RU2438008C1 - Procedure for simultaneous operation of several objects in producer and device for its implementation - Google Patents

Abstract

FIELD: gas and oil production.

SUBSTANCE: procedure consists in lowering production string equipped with devices for fluid lifting. Also, energy of flow of full fluid yield from a high pressure reservoir is used both for its proper lifting along the production string and for lifting fluid of low pressure reservoir through the production string at a higher level by means of a jet unit. A gas-lift procedure is added to flowing well procedure for lifting mixture of fluid to facilitate fluid mixture lifting from both developed reservoirs to a wellhead with required reserve of pressure of its full flow. A combined lift installation including at least two units of well fluid lifting is disclosed for implementation of the procedure. The jet unit installed in the production string between the packers is used at the first stage as a mixing unit and as a lifting unit of mixture of fluids of two developed reservoirs. Also, a cavity of w working nozzle of the jet unit is hydraulically communicated with a bottomhole zone of a lower high pressure reservoir, while a cavity of its receiving chamber is hydraulically tied with a bottomhole zone of an upper low pressure reservoir.

EFFECT: raised efficiency of process of simultaneous development of several reservoirs with one producer.

2 cl, 1 dwg

Description

The invention relates to the oil and gas industry and can be used to organize joint operation by a producing well of at least two objects (formations, interlayers, etc.) of a multilayer field that are separated by formations of impermeable rocks. In particular, the invention can be used for hydrocarbon production from low-pressure watered reservoirs of an overlying object and hydromineral raw materials from collectors of a high-pressure underlying object.

There is a method of developing oil and gas condensate fields (patent No. 2079639, publ. 05.20.97, bull. No. 14), in which bypass wells are drilled behind the oil circuit to depths revealing an autonomous zone of superhydrostatic pressure, while creating a movable adjustable gas-water shaft on the oil circuit hydrocarbon deposits by controlled bypass of formation gas-saturated thermal water through drilled bypass wells from the superhydrostatic pressure zone under the oil-bearing zone developed deposits followed using overflow wells as operating at design overlying horizon.

The disadvantage of this method is the need for additional costs for drilling bypass wells, and their use as production leads to the irrational use of reservoir energy.

A known method for the development of oil and gas condensate fields as. No. 1818466, publ. 05/30/93, bull. No. 20. It provides for wiring horizontal wellbores along the lower part of the oil-saturated reservoir with the barrel rising to its upper part, into the gas cap. As a result of this, the rise of oil is carried out due to the energy of the compressed gas of the gas cap and at the same time due to the natural gas lift. Gas flow is regulated using a throttle installed in the production casing in the immediate vicinity of the gas-oil contact.

The disadvantage of this method is the fact that with the existing gas-hydraulic connection between the reservoirs, the pressure in the oil and gas reservoirs will quickly equalize, and this will make it impossible to use the energy of the gas cap for both maintaining pressure and active gas lift. In addition, this method cannot be used when gas, oil and aquifers are separated by impermeable rocks.

There is a method of separate operation of production well objects and one of the installation options for its implementation (patent No. 2328590, publ. 10.07.2008, bull. No. 19), selected as a prototype. The method includes lowering successively into the well two columns of pipes of large and smaller diameters, placed one in the other concentrically. A larger diameter column is equipped with a packer and a bypass assembly or element for a medium flow - a working agent or produced fluid. Operation is carried out by at least two objects of one well.

The disadvantage of this method is the necessity of using two columns of lifting pipes, which significantly increases the metal consumption of the lift structure. In addition, the energy of a high-pressure object is not used to the full to lift fluid from a low-pressure object along a wellbore, even if a certain amount of produced fluid from an object with a large reduced bottomhole pressure is directed through an inkjet pump to the lifting column of the object with a lower bottomhole pressure. It is also not provided, in the case of fountain operation of a high-pressure object using a jet apparatus, the presence of an additional elevator that would be able to compensate for the pressure loss of a fluid from a high-pressure object during the transfer of part of its energy to a fluid from a low-pressure object.

The aim of this invention is to increase the efficiency of the joint operation of several objects of one producing well.

This goal is achieved due to the fact that the joint operation of one lift column of at least two objects in the producing well is carried out using a fluid mixture of these objects along the tubing string of the jet apparatus for the elevator, after preliminary calculation of its operating parameters, while the joint operation is ensured by creating a depression on the upper low-pressure object (zone II of the drawing) and the pressure of the fluid mixture due to the energy of the full flow rate of the fluid from the lower high-pressure object (zone I), and d I complete mixture flow of fluids both lifting objects prior to the wellhead and a common depression on production facilities using the gas lift (zone III).

The reservoir energy of the lower high-pressure object, converted into the energy of the fluid flow, due to the operation of the jet apparatus, carries out both the lifting of the fluids of both objects along the barrel of the tubing string and creates a depression on the low-pressure object. And the gas lift at the final stage provides not only the rise of the fluid mixture to the wellhead with the necessary headroom, but also provides the corresponding level of general depression on production facilities.

The method of joint operation of production well objects includes launching a tubing string into a production well equipped with at least two packers, one adjustable throttle with a filter, one jet apparatus, one check valve and one gas-lift valve, and operating at least two objects of one well. The technological objective of the invention is achieved by the fact that the space of the well is disconnected between the casing and tubing at a depth below the upper object and at a depth slightly lower than the installation of at least the first gas lift valve, and the tubing is hydraulically connected through the throttle to the filter with the bottom hole zone object, and through the inkjet apparatus - with the bottomhole zone of the upper object.

To implement the method, technological operations are carried out involving at least two objects as producing and operated by the combined "fountain - pump - gas-lift" method. A packer is installed between the objects, while the full flow rate of the fluid of the high-pressure object through a filter that protects the working nozzle of the jet pump from the formation rock particles, and the throttle, which controls the flow rate, is sent to the jet apparatus, in which the fluid of both objects is mixed and energy is transferred the flow of a high-pressure object to the flow of a mixture of fluids of both objects for its rise along the guide axis of the tubing string. At the design level, check and gas lift valves are installed in the tubing string, and a packer is installed slightly below the installation level, which separates the annulus of the tubing into the zone associated with the bottom of the low-pressure object and the zone of high pressure gas supply from the wellhead. Due to the supply of high pressure gas, the final mixture of fluids of both objects is lifted to the wellhead with the required flow head.

To implement the inventive method, a combined jet pump-gas lift installation is proposed, including a combination of at least two nodes for raising the fluid of the well, where a jet apparatus, which is located in the first stage, is used as a mixing and lifting unit for the fluid mixture of two production objects the tubing string between the packers, while the cavity of its working nozzle is hydraulically connected to the bottom-hole zone of the lower high-pressure object, and the cavity of its receiving chamber is hydraulically connected to the bottom th upper low pressure zone of the object, the working agent of the jet apparatus is a high-pressure stream of a lower object fluid, and the node of the second stage lifting reservoir fluid mixture are included in the column gas lift and return valves located above the upper packer.

The principal view of the installation is shown in the drawing, where 1 is the production casing; 2 - tubing string; 3 - gas lift valve; 4 - check valve; 5 - top packer; 6 - diffuser; 7 - inkjet apparatus; 8 - mixing chamber of the inkjet apparatus; 9 - receiving chamber of the inkjet apparatus; 10 - working nozzle of the jet apparatus; 11 - interval perforation on the upper operational object; 12 - lower packer; 13 - an adjustable throttle with a filter; 14 - interval perforation on the lower operational object.

The installation for implementing the method includes (see Fig. 1) a tubing string (2) deflated and installed in the production casing (1) of the well, equipped with at least two packers (upper (5) and lower (12)), one adjustable a throttle with a filter (13), one jet device (7), one check valve (4) and one gas-lift valve (3). The objective of the invention, from a technical point of view, is achieved by the fact that the installation includes elements combined into three nodes (located in the corresponding three zones), providing the simultaneous action of three methods of raising the well fluid: adjustable throttle with a filter (13); inkjet apparatus (7) with a packer (12); check valves (4) and gas lift (3) valves with packer (5). At the same time, an adjustable throttle with a filter (13) installed in the lower part of the tubing string (zone I) hydraulically connects the bottom-hole zone of the lower high-pressure formation with the cavity of the tubing string tubing through the perforation interval (14), and the tubing stem section from the outlet of the adjustable throttle with the filter (13) to the outlet of the working nozzle (10) of the jet apparatus (7) is an element of the column, which serves for the fountain lifting of the fluid of a high-pressure object. The inkjet apparatus (7), by means of a receiving chamber (9), a mixing chamber (8) and a diffuser (6) (zone II), hydraulically connects the tubing string to the bottomhole zone of the upper low-pressure object, and the packer (12) is an installation element separating annulus of the well into the operational zones of the lower and upper objects. The part of the barrel from the outlet of the diffuser (6) to the check valve (4) is an element of the fountain-pump lift of the fluid mixture of both objects. The non-return valve (4) is an element separating the fountain-pump and gas-lift sections of the fluid mixture lifting, and the packer (5) separates the operational zone of the upper object from the part of the annular space intended for supplying high-pressure gas. The gas lift section of the fluid mixture lift (zone III) includes a gas lift valve (3) and a section of the tubing string from the non-return valve to the wellhead.

