CN110593830A - Layered water injection device for oil field water injection well - Google Patents

Abstract

The invention belongs to the field of oil recovery technology. In order to prevent the layered water injection device from creeping up and down in the well and ensure that the pressure is effectively transmitted to the water injection layer, the technical solution adopted in the present invention is: a layered water injection device for oilfield water injection wells, which includes an anchor seal device, and the anchor seal device It includes a central tube, the two ends of the central tube are provided with connectors, the axis of the connector is provided with a through hole connected with the central tube, and a rubber tube is provided outside the central tube, and the feature is that the rubber tube is divided into at least Two sections of the area, the two ends of the rubber tube and the connection between each two sections of the area are vulcanized into one with the central tube, and pressure-permeable holes are respectively set on the wall of the central tube in each section of the area, and each section forms an independent sealed cavity.

Description

Layered water injection device for oil field water injection well

technical field

The invention belongs to the technical field of oil field recovery, and specifically refers to a layered water injection device for low-permeability oil reservoir exploitation by adopting a water injection process.

Background technique

When the oil field uses the water injection process to extract oil from the low-permeability oil layer, it needs to pressurize the water injection well, and transmit the pressure to the reservoir layer through water to force the oil to seep out. A wellbore casing is provided inside the water injection well, and pressure holes of different depths are provided on the casing according to formations of different depths, and the pressure is transmitted to formations of corresponding depths by applying different pressures. Therefore, when pressurizing, it is necessary to block the interior of the deep water well in layers to ensure that the pressure can be accurately transmitted to the corresponding formation. The layered sealing device is usually called an anchor sealing device, which requires that the anchor sealing device can effectively block the water layer, and at the same time, the anchor sealing device cannot move up and down on the well wall. The traditional anchor sealing device uses a mechanical Expanding claw structure, when pressurized, the anchoring device is anchored on the well wall casing of the deep water well by using the expanding claw. When the pressure is removed, the expanding claw automatically retracts and separates from the well wall casing. Mechanical anchor seal or anchoring device The advantage is that the anchoring force is strong, which can effectively prevent the anchor seal device from moving up and down on the well wall casing. The disadvantage is that due to the influence of the downhole environment, the anchor seal device is easy to corrode and rust, and it is easy to cause the opening and closing of the expansion claw to lose control , When the pressure is removed, if the expansion claw cannot form a retraction, the anchor sealing device cannot be taken out from the well. In order to solve the technical defects of the traditional mechanical anchor seal device, ZL2016207926706 discloses a pressure-bearing expansion type anchor seal integrated fracturing packer, which is composed of an upper joint, a central pipe, an inner core, a rubber tube, Composed of connecting hole, anchor body, screen pipe, and lower joint; the largest outer diameter of the anchor body is tooth-shaped, the inner side of the anchor body is connected to the inner core through vulcanization, and the outer side of the anchor body is connected to the rubber barrel through vulcanization. The barrel and the anchoring body are vulcanized and installed outside the central tube. The upper part of the central tube is connected to the upper joint through a screw, and the lower part of the central tube is connected to the lower joint through a screw. The lower part of the anchoring body is housed, the center pipe is provided with a screen tube, and the inner core and the upper and lower parts of the anchoring body are provided with communicating holes. The expansion of the anchoring body drives the rubber tube to rise to block, and when the pressure disappears, the elasticity of the rubber tube drives the anchoring body to retract. It is stated in the specification of the application that the packer can withstand a high pressure of 80MPa, but in actual application, the expansion pressure on the anchor body will only be equal to the pressure difference between the filling pressure and the water layer at the bottom of the packer. A water distributor is connected to the bottom of the packer. The opening pressure of the water distributor is set to 1MPa. When the pressure valve is opened, the injection pressure is transmitted to the water layer at the bottom of the packer, and the pressure is transmitted to the low-permeability reservoir through the bottom water layer. It can be seen that if the injection pressure is set to 80MPa, the pressure is applied through the center pipe and transmitted to the anchor body through the screen tube, but the outside of the anchor body is also subject to a pressure of 79MPa, that is, the expansion of the anchor body The pressure is only 1MPa. Since the inner core, the rubber tube and the anchor body are vulcanized together, this pressure can seal the water layer after the rubber tube and the anchor body are raised, but the anchoring force of the anchor body Far from being enough, it is easy to cause the anchor seal device to creep up and down on the well wall, resulting in failure of pressure transmission.

