Inhibitor feed device and method for protecting well equipment

Abstract

The invention relates to means for protecting downhole production equipment or surface oilfield equipment against corrosion, scale and deposits of salt or paraffin. A device for feeding an inhibitor into a wellbore or into the pipes of surface oilfield equipment comprises a receptacle container which is designed for attachment to downhole production equipment or for placement inside the pipes of surface oilfield equipment. Said container contains separate receptacles for receiving an inhibitor, the receptacles being configured in the form of hollow cylinders, each of which has mounted therein at least one removable metering device comprising a metering disc, a filter element and a chamber for a saturated solution of inhibitor. The hollow cylinders are provided with metering holes designed to allow hydraulic communication between the inside of the saturated inhibitor solution chambers and a wellbore or the inside of pipes of surface oilfield equipment. The metering devices are designed so that the metering discs and filter elements can be replaced. The invention further relates to a method for using the claimed device to protect downhole production equipment or surface oilfield equipment against corrosion, scale and deposits of salt or paraffin. The invention makes it possible to adjust the inhibitor metering regimes depending on the nature of the deposits.

Description

[0001] Inhibitor Delivery Device and Method for Protecting Well Equipment

[0002] DESCRIPTION

[0003] Field of technology to which the invention relates

[0004] The invention relates to methods and devices for protecting deep-well pumping equipment (DPE) of drilling wells and surface oilfield equipment (SOE) from corrosion, scale, salt or paraffin deposits by delivering an inhibitor into the production well or into the annular space of the SOE.

[0005] State of the art

[0006] The Tril® adjustable submersible well container (https: / / clck.ru / 39NaGP, published February 8, 2011) is known from the prior art. It is equipped with an adjustable multi-stage dosing mechanism. After lowering the downhole pumping equipment (DPE), including the Tril container, and starting the well, the produced fluids wash the container, from which the inhibitor or its saturated solution is gradually dissolved in the produced fluids, thereby achieving self-dosing of the reagent. The dosing mechanism is adjusted once, before lowering the container into the well.

[0007] Also known is a DEVICE FOR FEEDING A REAGENT INTO A WELL, GROUND EQUIPMENT AND A METHOD FOR FEEDING A REAGENT (RU2552276C1, published 2015.06.10), in which a container consisting of sections is used as a device for feeding a reagent. In each section of the container, one or more cartridges with a reagent are located. The cartridge is closed at the ends with plugs with adjustable primary metering mechanisms or at one end with a blind plug, and at the other - with a plug with adjustable primary metering mechanisms, wherein the adjustable secondary metering mechanisms, through which hydraulic communication with the downhole or intra-tube space is carried out, are located in that part of the container sections that is formed between the adjustable primary metering mechanisms of the cartridges and the blind plug of the container section, or the end of the container section, or another cartridge.Adjustment and configuration of the primary dosing mechanisms is performed during assembly of the device at the factory. The prototype of the claimed technical solution can be considered the METHOD OF FEEDING LIQUID AND SOLID REAGENTS AND THE DEVICE FOR ITS IMPLEMENTATION (RU2342519C2, published 2008.12.27), in which the device is designed as a chamber container connected to the lift pipes or the internal space of the pipe. The chamber container consists of several hollow cylinders with openings, hydraulically connected to the well or internal space.The container consists of chambers connected in series at the ends with filters or filters installed in each chamber, which act as initial dosing devices, while the openings through which hydraulic communication with the downhole or intra-pipe space is carried out and which act as secondary dosing devices are located only in the pre-mixing tank, which is formed between the filter and the blind plug of the chamber or between two filters.

[0008] All of the above technical solutions involve pre-setting the minimum inhibitor flow rate depending on the known operating parameters of the well or NNO, however, the disadvantage of the analogs and the prototype is the fixed mounting of the dosing devices in the housing, the lack of the ability to adjust or replace them, and, therefore, the lack of the ability to change the operating mode of the device during operation, for example, when changing the operating parameters of the well, in particular, the parameters of water cut or flow rate, which can lead to a decrease in the effectiveness of equipment protection, a reduction in the service life of the device and, ultimately, cause the need for a complete replacement of the device.

[0009] Disclosure of the essence of the invention

[0010] The objective of the present invention is to eliminate the disadvantages of known solutions, in particular, by creating a device for feeding an inhibitor into a well or into the in-tube space of ground-based oilfield equipment with replaceable filter-dosers and / or their components, allowing for the adjustment of the operating modes of the device during operation, and a method for its use, allowing, in the event of a sharp change in the operating parameters of a well or oilfield equipment, for changing the operating parameters of the device.

[0011] The stated problem is solved by the claimed invention, which, in its first aspect, is a device for feeding an inhibitor into a well or into the intra-tube space of ground oil field equipment, including a capacitive container made with the possibility of being connected to the GNO or placed into the intra-tube space of the NNO, containing separate containers for placing the inhibitor in them, made in the form of hollow cylinders, inside each of which at least one dosing device is mounted, containing a dosing disk, a filter element and a chamber for a saturated solution of the inhibitor, wherein in the hollow cylinders there are dosing holes made with the possibility of hydraulic communication of the internal space of the chambers of the saturated solution of the inhibitor with the well or the intra-tube space of the NNO, characterized in that,that the dosing devices with a chamber of saturated inhibitor solution are fixed in hollow cylinders in a removable manner and are designed with the possibility of replacing the dosing disks and filter elements.

[0012] In particular, the containers for storing the inhibitor are separated from each other by dosing devices or blind plugs.

[0013] In particular, the dispensing device contains one or more gaskets made of a material capable of elastic deformation, for example, heat-resistant oil-resistant rubber.

[0014] In particular, the dosing discs are made of metal or synthetic material.

[0015] The claimed invention in its first aspect ensures the achievement of the following technical result - the possibility of replacing dosing devices and / or their parts during operation.

[0016] In this case, the term "inhibitor" refers to a chemical substance or mixture of chemical substances that prevent or hinder physical and chemical processes that complicate the operation of production equipment, such as corrosion, deposits of salts, resins or paraffins, and scale formation.

[0017] The said problem is also solved by the claimed invention, which, in its second aspect, is a method of using the claimed device for protecting a well or a downhole drilling and processing facility from corrosion, scale, salt or paraffin deposits, characterized in that the well operating parameters and the nature of the complications that impede the operation of the equipment are determined; the type of inhibitor required is determined based on the nature of the complications; the amount of inhibitor required to protect the equipment is determined by calculation, based on the nature of the complications and the well operating parameters, and an inhibitor of a certain type and in a certain amount is placed in the device's tank; the required throughput of the dosing devices for maintaining the minimum effective dosage of the inhibitor is determined by calculation, based on the well operating parameters and the type of inhibitor, the dosing disks in them are replaced with disks with an appropriate throughput, and they are mounted in the device's tank;by calculation, based on the well operating parameters, the number and / or area of ​​open metering holes required to maintain the minimum effective concentration of inhibitor in the produced fluid is determined, and the rest are plugged; the claimed device is placed in the wellbore or in the intra-tube space of the wellbore control system; the inhibitor is dissolved by the produced fluid penetrating the device through the metering holes hydraulically connected to the wellbore or the intra-tube space of the wellbore control system and filling the chambers of the saturated inhibitor solution of the dosing devices, passing through the metering elements into the containers filled with the inhibitor, dissolving it and creating a saturated inhibitor solution in the chambers of the dosing devices, while the inhibitor is dosed into the produced fluid due to the flow of the resulting solution from the chambers of the dosing devices into the wellbore or into the intra-tube space of the wellbore control system through the metering holes;and characterized in that the operating parameters of the well or NNO are monitored and, if the operating parameters of the well or the parameters of the produced liquid change: the required minimum throughput of the dosing devices is determined by calculation based on the changed operating parameters of the well; the device is removed from the wellbore or from the intra-tube space of the NNO; the device is disassembled into containers, the dosing device or dosers are dismantled; the amount of inhibitor is replenished or the chambers of the device are filled with a different type of inhibitor; the dosing devices are replaced and / or the dosing disks in the dosing devices are replaced with disks with holes of a different diameter and / or the filter elements are replaced; the device is assembled in a container; the device is adjusted by opening the required number of dosing holes, determined by calculation based on the changed operating parameters of the well or the produced liquid;place the declared device into the wellbore or into the internal space of the wellbore.

[0018] The claimed invention in its second aspect ensures the achievement of the following technical results: the ability to change the operating parameters of the device when the operating conditions of the well or NNO change; an increase in the operating life of the device; an increase in the production time of the well or NNO.

[0019] Brief description of the drawings:

[0020] Fig. 1. General view of the claimed device in section.

[0021] Fig. 2. Dosing device with a chamber for a saturated inhibitor solution.

[0022] The following are indicated on the figures: 1 - body; 2 - coupling; 3 - thread; 4 - dispenser; 5 - fixing bolts; 6 - metering holes; 7 - inhibitor; 8 - lower metering disk; 9 - tightening bolts; 10 - upper metering disk; 11 - sealing gasket; 12 - filter element; 13 - lower thrust disk; 14 - upper thrust disk; 15 - thrust plates; 16 - chamber of saturated inhibitor solution; 17 - nuts.

[0023] The device for feeding an inhibitor into a well (Fig. 1) comprises a cylindrical container in a housing 1, which is a section of tubing (oil well tubing) with a nominal diameter of 48.0 mm and a length of 0.5 m and a wall thickness of 5.0 mm, or an assembly of several such sections, interconnected by rigid metal couplings 2 on threads 3, or a flexible connection. A blind metal plug (not shown in the figures) is installed at the lower end of the lower section.

[0024] One or more dosing devices 4 are mounted inside the cylindrical housing 1, pre-fixed in place with bolts 5 through threaded dosing holes 6, and, in the embodiment with one dosing device, the opposite end of the housing 1 is welded with a blind metal plug (not shown in the figures). In the space formed by the dosing devices 4 (or the dosing device and the plug) and the walls of the housing 1, a liquid or solid inhibitor is located

[0025] 7.

[0026] The dosing device 4 contains a lower dosing disk 8, made of sheet metal or synthetic material, in the center of which at least one dosing hole is made with a diameter selected depending on the properties of the selected inhibitor and the operating parameters of the well, and four square holes along the perimeter for tightening bolts 9 with square heads, and an upper dosing disk 10, similar to disk 8, and characterized in that the holes for bolts 9 are made round, separated by a sealing gasket 11 with a filter element 12.

[0027] The sealing gasket 11, made of a moisture-resistant, oil-resistant, heat-resistant elastic material, has a central opening for installing a filter element 12, made of a filter material with a certain throughput, for example, based on ultra-high molecular weight polyethylene (UHMWPE) or polytetrafluoroethylene (PTFE), and is intended for sealing and fixing the dosing device in the housing 1, as well as sealing the installation of the filter element 12 in the dispenser.

[0028] Above the dosing disk 10, through another sealing gasket 11, a lower thrust disk 13 is installed, having one round hole in the center and four holes for bolts 9, made of sheet metal or synthetic material, and an upper thrust disk 14 similar to it, separated from each other by thrust plates 15, made of a steel sheet with a thickness of 2 - 4 mm, or steel thrust cylinders-tubes (not shown in the figures), put on bolts 9, and forming the skeleton of the chamber 16 of the saturated inhibitor solution, the space of which is limited by the walls of the housing 1 and thrust disks 13 and 14.

[0029] Bolts 9 are inserted into the square holes of the metering disk 8 and secured with nuts 17.

[0030] The final fixation and sealing of the dosing device 4 in the housing 1 is achieved by tightening the structure with bolts 9 and nuts 17, during which the elastic sealing gaskets 11, placed between the metal disks 8, 10 and 13, undergo elastic deformation, during which their diameter increases due to a decrease in thickness, the outer edges of the gaskets 11 tightly adjoin the inner walls of the cylindrical housing 1, fix the device and exclude the hydraulic connection of the chamber 16 of the saturated inhibitor solution with the container containing the inhibitor 7, in addition to the openings of the dosing disks 8 and 10 with the filter element 12.

[0031] Thus, the claimed technical result - the possibility of replacing the dosing devices and / or their parts during operation, is achieved due to the fact that the dosing devices 4 with the chamber 16 of the saturated inhibitor solution are fixed in the housing 1 in a removable manner, for example, fixed in the housing 1 of the device by means of bolts 5, made with the possibility of removal / installation, and / or fixed by a tight fit due to the reversible elastic deformation of the sealing gaskets 11 adjacent to the walls of the housing 1 when tightening the nuts 17, and / or fixed in the housing 1 by internal retaining rings (not shown in the figures), made with the possibility of removal / installation, and the dosing device 4 itself is made of dosing disks 8 and 10, made with the possibility of replacing them with disks with other diameters of holes, separated by a gasket 11 with a filter 12, also made with the possibility of replacing with another diameter, and a chamber 16 of the saturated inhibitor solution,formed by thrust disks 13 and 14, separated by thrust plates 15, and the entire structure is made collapsible on bolts 9 with nuts 17.

[0032] The claimed device is used in the following manner:

[0033] They determine the well operating parameters (flow rate, water cut, time between repairs (TBR) and the nature of complications that impede the operation of the equipment (corrosion, deposition of salts, resins or paraffins, scale formation).

[0034] The type of inhibitor required is determined, for example, an inhibitor against ASPD (asphalt, resin, and paraffin deposits), or an inhibitor against ASPD and emulsion formation, or an inhibitor against salt deposits, or an inhibitor against corrosion, or a combination of the specified reagents.

[0035] The amount of inhibitor required to protect equipment over a certain expected long-term period is determined by calculation.

[0036] By calculation, based on the well operating parameters and the inhibitor type, the required throughput of the dosing devices is determined to maintain the minimum effective dosage of the inhibitor, after which the structure of the dosing device 4 is assembled with the chamber 16 of the saturated inhibitor solution, using the dosing disks 8 and 10 with holes, the diameter or the sum of the diameters of which corresponds to the calculated throughput, without finally tightening the nuts 17 of the bolts 9, and placed inside the cylindrical body 1 of the device, placing the upper thrust disk 14 along the start line of the thread 3 to create the maximum free volume inside the body 1.

[0037] Using calculations based on the well operating parameters, the number and / or area of ​​metering holes 6 required to maintain the minimum effective inhibitor concentration in the produced fluid is determined. Through metering holes 6 are then drilled in the wall of housing 1 so that they are located within the volume of chamber 16, which contains the saturated inhibitor solution, and threads are cut into them. The number of metering holes is determined based on the properties of the inhibitor and the estimated performance of the device (minimum two holes per chamber).

[0038] Screw the fixing bolts 5 into the dosing holes 6, having first fixed the dosing device 4 in the housing 1.

[0039] Tighten nuts 17 on bolts 9, ensuring final fixation and sealing of the dispensing device 4 in housing 1 due to the elastic deformation of gaskets 11.

[0040] From the other end of the housing 1, the housing is filled with the selected inhibitor 7, after which, according to the procedure described above, the second dosing device 4 is mounted, dosing holes 6 are made and they are closed with bolts 5.

[0041] The required number of housings 1 assembled in this manner are connected into a container by connecting them with couplings 2 on threads 3 or flexible adapters, while a blind metal plug is screwed onto the lower end of the lower housing 1.

