for a longer period and reduce unit costs during well operation, as well as increase the utilization rate downhole equipment and the reliability of the downhole installation.

This problem is solved, and the technical result is achieved in terms of the method, as an object of the invention, due to the fact that the method of simultaneous and separate operation of several productive horizons includes the descent of the liner with packers, borehole chambers and separation units onto the tubing string, installing the liner in the well and the operation of the latter, while collecting the liner on tubing and tubing and lowering the nipple funnel first with a pressure or flow regulator with a return to with a valve or plug, then tubing with one or more borehole chambers or overflow couplings, and the last or top of the latter is placed at a distance of at least 2 internal diameters of the production casing of the lower holes of the perforation interval of the lower (first) productive horizon, then one is connected to the tubing or several additional borehole chambers or overflow couplings, with its or its lower position being higher than at least 2 internal diameters of the production casing of the upper holes of the interval perforations of the lower (first) productive horizon, then the packer of the lower (first) section of the liner is attached to the tubing, thus completing the assembly of the latter, then the second and subsequent sections of the liner are assembled and attached depending on the number of productive horizons that will be operated, except for installation they have nipple funnels, and the packer of each section of the shank is set to a height of at least 10 meters from the upper holes of the perforation interval of the developed productive horizon for boron gas released from oil and the formation of a gas cap under the packer or packers, and after installing the last packer, a disconnection unit is attached and one or more borehole chambers are installed on the tubing, and then the packers are put into working position, dividing productive horizons, and then start well operation.

Downhole chambers or overflow couplings are equipped with pressure regulators and adjust the latter and the bottomhole pressure regulator of the nipple funnel to the opening pressure greater than the pressure of the liquid column in the tubing string at the place of their installation.

Well operation is divided into at least two stages, the first stage is fountain operation to natural depletion modes and the second stage is gas lift or pump operation until the hydrocarbon reserves are completely depleted, and in the latter case, pump or gas lift equipment is installed on the tubing.

This problem is solved, and the technical result is achieved in part of the device, as an object of the invention, due to the fact that the well installation includes a liner mounted on a string of tubing with the ability to disconnect, including one or more sections, each of which is equipped with a packer, well chambers with valves or by-pass couplings, one or more disconnection units, while the lower section of the shank is equipped with a nipple funnel with pressure or flow control with check valve m, or plug, the packer of each section of the liner is placed above the upper holes of the perforation interval of the productive horizon by at least 50 m to collect gas released from the oil and form a gas cap under the packer, well chambers or overflow couplings are installed under the packer on the tubing, part is placed at or above a distance of more than 2 internal diameters of the production string above the upper holes of the perforation interval, and the other part is placed at or below the lower holes of the perforation interval cations at a distance of more than 2 internal diameters of the production casing, while the borehole chambers or overflow couplings are equipped with valves for gas bypass at the upper position relative to the perforation interval of the productive horizon in the production casing and liquid bypass at their lower location relative to the perforation interval in the production casing from the annular the space of the well into the tubing string.

During the experiments, it was found that the effectiveness of this method of operating the above-described downhole installation is achieved by:

1. Protection of the bottomhole zone of the well from the harmful effects of gas, which, falling with the fluid from the productive horizon (formation) into the annular space of the well surrounding the liner of the pipe string, is separated by natural separation, floats and accumulates under the packer, forming a gas cap, then through downhole chambers or overflow couplings enter the cavity of the tubing of the liner without contacting the rock of the productive horizon and without damaging it.

2. Protection of the bottom-hole zone of the well from the harmful effects of water, which, falling from the productive horizon with the fluid extracted from the well into the annular space of the well surrounding the liner of the pipe string, due to changes in thermodynamic equilibrium and under the influence of ambient temperature, is released into the free phase and, as the heaviest the agent goes down, and through the nipple funnel and borehole chambers or overflow couplings it enters the cavity of the tubing, does not contact the rock of the productive horizon and does not it has a hydrophilizing effect, in which the productive horizon in the bottomhole zone of the well selectively begins to pass water into the well, creating additional resistance for hydrocarbons.

3. Protection of the bottom-hole zone of the well from contacts with the kill fluid during repair work on the well by changing tubing or pumping equipment.

Also, the effectiveness of this method is achieved due to the fact that the operation of the well can be divided into two stages with one run-down layout of the underground equipment of the liner:

the first stage is a fountain of operation, efficiency is achieved due to a longer period of gushing;

the second stage is gas-lift or pump operation, efficiency is achieved due to a slower increase in water cut in the well fluid at a natural rate, i.e., more complete production of hydrocarbon reserves.

In addition, the present invention allows for the joint development of an oil reservoir and a gas cap, using the energy of the gas to lift the fluid, as well as to prevent the formation of gas and water cones in the bottomhole zone of the well.

Ultimately, this makes it possible to increase the reliability and efficiency of the development of multilayer fields, taking into account the products being mined, and it is possible to regulate and optimize the regime for each of the productive horizons both by changing their characteristics and by changing the parameters of the well installation.

Figure 1 schematically shows a well installation for simultaneous and separate operation of several productive horizons, assembled for fountain operation.

Figure 2 schematically shows a well installation for simultaneous and separate operation of several productive horizons, at the time of installation of a pipe string with pump or gas lift equipment on the liner.

Figure 3 presents a diagram of the interaction between the elements of the liner section and the borehole fluids and gas in the well using the example of the lower section of the liner of a well installation.

The downhole installation includes a production string 1, a tubing string 2, a borehole chamber 3, a two-piece liner 4 (liner sections and its structural elements can be connected using disconnectors, which are not shown in the drawings), a disconnection unit 5, through which the liner is connected with the rest of the pipe string 2, a funnel nipple 6 with a pressure or flow regulator with a check valve or plug, a packer 7 of the lower (first) section, a borehole chamber 8 or an overflow clutch (one or more ) the lower section located below the holes of the perforation interval in the production casing 1, the borehole chamber 9 or the overflow sleeve (one or more) of the lower section located above the holes of the perforation interval in the production casing 1, the packer 10 of the upper (second) section, the borehole chamber 11 or an overflow clutch (one or more) of the upper section located below the holes of the perforation interval in the production casing 1, a borehole chamber 12 or an overflow clutch (one or several) of the upper section located above holes perforation interval in the production casing 1. In addition, figure 1 shows the lower (first) productive horizon 13, the upper (second) productive horizon 14, free gas (gas cap) 15, produced (hydrocarbon) liquid 16, water 17 in free phase. This layout of the well installation is intended for its fountain operation.

In the case of pumping or gas lift operation with pumping out a predominantly hydrocarbon medium, such as oil (see Fig. 2), a downhole pumping unit 18 is installed on the pipe string 2 above the separation unit 5, and in this section of the pipe string 2 can be dismantled downhole chambers 3.

The method is implemented as follows:

At the first stage of well operation in fountain mode, depending on the number of productive horizons, the number of liner sections 4 is determined, then it is collected on tubing 2 (tubing) and lowered into the well in a known manner, in the following sequence: funnel nipple 6 with regulator pressure or flow with check valve or plug; through several tubing, one or more borehole chambers or overflow couplings 8 are installed, based on the fact that they are lower than the lower (first) productive horizon 13 at a distance of no more than 2 internal diameters of production casing 1, then another one or several downhole chambers or overflow couplings 9, based on the fact that they are higher than the upper holes of the perforation interval of the lower (first) productive horizon 13 at a distance of at least 2 internal diameters th column 1 and satisfy the conditions for the calculation (see Figure 3).:

P _r2> P _nkt2,

where R _g2 is the pressure of the gas released from the wellbore fluid at the level of the borehole chambers or bypass couplings 9;

P _{tubing 2} - the pressure of the liquid column in the tubing inside the borehole chambers or bypass couplings 9;

then, through several tubing, the packer of the lower (first) section is installed.