Contents of the invention

Aiming at the technical problems existing in the anchor seal devices in the prior art, the present invention provides an anti-creep layered water injection device for oil field water injection wells. The independent expansion sealing cavity can not only effectively block the water layer through the multi-section sealing cavity, but also greatly improve the anchoring force, prevent the device from creeping up and down in the well, and ensure the effective transmission of pressure to the oil layer.

In order to achieve the above-mentioned technical purpose, the technical solution adopted by the present invention is: a layered water injection device for oilfield water injection wells, which includes an anchor seal device, and the anchor seal device includes a center pipe, with connectors at both ends of the center pipe, The axis of the connector is provided with a through hole connected with the central tube, and a rubber tube is provided outside the central tube. The connection between them is vulcanized as one with the central tube, and pressure-permeable holes are respectively provided on the central tube wall in each section area, and each section area forms an independent sealed cavity.

Further, the surfaces of one or more of the sealed cavities are provided with guide grooves extending in the axial direction.

Further, a ferrule is provided at the part where the rubber tube and the central tube are vulcanized as one, and the ferrule is stuck on the outside of the rubber tube and vulcanized as one with the rubber tube.

Further, the connectors at both ends of the central tube are provided with bushings, and the bushings fit over the two ends of the central tube and press the ends of the ferrules at both ends of the rubber tube.

Further, one or more surfaces in the sealing cavity are provided with annular anti-slip threads.

Further, the bottom of the anchor sealing device is also connected to a water distributor, the water distributor includes a water distribution pipe, one end of the water distribution pipe is provided with a pipe head connected to the end connector of the central pipe, and the lumen at the other end of the water distribution pipe is There is a plugging device inside, and a water injection hole is provided on the pipe wall of the water distribution pipe. A movable sealing pressure ring and a fixed sealing pressure ring are respectively arranged on the pipe walls on both sides of the water injection hole. Through the movable sealing pressure ring and the fixed sealing The clutch of the pressure ring contact surface controls the opening and closing of the water injection hole; the movable sealing pressure ring is located on the side close to the pipe head, and a spring is arranged between the movable sealing pressure ring and the pipe head, and the spring is set on the water distribution pipe. One end is against the pipe head, and the other end is against the movable sealing pressure ring.

Further, an adjustment ring is provided on the pipe head, and the adjustment ring is screwed to the pipe head, and the end of the spring that abuts against the elbow means abuts against the adjustment ring.

Further, the blocking device at one end of the water distribution pipe means that an end plate is provided at the end, and the end plate closes the end of the water distribution pipe.

Further, it also includes a well flushing pipe, one end of the well flushing pipe is located inside the water distribution pipe and is fixed to the inner wall of the water distribution pipe. The sealing ball can close or open the end of the well flushing pipe under pressure; the wall of the well flushing pipe is provided with a well flushing hole.

Further, a sealing ball floating blocking rod is provided in the inner cavity of the water distribution pipe above the sealing ball.

The beneficial effects of the present invention are: by setting multiple independent sealing chambers, the sealed chambers at the bottom end can be sealed in layers by using the sealed chambers inflated at the bottom, so that the upper sealed chambers can be subjected to the same pressure as the applied pressure, so that the anchoring force can be greatly improved. Lifting, the position of the anchor seal device on the well wall is fixed to ensure that the pressure can be accurately transmitted to the formation to be applied. The layered anti-creep water injection device is not easy to corrode, and is convenient to be separated from the well wall casing, and the device can be smoothly lifted out of the well at any time to facilitate the replacement operation of the device.

Description of drawings

Accompanying drawing 1 is the structural sectional view of anchoring device.

Accompanying drawing 2 is the enlarged schematic view of A in accompanying drawing 1.

Accompanying drawing 3 is the structural sectional view of water distributor.

Accompanying drawing 4 is the sectional view of the structure after the anchor device, the water distributor and the well flushing pipe are assembled.

Accompanying drawing 5 is the sectional view of C-C direction structure in accompanying drawing 1.

Accompanying drawing 6 is the schematic diagram of the state of the anchor sealing device in the well.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1

As shown in accompanying drawing 4, the layered water injection device for the oilfield water injection well comprises three parts connected by an anchor sealing device 20, a water distributor 21 and a well cleaning pipe 22.

As shown in accompanying drawing 1, in this device, anchor sealing device comprises central tube 1, and the two ends of central tube have connector 2, and the axle center of connector 2 is provided with the through hole that runs through with central tube, and connector 2 The function is to be connected with the pressurized pipe or other parts, and the rubber cartridge 3 is arranged on the outside of the center pipe 1 .

As shown in Figure 1, the rubber tube 3 is divided into three sections, and the two ends of the rubber tube and the connection between the two sections are vulcanized into one with the central tube 1, so that the rubber tube forms three independent expandable parts. Shrunken sealed cavity. As shown in Figure 2, the central tube wall in each area is respectively provided with pressure-through holes 4, when the pressure in the central tube 1 increases, three independent sealed cavities can be generated through the pressure-through holes 4. After expansion, when the pressure in the central tube disappears, the three independent sealing chambers retract. In this embodiment, the central tube corresponding to each independent sealed cavity is provided with 8 pressure penetration holes, and the 8 pressure penetration holes are divided into two rows and symmetrically distributed on the tube wall of the central tube.

During production, the outer diameter of the rubber tube can be determined according to the diameter of the casing on the well wall. When drilling in the oil field, the casing in the well is left on the well wall. Generally, the inner diameter of the casing is 124mm, so the anchor seal The outer diameter of the rubber cylinder of the device is set to 110mm when it is not inflated, the overall length of the rubber cylinder is set to 1220mm, plus the overall length of the connectors at both ends is 1390mm, and the lengths of the three independent sealing chambers are set to 300mm respectively. The vulcanized connection length between the two sealed chambers and between the end of the rubber cylinder and the central tube is 80mm. There is a 7mm expansion and contraction zone between the rubber tube 3 and the well wall casing. When the three independent sealing cavities on the rubber tube expand, the surface of the sealing cavity and the well wall casing form a state of close contact, which acts as a layered seal. Blocking and anchoring.

The principle of this design is: as shown in Figure 4, the layered water injection device is also connected with a water distributor at the bottom of the anchor sealing device. , the anchor seal device and the water distributor are lowered along the well wall casing to the set depth, which is generally 1000-3000m. The pressure hole 4 transmits to the inside of the sealing chamber to force the expansion of the three sealing chambers, so that the outer wall of the sealing chamber is in close contact with the inner wall of the casing. At the same time, the pressure in the center pipe forces the water distributor to open, and the pressure is transmitted to the bottom of the water distributor, so that the water at the bottom of the water distributor forms a high pressure, which is transmitted to the formation through the pressure hole on the casing, forcing the oil in the low-permeability reservoir to seep out.

Since the water distributor generally requires a pressure of 1MPa to open, if a pressure of 20MPa is applied to the center pipe through the pressurized pipe, when the water distributor is opened, the water at the bottom of the water distributor will bear a pressure of 19MPa. It will be delivered to the seal cavity at the bottom of the anchor seal. If the anchor-sealing device adopts a single sealing chamber swelling method, the actual expansion pressure of the sealing chamber is only 1MPa. The anchoring force between them will be far from enough. Under the action of the bottom pressure, the anchoring device will creep up and down along the wellbore casing, resulting in the failure of pressure transmission to the formation.

