RU2549660C1 - System and method of operation of oil field areas with high watercut - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to oil and gas industry, in particular to operation of the oil fields with high watercut of the produced product. As per this method the total number of field wells with high watercut is determined. Geometrical location of the source deposit in relation to the absorbing horizon is determined for each well. Injectability of the absorbing horizon is determined for each well. Day volume of produced water is determined for each well. Based on the obtained data, at least on the geometrical location of the source deposit in relation to the absorbing horizon, and on condition that injectability of the absorbing horizon exceeds the day volume of the produced water, the type of double action pump system is determined. This is determined for each well on condition to ensure the further injection of the produced water to the absorbing above or below deposit. During injection of the produced water to the above deposit less volume is supplied to the flowline in comparison with volume pumped out using the well subsurface pump unit. Under wellhead tee the additional seal of the wellhead stock is installed to accept pressure. During injection of the produced water to the below deposit the subsurface pump unit is equipped with tail and additional plunger for water linked with main plunger and ensuring the possibility to overcome the absorbing deposit pressure. At least one field well with high watercut is operated using the bottomhole pump unit with definite pump system.

EFFECT: increased operation efficiency due to use of more effective gravity separation of water and oil in well.

4 cl, 4 dwg

Description

Technical field

The invention relates to the oil industry, and in particular to methods and devices for the exploitation of oil fields with high water cut of produced products.

State of the art

A known installation is a downhole sucker rod pump (USHN) with a double-acting pump (RU 2364708 C1, publ. 08/20/2009) for a well with a casing string, two open layers and a packer located between the open layers, containing a piston, a cylinder with a lower discharge valve, an upper and lower inlet openings with suction valves located above the packer and, respectively, above and below the piston, a plunger with an upper discharge valve made, like the piston, with the possibility of reciprocating movement, the column t rub, on which a sucker rod pump was lowered into the well, the outlet of which via a pipe string is communicated through the upper discharge valve to the wellhead, and through the lower pressure valve to the under-packer space. According to the invention, the piston is arranged to follow the plunger up due to the pressure drop above this piston and under this piston until the cylinder cavity communicates with the upper inlet for oil to enter the cylinder cavity through this hole until the plunger stops in its highest position , and its subsequent movement down the plunger under the action of the weight of the rod string to their extreme lower position. At the same time, with an increase in water cut of oil, it is possible to lower the rod string down, and with a decrease in water cut, it is possible to raise the rod string.

A well-known installation of a well sucker rod pump with a double-acting pump (RU 2483228 C1, publ. 05.27.2013) containing a casing with two exposed layers, a pump running on a pipe string located in the casing with the formation of the annular space between them, which is separated by a packer located between exposed layers. The pump is equipped with a plunger, pressure valve and piston, made with the possibility of reciprocating movement, upper and lower inlet openings with suction valves located above the packer and, respectively, above and below the piston. The pump outlet from above through a pipe string is communicated through the discharge valve with the wellhead, and from below through the lower discharge valve with a sub-packer space. The piston is made free with the possibility of interaction from above with the plunger and limited reciprocating movement. The plunger below is equipped with a rod inserted into the piston with the possibility of limited reciprocating movement. In the casing string there is additionally a pipe with a check valve, which communicates the pump cavity between the piston and the lower discharge valve with a flow line through the shut-off element and wellhead measuring equipment. The installation allows to increase the efficiency of oil production from a waterlogged well by providing direct control of the quality and quantity of water pumped into the lower reservoir.

The disadvantage of the installations is that when using them for the selection of highly watered products, it is possible to pump the selected fluid only into the underlying formation, which significantly reduces the possibility and expediency of their use in developing existing horizons. Such installations do not allow to involve in the development all available wells of the field where only an overlying receiving formation is possible.

A known method of operating a high-water oil well (RU 2394153 C1, publ. 07/10/2010), in which separate pumping of oil from the reservoir to the surface with preliminary gravitational separation of the products in the well into oil and water and injection of separated water into the receiving reservoir. Above the packer, a pump is placed on the pipe string, communicated with an inlet with a sub-packer space, and an outlet through radial holes in a pipe string with a super-packer space. Pipes of smaller diameter are located under the radial openings from the conditions of gravitational separation of products into oil and water. The separated oil is lifted along the annulus and the pipe string with the possibility of regulating its flow rate at the mouth, and water, controlling its amount, is pumped through the annulus into the receiving formation due to the pressure of the liquid column in the well and the excess pressure created by the pump. The interval of the receiving formation is reported by a separate tube with wellhead measuring equipment, based on the readings of which the quality of the water pumped into the receiving formation is controlled. It is possible to separate the emulsion before injection into the annulus into oil and water by a separator. The technical result consists in increasing the profitability of operation by lifting oil to the surface with a minimum amount of water and pumping most of the water into the overlying receiving formation with the possibility of controlling its quantity and quality.

The disadvantage of this method is that when using it for the selection of highly watered products, it is possible to pump the selected fluid only into the overlying formation, which also significantly reduces the possibility and expediency of its use in the development of existing horizons. Such installations do not allow to involve in the development of all available wells of the field, where only the underlying receiving formation is possible.

Summary of the invention

The problem solved by the present invention is to provide an effective method and system for the exploitation of oil fields with high water cut of produced products by using the technology of downhole gravity separation of water and oil using double-acting pumping systems and subsequent injection of water into an absorbing overlying or underlying formation without lifting it to the surface.

The technical result consists in expanding the technology of gravity separation and subsequent discharge of associated produced water without lifting it to the surface of the entire field, including all available horizons due to the unification of the downhole equipment used.

The present invention also allows to reduce the cost of the application and implementation of gravity separation technology with associated water discharge at the field by reducing the cost of the equipment used, because system nodes can be made of standard equipment based on SHGN.

The specified technical result is achieved by the proposed method of operation of high-water sections of oil fields, containing the stages at which

determine the total number of wells with high water cut;

determine the geometric location of the donor formation in relation to the absorbing horizon for each well;

determining the injectivity of the absorbing horizon for each well;

determine the daily volume of produced water for each well;

on the basis of the data obtained, at least in terms of the geometrical location of the donor layer with respect to the absorbing horizon, and also from the condition that the injectivity of the absorbing horizon is higher than the daily volume of produced water, the type of double-acting pump system that provides subsequent injection of produced water is determined in a pre-lying overlying or underlying formation for each well;

at least one well of a field with high water cut is operated using a well sucker rod pump unit with a certain type of pumping system.

According to a preferred embodiment, the total number of wells of a high water cut field is preliminarily determined based on at least one water cut characteristic of the donor formation for the well.

The specified technical result is also achieved by the operation system of high-water sections of oil fields according to the above method, and the system containing

a computing unit configured to, based on input data including at least data on the depth of the donor formation and the absorbing horizon, the injectivity of the absorbing horizon and the daily volume of produced water, determine the type of double-acting pump system that provides the subsequent injection of produced water in an absorbing overlying or underlying formation;

at least one borehole sucker-rod pumping unit with a double-acting pumping system, which provides for subsequent injection of produced water in an absorbing overlying formation;

at least one borehole sucker-rod pumping unit with a double-acting pumping system, which ensures subsequent injection of produced water in the absorbing underlying formation.

According to a preferred embodiment, the input data further includes a water cut characteristic of the donor formation for the well.

Brief Description of the Drawings

Figure 1 schematically shows a General view of the site of the oil field

Figure 2 shows a block diagram of the sequence of steps of the method.

Figure 3 schematically shows a General view of a double-acting pumping system (NSDD) with USHN for pumping water into an overlying formation.

Figure 4 schematically shows a General view of a double-acting pumping system (NSDD) with USHN for pumping water into the underlying reservoir.

Description of Preferred Embodiments

Figure 1 schematically shows a section of an oil field composed of three layers, respectively an absorbing underlying formation, a donor formation and an absorbing overlying formation. Depending on the physical availability of the absorbing layer, as well as on the parameters of its injectivity with respect to the estimated daily volume of produced water, an underlying or overlying layer can be selected as an absorbing layer for each well in the field.

Figure 2 presents a block diagram of the sequence of steps of the proposed method. According to the method of operating high-water sections of oil fields in step S1, the total number of wells of a field with high water cut is determined. In particular, such a determination can be made based on a comparison of at least one water cut characteristic of a donor formation for a well with at least one predetermined threshold value. Next, in step S2, the geometrical location of the donor formation with respect to the absorbing horizon for each well is determined. As input data for this stage, data on the depths of the beds can be provided. If, as a result of step S2, it is determined that there is one absorbing layer in the well located above the donor layer, then the type of the double-acting pumping system, which pumps the produced water into the absorbing overlying layer, is preliminarily determined and proceed to step S3. If, as a result of step S2, it is determined that there is one absorbing layer in the well located below the donor layer, then the type of the double-acting pumping system, which provides the injection of produced water into the absorbing underlying layer, is preliminarily determined and proceed to step S3. If as a result of step S2 it is determined that the well has two absorbing layers located above and below the donor layer, then the type of the double-acting pumping system, which pumps the produced water into the absorbing overlying layer, is preliminarily determined and proceed to step S3. At step S3, the injectivity of the preselected absorbing layer (horizon) in m ³ / day for the well, the water cut of the donor layer and the daily amount of produced water in m ³ / day for the well are determined. Next, in step S4, the data obtained in step S3 is compared. If, as a result of step S4, it is determined that the injectivity of the preselected absorbing layer is higher than the daily amount of produced water in the donor layer, then the pre-selected type of pumping system is considered finally selected and proceed to step S5. In step S5, a well is operated. If, as a result of step S4, it is determined that the injectivity of the pre-selected absorbing layer is lower than the daily amount of produced water in the donor layer, and in step S2 it is determined that there are two absorbing layers in the well, then the type of pumping system is selected as the pre-selected type a double-acting system that pumps the produced water into the absorbing underlying formation and proceeds to step S3 again. If, as a result of step S4, it is determined that the injectivity of the pre-selected absorbing formation is lower than the daily volume of produced water in the donor reservoir and the well has one absorbing reservoir or the injectivity of the pre-selected absorbing reservoir is lower than the daily volume of produced water in the donor reservoir and as pre-selected type of pumping system, the type of double-acting pumping system is selected, which ensures the injection of produced water into the absorbing underlying formation, then annuyu well not involve the development of this technology.

