Forward and reverse circulation combined cementing tool and method

Abstract

The present disclosure relates to the technical field of petroleum extraction, and disclosed are a forward and reverse circulation combined cementing tool and method, aiming to solve the problem of poor adaptability when using forward or reverse circulation cementing alone. The forward and reverse circulation combined cementing tool comprises a cross-circulation sub (2) and a reverse circulation cementing choke float shoe (3) which are arranged from top to bottom; the reverse circulation cementing choke float shoe (3) comprises a choke assembly (33) and a one-way valve (32), and the choke assembly (33) comprises a control module (332) and a choke module (333). The forward and reverse circulation combined cementing tool and method make full use of the advantages of forward and reverse circulation cementing processes, achieving pressure balance and cement slurry delivery, solving the problems of ultra-long cementing sections and complex formation cementing, greatly improving cementing quality and construction efficiency, and the cementing tool and method are suitable for cementing operations in oil and gas wells under complex geological conditions.

Description

Cementing tool and cementing method combining positive circulation and reverse circulation

[0001] Related applications

[0002] The present application claims priority to Chinese Patent Application No. 202411303027.8, filed on September 18, 2024, and incorporates by reference the entire disclosure of the aforementioned patent application as part of the present application. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of oil exploitation, in particular to a cementing tool combining positive circulation and reverse circulation, and a cementing method combining positive circulation and reverse circulation. BACKGROUND

[0004] Positive circulation cementing is a traditional cementing process, mainly applied to injecting cement slurry into the oil and gas wellbore to achieve formation sealing and isolation. Reverse circulation cementing is a special cementing process, different from traditional positive circulation cementing. In positive circulation cementing, cement slurry is injected from the inside of the casing and enters the annular area between the wellbore and the casing by displacing drilling fluid, ultimately achieving formation sealing. In reverse circulation cementing, cement slurry is injected directly from the annulus between the casing and the well wall, pushing the drilling fluid back to the surface from the inside of the casing, so that the cement slurry can directly fill the casing annulus to achieve efficient sealing.

[0005] With the increasing complexity of oil and gas exploration and development targets and the increasingly harsh geological conditions, the engineering and technical difficulties are also increasing. For some special formations, such as ultra-long sealing segments, low pressure-bearing capacity formations, and oil and gas wells facing easy leakage, large temperature difference, high temperature and high pressure environments, it is difficult to simply use positive circulation or reverse circulation cementing processes. SUMMARY

[0006] To solve the problem of poor adaptability of simply using positive circulation or reverse circulation cementing, the present disclosure provides a cementing tool and cementing method combining positive circulation and reverse circulation, which fully utilizes the advantages of positive circulation and reverse circulation cementing processes, achieving pressure balance and cement slurry transportation, and solving the problems of ultra-long sealing segments and complex formation cementing, greatly improving cementing quality and construction efficiency, and being suitable for oil and gas well cementing operations under complex geological conditions.

[0007] The technical solution adopted by the present disclosure to solve its technical problems is:

[0008] The application discloses a cementing tool combined with positive circulation and reverse circulation, which comprises a cross circulation nipple arranged in an up-down mode and a reverse circulation cementing cutoff float shoe.

[0009] The application discloses a cementing method combined with positive circulation and reverse circulation.

[0010] Step 1, preparation before construction;

[0011] The reverse circulation cementing cutoff float shoe receives the excitation target signal through a receiver on the ground and saves the excitation target signal in a storage through a control unit.

[0012] Step 2, the cementing tool combined with positive circulation and reverse circulation is lowered into the wellbore.

[0013] Step 3, flushing fluid is injected into the cementing tool combined with positive circulation and reverse circulation.

[0014] Step 4, signal cement slurry and cementing cement slurry are sequentially injected into the cementing tool combined with positive circulation and reverse circulation, the signal cement slurry is a mixture of an excitation beacon and cement slurry, the volume of the signal cement slurry is 0.5m 3 -2m 3 , and the volume of the cementing cement slurry is equal to the volume of the lowermost annulus of the wellbore.

[0015] Step 5, displacement fluid is injected into the cementing tool combined with positive circulation and reverse circulation.

[0016] Step 6, the signal cement slurry flows to the reverse circulation cementing cutoff float shoe, the control unit compares the excitation signal emitted by the excitation beacon with the excitation target signal stored in the storage, and the control module controls the cutoff module to close the upper inner flow channel.

[0017] The cementing tool combined with positive circulation and reverse circulation and the cementing method make full use of the advantages of the positive circulation and reverse circulation cementing processes, realize pressure balance and cement slurry conveying, solve the problems of long cementing section and cementing in complex formations, greatly improve the cementing quality and construction efficiency, and are suitable for cementing operations of oil and gas wells under complex geological conditions. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which form a part of this disclosure, are included to provide a further understanding of the disclosure, illustrate the preferred embodiments of the disclosure, and explain the principles of the disclosure. The drawings illustrate the principles of the disclosure. It will be appreciated that the drawings are not meant as limitations but as a means of presentation of the embodiments illustrated.

[0019] Figure 1 is a schematic view of a positive and reverse circulation combined cementing tool of the present disclosure in a wellbore.

[0020] Figure 2 is a schematic view of a cross circulation nipple of the present disclosure.

[0021] Figure 3 is a schematic view of a reverse circulation cementing flow shut-off float shoe of the present disclosure with a flow shut-off assembly in a closed state.

[0022] Figure 4 is a schematic view of a reverse circulation cementing flow shut-off float shoe of the present disclosure with a flow shut-off assembly in an open state.

[0023] Figure 5 is a schematic view of a flow shut-off assembly of the present disclosure.

[0024] Figure 6 is an enlarged schematic view of section A of Figure 5 of the present disclosure.

[0025] Figure 7 is a schematic view of a control module of the present disclosure.

[0026] Figure 8 is a schematic view of a flow shut-off assembly of the present disclosure in a closed state.

[0027] Figure 9 is a connection schematic of a control module of the present disclosure.

[0028] Figure 10 is a control logic diagram of a flow shut-off assembly of the present disclosure.