In this application, three independently inflatable sealing chambers are set. When a pressure of 20 MPa is applied to the pressurized pipe, the sealing chamber at the bottom of the anchoring device is expanded by a pressure of 1 MPa, and the pressure on the top sealing chamber is 20 MPa minus the water depth pressure. Taking 2000 meters as an example, the water depth pressure is 0.0184MPa, which is basically negligible. After the bottom sealing chamber expands, it forms a layered blockage on the water body. The blocking of the upper two sealing chambers will not be transmitted to the upper two sealing chambers, so the top sealing chamber and the middle anchoring chamber completely receive the applied pressure of 20MPa, and the expansion force on the two sealing chambers increases sharply, so that they are compatible with the well wall casing The friction force between them increases, and the anchoring force increases sharply, which ensures the stability of the position of the anchor seal device on the wellbore casing, and stabilizes the pressure transmitted to the corresponding formation at 19MPa.

In order to further increase the anchoring force, an annular anti-slip thread 7 can be provided on the surface of the top and the middle sealing cavity to increase the friction between it and the well wall casing.

It can be seen from the above description that the rubber cartridge is at least set up as two independent sealing chambers, the bottom sealing chamber plays a role of layered sealing, and the upper sealing chamber is mainly used for anchoring. Except for this embodiment, the rubber cartridge can also be set into three More than one sealing chamber, the number should be reasonably determined according to the required anchoring force.

In addition, when making the anchor seal device, there is another key factor that, except for the sealing cavity at the bottom, as shown in Figure 5, the surface of the other sealing cavity is provided with a guide groove 23 extending in the axial direction. The flow groove 23 can adopt a linear structure parallel to the axis and extend in the axial direction, or can be arranged in a spiral shape extending in the axial direction on the surface of the sealing cavity. The effect of setting the axial guide groove 23 will be described with reference to FIG. 6 . As shown in Figure 6, the anchoring and sealing device is located inside the casing 24, which is filled with water. When the central pipe of the anchoring and sealing device is pressurized, the three sealing cavities will inevitably force the anchoring and sealing The water body between the device and the well wall casing rises up to make room for the expansion of the sealed cavity. It has been verified by experiments that when the pressurization test is carried out, the bottom sealing cavity first rises when the pressure is transmitted to the bottom. After the bottom sealing cavity rises, it forms a layered seal to the water body, and then the upper sealing cavity begins to expand. Through In the test of 3 sealed chambers, after the bottom sealed chamber swelled, and then the top sealed chamber swelled, the resulting problem was that the top and bottom sealed chambers expanded to form a layered blockage of the water body, and the outside of the middle sealed chamber There is no space for the water body to discharge, and the middle sealed cavity will cause failure of swelling. When the axial diversion grooves 23 are arranged on the surfaces of the upper two sealing chambers, under the action of high pressure, the water outside the middle sealing chamber will be forced to surge up through the diversion grooves, leaving room for the middle sealing chamber to expand. When the upper two sealing cavities fully accept the applied pressure, they fully expand and form a tight fit with the well wall casing 24, thereby playing an anchoring role.

The expansion effect of setting more than three sealed cavities can be deduced through the experiment of setting three sealed cavities. When multiple sealing cavities are provided, the multiple sealing cavities cannot be expanded synchronously, which will cause the water body outside some of the sealing cavities to fail to drain, resulting in failure of expansion of the sealing cavities. When the surface of other sealing chambers except the bottom sealing chamber is provided with axial guide grooves, when the sealing chamber expands, the peripheral water body will be forced to surge up along the axial guide grooves, thereby making room for the expansion of the sealing chamber .

When increasing the anchoring force or carrying out multi-layer water injection operations, multiple anchor sealing devices can be used in series. In this environment, except for the bottom sealing cavity of the bottom anchor sealing device, other Axial guide grooves can be arranged on the surface of all sealing chambers of the sealing chamber and other anchor sealing devices.

As shown in accompanying drawing 1, in order to prevent the vulcanization part of the rubber cylinder from cracking, a ferrule 5 is provided on the part where the rubber cylinder 3 and the central tube 1 are vulcanized as one. The barrel is vulcanized as one.

As shown in Figure 1, the connectors 2 at both ends of the central tube 1 are provided with sleeves, which are placed on both ends of the central tube and press the ends of the ferrules 5 at both ends of the rubber tube to prevent the ends of the rubber tube from Cracking occurs.

