A multifunctional foam generator and its application

Abstract

The present invention belongs to the technical field of foam fluids in oil and gas fields, and specifically relates to a multifunctional foam generator and its application. The multifunctional foam generator includes a gas nozzle, a liquid nozzle, a linkage turbine system, a liquid inlet pipe, a foaming chamber and a liquid outlet pipe. The linkage turbine system includes an inlet turbine and an outlet turbine. The gas nozzle is located on the left side of the inlet turbine, the liquid nozzle is located above the inlet turbine, the outlet turbine is located on the liquid outlet pipe, the foaming chamber is located between the liquid inlet pipe and the liquid outlet pipe, and a crankshaft reciprocating stirring device is provided in the foaming chamber. By providing a crankshaft reciprocating stirring device, the present invention can fully shear and stir the gas, liquid, and solid fluids transported from the liquid inlet pipe after entering the foaming chamber, effectively avoiding the problem of poor foam generation effect. By providing a linkage turbine system, the present invention can ensure the smooth discharge of foam.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field foam fluids, and particularly relates to a multifunctional foam generator and application thereof. Background Art

[0002] Foam fluids possess unique structural characteristics and flow properties, making them widely used in oil and gas field development operations such as drilling, completion, and well stimulation. For example, the low density and high viscosity of foam fluids allow them to effectively displace sand particles as drilling fluids, preventing lost circulation and stuck pipe. Foam fluids also utilize their strong ability to carry solid particles, minimal damage to reservoir formations, and the ability to block large particles without blocking small ones, as well as water without blocking oil, to seal highly permeable formations and effectively alleviate interlayer conflicts. In recent years, the application and development of three-phase foams—particle foams, gel foams, and solidified foams—has been a key area of innovation in oil and gas production technology. These foams, each with unique properties and advantages, can play a key role in different oilfield environments and production stages.

[0003] Currently, many types of foam generators have been developed, but there are still some problems in their field application. For example, patent publication number CN112112613A discloses an air foam generator placed at the bottom of a well. Air and foaming liquid are initially mixed in a gas-liquid mixing chamber to form a gas-liquid mixture. The gas-liquid mixture enters the foam generating chamber from the gas-liquid mixing chamber. The spiral blades rotate under the fluid pressure of the gas-liquid mixture, on the one hand, fully stirring and foaming the gas-liquid mixture, and on the other hand, applying thrust toward the outlet to the formed foam. However, this foam generator is only suitable for the generation of gas-liquid two-phase foam, and bottom-hole operations increase the complexity of operation and subsequent maintenance.

[0004] Patent publication number CN206980494U discloses a foam generator for high-pressure operations in oil and gas wells. The device utilizes a thickened, high-pressure-resistant mother pipe with a propeller and a spiral stirring block installed within the inner cavity. The propeller cuts the gas entering the intake pipe, while the spiral stirring block forms a uniform foam. This foam generator improves pressure resistance and increases the ability to cut gas slugs, but is only suitable for generating gas-liquid two-phase foam.

[0005] Patent publication number CN210798942U discloses a three-phase foam generation device for foam fracturing. This device first mixes proppant particles with a foam base fluid and evenly feeds it into a sand-carrying feed pipe. Nitrogen is then injected into the sand-carrying feed pipe through an inlet port. A vibration tube vibrates and mixes the gas, proppant particles, and foam base fluid to form a foam fracturing fluid. Premixed particles in this device can precipitate, resulting in uneven mixing of the solution and particles. Furthermore, solid particles can clog the inlet port, preventing foam generation.

[0006] Patent publication number CN2033439U discloses a foam generator for foam drilling. The device generates foam by mixing gas generated by a gas distribution plate with cement slurry. During use, cement slurry easily enters the gas distribution plate, causing blockage of the gas pipeline.

[0007] Patent publication number CN109519135A discloses a foam generator for generating cement slurry foam. This device introduces cement slurry and gas into a mixing and foaming chamber within the main body of the foam generator for mixing and foaming. A foam homogenizer within the main body homogenizes the foam fluid from the mixing and foaming chamber to produce uniform cement slurry foam. However, the device's gas control components are complex, and backflow of cement slurry can easily block the gas outlet during pressure fluctuations. Furthermore, the solid feed method relies solely on gravity, resulting in uneven solid-liquid mixing.

[0008] The patent with publication number CN103861511B discloses a porous spiral foam generating device for mining. The device uses a compressed air pipeline and a foaming liquid pipeline to mix the gas and liquid phases, which can achieve low-resistance and high-efficiency mixing of the gas and liquid phases. It adopts a mesh high-multiple foaming and a spiral low-resistance and high-efficiency heat and mass transfer coupling mechanism for foaming, which greatly improves the foaming performance of the device. The foam produced has a low air-to-foam ratio, a large foaming volume, and a high foaming rate. However, mining foam generators are used to generate foam for fire extinguishing or dust suppression, mainly gas-liquid two-phase foam. The gas and liquid do not need to be pre-mixed and can be generated only after passing through a mixing chamber. In addition, the density of foam used in coal mines is relatively low, and the working conditions are generally normal temperature and pressure. Therefore, the structure of coal mine foam generators is relatively simple, and the strength of the foam generated is relatively low. It cannot be applied to the high-temperature and high-pressure environment of oil and gas wells and the generation of three-phase foam with higher performance requirements.

[0009] As can be seen, foam generators for oil and gas wells have high requirements for injection equipment, injection processes, and injection conditions. Most existing foam generators for oil and gas well operations are only suitable for generating gas-liquid two-phase foam. The few foam generators that can be used for three-phase foam generation also suffer from the drawbacks of uneven solid-liquid mixing and easy clogging. Therefore, the development of a multifunctional foam generator suitable for all stages of oil and gas well development and production is an urgent issue to be addressed in oil and gas well foam stimulation. Summary of the Invention

[0010] In order to solve the above-mentioned drawbacks of the prior art, the present invention discloses a multifunctional foam generator, which adopts the following technical means:

[0011] A multifunctional foam generator comprises a gas nozzle, a liquid nozzle, a linked turbine system, a liquid inlet pipe, a foaming chamber and a liquid outlet pipe, wherein the linked turbine system comprises an inlet turbine and an outlet turbine, wherein the inlet turbine and the outlet turbine are connected via a connecting shaft, the inlet turbine is located above the liquid inlet pipe, and the outlet turbine is located on the liquid outlet pipe, the gas nozzle is located on the left side of the inlet turbine, and the liquid nozzle is located above the inlet turbine, and the gas and liquid for generating foam flow into the liquid inlet pipe after impacting the inlet turbine from the gas nozzle and the liquid nozzle respectively. The gas inlet and the liquid inlet of the present invention adopt a nozzle mode, so that the fluid flow rate is increased and the impact of the fluid on the turbine is enhanced.

[0012] The foaming chamber is located between the liquid inlet pipe and the liquid outlet pipe, and the foaming chamber includes a chamber I and a chamber II that are not connected to each other. A crankshaft reciprocating stirring device is provided in the foaming chamber, and the crankshaft reciprocating stirring device includes a crankshaft and stirring shafts I and II connected to the crankshaft. The crankshaft longitudinally penetrates chamber I and chamber II and is connected to the transmission shaft of the motor arranged outside the foaming chamber. The stirring shafts I and II are respectively arranged in chamber I and chamber II. The stirring shafts I and II are both provided with porous threaded plates. The crankshaft rotates to drive the stirring shafts I and II to reciprocate left and right in chamber I and chamber II, respectively, and at the same time, the movement directions of the stirring shafts I and II are opposite.

[0013] One-way check valves I and II are installed at the front ends of chambers I and II. When the fluid in chamber I flows toward the liquid outlet, one-way check valve I is open; when the fluid in chamber I flows toward the liquid inlet, one-way check valve I is closed. When the fluid in chamber II flows toward the liquid outlet, one-way check valve II is open; when the fluid in chamber II flows toward the liquid inlet, one-way check valve II is closed. A screen is installed within the foaming chamber at the rear ends of chambers I and II. The screen's maximum aperture is greater than three times the diameter of the solid particles in the foaming liquid, ensuring smooth discharge of the generated three-phase foam. The aperture can be adjusted according to the foaming medium.

[0014] Foam used in oil fields needs to maintain stability for a long time in the reservoir environment and cannot quickly break or lose performance after contact with oil, so as to ensure that it can play an effective role in the oil displacement or profile adjustment process. Therefore, the quality of foam used in oil fields needs to be strictly controlled. At the same time, in oil and gas well operations, the use of three-phase foam is more extensive. After the solid phase components are added, the difficulty of foam generation is further increased. Therefore, the quality of the generated foam becomes a key indicator for judging the performance of the foam generator. When conventional foam generators prepare foam, the foam is mainly generated by the flow of gas and liquid through the spiral structure, orifice plate structure or turbulent flow structure set in the generator. The residence time of gas and liquid flowing through the above-mentioned structure is too short, resulting in insufficient shear stirring of the foam by this type of structure, and often there will be uneven foaming phenomenon of "one section of foam, one section of liquid", resulting in the foam quality prepared by existing foam generators is not high.

[0015] The present invention provides a crankshaft reciprocating stirring device in the foaming chamber. The rotation of the crankshaft can drive the stirring shaft and the porous spiral plate to reciprocate left and right in the foaming chamber, so that the gas-liquid fluid or gas-liquid-solid fluid entering the foaming chamber can be fully mixed to form foam during the reciprocating stirring process of the porous spiral plate, thereby increasing the residence time of the fluid in the foaming chamber and improving the foam generation quality.

[0016] The present invention provides two relatively independent chambers I and II in a foaming chamber, respectively provides one-way check valves I and II at the front ends of chambers I and II, and respectively provides stirring shafts I and II in chambers I and II that move in opposite directions at the same time, so that the stirring shafts I and II do not interfere with the liquid inlet of the liquid inlet pipe while achieving reciprocating motion.