According to a second aspect of the present invention, a system for exploiting oil fields with a high water cut of produced products comprises a computing unit configured to, based on input data including data on the depth of the donor formation and the absorbing horizon, the injectivity of the absorbing horizon and the daily volume of produced water , determining the type of double-acting pumping system, which ensures subsequent injection of produced water in the absorbing overlying l for the underlying layer. The input data for such a computing unit can be data obtained directly from external sensors of the system, or pre-processed data or data obtained as a result of indirect measurements. Such a computing unit may comprise a computer-readable medium with a program recorded thereon, allowing the steps of the claimed method to be carried out.

In addition, the inventive system comprises at least one borehole sucker-rod pumping unit with a double-acting pumping system, which provides for subsequent injection of produced water in an absorbing overlying formation.

This installation and its location relative to the layers shown in figure 3.

In the flooded well 1, from which the absorbing formation 2 located above the producing formation 3 is accessible and perforated, a sucker rod pump 5 is lowered on the tubing string 4. The opened formations are disconnected by the packer 6. The pump 5 is installed at a depth in order to ensure sufficient pressure for normal operation at the reception. From the inlet valve 7 of the pump 5 to the packer 6, a shank 8 is used. In the tubing string 4 above the pump 5, nozzles 9 with holes 10 are installed at a certain distance from the wellhead and directly below the wellhead. The plunger 11 of the pump 5 is made with a controlled discharge valve 12 and connected to rod string 13. On the flow line 14, a device 15 is installed that limits and regulates the flow of fluid into the flow line (fitting), as well as a valve 16, a pressure gauge 17 and a sampler 18. In order to quickly determine the productivity, the flow line is set flax flow meter 19. To assess the quality of the water (content of mechanical impurities and oil products) injected into the absorption layer 2, an additional pipe string 20 is connected to the sampler 21. A pressure in the annulus 22 at the wellhead is controlled by a manometer 23.

Installation works as follows.

Watered products from the underlying productive donor formation 3 through the liner 8 enters the pump 5 and then through the tubing string 4 rises to the nozzles 9 and through the openings 10 enters the cavity of the production casing of the well. Below the holes 10 in the well will be water, since the density of water is higher than the density of oil.

Products at a slow speed rises to the wellhead over the entire cross section of the well, while there is a gravitational separation of water and oil. The adjusting device 15 is experimentally tuned so that, by virtue of fitting, to supply significantly less liquid to the flow line than the pump is pumping out of the reservoir. At the same time, overpressure is created in the well, under the influence of which the main amount of water is pumped into the absorption layer 2, and all oil taken from the productive formation that floats to the wellhead along the production string, and a small amount of water enter the flow line.

The amount of water pumped into the absorbing layer is defined as the difference between the pump capacity and the amount of liquid lifted to the surface, and can be varied widely by a regulating device 15. The productivity of fluid selection from the reservoir is regulated by changing the USHN operating mode (stroke length - swing frequency). Water quality is monitored at the required frequency by analyzing samples taken through the sampler 21 from the cavity of the additional pipe string 20, where water flows from the lower part of the well under the influence of excess pressure controlled by a pressure gauge 23.

Since the pressure at the wellhead above 40 atm, that is, above the working pressure of a standard wellhead stuffing box 24, may be required to pump the required amounts of water into the absorbing layer, an additional seal 26 of the wellhead shaft 27 is placed under the tee 25. The additional seal 26 is designed to absorb the pressure created in the operational the column, while minor leaks occur, will flow into the tee 25 and through branch 28 to the flow line 14 after the control device 15, where the oil pressure will already be Yes. Thus, the wellhead seal 24 operates in its usual conditions.

The inventive system also contains at least one borehole sucker-rod pumping unit with a double-acting pumping system, which ensures subsequent injection of produced water into the absorbing underlying formation.

This installation and its location relative to the layers shown in figure 4.