Example 2

As shown in Figure 4, the layered water injection device also includes a water distributor connected to the anchor seal device, the structure of the water distributor is shown in Figure 3, the water distributor includes a water distribution pipe 8, and one end of the water distribution pipe is provided with The pipe head 9 connected to the end connector can connect the water distributor to the anchor sealing device through the cooperation of the pipe head 9 and the other connectors 2 . The other end of the water distribution pipe 8 is provided with a plugging device inside the lumen. If the water distribution pipe is not connected to other devices, the end of the water distribution pipe 8 can be provided with an end plate for direct sealing. In this embodiment, the water distribution device is also It is connected with the flushing pipe, and the structure of the plugging device will be further described later. As shown in Figure 3, a water injection hole 10 is provided on the pipe wall of the water distribution pipe 8, and a movable sealing pressure ring 11 and a fixed sealing pressure ring 12 are respectively provided on the pipe walls on both sides of the water injection hole 10. The ring 11 can slide to separate or contact the contact surface between the fixed sealing pressure ring 12, and the opening and closing of the water injection hole 10 is controlled by the clutch of the two contact surfaces.

As shown in Figure 3, the movable sealing pressure ring 11 is located on the side close to the pipe head 9, and a spring 13 is arranged between the movable sealing pressure ring 11 and the pipe head 9, and the spring 13 is sleeved on the water distribution pipe 8, and one end thereof is connected to the The pipe head is offset, and the other end is offset against the movable sealing pressure ring.

Through the pipe head 9, the lumen of the water distribution pipe 8 is connected with the lumen of the central pipe 1 of the anchor sealing device. There is a plugging device, high pressure is generated in the water distribution pipe 8, and the high pressure is transmitted to the inside of the water injection hole 10 to push the movable sealing pressure ring 11 to slide in the direction of the pipe head 9, the water injection hole 10 is opened, and the applied pressure is transmitted to the bottom of the anchor sealing device for sealing In the water body below the cavity, the pressure is transmitted to the formation through the water body.

It can be seen that the opening of the water injection hole 10 of the water distributor needs to overcome the elastic force of the spring 13, that is, the opening of the aforementioned water distributor requires 1 MPa.

As shown in accompanying drawing 3, an adjustment ring 14 is provided on the pipe head 9, and the adjustment ring 14 is threadedly connected with the pipe head 9, and the end of the spring 13 which is in contact with the elbow 9 means that it is in contact with the adjustment ring 14. By adjusting the adjustment ring The position of 14 on the elbow controls the compressed length of the spring 13, thereby regulating the pressure required for the water distributor to open.

Further, the blocking device at one end of the water distribution pipe means that an end plate is provided at the end, and the end plate closes the end of the water distribution pipe.

Example 3

Since the water body in the well below the sealing chamber at the bottom of the anchor sealing device is in a closed state for a long time, in the process of repeated pressure application, the water body in this part of the well will be polluted and the water body will deteriorate. Therefore, this part of the water body needs to be replaced regularly. For this reason, in the present embodiment, a well-flushing pipe is added. The structure and connection relationship of the well flushing pipe are shown in accompanying drawing 3, and also include the well flushing pipe 15, one end of the well flushing pipe 15 is located inside the water distribution pipe 8 and is fixed with the inner wall of the water distribution pipe 8, and the plugging device at the end of the water distribution pipe 8 In this embodiment, it means that the end of the well cleaning pipe 15 is provided with a sealing ball 16, and the sealing ball is a metal ball. Ring 17, the sealing ball 16 is surrounded by the sealing ring 17 after falling, which ensures the sealing of the end of the well cleaning pipe 15. As shown in accompanying drawing 3, several well-flushing holes 18 are provided on the pipe wall of the well-flushing pipe 15 .

