Systems and methods for isolation and chemical injection in completion strings for oil wells with open intervals

Abstract

A system for isolation and chemical injection in a completion string for an oil well having an open interval includes an expandable inner bag and swellable material, a chemical injection hydraulic line circuit of a chemical injection system, and at least one chemical injection mandrel. The chemical injection hydraulic line circuit is of the feedthrough type and is in fluid communication with the inner bag and at least one expandable and swellable packer. In addition, methods of isolation and chemical injection in a completion string for a well having an open interval are disclosed.

Description

Technical Field

[0001] The present invention relates to the technical field of methods and apparatuses for isolating wellbore intervals in oil wells. More specifically, the present invention relates to systems and methods for isolating and chemically injecting a completion string having open intervals. Background Art

[0002] A swellable packer is an isolation device that typically relies on an elastomeric material to swell and form an annular seal when immersed in certain well production fluids. The elastomeric materials used in these packers are typically sensitive to oil or water.

[0003] The placement of a swellable packer is typically carried out by the operation of lowering these packers in a completion string to a designed depth. After positioning the swellable packer in the interval selected in the completion design, the swelling process is initiated, and when completed, selectivity of the production intervals between the swellable packers is obtained.

[0004] However, swellable packers involve some risks and difficulties associated with their use. Notably, after being positioned at the designed depth, a swellable packer may take 3 to 10 days to complete its swelling process. During this swelling period, it is not advisable or possible to carry out chemical treatment operations in the well interval because it cannot be guaranteed that the interval will be selective. In other words, during the swelling period, it cannot be guaranteed that the seals performed by the swellable packers are strong enough to allow pressurization around the packers, thus ensuring their sealing against the formation.

[0005] Therefore, some undesirable situations may occur if the packers are not waited for a long time to complete the swelling process. For example, in the case of intervals with a significant static pressure difference or intervals with a fracture gradient close to the pumping pressure value to be used in the chemical treatment, due to the lack of selectivity (which is due to the packers not having completed the necessary swelling time), there is a risk of situations ranging from the flow being diverted to undesired intervals due to fracturing occurring in intervals with a lower fracture gradient value (which may occur simply due to the value of the resulting hydrostatic pressure as a function of the true vertical depth (TVD) associated with the weight of the fluid to be used in the treatment).

[0006] Therefore, there is a need for advancements in solutions for isolating completion intervals to isolate between production intervals faster and at a reduced cost.

[0007] Prior Art

[0008] The prior art discloses some documents containing teachings regarding methods and apparatuses for isolating and / or treating wellbore intervals.

[0009] Document US 7322422 B2 discloses a completion assembly for use in a well, which includes at least one expandable packer, at least one control line, and at least one pressurized fluid source, wherein at least one pressurized fluid source is in fluid communication with at least one expandable packer through at least one control line.

[0010] Document WO 2005052308 A1 discloses an expandable (bag) having a swellable layer. The swellable layer can be bonded or attached to an element, or can be connected or otherwise attached to a mandrel. When expanded with a fluid, the element expands into sealing contact with the surrounding pipe or borehole. The fluid is absorbed into the swellable layer or otherwise interacts with the swellable layer such that in a preferred embodiment, after mixing with a layer filler (which is used to maintain the uniform sealing of the expandable element in the event of a seal element failure), the total occupied volume of the swellable layer and the fluid is retained.

[0011] Document US 8499843 B2 discloses a sealing system for use in a borehole to seal an outer surface such as a casing or an open borehole, such as a packer. The sealing system includes a swellable material that changes from an unexpanded state to an expanded state to create a seal when the swellable material contacts a trigger fluid.