[0029] Figure 11 is a schematic view of a well cemented with a single stage positive and reverse circulation combined cementing tool of the present disclosure.

[0030] Figure 12 is a schematic view of a well cemented with a two stage positive and reverse circulation combined cementing tool of the present disclosure.

[0031] Explanation of reference signs: 1, casing; 2, cross circulation nipple; 3, reverse circulation cementing cutoff float shoe; 4, wellbore annulus; 5, casing internal cavity; 6, well wall; 21, upper joint section; 22, lower joint section; 23, inner section body; 24, packoff structure; 25, first passage; 26, second passage; 31, outer shell; 32, one-way valve; 33, cutoff assembly; 311, shell wall; 312, internal flow channel; 321, lower shell body; 322, valve core; 323, valve stem; 324, support hole plate; 325, first spring; 3211, lower cylinder wall; 3212, lower internal flow channel; 331, upper shell body; 332, control module; 333, cutoff module; 3311, upper cylinder wall; 3312, upper internal flow channel; 3313, annular internal cavity; 3314, outer peripheral wall; 3315, inner peripheral wall; 3321, signal detector; 3322, control unit; 3323, execution unit; 3324, receiver; 3325, memory; 3326, power supply; 3327, electromagnetic actuator; 3328, magnetic blocking pin; 3331, baffle clamping groove; 3332, second spring; 3333, baffle; 3334, third spring; 3335, baffle slide; 3336, blocking pin slide; 101, first wellbore annulus section; 102, first casing internal cavity section; 103, second wellbore annulus section; 104, second casing internal cavity section; 105, third wellbore annulus section; 106, third casing internal cavity section; 107, non-cement slurry region; 108, cement slurry region. DETAILED DESCRIPTION

[0032] It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. The present disclosure will be described in detail below with reference to the drawings and in combination with the embodiments.

[0033] For the convenience of understanding and description, absolute positional relationships are adopted in the following description of the present disclosure, and the orientation word "up" represents the upper side direction in FIG. 1, the orientation word "down" represents the lower side direction in FIG. 1, the orientation word "left" represents the left side direction in FIG. 1, the orientation word "right" represents the right side direction in FIG. 1, the orientation word "front" represents the direction perpendicular to the paper of FIG. 1 and pointing to the inside of the paper, and the orientation word "back" represents the direction perpendicular to the paper of FIG. 1 and pointing to the outside of the paper. The present disclosure adopts the observation visual angle of the reader or user for description, but the above orientation words cannot be understood or interpreted as a limitation on the protection scope of the present disclosure. As for the size and angle of the components, the person skilled in the art can specifically determine according to the actual needs.

[0034] As shown in FIG. 1, the cementing tool of the embodiment of the present disclosure comprises a cross circulation nipple 2 and a reverse circulation cementing float shoe 3 arranged in an up-down manner. The cross circulation nipple 2 is added to the cementing tool, and the reverse circulation cementing float shoe 3 is used at the bottom of the cementing tool. After the cementing operation is completed, the wellbore annulus below the cross circulation nipple 2 is cemented by the cement slurry, and the wellbore annulus above the cross circulation nipple 2 and the casing are filled with non-cement slurry such as fresh water and drilling fluid.

[0035] As shown in FIG. 2, the cross circulation nipple 2 can make the wellbore annulus 4 above the cross circulation nipple 2 not communicate with the wellbore annulus 4 below the cross circulation nipple 2. The cross circulation nipple 2 contains a first channel 25 and a second channel 26. The first channel 25 can make the internal cavity 5 of the casing above the cross circulation nipple 2 communicate with the wellbore annulus 4 below the cross circulation nipple 2. The second channel 26 can make the internal cavity 5 of the casing below the cross circulation nipple 2 communicate with the wellbore annulus 4 above the cross circulation nipple 2.

[0036] The cross circulation nipple 2 contains an inner nipple body 23 and a pack-off structure 24 arranged in an inner-outer manner. The upper end of the inner nipple body 23 is provided with an upper joint segment 21, which can be an internal thread segment. The lower end of the inner nipple body 23 is provided with a lower joint segment 22, which can be an external thread segment. The inner nipple body 23 and the pack-off structure 24 are sealingly connected. The pack-off structure 24 can be sealingly connected with the inner surface of the well wall 6.

[0037] As shown in FIG. 2, the inner nipple body 23 is a vertical cylindrical structure. The upper end of the first channel 25 is located on the upper surface of the inner nipple body 23. The lower end of the first channel 25 is located on the side peripheral surface of the inner nipple body 23. The lower end of the first channel 25 is lower than the pack-off structure 24. The upper end of the second channel 26 is located on the side peripheral surface of the inner nipple body 23. The upper end of the second channel 26 is higher than the pack-off structure 24. The upper end of the second channel 26 is located on the lower surface of the inner nipple body 23.

[0038] The pack-off structure 24 can select different existing pack-off structures according to the working conditions. For example, the pack-off structure 24 can adopt oil-swelling or water-swelling pack-off, hydraulic pack-off, etc. The pack-off structure 24 is used to pack off the wellbore annulus, so that the wellbore annulus above and below the nipple is not communicated.

[0039] As shown in FIG. 3 to FIG. 4, the reverse circulation well cementation flow control float shoe 3 comprises an outer shell 31, the outer shell 31 is a vertical cylindrical structure, the outer shell 31 comprises a shell wall 311 and an inner flow channel 312, the inner flow channel 312 comprises an upper and lower flow control assembly 33 and a one-way valve 32, the flow control assembly 33 comprises an upper shell 331, the upper shell 331 is also a vertical cylindrical structure, the upper shell 331 comprises an upper cylindrical wall 3311 and an upper inner flow channel 3312, the upper cylindrical wall 3311 comprises a control module 332 and a flow control module 333, the control module 332 can control the flow control module 333 to close the upper inner flow channel 3312.