The cleaning principle of setting the well cleaning pipe is as follows: when the water injection operation is performed, the high pressure in the water distribution pipe 8 will compress the sealing ball 16 and the end of the well cleaning pipe 15, and the end of the well cleaning pipe 15 will be closed, and the high pressure will be injected into the well. Hole 10 passes out. When the cleaning operation is performed, the pressurizing pipe is connected with the water pump, negative pressure is generated in the central pipe 1 and the water distribution pipe 8, the sealing ball 16 floats up under the action of water depth pressure and negative pressure, and the end of the well cleaning pipe 15 is opened, At this time, the water well flushing hole 18 below the anchor sealing device enters the inside of the well flushing pipe 15 and is continuously extracted to the outside of the well to realize well flushing. Once the pipe is anchored, the water injection operation can be realized again.

As shown in FIG. 3 , a sealing ball floating 19 is provided in the inner cavity of the water distribution pipe above the sealing ball 16 , and the floating height of the sealing ball 16 is limited by the gear lever 19 .

Claims (10)

1. A layered water injection device for an oil field water injection well, which includes an anchor seal device, the anchor seal device includes a center pipe, the two ends of the center pipe are provided with connectors, and the axis of the connector is provided with a hole that communicates with the center pipe The through hole is provided with a rubber tube outside the central tube, and the feature is that the rubber tube is divided into at least two sections, and the two ends of the rubber tube and the connection between each two sections are vulcanized into one with the central tube, The wall of the central pipe in each section area is respectively provided with pressure-permeable holes, and each section area forms an independent sealed cavity. 2 . The layered water injection device for oilfield water injection wells according to claim 1 , wherein one or more surfaces of the sealed cavities are provided with diversion grooves extending in the axial direction. 3 . 3. A layered water injection device for oil field water injection wells according to claim 1, characterized in that: a ferrule is provided on the part where the rubber tube and the center pipe are vulcanized as one, and the ferrule is stuck on the outside of the rubber tube and It is integrated with the vulcanization of the rubber cartridge. 4. A layered water injection device for oil field water injection wells according to claim 3, characterized in that: the connectors at both ends of the central pipe are provided with sleeves, and the sleeves are placed on the two ends of the central pipe and are aligned with the rubber sleeve. The ends of the ferrule at both ends are pressed. 5 . The layered water injection device for oilfield water injection wells according to claim 1 , wherein one or more surfaces of the sealing chambers are provided with annular anti-slip threads. 5 . 6. A layered water injection device for oilfield water injection wells according to claim 1, characterized in that: the bottom of the anchor sealing device is also connected to a water distributor, the water distributor includes a water distribution pipe, and one end of the water distribution pipe is provided There is a pipe head connected to the connector at the end of the central pipe, a plugging device is provided inside the lumen at the other end of the water distribution pipe, a water injection hole is provided on the pipe wall of the water distribution pipe, and a A movable sealing pressure ring and a fixed sealing pressure ring are respectively provided, and the opening and closing of the water injection hole are controlled by the clutch of the contact surface of the movable sealing pressure ring and the fixed sealing pressure ring; the movable sealing pressure ring is located on the side close to the pipe head, A spring is arranged between the movable sealing pressure ring and the pipe head, and the spring is sleeved on the water distribution pipe, and one end of the spring is against the pipe head, and the other end is against the movable sealing pressure ring. 7. A layered water injection device for oilfield water injection wells according to claim 6, characterized in that: an adjustment ring is provided on the pipe head, and the adjustment ring is screwed to the pipe head, and the spring is connected to the elbow The end that offsets means offsets with the adjusting ring. 8. A layered water injection device for oilfield water injection wells according to claim 6, characterized in that: the plugging device at one end of the water distribution pipe is provided with an end plate at the end, and the end plate connects the end of the water distribution pipe department closed. 9. A layered water injection device for oilfield water injection wells according to claim 6, characterized in that: it also includes a well flushing pipe, one end of the well flushing pipe is located inside the water distribution pipe and fixed to the inner wall of the water distribution pipe, the The plugging device at the end of the water distribution pipe means that a sealing ball is provided at the end of the well flushing pipe, and the sealing ball can close or open the end of the well flushing pipe under pressure; Wash the well hole. 10. A layered water injection device for oil field water injection wells according to claim 9, characterized in that: a sealing ball floating stop rod is arranged in the inner cavity of the water distribution pipe above the sealing ball.