[0012] Document PI 0314637-5B1 discloses an apparatus and method for forming an annular insulator in a wellbore after installation of a production pipe. When the production pipe is advanced into the wellbore, an annular sealing device is carried within or inside the production pipe. In combination with the expansion of the pipe, the seal unfolds to form an annular insulator. The expandable element carried in the pipe can be expanded with a fluid carried in the pipe and forced into the expandable element during pipe expansion. Reactive chemicals can be carried in the pipe and injected into the annular crown to react with each other and with the surrounding fluid to swell and harden within the annular seal. An elastic sleeve, ring, or band carried in the pipe can be expanded to contact the wellbore wall and, in combination with the expansion of the pipe, can increase its radial dimension to form an annular insulator.

[0013] However, the pipe in Document PI 0314637-5 is apparently a small-diameter pipe, and its flow rate is generally in the range of 2 to 4 liters per minute, which is just sufficient to meet the expansion requirements of the packer.

[0014] In addition, it is known from the prior art that depending on the chemical products to be used in the pipe, a specific metallurgy is required to resist differences in pH and / or alkalinity, and differences in value ranges, which may be corrosive to the pipes used normally, thereby causing damage to the pipes.

[0015] It is evident that there are persistent deficiencies in the prior art. Accordingly, the features and advantages of the present invention will become clearly apparent from the following detailed description and with reference to the accompanying drawings, which are provided only as preferred and non-limiting embodiments. Summary of the Invention

[0016] The present invention discloses a system for isolation and chemical injection in a completion string for a well having an open interval, the system including an expandable inner bag and a swellable material, a hydraulic chemical injection pipeline loop of a chemical injection system, and at least one chemical injection mandrel. The chemical injection hydraulic pipeline loop is a feed-through type and is in fluid communication with the inner bag of at least one expandable and swellable packer. Additionally, a method for isolation and chemical injection in a completion string for a well having an open interval is disclosed. Brief Description of the Drawings

[0017] To supplement this description and obtain a better understanding of the features of the present invention, the accompanying drawings are shown by way of example and not limitation, in which its preferred embodiments are presented.

[0018] Figure 1 A packer and hydraulic pipeline assembly according to a preferred embodiment of the present invention is shown.

[0019] Figure 2 An exemplary sequence of expansion of a packer according to a preferred embodiment of the present invention is shown.

[0020] Figure 3 An exemplary sequence of swelling of a packer according to a preferred embodiment of the present invention is shown.

[0021] Figure 4 A check valve in a valve assembly in the hydraulic pipeline is shown in more detail.

[0022] Figure 5 A packer assembly further including a sliding sleeve valve and a chemical injection mandrel is shown.

[0023] Figure 6 The preferred installation and placement sequence of each packer is shown.

[0024] Figure 7 Alignment of the original inhibitor fluid circulation loop for selectively releasing the applicable chemical injection mandrel in the string using the sliding sleeve valve is shown.

[0025] Figure 8 Final swelling of the packer after selective release of the original loop alignment is shown. Detailed Description of the Invention

[0026] The present invention relates to a system and method for isolation and chemical injection in a completion string for a well having an open interval.

[0027] A major technical problem of the present invention is to ensure the isolation of the intervals of these wells during the completion stage of open production wells, where swellable packers are usually applied, which generally takes a long time to complete the swelling process before chemical treatment can be carried out in the production intervals.

[0028] The solution achieved by the present invention enables faster isolation and treatment between production intervals. For isolation, two general steps are involved. First, the internal component of the packer is inflated with a fluid so that it can already adhere to the production formation, thereby achieving an initial seal. Second, when the swellable (elastomeric) material of the packer swells after contact with the fluid, the overall adhesion of the packer will gradually increase, thereby further improving the sealing process related to the open wellbore. In this way, the proposed solution enables the process of laying the packer to be advanced. If necessary, by accelerating the process of laying the packer, the chemical treatment of the production area can also be advantageously anticipated.

[0029] More specifically, as Figure 1 shown, the present invention includes a packer equipped with an expandable internal component, an inner pipe, an external thread, and an internal thread, a hydraulic line, a check valve, and a rupture disc.

[0030] The packer is inflated using a selected hydraulic fluid that will be positioned inside the expandable bag of the packer. To make this possible, the hydraulic line of the chemical injection system installed in the completion string, which was originally intended to convey a scale inhibitor product to the chemical injection mandrel (CIM), is modified to pass between the outer rubber of the packer and the production string. The hydraulic line is a feed-through type related to the packer; this means that the line passes through the space between the string and the packer rubber parallel to the string. For this purpose, the packer assembly also includes a sliding sleeve door (SDD) valve that releases the corresponding chemical injection mandrel for each well interval, as Figure 5 shown.

[0031] The selected hydraulic fluid has two functions. The first is to promote the inflation of the inner bag in the packer through fluid communication with the feed-through hydraulic line, as sequentially shown in Figure 2 . The second function is that the selected hydraulic fluid reacts with the packer rubber on its internal component, thereby causing the packer rubber to gradually swell from the inside out, as sequentially shown in Figure 3 .

[0032] For this purpose, as Figure 4As shown, the packer has a set of valves equipped with check valves in the pipeline. The check valves are preferably of the double check valve type, and their purpose is to allow the flow to flow into the interior of the bag in the packer along the pipeline direction, which is intended for the packer inflation process. The check valves allow the hydraulic fluid to enter the interior of the bag to expand the packer, but do not allow the hydraulic fluid to leave the interior of the bag.

[0033] It should also be understood that after the packer is inflated, the locking of the check valves allows the fluid placed in the bag to remain in the bag to promote the absorption of the packer rubber and thus promote swelling.

[0034] The gradual swelling of the packer rubber caused by the reaction of the packer rubber with the selected hydraulic fluid will serve as a supplementary method for fixing the packer to the wellbore wall. More specifically, the liquid used to expand the packer will be absorbed by it, entering the secondary swelling process from the initial expansion process, and thus transforming the bag initially expanded due to the fluid into a consolidated bag material layer. The consolidated bag material layer will be positioned between the wellbore wall and the pipe string, thus closing the annular space between the pipe string and the wellbore wall.

[0035] After the packer is sealed, when the internal pressure in the packer bag reaches or is induced to reach a specific design value, the rupture disc installed in the feedthrough pipeline loop will rupture. In this sense, synchronization can be achieved between the check valves of each packer and the rupture discs located after each packer.

[0036] Therefore, as Figure 6 shown, each packer can be inflated individually after the previous packer is inflated. More specifically, the mentioned set of valves can achieve an operating sequence with the goal of satisfying the sequence of installation and placement of each packer in the annular space between the pipe string and the wellbore wall in each section (by inflation and swelling).

[0037] It should also be understood that considering the hydrostatic pressure at the depth of the corresponding packer, the rupture pressure values of the rupture discs can be adjusted in an increasing manner between the packers, so that the pressure values required for each disc to rupture increase sequentially from top to bottom.

[0038] In addition, as Figure 7 shown, after the installation and placement of the corresponding packer, the valve assembly allows the selective release of the alignment between the original inhibitor fluid circulation loop and the corresponding chemical injection mandrel of the pipe string with the use of a sliding sleeve door valve (SDD) applicable to each well section. In addition, Figure 8 it is shown that after the selective release of the alignment of the original loop, the corresponding packer finally swells over time.

[0039] It will be understood that the modification of the hydraulic pipeline in the present invention, which was originally a chemical injection system installed in the completion string and aimed at delivering a scale inhibitor product to the chemical injection mandrel, brings a series of advantages over the prior art.

[0040] One of these advantages is related to the flow loss problem. In the technical field of the present invention, in order to meet the flow rate required for chemical treatment in the well, it is an unusual solution to reuse the chemical injection system to expand and swell the packer and then perform the treatment. It has been observed that in offshore (subsea) facilities, the chemical treatment flow rate into the well reservoir is usually high, and the average variation range can be from 3 barrels per minute to 10 barrels per minute (1 barrel = 159 liters), and therefore, the pipeline usually used to expand the packer will not be suitable for subsequent chemical treatment.