[0040] In the one-way valve 32, the one-way valve 32 comprises a lower shell 321, the lower shell 321 is also a vertical cylindrical structure, the lower shell 321 is fixedly connected with the outer shell 31 in a matched sealing manner, the lower shell 321 comprises a lower cylindrical wall 3211 and a lower inner flow channel 3212, the inlet end of the lower inner flow channel 3212 is downward, the outlet end of the lower inner flow channel 3212 is upward, the lower inner flow channel 3212 comprises a valve stem 323 and a valve core 322 connected in an upper and lower manner, the valve stem 323 is connected with the lower shell 321 through a support hole plate 324, the valve core 322 is connected with the support hole plate 324 through a first spring 325, the first spring 325 can provide a restoring force to the valve core 322, and the one-way valve 32 is in a normally closed state.

[0041] The axis of the outer shell 31, the axis of the one-way valve 32 and the axis of the flow control assembly 33 coincide, the upper end of the outer shell 31 is the outlet end of the reverse circulation well cementation flow control float shoe 3, the lower end of the outer shell 31 is the inlet end of the reverse circulation well cementation flow control float shoe 3, the upper end of the outer shell 31 is internally provided with an internal thread, and the lower end of the outer shell 31 is externally provided with an external thread. The inlet end of the lower inner flow channel 3212 is in communication with the inlet end of the reverse circulation well cementation flow control float shoe 3, and the outlet end of the upper inner flow channel 3312 is in communication with the outlet end of the reverse circulation well cementation flow control float shoe 3. The lower cylindrical wall 3211 comprises an annular valve seat. The function of the one-way valve 32 is the same as that of the one-way valve, that is, the fluid can only enter from the inlet of the one-way valve 32 and be discharged from the outlet, but cannot enter from the outlet and be discharged from the inlet.

[0042] As shown in FIG. 3 to FIG. 8, under normal circumstances, the one-way valve 32 is in a normally closed state, the valve core 322 is sealingly connected with the valve seat, and the first spring 325 is in a compressed state. After the fluid enters the lower inner flow channel 3212 from the inlet end of the lower inner flow channel 3212, the fluid can push the valve core 322 and the valve stem 323 to move upward, the valve core 322 is separated from the valve seat, and the fluid can flow through the through hole in the valve core 322 and the support hole plate 324 and then be discharged from the outlet end of the lower inner flow channel 3212, at this time, the one-way valve 32 is in an open state. After the pressure of the fluid disappears, the first spring 325 can provide a restoring force to the valve core 322, the valve core 322 restores to be sealingly connected with the valve seat, and the one-way valve 32 restores to be in a closed state.

[0043] In the intercepting assembly 33, the upper shell 331 and the outer shell 31 are sealingly connected and fixed, an annular inner cavity 3313 is arranged in the upper cylinder wall 3311, the annular inner cavity 3313 is used for mounting the control module 332 and the intercepting module 333, the control module 332 and the intercepting module 333 are located in the annular inner cavity 3313, the upper inner flow channel 3312 penetrates the upper shell 331 along the axis direction of the upper shell 331, the inlet end of the upper inner flow channel 3312 faces downward, the outlet end of the upper inner flow channel 3312 faces upward, and the inlet end of the upper inner flow channel 3312 is in communication with the outlet end of the lower inner flow channel 3212. The upper shell 331 is made of an anti-erosion metal, and the physical properties thereof are not less than the properties of the casing.

[0044] As shown in FIG. 9, the control module 332 is used for receiving an excitation signal before being lowered into a well and storing the excitation signal locally, and when the excitation signal is detected after being lowered into the well, the control module 332 controls the actuator to perform an action. The control module 332 comprises a signal detector 3321, a control unit 3322 and an execution unit 3323 connected in sequence, the control unit 3322 is connected with a memory 3325, the signal detector 3321 can detect an electric signal, an acoustic signal or a magnetic signal in the upper inner flow channel 3312 in real time, the memory 3325 is used for storing information of a target signal, and the signal stored in the memory 3325 can be read and written by the controller. The execution unit 3323 can start to perform an action after receiving an action execution instruction.

[0045] As shown in FIG. 10, the signal detector 3321 can adopt an existing electric signal, acoustic signal or magnetic signal detection sensor. The signal detector 3321 can detect an electric signal, an acoustic signal or a magnetic signal in the upper inner flow channel 3312 in real time, and send the real-time detection signal to the control unit 3322. The control unit 3322 compares the real-time detection signal with the target signal stored in the memory 3325 in real time. When the real-time detection signal is consistent with the target signal, the control unit 3322 sends a control instruction to the execution unit 3323, and the execution unit 3323 controls the intercepting module 333 to close the upper inner flow channel 3312.

[0046] As shown in FIG. 9, the control unit 3322 is further connected with a receiver 3324 and a power supply 3326. The receiver 3324 can be one or more. The receiver 3324 is used for receiving an excitation signal on the ground. The control unit 3322 can receive a target signal through the receiver 3324 and store the target signal in the memory 3325. The power supply 3326 can adopt an existing dry battery or rechargeable battery. The power supply 3326 is used for supplying power to the control module 332, so as to ensure that the well cementing tool with the combination of positive circulation and reverse circulation can be autonomously controllable and reliably operated. The endurance time of the power supply 3326 is not less than 1.5 times of the total time from the beginning of lowering into the casing to the end of the well cementing operation.

[0047] As shown in FIGS. 5 to 8, the execution unit 3323 contains an electromagnetic execution device 3327, which can be an electromagnet of the prior art, and a magnetic blocking pin 3328. The electromagnetic execution device 3327 can attract the magnetic blocking pin 3328 and move the magnetic blocking pin 3328 towards the electromagnetic execution device 3327 by using the electromagnetic force generated by itself.

[0048] The control module 332 and the intercept module 333 can be connected or integrated. The intercept module 333 is made of metal or an erosion-resistant material and is used to cooperate with the execution device to close the fluid passage. The intercept module 333 contains a blocking plate 3333 and a second spring 3332 connected in sequence. The blocking plate 3333 is perpendicular to the axis of the upper housing 331. The intercept assembly 33 is in a normally open state, i.e., in the normal state, the intercept assembly 33 is in an open state, i.e., the upper inner flow passage 3312 is also in an open state. When the upper inner flow passage 3312 is in an open state, the blocking plate 3333 is entirely located in the upper barrel wall 3311, the magnetic blocking pin 3328 is inserted into the blocking plate 3333, and the second spring 3332 is in a compressed state. The magnetic blocking pin 3328 can block the movement of the blocking plate 3333 along the diameter direction of the upper housing 331.