[0017] The one-way check valve I, one-way check valve II, crankshaft reciprocating stirring device and sieve plate in the present invention form two relatively closed spaces, allowing the gas, liquid and solid fluids entering the foaming chamber to fully form foam during the reciprocating stirring process of the porous spiral plate, thereby increasing the residence time of the fluid in the foaming chamber and improving the quality of foam generation. The provision of the sieve plate increases the resistance of the fluid through the foaming chamber, preventing the premature discharge of incompletely generated foam, allowing the generated foam to enter the liquid outlet pipe evenly, and ensuring the stability of the foam flow rate. However, the provision of this structure will undoubtedly increase the resistance to the generated foam being discharged from the foam generator. In addition, during on-site operations in oil fields, the injection pressure may be equivalent to the formation pressure, which can make foam injection difficult. The present invention solves this problem well through a linked turbine system. The inlet turbine rotates under the joint impact of the gas and liquid, and the outlet turbine is driven to rotate by the connecting shaft to generate negative pressure, which is conducive to the discharge of the generated foam and allows the foam to be smoothly injected into the formation.

[0018] At the same time, in the prior art, due to the uneven mixing of solids and liquids when generating three-phase foam, it is easy for solid particles to clog the conveying pipeline and the conveying port. In the foam generator of the present invention, first, the solid and liquid to be mixed are pre-mixed evenly, and then the input pump is used to impact the inlet turbine in the form of a jet to enter the liquid inlet pipe, thereby ensuring the uniformity of the solid-liquid mixing. Secondly, a one-way check valve I and a one-way check valve II are provided on the left side of the foaming chamber. The fluid entering the foaming chamber is sheared by the reciprocating motion of the porous spiral plate to form foam. When the porous spiral plate moves to the right, the fluid can be sucked into the chamber, and at this time, the one-way check valve I or the one-way check valve II is opened; when the porous spiral plate moves to the left, the one-way check valve I or the one-way check valve II is closed. The fluid entering the foaming chamber is fully sheared in a relatively closed space, effectively avoiding the problems of solid phase deposition and insufficient foaming in the three-phase foam.

[0019] Furthermore, the crankshaft includes a main shaft, a crank I and a crank II, the crank I and the crank II are respectively located in the chamber I and the chamber II, and the stirring shaft I and the stirring shaft II are respectively connected to the crankshaft through the connecting rod I and the connecting rod II.

[0020] The main shaft is mounted on the foaming chamber via a bearing, and the cranks I and II are arranged on the main shaft. A connecting rod shaft diameter I is provided on the side of the crank I away from the main shaft, and a connecting rod shaft diameter II is provided on the side of the crank II away from the main shaft. The connecting rod shaft diameter I and the connecting rod shaft diameter II are respectively located on both sides of the main shaft, one end of the connecting rod I is connected to the connecting rod shaft diameter I via a bearing, and the other end is rotatably connected to the stirring shaft I, one end of the connecting rod II is connected to the connecting rod shaft diameter II via a bearing, and the other end is rotatably connected to the stirring shaft II.

[0021] Furthermore, the porous foam generator of the present invention also includes a foam monitoring system, which includes a controller and a conductivity electrode connected to the controller signal, a pressure sensor I, a pressure sensor II, a clamp-type flow meter and a foam outlet electric valve.

[0022] The pressure sensor I, pressure sensor II, and clamp-type flowmeter are arranged on the liquid outlet pipe in front of the outlet turbine, the conductivity electrode is arranged on the foaming cavity at the rear end of the screen, and the foam outlet electric valve is arranged on the liquid outlet pipe behind the outlet turbine; a fluid channel is provided between the outlet turbine and the inlet turbine.

[0023] Furthermore, the controller is used to monitor the detection data of the conductivity electrode, pressure sensor I, pressure sensor II and clamp-type flowmeter. The controller determines whether the density of the generated foam is qualified based on the detection data of the conductivity electrode. If it is unqualified, the controller controls the foam outlet electric valve to close; the controller determines whether the viscosity of the generated foam is qualified based on the detection data of the pressure sensor I, pressure sensor II and clamp-type flowmeter. If it is unqualified, the controller controls the foam outlet electric valve to close.

[0024] The quality of oilfield foam is primarily reflected in its density and viscosity. Foam consists of a gas phase and a liquid phase, with the liquid phase conducting electricity and the gas phase not. The conductivity method for measuring foam performance is based on this principle. This paper uses conductivity as a measure of bubble density, and changes in bubble density can cause changes in conductivity. In practice, a standard conductivity value for the foam is set based on specific production and usage requirements. If the prepared foam does not meet the standard, the electric valve at the foam outlet closes, and the foam flows from the fluid channel back into the liquid inlet pipe and foaming chamber for re-foaming until the foam density meets the standard.

[0025] The viscosity of the foam in the present invention is determined by the detection data of pressure sensor I, pressure sensor II and clamp-type flow meter, as shown in the following formula:

[0026]

[0027] Where, η is the foam viscosity, Pa·s; △P -pressure difference, Pa, △P Specifically refers to the difference in foam pressure detected by pressure sensor I and pressure sensor II; the value of g is 9.8N / kg; D is the diameter of the liquid outlet pipe, m; L is the length of the liquid outlet pipe between pressure sensor I and pressure sensor II, m; Q is the foam flow rate detected by the clamp-type flow meter, m 3 / s.

[0028] The controller uses the above formula to determine whether the foam viscosity meets the standard. In actual work, the standard value of the foam viscosity is set according to the specific production and use requirements. When the prepared foam does not meet the standard, the foam outlet electric valve is closed, and the foam flows back from the fluid channel to the liquid inlet pipe and foaming chamber for re-foaming until the foam viscosity meets the standard.

[0029] Furthermore, the multifunctional foam generator includes a mounting seat positioned between the liquid inlet and outlet pipes. The connecting shaft is mounted on the mounting seat via a bearing, and the fluid channel is positioned above the mounting seat. A one-way check valve III is provided in the fluid channel. When fluid flows from the outlet turbine to the inlet turbine, the one-way check valve III is open. By providing the one-way check valve III, when the foam outlet electric valve is closed, the foam fluid can flow from the outlet turbine through the fluid channel back to the inlet turbine, while preventing fluid from flowing from the inlet turbine to the outlet turbine. In other words, the provision of the one-way check valve III restricts fluid flow in the fluid channel to a single direction.

[0030] Furthermore, the liquid inlet pipe is a rough liquid inlet pipe with a protrusion Ⅰ on the inner wall, and a mixed fluid inlet is provided below the inlet turbine. The liquid inlet pipe is detachably connected between the mixed fluid inlet and the foaming chamber, and a suitable liquid inlet pipe can be selected according to the foaming medium.

[0031] Furthermore, the multifunctional foam generator includes a heating jacket and a temperature control system. The heating jacket is located outside the foaming chamber and is connected to the temperature control system. The temperature control system is used to adjust the heating temperature. The temperature control system uses existing technology and will not be described in detail here. In actual oil and gas well construction sites, carbon dioxide is a common injection gas. The heating jacket on the foam generator prevents the injected carbon dioxide from evaporating and absorbing heat, which could cause the foam generator to freeze.

[0032] Furthermore, the linked turbine system, foaming chamber, porous spiral plate, crankshaft, liquid inlet and outlet pipes are all made of Hastelloy. This alloy is resistant to high temperatures, acids and alkalis, and has a pressure bearing capacity of up to 100 MPa, making it suitable for most oil and gas production stimulation operations.

[0033] Furthermore, the porous spiral plate includes a spiral blade and a plurality of rough holes evenly distributed on the spiral blade. The multiple shearing effects of the rough holes on the porous spiral plate can further improve the quality of foam generation. The rough holes can be formed by providing protrusions II on the inner wall of the holes.

[0034] The present invention also discloses the use of any of the multifunctional foam generators described above, for generating two-phase foam or three-phase foam in oil and gas well operations. The three-phase foam is any one of particle foam, gel foam and solidified foam.

[0035] Furthermore, the oil and gas well operation is any one of foam drilling, foam plugging, foam fracturing and foam flowback.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention utilizes a linked turbine system to create a fluid inflow and foam discharge cycle. The inlet gas-liquid fluid drives the inlet turbine to rotate, while the outlet turbine generates negative pressure, allowing the foam fluid to be discharged smoothly. A crankshaft reciprocating stirring device is installed within the foaming chamber. The porous spiral plate in this device promotes the formation of uniform and stable foam through reciprocating motion and shearing action, effectively avoiding the uneven fluid mixing and poor foam generation associated with conventional foam generators lacking a stirring device.

[0038] The present invention sets up a foam monitoring system, which can detect the quality of foam generation in real time after the foam is generated, and controls the flow direction of the foam through the foam outlet electric valve to achieve the recycling of low-quality foam, further ensuring the stability of the generated foam.

[0039] The multifunctional foam generator of the present invention can adapt to various environments and fluid conditions, thereby meeting the production increase operations of oil and gas fields at different stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the overall structure of the multifunctional foam generator according to Example 1 of the present invention;

[0041] Figure 2 Schematic cross-sectional view of the porous spiral plate in Example 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of a single hole on the porous spiral plate in Example 1 of the present invention;

[0043] Figure 4 for Figure 1 A cross-sectional view taken along the dotted line AA′;

[0044] Figure 5 Schematic diagram of the structure of the crankshaft in Example 1 of the present invention;

[0045] Figure 6 Schematic diagram of the structure of the screen in Example 1 of the present invention;

[0046] Figure 7 The curves of the apparent viscosity of the foams generated in Examples 3 to 5 versus shear rate are shown.

[0047] Among them, 1-gas nozzle, 2-liquid nozzle, 3-liquid inlet pipe, 4-1-chamber I, 4-2-chamber II, 5-liquid outlet pipe, 6-inlet turbine, 7-outlet turbine, 8-1-main shaft, 8-2-crank I, 8-3-crank II, 8-4-connecting rod shaft diameter I, 8-5-connecting rod shaft diameter II, 9-1-stirring shaft I, 9-2-stirring shaft II, 10-motor, 11-porous spiral plate, 11-1-spiral blade, 11-2-rough hole, 11-3-protrusion II, 12-screen, 13-1-check valve I, 13-2-check valve II, 14-conductivity electrode, 15-pressure sensor I, 16-pressure sensor II, 17-clamp-type flowmeter, 18-foam outlet electric valve, 19-mounting seat, 20-fluid channel, 21-check valve III, 22-protrusion I, 23-inlet pipe, 24-foam outlet. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings.

[0049] To describe the required spatial relationship, we can define three orthogonal directions: "front and back", "left and right", and "up and down (or vertical)", and define the spatial rectangular coordinate system through the relative position relationship.

[0050] Example 1

[0051] like Figures 1 to 6 As shown, this embodiment discloses a multifunctional foam generator, including a gas nozzle 1, a liquid nozzle 2, a linked turbine system, a liquid inlet pipe 3, a foaming chamber, a liquid outlet pipe 5 and a foam monitoring system.

[0052] The linked turbine system includes an inlet turbine 6 and an outlet turbine 7, which are connected by a connecting shaft. A mounting seat 19 is provided on the multifunctional foam generator, and the mounting seat 19 is located between the liquid inlet pipe 3 and the liquid outlet pipe 5. The connecting shaft is installed on the mounting seat 19 through a bearing. A fluid channel 20 is provided above the mounting seat 19, and a one-way check valve III 21 is provided on the fluid channel 20. The inlet turbine 6 is located above the liquid inlet pipe 3, and the outlet turbine 7 is located on the liquid outlet pipe 5.

[0053] The gas nozzle 1 is located on the left side of the inlet turbine 6 at the rear end of the intake pipe 23, and the liquid nozzle 2 is located above the inlet turbine 6. The gas and liquid used to generate foam impact the inlet turbine 6 from the gas nozzle 1 and the liquid nozzle 2 respectively and then flow into the liquid inlet pipe 3.

[0054] The liquid inlet pipe 3 is a rough liquid inlet pipe with a protrusion Ⅰ22 on the inner wall. A mixed fluid inlet is provided below the inlet turbine 6. The liquid inlet pipe 3 is detachably connected between the mixed fluid inlet and the foaming chamber, for example, by a threaded connection.

[0055] The foaming chamber is located between the liquid inlet pipe 3 and the liquid outlet pipe 5, and the foaming chamber includes a chamber I4-1 and a chamber II4-2 that are not connected to each other. A crankshaft reciprocating stirring device is provided in the foaming chamber, and the crankshaft reciprocating stirring device includes a crankshaft and a stirring shaft I9-1 and a stirring shaft II9-2 connected to the crankshaft. The crankshaft longitudinally penetrates the chamber I4-1 and the chamber II4-2 and is connected to the transmission shaft of the motor 10 arranged outside the foaming chamber. The stirring shaft I9-1 and the stirring shaft II9-2 are respectively arranged in the chamber I4-1 and the chamber II4- 2, the stirring shaft I9-1 and the stirring shaft II9-2 are each provided with a porous threaded plate 11, which is driven by the rotation of the crankshaft to drive the stirring shaft I9-1 and the stirring shaft II9-2 to reciprocate left and right in the chamber I4-1 and the chamber II4-2 respectively, and at the same time, the movement directions of the stirring shaft I9-1 and the stirring shaft II9-2 are opposite; the front ends of the chamber I4-1 and the chamber II4-2 are each provided with a one-way check valve I13-1 and a one-way check valve II13-2, and the foaming cavity at the rear ends of the chamber I4-1 and the chamber II4-2 is provided with a screen 12.

[0056] Furthermore, the crankshaft includes a main shaft 8-1, a crank I 8-2 and a crank II 8-3, the crank I 8-2 and the crank II 8-3 are respectively located in the chamber I 4-1 and the chamber II 4-2, the stirring shaft I 9-1 and the stirring shaft II 9-2 are respectively connected to the crankshaft through the connecting rod I and the connecting rod II, the crank I 8-2 and the crank II 8-3 are arranged on the main shaft 8-1, and the crank I 8-2 is provided with a connecting rod shaft on the side away from the main shaft 8-1. Connecting rod diameter I 8-4 is provided on the side of crank II 8-3 away from main shaft 8-1. Connecting rod diameters I 8-4 and II 8-5 are located on either side of main shaft 8-1. One end of connecting rod I is connected to connecting rod diameter I 8-4 via a bearing, and the other end is rotatably connected to stirring shaft I 9-1. One end of connecting rod II is connected to connecting rod diameter II 8-5 via a bearing, and the other end is rotatably connected to stirring shaft II 9-2. Furthermore, a heating jacket is provided on the outside of the foaming chamber, and the heating jacket is signal-connected to a temperature control system.

[0057] Furthermore, the porous spiral plate 11 includes a spiral blade 11-1 and a plurality of rough holes 11-2 evenly distributed on the spiral blade 11-1. The inner wall of the rough hole 11-2 is provided with a protrusion II 11-3 to increase the roughness of the rough hole 11-2.

[0058] The foam monitoring system includes a controller, a conductivity electrode 14, a pressure sensor I 15, a pressure sensor II 16, a clamp-on flowmeter 17, and a foam outlet electric valve 18, all connected to the controller. The pressure sensor I 15, the pressure sensor II 16, and the clamp-on flowmeter 17 are located on the liquid outlet pipe 5 in front of the outlet turbine 7. The conductivity electrode 14 is located in the foaming chamber at the rear end of the screen 12. The foam outlet electric valve 18 is located on the liquid outlet pipe 5 behind the outlet turbine 7. The controller is used to monitor the detection data of the conductivity electrode 14, the pressure sensor I 15, the pressure sensor II 16, and the clamp-on flowmeter 17. The controller determines whether the density of the generated foam meets the requirements based on the detection data of the conductivity electrode 14. If the density fails, the controller controls the foam outlet electric valve 18 to close. The controller also determines whether the viscosity of the generated foam meets the requirements based on the detection data of the pressure sensor I 15, the pressure sensor II 16, and the clamp-on flowmeter 17. If the viscosity fails, the controller controls the foam outlet electric valve 18 to close.

[0059] The linked turbine system, the foaming chamber, the porous spiral plate 11, the crankshaft 8, the liquid inlet pipe 3 and the liquid outlet pipe 5 are all made of Hastelloy.

[0060] The working process of the multifunctional foam generator of the present embodiment is as follows:

[0061] The gas and liquid (or solid-liquid mixture) impact the inlet turbine 6 from the gas nozzle 1 and the liquid nozzle 2 respectively. The inlet turbine 6 drives the outlet turbine 7 to rotate synchronously. The gas-liquid mixed fluid (or gas-solid-liquid mixed fluid) flows into the foaming chamber through the liquid inlet pipe 3. Driven by the crankshaft reciprocating stirring device, the mixed fluid reciprocates left and right in the foaming chamber and is sheared to form uniform and stable foam. Specifically, when the mixed fluid in chamber I4-1 flows to the right, the one-way check valve I13-1 opens, and the mixed fluid in the liquid inlet pipe 3 enters chamber I4-1. At this time, the mixed fluid in chamber II4-2 When the mixed fluid in chamber Ⅱ4-1 flows to the left, the one-way check valve Ⅱ13-2 is closed to prevent the fluid in chamber Ⅱ4-2 from flowing back into the liquid inlet pipe 3; when the mixed fluid in chamber Ⅰ4-1 flows to the left, the one-way check valve Ⅰ13-1 is closed to prevent the fluid in chamber Ⅰ4-1 from flowing back into the liquid inlet pipe 3. At this time, the mixed fluid in chamber Ⅱ4-2 flows to the right, the one-way check valve Ⅱ13-2 is opened, and the mixed fluid in the liquid inlet pipe 3 enters chamber Ⅱ4-2. Due to the rotation of the outlet turbine 7, a negative pressure is formed at the liquid outlet pipe 5, so that the generated foam fluid can be smoothly discharged from the foam outlet 24 after passing through the screen.

[0062] The foam monitoring system monitors the generated foam in real time during the foam preparation process. When the density or viscosity of the generated foam does not meet the standard, the controller controls the foam outlet electric valve 18 to close. At this time, the foam in the liquid outlet pipe 5 returns to the inlet turbine 6 through the fluid channel 20 and re-circulates until the foam quality meets the standard.

[0063] Example 2

[0064] This embodiment discloses a method for using the multifunctional foam generator of Example 1. The method is used to prepare three-phase foam. The specific steps are as follows:

[0065] Step 1: Pre-dissolve the foaming surfactant and / or solid particles in the injection water, connect the liquid nozzle 2 to the oil and gas well water injection pump; connect the air inlet pipe 23 to the oil and gas well CO2 or N2 injection high-pressure pipeline.

[0066] Step 2: After connecting the pipelines, open the gas inlet valve (located on the air inlet pipe 23) and the liquid inlet valve (located on the liquid nozzle 2), adjust the liquid flow at the oil and gas well injection pump end, and adjust the gas flow at the oil and gas well CO2 or N2 injection high-pressure pipeline end to meet the required injection gas-liquid ratio.

[0067] Step 3: Foam Generation: High-pressure gas from the gas injection line impacts the inlet turbine 6 through the gas nozzle 1. Simultaneously, the liquid nozzle 2 also impacts the inlet turbine 6. This dual impact of gas and liquid propagation drives the inlet turbine 6 to rotate at high speed. The mixed fluid enters the foaming chamber through the liquid inlet pipe 3. The motor 10 drives the porous spiral plate 11 in reciprocating motion, shearing the foam into a uniform foam. Finally, the high-speed rotation of the coupled outlet turbine 7 generates negative pressure, facilitating the smooth discharge of the foamed fluid from the foam outlet 24.