For the second section of the liner containing the borehole chambers or overflow couplings 11 and 12 and the packer 10, as well as for subsequent sections of the liner (not shown in the drawing), the assembly principle and procedure is repeated, except for installing a nipple funnel 6 with a pressure or flow regulator with a reverse valve or plug, it is missing.

The above-described installation of packers 7 and 10 between the sections of the shank 4 is selected based on the existing perforation intervals of the productive horizons 13 and 14. It is most advisable to install the packers 7 and 10 at the maximum possible height from the upper holes of the perforation interval of the shared productive horizons 13 and 14. In this case, experimentally it was found that the best results were achieved when the packer was placed above the perforation interval at a distance of at least 10 meters, which allows full use of pressure of the gas in the gas cap to create a gas lift effect in the pipe string and at the same time create sufficient space for removing gas from the perforation interval productive horizons 13 and 14.

After assembling the last packer 10, a disconnection unit 5 is installed (one or after each section, depending on the task being solved).

If necessary, pressure regulators are installed in the nipple funnel 6 and downhole chambers 8, 9, 11 and 12, charged and adjusted so that they correspond to the dependencies:

_(Zab P> P _CNT) ≤R _charge = P _zar2> (F _r2> P _nkt2)

where R _zar - pressure charging valves in the nipple funnel 6 and downhole chambers 8, 11;

P _zab - bottomhole pressure at the development sites at the level of the borehole chambers 8, 11;

R _tubing - pressure in the tubing for the development objects inside the borehole chambers 8, 11;

R _zar2 - pressure charging valves in the nipple funnel 6 and downhole chambers 8, 11;

R _g2 - gas pressure at the development sites at the level of the borehole chambers 9, 12;

R _{tubing 2} - pressure in the tubing at the development objects inside the borehole chambers 9, 12.

After several tubing from the separation unit 5, a borehole chamber 3 is installed for technological purposes (various treatments and development of the well) and the liner is lowered to the design depth on the tubing 2, the packers 7, 10 are brought into working position.

Next, work is carried out to launch the well in a fountain mode. During well operation, due to the pressure drop, fluid from the productive horizons 13, 14 enters the annular space between the sections of the liner 4 and the production string 1. Under natural separation conditions, gas is released from the well fluid and begins to accumulate under packers 7, 10, displacing the fluid level to the level P _g1 , and form the volume of free gas (gas cap) 15 (see figure 3). At the same time, water in the borehole fluid, due to changes in thermodynamic equilibrium and under the influence of ambient temperature, is released into the free phase and, as the heaviest agent, goes down and accumulates in the free phase 17. Between the volume of free gas 15 and water in free phase 17, the hydrocarbon component of the fluid 16 is accumulated. When the desired pressure is reached, the valves open and the well fluid and gas through the borehole chambers 8, 9, 11 and 12 or bypass couplings and through the nipple funnel 6 enter liner 4 tubing 2 and on them further to the surface in the oil gathering network.

The flow of gas from area 15 into the tubing 2, through the borehole chambers or bypass couplings 9, 12 is caused by the fact that the gas pressure in the plane of the point P _{g2 is} always higher than the fluid pressure P _gct2 in the same plane and due to the difference the heights and densities of the liquid and gas agents of their interdependence are as follows:

P _nct1 = P _g1 .

When fluid is displaced by gas in the annular space of the well, the gas pressure at the phase boundary P _g1 will always be equal to or greater than the fluid pressure in the tubing 2 in this plane, due to the difference in the liquid columns:

P _nct1 > P _nct2 .

But given the low density of the gas compared with the liquid, we can accept:

P _g1 = P _g2 .

And, therefore, the expression will be true:

P _r2 > P _nkt2 .