[0049] One end of the second spring 3332 is connected to one end of the blocking plate 3333. When it is necessary to close the intercept assembly 33, i.e., to close the upper inner flow passage 3312, the electromagnetic execution device 3327 can make the magnetic blocking pin 3328 disengage from the blocking plate 3333, and the second spring 3332 can make the blocking plate 3333 enter the upper inner flow passage 3312 and close the upper inner flow passage 3312. At this time, the intercept assembly 33 is in a closed state, i.e., the upper inner flow passage 3312 is also in a closed state.

[0050] The upper barrel wall 3311 includes an outer peripheral wall 3314 and an inner peripheral wall 3315. The outer peripheral wall 3314 is sleeved outside the inner peripheral wall 3315. The other end of the second spring 3332 is connected to the outer peripheral wall 3314. The upper barrel wall 3311 contains a blocking plate sliding channel 3335. The extension direction of the blocking plate sliding channel 3335 is perpendicular to the axis of the upper barrel wall 3311. The blocking plate 3333 is inserted into the blocking plate sliding channel 3335 in a matching manner. The blocking plate 3333 can slide along the blocking plate sliding channel 3335. The inner surface of the inner peripheral wall 3315 contains a blocking plate clamping groove 3331. When the blocking plate 3333 closes the upper inner flow passage 3312, the other end of the blocking plate 3333 is inserted into the blocking plate clamping groove 3331 in a matching manner.

[0051] As shown in FIGS. 5-8, the upper cylinder wall 3311 (i.e. the annular inner cavity 3313) can also contain a blocking pin slide 3336, the extension direction of the blocking pin slide 3336 is parallel to the axis of the upper cylinder wall 3311, the magnetic blocking pin 3328 is matched with the blocking pin slide 3336, the magnetic blocking pin 3328 can slide along the blocking pin slide 3336, the electromagnetic actuator 3327, the magnetic blocking pin 3328 and the baffle 3333 are sequentially arranged from top to bottom, in order to avoid the magnetic blocking pin 3328 from being separated from the baffle 3333 when it needs to be separated, the third spring 3334 is connected between the electromagnetic actuator 3327 and the magnetic blocking pin 3328, and the third spring 3334 is normally in a natural state.

[0052] In the above introduction, the baffle 3333 cannot open the upper inner flow channel 3312 after closing the upper inner flow channel 3312, in order to realize that the baffle 3333 can freely open and close the upper inner flow channel 3312, the execution unit 3323 can adopt an electric push rod, the electric push rod is connected with the baffle 3333, and the electric push rod can move the baffle 3333 left and right. Alternatively, the execution unit 3323 can also contain a motor, a gear and a rack connected in sequence, the rack is connected with the baffle 3333, so that the baffle 3333 moves left and right.

[0053] In the combination of positive and reverse circulation cementing tools, the reverse circulation cementing shut-off float shoe 3 is located at the lower end of the combination of positive and reverse circulation cementing tools, the combination of positive and reverse circulation cementing tools comprises one or more cross circulation joints 2, the plurality of cross circulation joints 2 are arranged in the up-down direction, the adjacent two cross circulation joints 2 can be directly or indirectly connected through one or more casings 1, the adjacent two casings 1 can be connected through a reverse circulation float collar, and the lowermost cross circulation joint 2 and the reverse circulation cementing shut-off float shoe 3 can be directly or indirectly connected through one or more casings 1.

[0054] In the combination of positive and reverse circulation cementing tools, using one cross circulation joint 2 can be called a single-stage combination of positive and reverse circulation cementing tools, using three cross circulation joints 2 can be called a double-stage combination of positive and reverse circulation cementing tools, and using a plurality of cross circulation joints 2 can be called a multi-stage combination of positive and reverse circulation cementing tools. The reverse circulation float collar controls the fluid to flow in one direction only, so that the fluid can only flow from the wellbore annulus to the casing, and the fluid cannot flow from the casing to the wellbore annulus.

[0055] The design position of the cross circulation joint 2 in the combination of positive and reverse circulation cementing tools is that the cross circulation joint 2 is generally designed at the junction of the cement slurry and the displacement fluid, and the design position of the cross circulation joint 2 is the top of the cemented layer section, for example, if it is required to cement the wellbore annulus with a distance of 500 m from the bottom of the well, the cross circulation joint 2 is added in the casing string corresponding to the distance of 500 m from the bottom of the well.

[0056] During operation, the volume of each type of cementing fluid in the wellbore is designed, especially the volume of cementing slurry in the annulus of the formation sealing section. Generally, the preflush, postflush and other non-cementing fluid enter into the casing, and the cementing slurry remains in the annulus of the wellbore to seal the formation. If the volume of the annulus of the wellbore to be sealed from the bottom of the well to 500 m is V1, the designed volume of the cementing slurry is V2=V1+C, wherein C is an additional amount, generally 2 m 3 -3 m 3 .

[0057] A cementing method combining the positive circulation and the reverse circulation will be introduced below. The cementing method combining the positive circulation and the reverse circulation adopts the cementing tool combining the positive circulation and the reverse circulation, and sequentially includes the following steps:

[0058] Step 1, preparation before operation;

[0059] The reverse circulation cementing shut-off float shoe 3 receives the excitation target signal through the receiver 3324 on the ground, and saves the excitation target signal in the storage 3325 through the control unit 3322.