The proposed method and device for its implementation can be implemented by analogy with the following example.

Example.

The technological indicators of the proposed method and the combined installation for its implementation are determined by the example of experimental well No. 197 of the gas treatment facility - 5 of the Vuktylskoye oil and gas condensate field.

Initial data: depth of well No. 197 is 3239 m; diameter of the production casing - 168 mm; the lift column is assembled from tubing with a diameter of 73 mm; the perforation interval of the upper production facility (Upper Visean-Bashkir deposits) is 3239-3189 m, reservoir pressure is at the level of 12 MPa; with a magnitude of depression of 2.5 MPa, the calculated flow rate of the liquid of the upper object is Q = 48.2 m ³ / day; the perforation interval of the lower production facility (undivided deposits of the Steshevsky, Tarusian horizons of the Serpukhov layer and the Venezian Visean layer of the Lower Carboniferous) 3340-3335 m, reservoir pressure is at the level of 31 MPa; with a magnitude of depression of 3 MPa, the calculated fluid rate of the lower object is Q = 50.2 m ³ / day; the necessary height of the level of the spout above the surface of the earth, a = 3 m; the density of the liquid (emulsion of produced water and liquid hydrocarbons) is equal to 1114 kg / m ³ .

и относительный перепад давления, создаваемый струйным насосом (Δр_c/Δр_р)=f(u), где:The achievable differential pressure of the jet pump with a diffuser, the pressure in the characteristic sections of the jet pump, the optimal ratio of the sections

and the relative pressure drop created by the jet pump (Δp _c / Δp _p ) = f (u), where:

f _p1 is the area of the output section of the working nozzle;

f ₃ - the area of the output section of the mixing chamber;

Δp _s / Δp _p is the relative pressure drop created by the jet pump;

Δp _c = p _with -p _and - pressure drop created by the jet pump;

Δp _p = p _p -p _and - the pressure drop of the working stream;

f (u) function - u = G _and / G _p - injection coefficient, i.e. the ratio of G _and is the mass flow rate of the injected stream to G _p is the mass flow rate of the working stream.

The calculation is based on the following conditions: the working and injected medium is the same type of water-hydrocarbon fluid, for which the specific volumes of the working, injected and mixed flows are the same, i.e. v _p = v _n = v _s . The injection coefficient u = 2, the pressure of the injected flow in the inlet section p _and = 12 MPa; the pressure of the working stream before entering the nozzle p _p = 28 MPa; change in pressure of the injected flow Δp _and = 16 MPa.

The optimal ratio of the sections is determined by the formula:

where a = φ ₂ ;

.

.

With the recommended experimentally determined values (φ ₁ = 0.95; φ ₂ = 0.975; φ ₃ = 0.9; φ ₄ = 0.925), the values - a, b and c will have the following values:

a = 0.975;

b = - [0.975 + 1.19 (1 + u) ² -0.78u ² ] = - [0.975 + 10.71-3.12] = - 8.565;

c = 1.19 (1 + u) ² = 10.71.

Optimum cross-sectional ratio

The value n = f ₃ / f _{and 2 is} determined by the formula n = 6.92 / (6.92-1) = 1.17.

The achievable relative pressure difference is calculated by the formula:

Based on the obtained value of the relative pressure difference, the possible pressure difference of the jet pump Δp _s = 0.12 · 16 = 1.94 MPa is determined.

In this case, the pressure of the mixed stream at the outlet of the diffuser - _with p = p + Ap _{and c} = 12 + 1.94 = 13.94 MPa, and the pressure of the injected flow in the inlet section of the cylindrical mixing chamber - p ₂ = p _{and to} -Δr = 12-1.94 = 10.06.

The values of the optimal cross section and pressure drop of the pump were obtained based on the conditions for placing the jet pump at the bottom of the Bashkir deposits and with an injection coefficient u = 2. To determine the optimal values of the given initial parameters, calculations similar to the above were performed.

The location of the pump remains the same, i.e. the pressure of the injected stream in the inlet section and the pressure of the working stream before entering the nozzle will have the same values p _and = 12 MPa, p _p = 28 MPa, the value of the injection coefficient varies within 1-2. The calculation results are presented in table 1.

Table 1 Injection coefficient calculation results u

Δp _s , MPa r _s , MPa p ₂ , MPa G _c , m ³ / day one 3.6 3,7 15.7 8.3 96.4 1,5 5.15 2.6 14.6 9.4 80.33 2 6.92 1.94 13.94 10.06 72.3

As can be seen from the data in the table, with a decrease in the injection coefficient, the characteristics of the jet elevator improve, reaching the optimal value for these conditions at u = 1.3-1.6.

The characteristics of the gas lift needed to complete the lifting of the well products to the day surface are determined as follows. The magnitude of the rise of the borehole fluid due to the operation of the jet pump will be:

In this case, the height of the gas lift will be equal to h _gas = 3242- (25 + 1336) = 1881 m.

According to the formula H = Kh, the depth of installation of the gas lift valve is determined from the level of the spout. The coefficient K is selected in accordance with the pressure at the mouth of the high pressure gas and the depth of the well, as well as taking into account experimentally identified optimal values. In this case, the coefficient K = 1.59. It does not fall into the interval of optimal values, but if we take the recommended K = 2, then H will be a value exceeding the depth of the well.

Specific gas flow rate - R _opt for lifting one cubic meter of liquid to a selected level of spout is determined from the ratio (A.P. Krylov's equation * for the specific gas consumption of the gas lift lift “Oil production reference book” edited by Sh.K. Gimatudinov p. 228) :

where R _opt - specific gas consumption in m ³ / t; V _opt is the optimal volume of injection gas in t / day; L is the length of the lift in m; d is the diameter of the lifting pipes in mm; ρ is the density of the fluid in kg / m ³ ; p ₁ and p ₂ - pressure at the shoe and at the mouth in Pa.

The total gas flow required to raise the estimated daily flow rate to the level of the spout will be:

W = Q · αR _opt = 80.33 · 79.83 = 6413 m ³ / day.

The flow rate of the mixture at the spout will be q = W + Q = 6413 + 80.33 = 6493.33 m ³ / day.

The working gas pressure of the gas lift is determined by the formula:

p _slave = 0.01 [h (K-1) +5] = 0.01 [1881 (1.59-1) +5] = 11.15 MPa.

This pressure is almost two times higher than the wellhead pressure provided by high-pressure gas. Therefore, in order to ensure the stable operation of the gas lift, the height of the gas lift is divided into two replacement chambers by installing a second check valve and a second gas lift valve at a depth of 941 m.

Thus, the obtained basic characteristics of the lift are as follows: daily gas flow rate - 6413 m ³ / day; working pressure - 5.57 MPa. It should be noted that in the above calculations, the possible presence of free and dissolved gas in the reservoir fluid was not taken into account. Their presence will improve the performance of the proposed gas lift.

Claims (2)

1. A method of operating several objects in a production well by lowering into it a tubing string equipped with fluid lifting devices, characterized in that the joint operation of several facilities is carried out by means of a single tubing string acting as an elevator string for two or more objects in the production well, while for lifting the fluid mixture of these objects along the tubing string, an inkjet apparatus installed in the tubing string is used pressure pipes in the zone of the upper low-pressure object, and joint operation is ensured by creating a depression on the upper low-pressure object and the pressure of the fluid mixture due to the energy of the full flow rate of the fluid from the lower high-pressure object, while to complete the rise of the flow of the fluid mixture of both objects to the wellhead and create a common Depression on these objects uses gas lift. 2. The device for implementing the method according to claim 1, including a tubing string lowered into the production well with a throttle, equipped with at least two packers located between production facilities, and a unit for lifting and mixing the flow of medium - working agent and produced fluid, characterized in that it includes a combination of at least two nodes for raising the fluid of the well, where as a node for mixing and lifting the mixture of fluids of two production facilities at the first stage, an inkjet apparatus is used, the second is located in the tubing string between the packers, while the cavity of its working nozzle is hydraulically connected to the bottom-hole zone of the lower high-pressure object, and the cavity of its receiving chamber is hydraulically connected to the bottom-hole zone of the upper low-pressure object, the fluid flow of the lower high-pressure object is the working agent of the jet apparatus and the unit of the second stage of raising the mixture of reservoir fluids are gas-lift and check valves located in the column above the upper packer.