[0068] Example 3

[0069] The foam volume and stability test was carried out using the foam generator described in Example 1. The test included the following steps:

[0070] Step 1: Dissolve zwitterionic surfactant YL-3J (Dongying Hehui Chemical Company) and 15% by mass of fly ash particles (the amount added here refers to the mass ratio of fly ash to the total mass of injected water, surfactant, and fly ash) in the injected water. Connect liquid nozzle 2 to the water injection pump. Connect air inlet pipe 23 to the N2 gas cylinder.

[0071] Step 2: After connecting the pipelines, open the gas inlet valve and the liquid inlet valve, and adjust the flow rate at the water injection pump and N2 gas cylinder end to make the gas-liquid ratio 1:1, 3:1, and 5:1 respectively.

[0072] Step three, after the generated foam is stable, the foam volume and foam half-life are tested respectively using 100 mL of solution to generate foam as the standard; the viscosity-shear module of the Anton Paar MCR302 rotational rheometer is used to test the relationship curve between the gel foam viscosity and the shear rate. The foam volume and half-life data obtained by the experiment in this embodiment are shown in Table 1, and are compared with the foam generated by the conventional airflow method. The conventional airflow method refers to the standard SY / T 7494-2020 "Experimental Evaluation Method of Foaming Agents for Oil and Gas Fields".

[0073] The viscosity-shear rate relationship of the foam obtained in this embodiment is as follows: Figure 7 For details, see Figure 7 Medium YL-3J / 15% fly ash foam.

[0074] Table 1 Comparison of foam generation volume and half-life

[0075]

[0076] Table 1 shows that the foam volume and half-life of the foam generated by the foam generator of the present invention are higher than those of the foam generated by the conventional air flow method, which shows the effectiveness of the foaming mechanism of the foam generator of the present invention and can be used to generate various types of foam fluids.

[0077] Example 4

[0078] The rheological properties and interfacial viscoelasticity tests of particle-stabilized gel foam were conducted using the foam generator described in Example 1, including the following steps:

[0079] In step 1, polymer QC-6 (average relative molecular mass 5 million, provided on-site by the Northwest Branch of Sinopec (Xinjiang, China)), zwitterionic surfactant YL-3J (Dongying Hehui Chemical Company), and 10% by mass of fly ash were pre-dissolved in injection water to form a uniform polymer-surfactant solution (polymer concentration and surfactant concentration were both 0.6%). The liquid nozzle 2 was connected to the water injection pump, and the air inlet pipe 23 was connected to the N2 gas cylinder.

[0080] Step 2: After connecting the pipelines, open the gas inlet valve and the liquid inlet valve, and adjust the flow rate so that the gas-liquid ratio is 3:1.

[0081] Step 3: Collect the generated mixed fluid at the foam outlet, and use the viscosity-shear module of Anton Paar MCR302 rotational rheometer to measure the relationship between the viscosity of the gel foam and the shear rate. The relationship between the viscosity and shear rate of the gel foam obtained by the experiment in this embodiment is as follows: Figure 7 For details, see Figure 7 Medium YL-3J / QC-6 / 10% fly ash foam.

[0082] Example 5

[0083] The two-phase foam rheology and interfacial viscoelasticity tests were carried out using the foam generator described in Example 1. Except for not adding fly ash, the other steps were the same as in Example 3.

[0084] The viscosity-shear rate relationship of the two-phase foam obtained by the experiment in this embodiment is as follows: Figure 7 For details, see Figure 7 Medium YL-3J foam.

[0085] Figure 7 The foam generator described in the present invention can generate uniform and stable two-phase and three-phase foams (such as solid particle foams and gel foams). Particles or polymers are stably suspended in the foam system, increasing the viscosity of the foam liquid, thereby enhancing the cohesion and adhesion of the foam, effectively preventing foam breakage.

Claims

1. A multifunctional foam generator, characterized in that: It comprises a gas nozzle (1), a liquid nozzle (2), a linked turbine system, a liquid inlet pipe (3), a foaming chamber and a liquid outlet pipe (5). The linked turbine system comprises an inlet turbine (6) and an outlet turbine (7), wherein the inlet turbine (6) and the outlet turbine (7) are connected via a connecting shaft, the inlet turbine (6) is located above the liquid inlet pipe (3), and the outlet turbine (7) is located on the liquid outlet pipe (5), the gas nozzle (1) is located on the left side of the inlet turbine (6), and the liquid nozzle (2) is located above the inlet turbine (6), and the gas and liquid for generating foam respectively impact the inlet turbine (6) from the gas nozzle (1) and the liquid nozzle (2) and then flow into the liquid inlet pipe (3); The foaming chamber is located between the liquid inlet pipe (3) and the liquid outlet pipe (5), and the foaming chamber includes a chamber I (4-1) and a chamber II (4-2) that are not connected to each other. A crankshaft reciprocating stirring device is provided in the foaming chamber, and the crankshaft reciprocating stirring device includes a crankshaft and a stirring shaft I (9-1) and a stirring shaft II (9-2) connected to the crankshaft. The crankshaft longitudinally penetrates the chamber I (4-1) and the chamber II (4-2) and is connected to the transmission shaft of the motor (10) arranged outside the foaming chamber. The stirring shaft I (9-1) and the stirring shaft II (9-2) are respectively arranged in the chamber I (4-1) and the chamber II (4-2). The stirring shaft I (9-1) and the stirring shaft II (9-2) are both provided with a porous threaded plate (11). The crankshaft rotates to drive the stirring shaft I (9-1) and the stirring shaft II (9-2) to reciprocate left and right in the chamber I (4-1) and the chamber II (4-2). At the same time, the movement directions of the stirring shaft I (9-1) and the stirring shaft II (9-2) are opposite. The front ends of the chamber I (4-1) and the chamber II (4-2) are both provided with a one-way check valve I (13-1) and a one-way check valve II (13-2), and the foaming cavities at the rear ends of the chamber I (4-1) and the chamber II (4-2) are provided with a screen (12).

2. The multifunctional foam generator according to claim 1, characterized in that: The crankshaft comprises a main shaft (8-1), a crank I (8-2) and a crank II (8-3), wherein the crank I (8-2) and the crank II (8-3) are respectively located in the chamber I (4-1) and the chamber II (4-2), and the stirring shaft I (9-1) and the stirring shaft II (9-2) are respectively connected to the crankshaft through the connecting rod I and the connecting rod II. The crank I (8-2) and crank II (8-3) are arranged on the main shaft (8-1); a connecting rod shaft diameter I (8-4) is provided on the side of the crank I (8-2) away from the main shaft (8-1); a connecting rod shaft diameter II (8-5) is provided on the side of the crank II (8-3) away from the main shaft (8-1); the connecting rod shaft diameter I (8-4) and the connecting rod shaft diameter II (8-5) are respectively located on both sides of the main shaft (8-1); one end of the connecting rod I is connected to the connecting rod shaft diameter I (8-4) through a bearing, and the other end is rotatably connected to the stirring shaft I (9-1); one end of the connecting rod II is connected to the connecting rod shaft diameter II (8-5) through a bearing, and the other end is rotatably connected to the stirring shaft II (9-2).

3. The multifunctional foam generator according to claim 1, characterized in that: The invention also includes a foam monitoring system, which includes a controller and a conductivity electrode (14), a pressure sensor I (15), a pressure sensor II (16), a clamp-type flow meter (17) and a foam outlet electric valve (18) connected to the controller signal. The pressure sensor I (15), the pressure sensor II (16), and the clamp-type flow meter (17) are arranged on the liquid outlet pipe (5) in front of the outlet turbine (7); the conductivity electrode (14) is arranged on the foaming cavity at the rear end of the screen (12); and the foam outlet electric valve (18) is arranged on the liquid outlet pipe (5) behind the outlet turbine (7); A fluid channel (20) is provided between the outlet turbine (7) and the inlet turbine (6).

4. The multifunctional foam generator according to claim 3, characterized in that: The controller is used to monitor the detection data of the conductivity electrode (14), the pressure sensor I (15), the pressure sensor II (16) and the clamp-type flow meter (17). The controller determines whether the density of the generated foam is qualified based on the detection data of the conductivity electrode (14); if it is unqualified, the controller controls the foam outlet electric valve (18) to close; The controller determines whether the viscosity of the generated foam is qualified based on the detection data of the pressure sensor I (15), the pressure sensor II (16) and the clamp-type flow meter (17). If it is unqualified, the controller controls the foam outlet electric valve (18) to close.

5. The multifunctional foam generator according to any one of claims 3 to 4, characterized in that: It also includes a mounting seat (19), the mounting seat (19) is located between the liquid inlet pipe (3) and the liquid outlet pipe (5), the connecting shaft is mounted on the mounting seat (19) through a bearing, and the fluid channel (20) is located above the mounting seat (19); The fluid channel (20) is provided with a one-way check valve III (21). When the fluid flows from the outlet turbine (7) to the inlet turbine (6), the one-way check valve III (21) is in an open state.

6. The multifunctional foam generator according to claim 1, characterized in that: The liquid inlet pipe (3) is a rough liquid inlet pipe with a protrusion I (22) on the inner wall. A mixed fluid inlet is provided below the inlet turbine (6). The liquid inlet pipe (3) is detachably connected between the mixed fluid inlet and the foaming chamber.

7. The multifunctional foam generator according to claim 1, characterized in that: It also includes a heating jacket and a temperature control system. The heating jacket is arranged outside the foaming cavity, and the heating jacket is connected to the temperature control system signal.

8. The multifunctional foam generator according to claim 1, characterized in that: The linked turbine system, foaming chamber, porous spiral plate (11), crankshaft, liquid inlet pipe (3) and liquid outlet pipe (5) are all made of Hastelloy.

9. Use of the multifunctional foam generator according to any one of claims 1 to 8, characterized in that: Used to generate two-phase foam or three-phase foam in oil and gas well operations.

10. The use of the multifunctional foam generator according to claim 9, characterized in that: The oil and gas well operation is any one of foam drilling, foam plugging, foam fracturing and foam flowback.

Images