[0060] Step 2, the cementing tool combining the positive circulation and the reverse circulation is lowered into the wellbore;

[0061] Step 3, flushing fluid is injected into the cementing tool combining the positive circulation and the reverse circulation;

[0062] Step 4, signal cementing slurry and cementing slurry are sequentially injected into the cementing tool combining the positive circulation and the reverse circulation. The signal cementing slurry is a mixture of the excitation beacon and the cementing slurry, the volume of the signal cementing slurry is 0.5 m 3 -2 m 3 , and the volume of the cementing slurry is equal to the volume of the lowermost annulus 4 of the wellbore. The excitation beacon is a signal carrier for triggering the action of the control module in the cementing tool, which can be composed of specific physical characteristics (such as electrical signal, magnetic signal or acoustic signal) or chemical characteristics (such as tracer), and mixed with the cementing slurry to form the signal cementing slurry.

[0063] Step 5, displacement fluid is injected into the cementing tool combining the positive circulation and the reverse circulation;

[0064] Step 6, the signal cementing slurry flows to the reverse circulation cementing shut-off float shoe 3, the control unit 3322 compares the excitation signal emitted by the excitation beacon with the excitation target signal stored in the storage 3325, and the control module 332 controls the shut-off module 333 to close the upper inner flow channel 3312.

[0065] The cementing method combining the positive circulation and the reverse circulation will be introduced in detail below taking the cementing tool combining the positive circulation and the reverse circulation as a single-stage cementing tool combining the positive circulation and the reverse circulation. The cementing method combining the positive circulation and the reverse circulation sequentially includes the following steps:

[0066] The well depth of a certain well is 2000m, the borehole size is Φ222.2mm, and the casing size is Φ139.7mm. According to the formation condition, the well bottom above 800m is selected for cementing.

[0067] Step 1, preparation before construction;

[0068] A single-stage positive and reverse circulation combined cementing tool is designed. The reverse circulation cementing flow shoe 3 is located at the lower end of the single-stage positive and reverse circulation combined cementing tool. The cross circulation nipple 2 is located above the reverse circulation cementing flow shoe 3. The distance between the cross circulation nipple 2 and the reverse circulation cementing flow shoe 3 is 800m. The cross circulation nipple 2 and the reverse circulation cementing flow shoe 3 are connected through the casing 1. The upper end of the cross circulation nipple 2 is connected to the casing 1. The outer diameter of the cross circulation nipple 2, the outer diameter of the reverse circulation cementing flow shoe 3 and the outer diameter of the casing 1 are all Φ139.7mm.

[0069] The amount of working fluid is calculated, as shown in Table 1 below.

[0070] Table 1, working fluid consumption table

[0071] The reverse circulation cementing flow shoe 3 receives the excitation target signal through the receiver 3324 on the ground and saves it in the memory 3325 through the control unit 3322. The initial state of the one-way valve 32 is closed, and the initial state of the flow blocking assembly 33 is open, that is, the lower inner flow passage 3212 is closed, and the upper inner flow passage 3312 is open. The positive and reverse circulation combined cementing tool receives the excitation target signal through the receiver 3324 on the ground and saves it in the memory 3325 through the control unit 3322. The baffles 3333 are all located in the upper cylinder wall 3311. The second spring 3332 is in a compressed state. The magnetic blocking pin 3328 is inserted with the baffles 3333. The magnetic blocking pin 3328 can block the baffles 3333 from moving along the diameter direction of the shell 31. The third spring 3334 is usually in a natural state.

[0072] The single-stage positive and reverse circulation combined cementing tool is combined;

[0073] Step 2, the single-stage positive and reverse circulation combined cementing tool is lowered into the borehole, and the drilling fluid is circulated;

[0074] Step 3, the construction pipeline is pressure tested at 25MPa. After 5 minutes of pressure stabilization and observation of whether there is a pressure drop, the pressure is released. The flushing fluid is injected into the single-stage positive and reverse circulation combined cementing tool. The volume of the flushing fluid is 12.5m 3 , and the injection flow rate of the flushing fluid is 1m 3 / min;

[0075] Step 4, signal cement slurry and cementing cement slurry are injected into the single-stage positive and reverse circulation combined cementing tool in sequence, the signal cement slurry is a mixture of a certain amount of excitation beacon and cementing cement slurry (i.e. the cement slurry in Table 1 above), the volume of the signal cement slurry is 0.5m 3 -2m 3 , the injection flow rate of the signal cement slurry is 1m 3 / min, the volume of the cementing cement slurry (i.e. the cement slurry in Table 1 above) is equal to the volume of the lowermost wellbore annulus 4, the volume of the cementing cement slurry is 19m 3 , and the injection flow rate of the cementing cement slurry is 1m 3 / min;

[0076] Step 5, displacement fluid is injected into the single-stage positive and reverse circulation combined cementing tool, the volume of the displacement fluid is 18.5m 3 , and the injection flow rate of the displacement fluid is 1m 3 / min;

[0077] Step 6, the signal cement slurry flows to the reverse circulation cementing shut-off float shoe 3, the cementing cement slurry enters from the lower end of the outer shell 31 and then discharges from the upper end of the outer shell 31, and the cementing cement slurry flows through the lower inner flow passage 3212 of the one-way valve 32 and the upper inner flow passage 3312 of the shut-off assembly 33. The signal detector 3321 transmits the signal in the casing (i.e. the upper inner flow passage 3312) in real time to the control unit 3322 for real-time comparison with the target signal stored in the memory 3325; when the excitation signal emitted by the excitation beacon matches the excitation target signal stored in the memory 3325, the control unit 3322 sends a control instruction to the execution unit 3323, i.e. the electromagnetic actuator 3327 is powered on (i.e. the electromagnetic actuator 3327 is activated after being powered on), the magnetic blocking pin 3328 moves upward and is separated from the baffle 3333, the second spring 3332 makes the baffle 3333 enter the upper inner flow passage 3312, and the baffle 3333 is matched and inserted into the baffle clamping groove 3331, so as to realize the closure of the upper inner flow passage 3312 by the baffle 3333. At this time, the state of the shut-off assembly 33 is closed, i.e. the upper inner flow passage 3312 is also closed, and then the one-way valve 32 also returns to the closed state; at this time, the cementing pump injection equipment construction pressure suddenly rises to 25MPa, and the operation is stopped.