[0041] Therefore, those skilled in the art should understand that the present invention is applied to multiple fields, such as the production development field, the construction of wells, and the completion equipment with open intervals; that is, without casing, and it accelerates the process of laying the packer.

[0042] The present invention is also used in the reservoir management field in water management, aiming to accelerate chemical treatment within the opportunity range, and in flow assurance (GARESC), to cooperate with the planning of active chemical treatment operations to prevent scaling in subsea systems (such as production pipelines, manifolds, and risers).

[0043] In addition, it will be understood that the present invention has a particular application in formations with a low fracture gradient where rapid annulus isolation is required, and thus allows the next operation to be carried out in a reservoir where the pressure value is higher than the fracture pressure of the layer isolated by the packer. Therefore, the present invention attempts to avoid the possibility of selective loss of intelligent completion caused by the possibility of fracture in the low fracture pressure area, thereby avoiding the occurrence of undesirable communication between the intervals isolated by the packer.

[0044] In addition to the above, the present invention also brings many other advantages. Some of them are listed below, but not exhaustively.

[0045] Economic and productivity advantages: Laying the packer that expands and then swells will accelerate the packing operation, and thus the isolation of the intervals will allow the selectivity of these intervals, enabling acidification and / or chemical treatment operations, such as inhibition and active squeeze, without the risk of cross-flow (inter-region communication) occurring immediately after expanding the packer. Therefore, these treatments can be carried out with the same rig that installs the completion string, thus reducing the costs associated with the operation of ships and / or light workover rigs ($153,000 per day).

[0046] Health and safety advantages: Reduce the need for additional operations using vessels and / or light workover rigs, and in addition to reducing the risk of collisions (collisions between vessels) caused by the combination of sea conditions and ship machinery failures, also reduce the risks associated with the docking between vessels and fixed production installations and / or light workover rigs and the operations using these vessels.

[0047] Reliability advantages: Improve the reliability of the selectivity of zonal isolation, because it ensures the isolation between the production zones of the well during the installation phase, which in previous models would take a long time to complete only through the chemical reaction of swelling the rubber with well fluids. It also improves fluid contact, and the fluid contact causes the swelling of the packer due to internal filling.

[0048] Environmental advantages: Reducing the use of well stimulation vessels (WSSV) and light workover rigs reduces carbon dioxide emissions and the waste discarded at sea by these vessels during their operations, which will contribute to environmental protection.

[0049] Social advantages: Given the proactive treatments that can be carried out, such as pre-inhibition and pre-extrusion, ensuring production maintenance directly contributes to maintaining royalty payments.

[0050] Preferred Embodiment

[0051] In a preferred embodiment, the present invention discloses a system for isolation and chemical injection in a completion string for a well having open zones, comprising:

[0052] At least one expandable and swellable packer assembly, which includes an expandable inner bag and a swellable material;

[0053] The chemical injection hydraulic pipeline circuit of the chemical injection system; and

[0054] At least one chemical injection mandrel,

[0055] Wherein the chemical injection hydraulic pipeline circuit is a feed-through type and is in fluid communication with the inner bag of at least one expandable and swellable packer. In a first configuration, the chemical injection hydraulic pipeline circuit provides fluid to fill the expandable inner bag, and the fluid reacts with the swellable material of at least one expandable and swellable packer.

[0056] Wherein the chemical injection hydraulic pipeline circuit further includes a corresponding valve assembly for each of at least one expandable and swellable packer, and wherein each valve assembly includes at least one double check valve and a rupture disk, and

[0057] After at least one inflatable and swellable packer is inflated, the chemical injection hydraulic line circuit is selectively switched to a second configuration for injecting scale inhibitor fluid through at least one chemical injection mandrel.

[0058] The system may also include a corresponding sliding sleeve door (SDD) valve for each well interval. Additionally, the inflatable and swellable packer assembly may further include external threads, an inner tube, and internal threads.

[0059] Preferably, the system is implemented in a completion string having three intervals, where the rupture disks include corresponding rupture pressure values in an increasing manner between the respective packers.