[0042] At the well or at the installation site on the wellhead, the container with the inhibitor assembled in this way is placed in the internal space of the wellhead, or is connected with its upper end to the submersible wellhead through a coupling 2 or an adapter, and is immersed in the well, having first adjusted the device by removing the required number of bolts 5 from the metering holes 6. The required area of ​​the open metering holes 6 is determined by a calculation method based on the selected inhibitor(s) and the operating parameters of the well.

[0043] The inhibitor is dissolved by the produced liquid, penetrating into the device through the metering openings 6, hydraulically connected with the wellbore or the intra-tube space of the NNO, and filling the chambers 16 with a saturated solution of the inhibitor of the dosing devices 4, entering through the dosing elements into the tanks of the body 1, filled with the inhibitor 7, dissolving it and creating a saturated solution of the inhibitor in the chambers of the dosing devices 4, while a metered supply of the inhibitor is carried out into the produced liquid due to the flow of the resulting solution from the chamber of the dosing device 4 into the wellbore or into the intra-tube space of the NNO through the metering openings 6;

[0044] Monitoring of well or wellhead operating parameters is carried out.

[0045] In the event of a significant change in the operating parameters of a well or a wellhead system, for example, water cut or flow rate, during an unscheduled, routinely scheduled, or major repair of a well, the wellhead system column with the container attached to it is lifted, the container is disconnected, or it is removed from the internal space of the wellhead system, and it is disassembled into separate bodies.

[0046] From one end of the housing 1, all bolts 5 are removed, nuts 17 on the upper dosing device 4 are loosened, as a result of which the gaskets 11 are reduced in diameter due to elastic deformation and the dosing device 4 is released in the housing 1 for its removal.

[0047] Using a calculation method, based on the changed operating parameters of the well, a new value for the required minimum throughput of dosing devices 4 is determined;

[0048] Disassemble the dosing device 4 by unscrewing the nuts 17 from the bolts 9, remove the bolts 9 and replace the dosing disks 8 and 10 with disks with holes of a different diameter, replace the filter element 12 if necessary, after which assemble the dosing device on the bolts 9 with nuts 17, without tightening them completely.

[0049] If necessary, add the amount of inhibitor or fill the capacity of housing 1 of the device with another type of inhibitor.

[0050] The dosing devices 4 are mounted into the housing 1, fixing their position with bolts 5 screwed into the dosing holes 6, after which the final fixation and sealing is carried out by tightening the nuts 17 on the bolts 9.

[0051] The housings 1 are reassembled into the container using couplings 2 or adapters.

[0052] The container is adjusted by opening the required number of metering holes 6, determined by calculation based on the changed operating parameters of the well or the produced liquid, by opening or closing part of the metering holes 6 with bolts 5. The declared device is placed in the wellbore or in the internal tubular space of the wellbore and operation continues.

[0053] Thus, the declared technical results - the ability to change the operating parameters of the device under changed operating conditions of the well or NNO, an increase in the operating life of the device and an increase in the production time of the well or NNO, are achieved due to the fact that the declared device is made disassemblable with the ability to refill with inhibitor, replace dosing devices and / or replace their structural elements.

[0054] Submersible well containers (SWC) of the claimed design were used to combat salt deposits and asphaltene and paraffin deposits in the complex well stock of the Ozen oil field (Kazakhstan).

[0055] A PSC consisting of 9 containers of 1.5 meters each with 9 open dosing holes (one in each container) was lowered into the well with a flow rate of 138 m 3 / day, water cut of 68% and an inter-repair period (IRP) of 122 days.

[0056] The well operated with the stated device for 228 days after commissioning, after which it was shut down due to a problem with the ESP. An increase in water cut of up to 80% was also recorded during the well's operation.

[0057] After lifting the ESP, no scale deposits were detected in the ESP. Thanks to the dismountable design, the internal dosing devices were removed from the containers, and the ESP was tested for residual inhibitor content, which was approximately 50%.

[0058] Taking into account the absence of salt deposits on / in the wellbore and the increase in water cut in the well, a decision was made to replace the dosing disks of the internal dosing devices with elements with a lower throughput (smaller diameter holes) to reduce the dosage of the inhibitor in the produced fluid and, accordingly, reduce the consumption of the inhibitor.