In the flooded well 1, from which the absorbing formation 2 located above the producing formation 3 is accessible and perforated, a double-acting regulated pump 29 is launched on the tubing string 4. The opened formations are disconnected by the packer 6. The installation of the controlled double-acting pump (LDR) 29 is located in the well above productive formation 3. On the cylinder 30 of the NDRM 29, a hole is made on the side, on which the side suction valve 31 for oil is located. A packer 6 is installed above the roof of the absorbing formation 2. An intermediate tubing string 32 is located below the PDDR 29. At the bottom of the intermediate tubing string 32 directly above the packer 6 is a valve block 33, consisting of a suction 34 and a discharge valve 37 for water. In the cylinder 30, a plunger 35 and an additional plunger 36 are located. The plunger 35 is made with a discharge valve 38 for oil and is connected to the rod string pump (SHN) 41. A rod 39 is attached to the lower end of the plunger 35, which is placed in the cavity 40 of the additional plunger 36 with the possibility of limited reciprocating movement of the additional plunger 36 relative to the rod 39. During operation, the installation drive reports to the column ШН 41 and the plungers 35 and 36 connected to it, the reciprocating movement. On figa shows the installation in the extreme lower position of the plungers. When the plunger 35 moves upward, an additional plunger 36 will follow the plunger 35 due to the resulting pressure drop. In the cavity of the intermediate tubing string 32 and under the additional plunger 36, water will flow from the well through the suction valve 34. An additional plunger 36 will follow the plunger 35 until the lower end of the plunger 35 reaches the side opening in the cylinder 30 (Fig. 4b). In this position, the pressure above and below the additional plunger 36 will equalize, its upward movement will stop, and the plunger 35 will continue to move up to its highest position (Fig.4c), while oil will flow through the suction valve 31 into the cylinder cavity under the plunger 35. Then the plunger 35 will begin to move down. The suction valve 31 closes, the additional plunger 36 remains in place, because for it to move down it needs to overcome the pressure of the absorbing formation. The discharge valve 38 opens and oil flows into the cylinder cavity above the plunger 35. With a further downward stroke, the plunger 35 abuts against the additional plunger 36 (Fig. 4b), pushes it down and moves to its lowest position (Fig. 4a). In this case, through the opened discharge valve 37, water from the liner is displaced into the absorption layer 2. Further, the cycles are repeated.

In the description of the invention, the elements shown in the singular should not be understood as used only in a single copy, but should be understood as used in the form of one or more elements, unless specifically indicated otherwise. The sequence of steps of the method and the sequence of functioning of the elements of the system should not be understood as rigid and unchangeable, unless explicitly stated otherwise. The disclosed steps and operations may follow in an order different from that described, part of the steps and operations may be omitted if the objective of the invention is achieved and its purpose is realized.

The described embodiments are preferred and not described in order to limit the scope of the invention, numerous other embodiments within the spirit of the invention, which should also be construed as falling within the scope of the claimed invention, will be apparent to those skilled in the art.

Claims (4)

1. A method of operating highly waterlogged sections of oil fields, comprising stages in which
determine the total number of wells with high water cut;
determine the geometric location of the donor formation in relation to the absorbing horizon for each well;
determining the injectivity of the absorbing horizon for each well;
determine the daily volume of produced water for each well;
on the basis of the data obtained, at least in terms of the geometrical location of the donor layer with respect to the absorbing horizon, and also from the condition that the injectivity of the absorbing horizon is higher than the daily volume of produced water, the type of double-acting pump system that provides subsequent injection of produced water is determined in the absorbing overlying or underlying formation for each well, while pumping produced water in the overlying formation, less liquid is pumped into the overflow line than is pumped out They use a borehole sucker rod pump installation, and under the tee at the wellhead, an additional wellhead rod seal is placed to absorb pressure, and when the produced water is pumped into the underlying formation, the sucker rod pump is equipped with a shank and an additional water plunger connected with the main plunger and providing the opportunity to overcome absorbing reservoir pressure;
at least one well of a field with high water cut is operated using a well sucker rod pump unit with a certain type of pumping system. 2. The method according to claim 1, in which the total number of wells of the field with high water cut is preliminarily determined based on at least one water cut characteristic of the donor formation for the well. 3. The operation system of highly watered sections of oil fields according to the method according to p. 1, containing
a computing unit configured to, based on input data including at least data on the depth of the donor formation and the absorbing horizon, the injectivity of the absorbing horizon and the daily volume of produced water, determine the type of double-acting pump system that provides the subsequent injection of produced water in an absorbing overlying or underlying formation; at least one borehole sucker-rod pumping unit with a double-acting pumping system, which provides for subsequent injection of produced water in an absorbing overlying formation;
at least one borehole sucker-rod pumping unit with a double-acting pumping system, which ensures subsequent injection of produced water in the absorbing underlying formation. 4. The system of claim 3, wherein the input data further includes a water cut characteristic of the donor formation for the well.

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