Multifunctional foam generator and application thereof

Abstract

The invention belongs to the technical field of oil and gas field foam fluid, and particularly relates to a multifunctional foam generator and application thereof. The multifunctional foam generator comprises a gas nozzle, a liquid nozzle, a linkage turbine system, a liquid inlet pipe, a foaming cavity and a liquid outlet pipe, the linkage turbine system comprises 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, and the liquid inlet pipe is located above the foaming cavity. The foaming cavity is located between the liquid inlet pipe and the liquid outlet pipe, and a crankshaft reciprocating type stirring device is arranged in the foaming cavity. By arranging the crankshaft reciprocating type stirring device, gas-liquid-solid fluid conveyed from the liquid inlet pipe can be fully sheared and stirred after entering the foaming cavity, and the problem that the foam generation effect is poor is effectively avoided. By arranging the linkage turbine system, it can be guaranteed that foam is discharged smoothly.

Description

Technical Field

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

[0002] Foam fluids have unique structural characteristics and seepage characteristics, and can be widely used in operations such as drilling, well completion, and stimulation of oil and gas wells in oil and gas field development. For example, the low density and high viscosity characteristics of foam fluids make them effective in discharging sand grains as drilling fluids, avoiding leakage and sticking of the drill; using the characteristics of strong ability to carry solid particles, small damage to the reservoir, blocking large pores rather than small pores, and blocking water rather than oil of foam fluids, they can be used to block high-permeability layers and effectively alleviate the interlayer contradiction. In recent years, the application and development of three-phase foams such as particle foam, gel foam, and solidified foam are important directions for the innovation of oil and gas production technologies. These foams have their own unique properties and advantages, and can play a key role in different oilfield environments and production stages.

[0003] Currently, there are many types of developed foam generators. However, there are still some problems in their on-site application. For example, the patent with the publication number CN112112613A discloses an air foam generator placed at the bottom of the well. Air and foaming liquid are preliminarily mixed in the gas-liquid mixing chamber to form a gas-liquid mixture. The gas-liquid mixture enters the foam generation chamber from the gas-liquid mixing chamber. The spiral blade rotates under the fluid pressure of the gas-liquid mixture. On the one hand, it fully stirs and foams the gas-liquid mixture, and on the other hand, it applies a thrust towards the outlet to the formed foam. However, this foam generator is only suitable for the generation of gas-liquid two-phase foams, and the bottom-hole operation increases the complexity of operation and subsequent maintenance.

[0004] The patent with the publication number CN206980494U discloses a foam generator for high-pressure operations in oil and gas wells. This device uses a thickened high-pressure-resistant main pipe, and a propeller and a spiral stirring block are installed in the inner cavity. The gas entering through the air inlet pipe is cut by the propeller, and uniform foam is formed by the spiral stirring block. This foam generator improves the pressure resistance and increases the cutting of gas slugs, but this foam generator is only suitable for the generation of gas-liquid two-phase foams.

[0005] The patent with the publication number CN210798942U discloses a three-phase foam generating device for foam fracturing. In this device, proppant particles are first mixed evenly with the foam base liquid and enter the sand-carrying feed pipe. Nitrogen is injected into the sand-carrying feed pipe through the injection holes, and the gas, proppant particles, and foam base liquid are oscillated and mixed through the oscillation pipe to form a foam fracturing fluid. The pre-mixed particles in this device may precipitate, resulting in uneven mixing of the solution and particles, and solid particles may block the injection holes, resulting in the inability to generate foam.

[0006] The patent with the publication number CN2033439U discloses a foam generator for foam drilling. This device generates foam by mixing the gas produced by the air distribution plate with cement slurry. During use, the cement slurry easily enters the air distribution plate, resulting in the blockage of the gas pipeline.

[0007] The patent with the publication number CN109519135A discloses a foam generator for generating cement slurry foam. This device mixes and foams by introducing cement slurry and gas into the mixing and foaming chamber inside the foam generator body part. The foam homogenizer inside the body part is used to homogenize the foam fluid from the mixing and foaming chamber to generate uniform cement slurry foam. However, the gas control components of this device are complex, and the cement slurry is prone to backflow and block the gas outlet when the pressure changes. Moreover, the solid feeding method only relies on its own gravity, resulting in the problem of uneven solid-liquid mixing.

[0008] The patent with the publication number CN103861511B discloses a mine-used porous spiral foam generating device. This device conducts gas-liquid two-phase mixing through the compressed air pipeline and the foaming liquid pipeline, which can achieve low-resistance and high-efficiency gas-liquid two-phase mixing. It uses a high-multiplicity foaming with a mesh surface and a spiral low-resistance and high-efficiency heat and mass transfer coupling mechanism for foaming, greatly improving the foaming performance of the device, with a low air-foam ratio, large foam production, and high foam formation rate for the generated foam. However, the mine-used foam generator is 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 but only need to pass through the mixing chamber to generate foam. In addition, the density of the mine-used foam is relatively low, and the working conditions are generally normal temperature and pressure. Therefore, the structure of the mine-used foam generator is relatively simple, and the strength of the generated foam is relatively low, making it inapplicable 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] Therefore, the foam generator for oil and gas wells has relatively high requirements in terms of injection equipment, injection process, injection conditions, etc. Most of the existing foam generators for oil and gas well operations are only applicable to the generation of gas-liquid two-phase foam. Among the few foam generators that can be used for the generation of three-phase foam, there are also drawbacks such as uneven solid-liquid mixing and easy blockage. Therefore, developing a multi-functional foam generator applicable to all development and production stages of oil and gas wells is an urgent problem to be solved in foam stimulation for oil and gas wells. Summary of the Invention

[0010] To solve the above-mentioned drawbacks of the existing technologies, the present invention discloses a multi-functional foam generator and adopts the following technical means: A multifunctional foam generator, comprising 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 inlet turbine and the outlet turbine are connected by 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. The gas and liquid used to generate foam respectively impact the inlet turbine from the gas nozzle and the liquid nozzle and then flow into the liquid inlet pipe. The gas inlet and liquid inlet of the present invention adopt the nozzle mode, which increases the fluid flow rate and enhances the impact of the fluid on the turbine.

[0011] The foaming chamber is located between the liquid inlet pipe and the liquid outlet pipe. The foaming chamber includes non-communicating chamber Ⅰ and chamber Ⅱ. A crankshaft reciprocating stirring device is provided in the foaming chamber. 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 a motor provided outside the foaming chamber. Stirring shafts Ⅰ and Ⅱ are respectively arranged in chamber Ⅰ and chamber Ⅱ. Porous threaded plates are provided on both stirring shafts Ⅰ and Ⅱ. By rotating the crankshaft, stirring shafts Ⅰ and Ⅱ are driven to reciprocate left and right in chamber Ⅰ and chamber Ⅱ respectively, and at the same moment, the moving directions of stirring shafts Ⅰ and Ⅱ are opposite.

[0012] One-way check valves Ⅰ and Ⅱ are provided at the front ends of chamber Ⅰ and chamber Ⅱ respectively. When the fluid in chamber Ⅰ flows towards the liquid outlet pipe, the one-way check valve Ⅰ is in the open state. When the fluid in chamber Ⅰ flows towards the liquid inlet pipe, the one-way check valve Ⅰ is in the closed state. When the fluid in chamber Ⅱ flows towards the liquid outlet pipe, the one-way check valve Ⅱ is in the open state. When the fluid in chamber Ⅱ flows towards the liquid inlet pipe, the one-way check valve Ⅱ is in the closed state. Screens are provided in the foaming chamber at the rear ends of chamber Ⅰ and chamber Ⅱ. The maximum aperture of the screen is more than three times the diameter of the solid particles in the foaming liquid, ensuring the smooth discharge of the generated three-phase foam, and the aperture can be adjusted according to the foaming medium.

[0013] