A zero residue multi-stage detonation fracturing method and system

Abstract

This invention relates to a zero-residue multi-stage deflagration fracturing method and system, addressing the problems of existing deflagration fracturing devices, such as well-water pollution, failure to achieve the expected fracturing effect, and low efficiency. The multi-stage deflagration fracturing method includes: Step 1: Preparing the deflagration fracturing charge, central tube, and guide plug in the deflagration fracturing system using a combustible material that is soluble in chloride ions; Step 2: During operation of the deflagration fracturing system, a detonator ignites the central tube and the deflagration fracturing charge; Step 3: The central tube burns, the deflagration fracturing charge deflagrates, and the guide plug burns simultaneously, thus performing multi-stage deflagration fracturing; Step 4: After deflagration fracturing is completed, the residue from the central tube, deflagration fracturing charge, and guide plug falls into the well water, where it dissolves completely, achieving zero residue. To achieve the above method, this invention also proposes two zero-residue multi-stage deflagration fracturing systems.

Description

Technical Field

[0001] This invention relates to a multi-stage deflagration fracturing system, specifically to a zero-residue multi-stage deflagration fracturing method and system. Background Technology

[0002] Currently used deflagration fracturing systems mostly employ a thick central aluminum tube as the carrier of the fracturing explosive (fracturing bomb), with multiple fracturing bombs connected in a string. The central aluminum tube is sealed; upon ignition, the high-temperature, high-pressure gas generated by the deflagration of the ignition explosive inside the central tube ruptures the tube wall, igniting the fracturing bomb outside. During combustion, the central aluminum tube is also shattered into fragments. After the fracturing bomb burns, a large amount of central aluminum tube debris falls into the wellbore, causing pollution and even bridging. The blockage accident severely affected the normal progress of the next process. In addition, this type of deflagration fracturing device has the following defects: First, due to the uneven distribution of ignition energy in the central aluminum tube or mechanical defects in the aluminum tube wall, the ignition intensity of the fracturing bomb is inconsistent and the ignition position is uncertain, so the pressure rise rate and peak pressure cannot be effectively controlled, and the expected fracturing effect cannot be achieved. Second, the fracturing bomb and the central aluminum tube are shattered during the combustion process and are in a free combustion state in the wellbore, which disperses the energy and reduces the working efficiency. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of existing deflagration fracturing devices, such as pollution of oil wells, failure to achieve the expected fracturing effect, and low work efficiency, and to provide a zero-residue multi-stage deflagration fracturing method and system.

[0004] The technical solution of this invention is as follows:

[0005] Zero-residue multi-stage deflagration fracturing technology is an effective production enhancement and injection measure adopted for the re-fracturing and transformation of old wells with reduced oilfield production capacity or new wells with insufficient production capacity due to low porosity and low permeability reservoirs. The special feature of this technology is that, in addition to the combustion of the combustors, the connecting guide plugs and dissolution booster tubes can also burn rapidly during deflagration fracturing, while fulfilling the connection and sealing functions. This further enhances the fracturing work on the formation, and the combustion into ash does not cause wellbore contamination. At the same time, it enhances the energy efficiency of fracturing. Furthermore, by setting up a catalyst chamber to fully dissolve the guide plugs and dissolution booster tubes, the guide plugs and dissolution booster tubes can be rapidly dissolved in water under the action of the catalyst, ensuring complete dissolution and no debris.

[0006] A zero-residue multi-stage deflagration fracturing method, characterized by the following steps:

[0007] Step 1: Prepare the central tube and guide plug in the deflagration fracturing system using a combustible material that is soluble in chloride ions;

[0008] Step 2: When the deflagration fracturing system is working, the detonator ignites the central tube and the deflagration fracturing charge;

[0009] Step 3: The central tube burns, the deflagration fracturing charge deflates, and the tail plug burns simultaneously, thus performing multi-stage deflagration fracturing.

[0010] Step 4: After the deflagration fracturing is completed, the residue from the central tube, deflagration fracturing charge, and guide plug falls into the well water. The residue is completely dissolved by the well water, achieving zero residue.

[0011] Furthermore, in step 1, a catalyst chamber is connected to the existing deflagration fracturing system. The catalyst chamber stores a catalyst, which is a chloride-containing compound. The catalyst chamber is made of a combustible material that is soluble in chloride ions.

[0012] In step 3, the central tube burns, the deflagration fracturing charge deflates, and the guide plug and catalyst chamber burn simultaneously. The catalyst in the catalyst chamber falls into the well water to form a catalyst liquid.

[0013] In step 4, the residue from the combustion of the central tube, the deflagration fracturing charge, the guide plug, and the catalyst chamber falls into the catalytic fluid. The residue dissolves rapidly under the action of the catalytic fluid. The chloride ion-containing compounds catalyze the dissolution of the central tube, connecting column, guide plug, catalyst chamber, and deflagration fracturing charge. That is, during deflagration fracturing, the chloride ion chamber is broken up, and chloride ions are released into the wellbore, providing a chloride ion concentration for the burning metal and rapidly and completely dissolving it.

[0014] Furthermore, the guide tail plug, central tube, and catalyst chamber are made of magnesium-aluminum alloy;

[0015] The chloride-containing compound is magnesium chloride or sodium chloride.

[0016] This invention also proposes a zero-residue multi-stage deflagration fracturing system to realize the aforementioned zero-residue multi-stage deflagration fracturing method, comprising a combustion element, a gun head assembly, and a detonator, characterized by:

[0017] It also includes a guide tail plug, a central tube, and an energy-enhancing dissolution unit;

[0018] The energy-enhancing dissolution unit includes a deflagration fracturing charge;

[0019] The central tube is disposed inside the deflagration fracturing column, and the outer wall of the central tube is in contact with the interior of the deflagration fracturing column.

[0020] The gun head assembly is sealed and installed at the upper end of the central tube, and the guide tail plug is sealed and installed at the lower end of the central tube; the upper end of the detonator is connected to the gun head assembly, and the lower end is located inside the upper end of the central tube.

[0021] The combustion element is disposed inside the central tube, and the upper end of the combustion element is connected to the lower end of the detonator;

[0022] The guide tail plug, central tube, and deflagration fracturing charge are made of combustible materials that are soluble in chloride ions.

[0023] Furthermore, in order to accelerate the dissolution rate of the central tube, deflagration fracturing charge, guide tail plug, etc., the energy-enhancing dissolution unit also includes at least one catalyst chamber; the deflagration fracturing charge and the catalyst chamber are coaxially connected.

[0024] The catalyst chamber contains compounds containing chloride ions;

[0025] The catalyst chamber is made of a combustible material that is soluble in chloride ions.

[0026] Furthermore, the guide tail plug, central tube, and catalyst chamber are made of magnesium-aluminum alloy;

[0027] The chloride-containing compound is magnesium chloride or sodium chloride.

[0028] This invention also proposes another zero-residue multi-stage deflagration fracturing system to realize the above-mentioned zero-residue multi-stage deflagration fracturing method, including a combustion element, a gun head assembly, and a detonator, which is characterized by:

[0029] It also includes a guide tail plug, at least two sequentially connected energy-enhancing and dissolving units, and a central tube with the same number of energy-enhancing and dissolving units that corresponds one-to-one;

[0030] The energy-enhancing dissolution unit includes a deflagration fracturing charge;

[0031] The central tube is located inside the deflagration fracturing column, and the outer wall of the central tube is in contact with the interior of the deflagration fracturing column. Adjacent central tubes are connected by a connecting column, and the connecting column is provided with a through hole along the axis of the central tube.

[0032] The gun head assembly is sealed and installed at the upper end of the first central tube, and the guide tail plug is sealed and installed at the lower end of the last central tube; the upper end of the detonator is connected to the gun head assembly, and the lower end is located inside the upper end of the first central tube.

[0033] The combustion element is disposed inside the central tube, with one end of the combustion element connected to the detonator and the other end passing through the through hole of the connecting column in sequence.

[0034] The guide plug, central tube, deflagration fracturing charge, and connecting column are made of combustible materials that are soluble in chloride ions.

[0035] Furthermore, the energy-enhancing dissolution unit also includes at least one catalyst chamber; the deflagration fracturing propellant and the catalyst chamber are coaxially connected;

[0036] The catalyst chamber contains compounds containing chloride ions;

[0037] The catalyst chamber is made of a combustible material that is soluble in chloride ions.

[0038] Furthermore, the guide tail plug, central tube, connecting column, and catalyst chamber are made of magnesium-aluminum alloy;

[0039] The chloride-containing compound is magnesium chloride or sodium chloride.

[0040] Furthermore, the energy-enhancing dissolution unit also includes a catalyst chamber, and the deflagration fracturing propellant and the catalyst chamber are coaxially connected; the deflagration fracturing propellant of two adjacent energy-enhancing dissolution units are connected to the catalyst chamber;

[0041] The catalyst chamber of the first energy-enhancing dissolution unit is located at one end near the gun head assembly, and the deflagration fracturing charge of the last energy-enhancing dissolution unit is located at one end near the guide tail plug.

[0042] The beneficial effects of this invention are:

[0043] 1. In this invention, by setting the guide tail plug, central tube, and deflagration fracturing charge as combustible materials that are soluble in chloride ions, the guide tail plug, central tube, and deflagration fracturing charge can burn during deflagration operations, generating high-temperature and high-pressure energy; and ensuring that the guide tail plug, central tube, and deflagration fracturing charge completely dissolve, leaving no metal residue in the wellbore after the deflagration operation, thus preventing pollution of the oil well. Furthermore, the combustion function of the guide tail plug, central tube, and deflagration fracturing charge increases the working time, further enhancing the fracturing effect and improving the working efficiency.

[0044] By using different materials for the central tube, connecting column, guide plug, and deflagration fracturing charge, the combustion rate of the central tube, connecting column, and guide plug is slightly lower than that of the deflagration fracturing charge (which contains explosives). This provides energy for the subsequent combustion of the deflagration fracturing charge, allowing for further fracturing of the formation and increasing the effective working time. This achieves multi-stage work in deflagration fracturing.

[0045] 2. In this invention, a catalyst chamber is added, and the catalyst chamber is made of a combustible material that is soluble in chloride ions. The catalyst chamber stores chloride-containing compounds that can accelerate the dissolution rate of the central tube, the deflagration fracturing charge, the guide tail plug, etc.

[0046] 3. In this invention, the guide tail plug, central tube, deflagration fracturing charge and catalyst chamber form a multi-energy tiered structure. The combustion gas of the combustion element and the combustion gas of the guide tail plug, central tube, deflagration fracturing charge and catalyst chamber work together as a power source to perform fracturing work on the formation for a long time, so that more radial fractures unaffected by geostress are formed in the near-wellbore zone.

[0047] 4. In this invention, since no metal residue falls into the wellbore after the deflagration operation, it will not cause pollution to the oil well. Therefore, there is no need to use well washing equipment for circulating flushing operations; it will not cause operational hazards for subsequent wellbore operations; and it eliminates the occurrence of bridging and blockage accidents.

[0048] 5. The system in this invention is also applicable to existing deflagration operation processes.

[0049] 6. In this invention, the chloride ion-containing compound plays a catalytic role in the dissolution of the central tube, connecting column, guide tail plug, catalyst chamber, and deflagration fracturing charge. That is, at the same time as deflagration fracturing, the chloride ion chamber is broken, and chloride ions are released into the wellbore, providing chloride ion concentration for the burning metal and rapidly and completely dissolving it. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0051] In the diagram, 1. Guide tail plug; 2. Central tube; 3. Deflagration fracturing charge; 4. Catalyst chamber; 5. Connecting column; 6. Detonator; 7. Combustion component; 8. Head assembly. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0053] This invention proposes a zero-residue multi-stage deflagration fracturing system, such as... Figure 1 As shown, it includes a gun head assembly 8, a detonator 6, a combustion element 7, a guide tail plug 1, three energy-enhancing and dissolving units connected in sequence, and three central tubes 2 corresponding to the three energy-enhancing and dissolving units.

[0054] The composition and connection method of each component are as follows:

[0055] The energy-enhancing dissolution unit includes a deflagration fracturing charge 3 and a catalyst chamber 4 connected in sequence, and the deflagration fracturing charge 3 and catalyst chamber 4 in the three energy-enhancing dissolution units are arranged alternately;

[0056] The guide tail plug 1 includes an interconnected guide post and a base; the catalyst chamber 4 stores a catalyst containing a chloride ion solid compound.

[0057] The central tube 2 is located inside the deflagration fracturing charge 3, and the outer wall of the central tube 2 is in contact with the inner wall of the deflagration fracturing charge 3. Two central tubes 2 are connected by a connecting column 5, and the connecting column 5 has a through hole along the axis of the central tube 2.

[0058] One end of the cannon head assembly 8 is connected to an external device, and the other end is sealed inside the first central tube 2 by a sealing ring. The catalyst chamber 4 in the first energy-enhancing dissolution unit is located on the side close to the cannon head assembly 8. The detonator 6 is installed at one end of the cannon head assembly 8 in the central tube 2, that is, the upper end of the cannon head assembly 8 is connected to the detonator 6.

[0059] The guide post of the guide tail plug 1 is set inside the last central tube 2, and the base of the guide tail plug 1 is set outside the last central tube 2. Through the detonator 6, the guide tail plug 1 and the connecting post 5, a sealed cavity is formed inside the three central tubes 2.

[0060] The combustion element 7 is located inside the central tube 2, with one end connected to the lower end of the detonator 6 and the other end passing through the through holes of the two connecting posts 5 in sequence.

[0061] The combustion element 7 can be a detonating cord or a burning strip.

[0062] The materials of the guide tail plug 1, the central tube 2, the deflagration fracturing charge 3, the connecting column 5, and the catalyst chamber 4 are magnesium-aluminum alloy.

[0063] The compounds containing chloride ions are magnesium chloride or sodium chloride.

[0064] To ensure the stability of the entire system, the base of the guide tail plug 1 is fitted with the end face of the last energy-enhancing dissolution unit, which supports the energy-enhancing dissolution unit and prevents axial movement.

[0065] The purpose of setting up the catalyst chamber 4 and storing chloride-containing compounds in the catalyst chamber 4 is to accelerate the dissolution rate of the guide tail plug 1, the central tube 2, the deflagration fracturing charge 3, and the connecting column 5.

[0066] The working principle of this invention is as follows:

[0067] During operation, the zero-residue multi-stage deflagration fracturing system is sent into the oil and gas well and positioned using a cable or tubing string. The well water contains chloride ions. The detonator 6 in the zero-residue multi-stage deflagration fracturing system is then detonated through the cable and the head assembly 8. The detonator 6 detonates the detonating cord or incendiary charge. After the detonating cord or incendiary charge detonates or deflagrates, the resulting explosion or deflagration gas ignites and cracks the central tube 2 and connecting column 5. This further ignites the deflagration fracturing charge 3, catalyst chamber 4, and guide tail plug 1, causing the deflagration fracturing charge 3 to deflagrate and establish a high-pressure environment in the wellbore, thereby performing fracturing work on the formation.

[0068] The solid chloride ion compound in the catalyst chamber 4 dissolves upon contact with the liquid, releasing chloride ions, which accelerates the dissolution of the residues in the central tube 2, connecting column 5, deflagration fracturing charge 3, catalyst chamber 4, and guide tail plug 1 after combustion.

[0069] The present invention also proposes a fracturing method based on the above system, comprising the following steps:

[0070] Step 1: When the deflagration fracturing system is working, detonator 6 ignites the central tube 2 and the deflagration fracturing charge 3;

[0071] Step 2: The central tube 2 burns, the deflagration fracturing charge 3 deflagrates, and the guide tail plug 1 burns simultaneously, thus performing multi-stage deflagration fracturing.

[0072] Step 3: After the deflagration fracturing is completed, the residue from the combustion of the central tube 2, the deflagration fracturing charge 3, and the guide plug 1 falls into the well water. The residue is completely dissolved by the well water, achieving zero residue.

Claims

1. A zero-residue multi-stage deflagration fracturing system, used to implement a zero-residue multi-stage deflagration fracturing method. Step 1: Prepare the central tube (2) and guide plug (1) of the deflagration fracturing system using a combustible material that is soluble in chloride ions; Step 2: When the deflagration fracturing system is working, the detonator (6) ignites the central tube (2) and the deflagration fracturing charge (3); Step 3: The central tube (2) burns, the deflagration fracturing charge (3) deflagrates, and the guide tail plug (1) burns at the same time, thus carrying out multi-stage deflagration fracturing; Step 4: After the deflagration fracturing is completed, the residue from the combustion of the central tube (2) and the guide tail plug (1) falls into the well water. The residue is completely dissolved by the well water, achieving zero residue. Including a combustion element (7), a gun head assembly (8), and a detonator (6), characterized in that: It also includes a guide tail plug (1), at least two sequentially connected energy-enhancing dissolution units and a central tube (2) that is the same number as and corresponds one-to-one with the energy-enhancing dissolution units; The energy-enhancing dissolution unit includes a deflagration fracturing charge (3); The central tube (2) is set inside the deflagration fracturing column (3), and the outer wall of the central tube (2) is in contact with the interior of the deflagration fracturing column (3). Two adjacent central tubes (2) are connected by a connecting column (5), and the connecting column (5) has a through hole along the axis of the central tube (2). The gun head assembly (8) is sealed and installed at the upper end of the first central tube (2), and the guide tail plug (1) is sealed and installed at the lower end of the last central tube (2); the upper end of the detonator (6) is connected to the gun head assembly (8), and the lower end is located inside the upper end of the first central tube (2); The combustion element (7) is located inside the central tube (2), and one end of the combustion element (7) is connected to the detonator (6), while the other end passes through the through holes of each connecting post (5) and is located inside the last central tube (2). The guide tail plug (1), central tube (2), deflagration fracturing charge (3) and connecting column (5) are made of combustible materials that can be dissolved by chloride ions; The energy-enhancing dissolution unit includes a catalyst chamber (4), and the deflagration fracturing charge (3) and the catalyst chamber (4) are coaxially connected; the deflagration fracturing charge (3) of two adjacent energy-enhancing dissolution units is connected to the catalyst chamber (4); The catalyst chamber (4) of the first energy-enhancing dissolution unit is located at one end near the gun head assembly (8), and the deflagration fracturing charge (3) of the last energy-enhancing dissolution unit is located at one end near the guide tail plug (1). The catalyst chamber (4) contains compounds containing chloride ions; The catalyst chamber (4) is made of a combustible material that is soluble in chloride ions.

2. The zero-residue multi-stage deflagration fracturing system according to claim 1, characterized in that: The guide tail plug (1), central tube (2), connecting column (5) and catalyst chamber (4) are made of magnesium-aluminum alloy; The chloride-containing compound is magnesium chloride or sodium chloride.

3. The zero-residue multi-stage deflagration fracturing system according to claim 2, characterized in that: In step 1, a catalyst chamber (4) is connected to the deflagration fracturing system. The catalyst chamber (4) stores a catalyst, which is a chloride-containing compound. The catalyst chamber (4) is made of a combustible material that is soluble in chloride ions. In step 3, the central tube (2) burns, the deflagration fracturing charge (3) deflagrates, and at the same time the guide tail plug (1) and the catalyst chamber (4) burn, and the catalyst falls into the well water to form a catalyst liquid; In step 4, the residues from the combustion of the central tube (2), the deflagration fracturing charge (3), the guide tail plug (1), and the catalyst chamber (4) fall into the catalyst solution, where they dissolve rapidly under the action of the catalyst solution.

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