[0059] After the well was restarted, the production time on the remaining half of the inhibitor amounted to more than 463 days, i.e. more than twice the previous one (228 days).

[0060] In total, the PSC effectively operated in the well for 691 days, increasing the well's production time by more than 5 times compared to the 122 days of production before implementation.

[0061] PSC.

Claims

FORMULA 1. A device for feeding an inhibitor into a well or into the intra-tube space of surface oil field equipment (OFE), comprising a capacitive container designed with the possibility of being connected to deep-well pumping equipment (DPE) or placed into the intra-tube space of the OFE, containing separate containers for placing the inhibitor in them, made in the form of hollow cylinders, inside each of which at least one dosing device is mounted, containing dosing disks, a filter element and a chamber for a saturated solution of the inhibitor, wherein in the hollow cylinders there are dosing holes designed with the possibility of hydraulic communication of the internal space of the chamber for a saturated solution of the inhibitor with the well or the intra-tube space of the OFE, characterized in that at least one dosing device contains at least two dosing disks, between which a filter element is fixed,and at least one dosing device with a chamber of a saturated inhibitor solution is fixed in each of the hollow cylinders in a removable manner and is designed with the possibility of replacing the dosing disks and filter elements.

2. The device according to claim 1, in which the containers for placing the inhibitor are separated from each other by dosing devices or blind plugs.

3. The device according to claim 1, in which the dispensing device contains one or more gaskets made of a material capable of elastic deformation, for example, heat-resistant oil-resistant rubber.

4. The device according to claim 1, wherein the dosing disks are made of metal or synthetic material.

5. A method for protecting a well or a downhole drilling and processing facility from corrosion, scale, salt or paraffin deposits, comprising using the device according to paragraph 1, characterised in that the well operating parameters and the nature of the complications hindering the operation of the equipment are determined; the type of inhibitor required is determined based on the nature of the complications; the amount of inhibitor required to protect the equipment is determined by calculation based on the nature of the complications and the well operating parameters, and an inhibitor of a certain type and in a certain amount is placed in the device's tank; the required throughput of the dosing devices for maintaining the minimum effective dosage of the inhibitor is determined by calculation based on the well operating parameters and the type of inhibitor, the dosing disks in them are replaced with disks with the appropriate throughput, and they are mounted in the device's tank;by calculation, based on the well operating parameters, the number and / or area of ​​open metering holes required to maintain the minimum effective concentration of inhibitor in the produced fluid is determined, and the rest are plugged; the claimed device is placed in the wellbore or in the intra-tube space of the wellbore; the inhibitor is dissolved by the produced fluid penetrating the device through the metering holes hydraulically connected to the wellbore or the intra-tube space of the wellbore and filling the chambers of the saturated inhibitor solution of the dosing devices, passing through the metering elements into the containers filled with the inhibitor, dissolving it and creating a saturated inhibitor solution in the chambers of the dosing devices, while the inhibitor is dosed into the produced fluid due to the flow of the resulting solution from the chambers of the dosing devices into the wellbore or into the intra-tube space of the wellbore through the metering holes;and characterized in that the operating parameters of the well or NNO are monitored and, when the operating parameters of the well or the parameters of the produced liquid change, the necessary one is determined by calculation, based on the changed operating parameters of the well; minimum capacity of the dosing devices; remove the device from the wellbore or from the intra-tube space of the wellbore; disassemble the device into containers, dismantle the dosing device or dosing devices; add to the amount of inhibitor or fill the chambers of the device with a different type of inhibitor; replace the dosing devices, and / or replace the dosing disks in the dosing devices with disks with holes of a different diameter, and / or replace the filter elements; assemble the device in the container; adjust the device by opening the required number of dosing holes, determined by calculation based on the changed operating parameters of the well or the produced liquid; place the declared device in the wellbore or in the intra-tube space of the wellbore.

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