[0060] In another preferred embodiment, the present invention discloses a method for isolation and chemical injection in a completion string having open intervals, comprising the following steps:

[0061] a. Introduce into the well an assembly of at least one inflatable and swellable packer including an inflatable inner bag and a swellable material, a chemical injection hydraulic line circuit of a feedthrough chemical injection system that is in fluid communication with the inner bag of the at least one inflatable and swellable packer, and at least one chemical injection mandrel;

[0062] b. In a first configuration, pump a first fluid through the chemical injection hydraulic line circuit to initiate inflation of the inflatable inner bag of the at least one inflatable and swellable packer;

[0063] c. Inflate the inflatable inner bag of the at least one inflatable and swellable packer with the first fluid until the outer portion of the inflatable and swellable packer contacts the wall of the well;

[0064] d. After completion of inflation of the inflatable inner bag of the at least one inflatable and swellable packer, stop pumping the first fluid;

[0065] e. Gradually increase the pressure of the first fluid until the rupture pressure of the rupture disk in the chemical injection hydraulic line circuit of the at least one inflatable and swellable packer is reached;

[0066] f. After the rupture disk ruptures, actuate the double check valve in the chemical injection and swellable hydraulic line circuit to lock the first fluid inside the at least one inflatable packer;

[0067] g. Repeat steps (b) to (f) for additional inflatable and swellable packers to isolate the corresponding open intervals in the well; and

[0068] h. Selectively change the chemical injection hydraulic line circuit to a second configuration;

[0069] i. Pump a second fluid through at least one chemical injection mandrel in a corresponding open interval in the well.

[0070] The method may also include actuating a corresponding sliding sleeve door (SDD) valve for each interval in the well. Additionally, the expandable and swellable packer assembly may also include an external thread, an inner tube, and an internal thread.

[0071] Preferably, the method is implemented in a completion string having three intervals, where corresponding rupture disks between respective packers are ruptured by increasing the pressure value.

[0072] Example

[0073] The operating sequence for activating rupture disks in a hydraulic line for injecting a scale inhibitor to sequentially expand packers in a completion string having open intervals is described below by way of example and not limitation (also seen in Figure 6 ):

[0074] - Pump hydraulic fluid through the inhibitor injection line to expand a first packer;

[0075] - Expand the inner bladder of the first packer until the external rubber of the packer contacts the wellbore wall;

[0076] - Interrupt pumping caused by hydrostatic pressure due to completion of filling of the inner bladder of the first packer;

[0077] - The pumping pressure will gradually increase until it reaches the rupture value of a first rupture disk at a point in the inhibitor injection line below the first packer;

[0078] - Activate a double check valve in the line of the first packer bladder to lock the fluid inside the first packer;

[0079] - Pump hydraulic fluid through the inhibitor injection line to expand the inner bladder of a second packer;

[0080] - Expand the inner bladder of the second packer until the external rubber of the packer contacts the wellbore wall;

[0081] - Interrupt pumping caused by hydrostatic pressure due to completion of filling of the inner bladder of the second packer;

[0082] - The pumping pressure will gradually increase until it reaches the rupture value of a second rupture disk at a point in the inhibitor injection line between the first and second packers;

[0083] - Activate a double check valve in the line of the second packer bladder to lock the fluid inside the second packer;

[0084] - After the second rupture disc ruptures, pump hydraulic fluid through the inhibitor injection line to expand the third packer;

[0085] - Expand the inner bag of the third packer until the outer rubber of the packer contacts the wellbore;

[0086] - Since the filling of the inner bag of the third packer is completed, interrupt the pumping caused by the hydrostatic pressure; and

[0087] - Activate the double check valve in the line of the bag of the third packer to lock the fluid inside the third packer.

[0088] Taking into account the hydrostatic pressure at the depth of each packer, for the rupture of each disc, the rupture pressure value of the rupture disc can be adjusted between the packers in an increasing manner, in the order from top to bottom, that is, from the first packer, the second packer, and the third packer. For example:

[0089] - In the top-to-bottom direction, at the depth point of the first rupture disc, the first rupture disc ruptures at a hydrostatic pressure difference of 500 PSI.

[0090] - In the top-to-bottom direction, at the depth point of the first rupture disc, the second rupture disc ruptures at a hydrostatic pressure difference of 1000 PSI.

[0091] - In the top-to-bottom direction, at the depth point of the first rupture disc, the third rupture disc ruptures at a hydrostatic pressure difference of 1500 PSI.

[0092] Those skilled in the art will appreciate the knowledge shown and will be able to reproduce the present invention in the specified embodiments and other variants covered by the scope of the appended claims.

Claims

1. A system for isolation and chemical injection in a completion string of an oil well having an open interval, Features ,include: at least one expandable and swellable packer assembly, the at least one expandable and swellable packer assembly comprising an expandable inner bag and a swellable material; Chemical injection hydraulic line circuits for chemical injection systems; as well as at least one chemical implantation mandrel, wherein the chemical injection hydraulic line circuit is of a feed-through type and is in fluid communication with the inner bag of the at least one expandable and swellable packer, wherein in a first configuration, the chemical injection hydraulic line circuit provides a fluid to fill the expandable inner bag, the fluid reacting with the swellable material of the at least one expandable and swellable packer, wherein the chemical injection hydraulic line circuit further comprises a respective valve assembly for each of the at least one expandable and swellable packer, and wherein the valve assemblies each comprise at least one dual check valve and a rupture disc, and wherein after the at least one expandable and swellable packer is expanded, the chemical injection hydraulic line circuit is selectively switched to a second configuration for injecting an antiscalant fluid through the at least one chemical injection mandrel.

2. The system according to claim 1, Features , also including a corresponding sliding sleeve valve for each layer interval of the well.

3. The system according to claim 1, Features The expandable and swellable packer assembly also includes an external thread, an inner tube and an internal thread.

4. The system according to claim 1, Features , implemented in a completion string with three intervals.

5. The system according to claim 1, Features , the rupture disks include corresponding rupture pressure values ​​in an increasing manner between each packer.

6. A method for isolation and chemical injection in a completion string of an oil well having an open interval, Features , including the following steps: a) introducing into the well an assembly of at least one expandable and swellable packer comprising an expandable inner bag and a swellable material, a chemical injection hydraulic line circuit in fluid communication with the inner bag of the at least one expandable and swellable packer fed through a chemical injection system, and at least one chemical injection mandrel; b) in a first configuration, pumping a first fluid through said chemical injection hydraulic line circuit to induce inflation of said expandable inner bag of said at least one expandable and swellable packer; c) inflating the expandable inner bag of the at least one expandable and swellable packer with the first fluid until an outer portion of the expandable and swellable packer contacts a wall of the well; d) stopping pumping of the first fluid after completing filling of the expandable inner bag of the at least one expandable and swellable packer; e) gradually increasing the pressure of said first fluid until a rupture pressure of a rupture disk in said chemical injection hydraulic line circuit of said at least one expandable and swellable packer is reached; f) after rupture of the rupture disk, actuating dual check valves in a chemical injection and swellable hydraulic line circuit to lock the first fluid inside at least one swellable packer; g) repeating steps (b) through (f) for additional expandable and swellable packers to isolate their respective open intervals in the well; as well as h) selectively changing the chemical injection hydraulic line circuit to a second configuration; i) pumping a second fluid through said at least one chemical injection mandrel of a corresponding open interval in said well.

7. The method according to claim 6, Features , further comprising introducing into the well a corresponding sliding sleeve valve for each interval of the well.

8. The method according to claim 6, Features The expandable and swellable packer assembly also includes an external thread, an inner tube and an internal thread.

9. The method according to claim 6, Features , implemented in a completion string with three intervals.

10. The method according to claim 6, Features , and also includes rupturing corresponding rupture disks between each packer by increasing the pressure value.

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