[0078] After the cementing operation is completed, the fluid distribution in the oil and gas wellbore is shown in FIG. 11, wherein the wellbore contains, from bottom to top, the first wellbore annulus section 101, the first casing internal cavity section 102, the second wellbore annulus section 103, and the second casing internal cavity section 104. The cement slurry is only located in the first wellbore annulus section 101, i.e. only the first wellbore annulus section 101 is the cement slurry area 108, and the rest is the non-cement slurry area 107.

[0079] The following will take the cementing tool combined with positive and reverse circulation as a two-stage cementing tool combined with positive and reverse circulation as an example to introduce the cementing method combined with positive and reverse circulation in detail. The cementing method combined with positive and reverse circulation provided by the embodiment of the disclosure adopts a cementing tool composed of a cross circulation nipple and a reverse circulation cementing cutoff float shoe, uses the first channel and the second channel of the cross circulation nipple in the cementing tool to realize the communication of the positive circulation and the reverse circulation path respectively, and uses the intelligent cutoff function of the cutoff float shoe to realize the cooperative operation of the positive circulation and the reverse circulation process, thereby solving the problems of cementing of an ultra-long cementing section and a complex formation. Mainly includes:

[0080] 1. Receiving and storing the target signal on the ground through the receiver;

[0081] 2. After the cementing tool is lowered into the wellbore, flushing fluid, signal cement slurry containing the excitation beacon and cement slurry with a volume equal to the annular volume of the wellbore are injected into the cementing tool in sequence;

[0082] 3. When the signal cement slurry flows to the cutoff float shoe, the control module compares the excitation signal with the stored target signal, and after confirming that they are consistent, controls the cutoff assembly to close the upper inner flow channel, including: triggering the electromagnetic actuator to act, attracting the magnetic blocking pin to release the locking of the baffle, making the pre-compressed second spring push the metal baffle to move transversely along the slide, and finally embedding the metal baffle into the baffle clamping groove to completely close the upper inner flow channel, while the one-way valve is closed under the action of the spring to form double sealing. In some specific embodiments, the cementing method combined with positive and reverse circulation comprises the following steps in sequence:

[0083] The well has a well depth of 4000m, a wellbore size of Φ222.2mm and a casing size of Φ139.7mm, and according to the formation condition, the bottom of the well is sealed for 0m-800m and 1200m-1800m two sections of formation;

[0084] Step 1. Preparing before construction;

[0085] The double-stage positive and reverse circulation combined cementing tool is designed, which comprises one reverse circulation cementing flow control float shoe 3 and three cross circulation short sections 2. The reverse circulation cementing flow control float shoe 3 is located at the lower end of the double-stage positive and reverse circulation combined cementing tool, the three cross circulation short sections 2 are located above the reverse circulation cementing flow control float shoe 3, the three cross circulation short sections 2 are arranged in the up-down direction at intervals, the distance between the lowermost cross circulation short section 2 and the reverse circulation cementing flow control float shoe 3 is 800 m, the distance between the lowermost cross circulation short section 2 and the middle cross circulation short section 2 is 400 m, the distance between the uppermost cross circulation short section 2 and the middle cross circulation short section 2 is 600 m, the cross circulation short sections 2 are connected by casings 1, the cross circulation short sections 2 and the reverse circulation cementing flow control float shoe 3 are connected by casings 1, and the upper end of the uppermost cross circulation short section 2 is externally connected with a casing 1. The outer diameter of the cross circulation short section 2, the outer diameter of the reverse circulation cementing flow control float shoe 3 and the outer diameter of the casing 1 are all Φ139.7 mm.

[0086] The amount of working fluid is calculated, as shown in Table 2 below.

[0087] Table 2, working fluid consumption table

[0088] The reverse circulation cementing flow control float shoe 3 receives the excitation target signal on the ground through the receiver 3324 and saves the excitation target signal in the memory 3325 through the control unit 3322. The initial state of the one-way valve 32 is closed, and the initial state of the flow control assembly 33 is open, that is, the lower inner flow passage 3212 is closed, and the upper inner flow passage 3312 is open. The positive and reverse circulation combined cementing tool receives the excitation target signal on the ground through the receiver 3324 and saves the excitation target signal in the memory 3325 through the control unit 3322. The baffles 3333 are all located in the upper cylinder wall 3311, the second spring 3332 is in a compressed state, the magnetic blocking pin 3328 is inserted with the baffles 3333, the magnetic blocking pin 3328 can block the baffles 3333 from moving in the diameter direction of the shell 31, and the third spring 3334 is usually in a natural state.

[0089] The double-stage positive and reverse circulation combined cementing tool is designed, which comprises one reverse circulation cementing flow control float shoe 3 and three cross circulation short sections 2. The reverse circulation cementing flow control float shoe 3 is located at the lower end of the double-stage positive and reverse circulation combined cementing tool, the three cross circulation short sections 2 are located above the reverse circulation cementing flow control float shoe 3, the three cross circulation short sections 2 are arranged in the up-down direction at intervals, the distance between the lowermost cross circulation short section 2 and the reverse circulation cementing flow control float shoe 3 is 800 m, the distance between the lowermost cross circulation short section 2 and the middle cross circulation short section 2 is 400 m, the distance between the uppermost cross circulation short section 2 and the middle cross circulation short section 2 is 600 m, the cross circulation short sections 2 are connected by casings 1, the cross circulation short sections 2 and the reverse circulation cementing flow control float shoe 3 are connected by casings 1, and the upper end of the uppermost cross circulation short section 2 is externally connected with a casing 1. The outer diameter of the cross circulation short section 2, the outer diameter of the reverse circulation cementing flow control float shoe 3 and the outer diameter of the casing 1 are all Φ139.7 mm.

[0090] Step 2, the double-stage positive and reverse circulation combined cementing tool is lowered into the wellbore, and the drilling fluid is circulated.

[0091] Step 3, the construction pipeline is pressure tested at 25 MPa, and the pressure is stabilized for 5 minutes and observed whether there is a pressure drop. After no pressure drop is found, the pressure is released. The flushing fluid is injected into the double-stage positive and reverse circulation combined cementing tool, the volume of the flushing fluid is 12.5 m 3 , and the injection flow rate of the flushing fluid is 1 m 3 / min.