Thus, it is clear how the gas is injected from the annular space of the well into the tubing string, where it performs useful work in raising the fluid. Also, with this arrangement of working elements in the shank section 4, the free gas does not contact the rock material of the object of development and does not contribute to the formation of a gas cone and the destruction of the rock material, and the water in the free phase also does not contact the rock material and does not hydrophilize it, creating an artificial obstacle for hydrocarbon inflow into the wellbore.

The second stage of operation occurs when it is necessary to increase the productivity of the well or when natural flowing stops. By pulling the tubing 2 using the separation unit 5, they are released from the liner 4, raised to the surface and then downhole pumping unit 18 is lowered to the tubing 2 (see FIG. 2) or the gas lift arrangement of the underground equipment, the wellhead is sealed and the pump installation 18 or gas lift is launched layout to work. The principle of operation of the shank sections 4 remains the same.

Thus, the inventive method of operation is more efficient and economical in comparison with the known methods, allows for more complete production of reserves and significantly prolongs the natural period of flowing of wells, as well as transfer to mechanized methods of producing liquid hydrocarbons at minimal cost and without affecting the bottom-hole zone of the well substances.

The present invention can be used in the oil and gas industry and other industries where they produce liquid from wells.

Claims (4)

1. A method for simultaneously separate operation of several productive horizons, including the descent of the liner tubing with packers, boreholes and separation units, installing the liner in the well and operating the liner, characterized in that the liner is assembled on tubing - tubing and first a nipple funnel with a pressure or flow regulator with a check valve or plug is lowered into the well, then tubing with one or more downhole chambers or overflow couplings, place the last or upper of the latter below at a distance of at least 2 internal diameters of the production casing of the lower holes of the perforation interval of the lower - first productive horizon, then attach one or more additional borehole chambers or overflow couplings to the tubing, and place it or the lower one above , at least 2 internal diameters of the production casing of the upper holes of the perforation interval of the lower-first productive horizon, then the lower-first packer is attached to the tubing of the shank section, thus completing the assembly of the latter, then the second and subsequent sections of the shank are assembled and attached, depending on the number of productive horizons that will be operated, except for installing a nipple funnel on them, with the packer of each section of the shank set to a height of at least 10 m from the upper holes of the perforation interval of the developed productive horizon for collecting gas released from oil and forming a gas cap under the packer or packers, and after installation, Lednov packer attached and above the last separation unit is installed on one or more tubing downhole cameras packers and then brought into the operating position, separating between a productive horizons and then proceed to operation of the well. 2. The method according to claim 1, characterized in that the borehole chambers or overflow couplings are equipped with pressure regulators and adjust both the latter and the bottomhole pressure regulator of the nipple-funnel to the opening pressure greater than the pressure of the liquid column in the tubing string at the place of their installation . 3. The method according to claim 1, characterized in that the operation of the well is divided into at least two stages, the first stage is fountain operation to natural depletion modes and the second stage is gas lift or pump operation until the hydrocarbon reserves are completely depleted, and in the latter case, higher the shank on the tubing is installed pumping or gas lift equipment. 4. A downhole installation comprising a liner mounted on a tubing string with the possibility of disconnecting, including one or more sections, each of which is equipped with a packer, downhole chambers with valves or bypass couplings, one or more disconnection units, characterized in that the lower section the shank is equipped with a nipple funnel with a pressure or flow regulator with a check valve or plug, the packer of each section of the shank is placed above the upper holes of the product perforation interval well at least 10 m to collect gas released from oil and form a gas cap under the packer, well chambers or bypass couplings are installed under the packer on the tubing, one part of which is placed above at a distance of more than 2 internal diameters of the production string above the upper holes in the perforation interval, and the other part is located below the lower holes of the perforation interval at a distance of more than 2 internal diameters of the production string, while the borehole chambers or overflow couplings are provided lapane for bypass gas at the upper position relative to the perforated interval productive horizon in the production tubing and fluid recirculation when the lower position relative to the perforated interval in the production string from the well annulus into the column of tubing.

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