[0092] Step 4: Sequentially inject signal cement slurry and cementing cement slurry into the dual-stage forward and reverse circulation cementing tool. The signal cement slurry is a mixture of a certain amount of trigger beacon and cementing cement slurry (i.e., the cement slurry in Table 1 above), and the volume of the signal cement slurry is 0.5 m³. 3 -2m 3 The injection velocity of the signal cement grout is 1m. 3 / min, the volume of cement slurry (i.e., the cement slurry in Table 1 above) is equal to the volume of the lowest annulus 4 in the wellbore, and the cement slurry volume is 19m³. 3 The injection velocity of the cement slurry is 1m. 3 / min, the density of both signal cement slurry and cementing cement slurry is 1.40 g / cm³. 3 ;

[0093] Step 5: Inject displacement fluid into the cementing tool with a two-stage forward and reverse circulation system. The volume of the displacement fluid is equal to the sum of the volumes of the second annulus section 103, the second casing internal cavity section 104, the third annulus section 105, and the third casing internal cavity section 106, counting from bottom to top within the wellbore. For example, the volume of the displacement fluid is 6 m³. 3 The injection flow rate of the displacement fluid is 1 m. 3 / min;

[0094] Then, cement slurry is injected into the cementing tool, which combines two-stage forward and reverse circulation. The volume of the cement slurry is equal to the volume of the third annulus section 105 in the wellbore counting from the bottom up. For example, the volume of the cement slurry is 14m³. 3 The cement grout injection velocity is 1m. 3 / min;

[0095] Then, displacement fluid is injected into the cementing tool with a combined two-stage forward and reverse circulation system. The volume of the displacement fluid is 34 m³. 3 The injection flow rate of the displacement fluid is 1 m. 3 / min;

[0096] Step 6, the signal cement slurry flows to the reverse circulation cementing shut-off float shoe 3, the cementing slurry enters from the lower end of the outer shell 31 and then discharges from the upper end of the outer shell 31, and the cementing slurry flows through the lower inner flow channel 3212 of the one-way valve 32 and the upper inner flow channel 3312 of the shut-off assembly 33. The signal detector 3321 transmits the signal in the casing (i.e. the upper inner flow channel 3312) in real time to the control unit 3322 for real-time comparison with the target signal stored in the memory 3325; when the control unit 3322 compares the excitation signal emitted by the excitation beacon with the excitation target signal stored in the memory 3325 and finds that they are consistent, the control unit 3322 sends a control instruction to the execution unit 3323, i.e. the electromagnetic actuator 3327 is powered on, the magnetic blocking pin 3328 moves upward and is separated from the baffle 3333, the second spring 3332 makes the baffle 3333 enter the upper inner flow channel 3312, and the baffle 3333 is matched and inserted into the baffle clamping groove 3331, so that the baffle 3333 closes the upper inner flow channel 3312. At this time, the state of the shut-off assembly 33 is closed, i.e. the upper inner flow channel 3312 is also closed, and then the one-way valve 32 also returns to the closed state; at this time, the cementing pump injection device construction pressure suddenly rises to 35 MPa, and the operation is stopped.

[0097] After the cementing operation is completed, the fluid distribution in the oil and gas wellbore is shown in FIG. 12, wherein the wellbore contains, from bottom to top, the first wellbore annulus section 101, the first casing internal cavity section 102, the second wellbore annulus section 103, the second casing internal cavity section 104, the third wellbore annulus section 105, and the third casing internal cavity section 106. The cement slurry is only located in the first wellbore annulus section 101 and the third wellbore annulus section 105, i.e. only the first wellbore annulus section 101 and the third wellbore annulus section 105 are the cement slurry region 108, and the rest are the non-cement slurry region 107.

[0098] The cementing method combining the positive circulation and the reverse circulation makes full use of the advantages of the positive circulation and the reverse circulation cementing processes, realizes the pressure balance and the cement slurry transportation, solves the problems of the ultra-long cementing section and the cementing of complex formations, greatly improves the cementing quality and the construction efficiency, and is suitable for the cementing operation of oil and gas wells under complex geological conditions.

[0099] The cementing method combining the positive circulation and the reverse circulation can reduce the amount of cement slurry used and the pollution to the formation during the construction process by selecting the cementing unstable formation section instead of the whole oil and gas wellbore, and better reflects the environmental friendliness and cost control. The use of the cross circulation nipple 2 and the reverse circulation cementing shut-off float shoe 3 does not affect the drilling fluid circulation after the casing is completed.

[0100] The above merely describes specific embodiments of the present disclosure, and cannot be used to limit the scope of the present disclosure, so replacement of equivalent components, or equivalent changes and modifications made within the scope of protection of the present disclosure should still belong to the scope of the present disclosure. In addition, the technical features in the present disclosure and between technical features, technical features and technical solutions, and between technical solutions can be used freely in combination.

Claims

1. A combination of positive and reverse circulation cementing tools, characterized in that, The positive and reverse circulation combined cementing tool comprises a cross circulation nipple (2) and a reverse circulation cementing float shoe (3) arranged in sequence; the reverse circulation cementing float shoe (3) comprises a shell (31) in a vertical cylindrical structure, the shell (31) comprises a shell wall (311) and an internal flow channel (312), the internal flow channel (312) comprises a cross blocking assembly (33) and a one-way valve (32) arranged in sequence, the cross blocking assembly (33) comprises an upper shell (331) in a vertical cylindrical structure, the upper shell (331) comprises an upper cylindrical wall (3311) and an upper internal flow channel (3312), the upper cylindrical wall (3311) comprises a control module (332) and a cross blocking module (333), and the control module (332) can control the cross blocking module (333) to block the upper internal flow channel (3312).

2. The positive and reverse circulation combined cementing tool of claim 1, wherein, The cross circulation nipple (2) can make the wellbore annulus (4) above the cross circulation nipple (2) not communicate with the wellbore annulus (4) below the cross circulation nipple (2), the cross circulation nipple (2) comprises a first channel (25) and a second channel (26), the first channel (25) can make the casing internal cavity (5) above the cross circulation nipple (2) communicate with the wellbore annulus (4) below the cross circulation nipple (2), and the second channel (26) can make the casing internal cavity (5) below the cross circulation nipple (2) communicate with the wellbore annulus (4) above the cross circulation nipple (2).

3. The positive and reverse circulation combined cementing tool of claim 2, wherein, The cross circulation nipple (2) comprises an inner nipple body (23) and a sealing structure (24) arranged in sequence, the upper end of the inner nipple body (23) is provided with an upper joint segment (21), the lower end of the inner nipple body (23) is provided with a lower joint segment (22), the sealing structure (24) can be sealingly connected with the well wall (6), the inner nipple body (23) is in a vertical cylindrical structure, the upper end of the first channel (25) is located on the upper surface of the inner nipple body (23), the lower end of the first channel (25) is located on the side surface of the inner nipple body (23), the lower end of the first channel (25) is lower than the sealing structure (24), the upper end of the second channel (26) is located on the side surface of the inner nipple body (23), the upper end of the second channel (26) is higher than the sealing structure (24), and the lower end of the second channel (26) is located on the lower surface of the inner nipple body (23).

4. The positive and reverse circulation combined cementing tool of claim 1, wherein, An annular inner cavity (3313) is arranged in the upper cylinder wall (3311), the control module (332) and the intercepting module (333) are located in the annular inner cavity (3313), the upper inner flow channel (3312) penetrates the upper shell (331) along the axis direction of the upper shell (331), the control module (332) comprises a signal detector (3321), a control unit (3322) and an execution unit (3323) connected in sequence, the control unit (3322) is connected with a memory (3325), the signal detector (3321) can send real-time detection signals to the control unit (3322), the control unit (3322) compares the real-time detection signals with target signals stored in the memory (3325) in real time, when the real-time detection signals are consistent with the target signals, the control unit (3322) controls the intercepting module (333) to close the upper inner flow channel (3312) through the execution unit (3323).

5. The positive and reverse circulation combined cementing tool of claim 4, wherein, The control unit (3322) is also connected with a receiver (3324) and a power supply (3326), the control unit (3322) can receive the target signals through the receiver (3324) and store them in the memory (3325), the execution unit (3323) comprises an electromagnetic actuator (3327) and a magnetic blocking pin (3328), the electromagnetic actuator (3327) can move the magnetic blocking pin (3328) to the direction close to the electromagnetic actuator (3327).

6. The positive and reverse circulation combined cementing tool of claim 5, wherein, The intercepting module (333) comprises a baffle (3333) and a second spring (3332) connected in sequence, the baffle (3333) is perpendicular to the axis of the upper shell (331), when the upper inner flow channel (3312) is in an open state, the baffle (3333) is entirely located in the upper cylinder wall (3311), the second spring (3332) is in a compressed state, the magnetic blocking pin (3328) is inserted into the baffle (3333), and the magnetic blocking pin (3328) can block the baffle (3333) from moving along the diameter direction of the upper shell (331).

7. The positive and reverse circulation combined cementing tool of claim 6, wherein, One end of the second spring (3332) is connected with one end of the baffle (3333), the electromagnetic actuator (3327) can make the magnetic blocking pin (3328) separate from the baffle (3333), and the second spring (3332) can make the baffle (3333) enter the upper inner flow channel (3312) and close the upper inner flow channel (3312).

8. The positive and reverse circulation combined cementing tool of claim 7, wherein, The upper cylinder wall (3311) comprises an outer peripheral wall (3314) and an inner peripheral wall (3315), the other end of the second spring (3332) is connected with the outer peripheral wall (3314), the upper cylinder wall (3311) comprises a baffle sliding channel (3335), the extension direction of the baffle sliding channel (3335) is perpendicular to the axis of the upper shell (331), the baffle (3333) is matched and connected with the baffle sliding channel (3335), the baffle (3333) can slide along the baffle sliding channel (3335), the inner surface of the inner peripheral wall (3315) comprises a baffle clamping groove (3331), when the baffle (3333) closes the upper inner flow channel (3312), the other end of the baffle (3333) is matched and inserted into the baffle clamping groove (3331).

9. The positive and reverse circulation combined cementing tool of claim 1, wherein, The reverse circulation well cementing cutoff float shoe (3) is located at the lower end of the positive and reverse circulation combined well cementing tool, the positive and reverse circulation combined well cementing tool comprises a plurality of cross circulation joints (2), the plurality of cross circulation joints (2) are arranged in the up-down direction, two adjacent cross circulation joints (2) are connected through a casing (1), and the cross circulation joint (2) and the reverse circulation well cementing cutoff float shoe (3) are connected through the casing (1).

10. A method for cementing a well by combining the positive and reverse circulation, characterized in that, The positive and reverse circulation combined well cementing method adopts the positive and reverse circulation combined well cementing tool of claim 1, and comprises the following steps in sequence: Step 1, preparation before construction; The reverse circulation well cementing cutoff float shoe (3) receives a target signal on the ground through a receiver (3324) and saves the target signal in a storage (3325) through a control unit (3322); Step 2, lowering the positive and reverse circulation combined well cementing tool into the wellbore; Step 3, injecting flushing fluid into the positive and reverse circulation combined well cementing tool; Step 4, injecting successively into said well cementing tool of the positive and negative circulation combined type, a signal cement slurry, which is a mixture of a shot beacon and a cement slurry, the volume of said signal cement slurry being 0.5 m 3 -2m 3 , and a cement slurry, the volume of said cement slurry being equal to the volume of the lowermost wellbore annulus (4); Step 5, injecting displacement fluid into the positive and reverse circulation combined well cementing tool; Step 6, the signal cement slurry flows to the reverse circulation well cementing cutoff float shoe (3), the control unit (3322) compares the target signal stored in the storage (3325) with the signal emitted by the target signal beacon, and the control module (332) controls the cutoff module (333) to close the upper inner flow channel (3312).

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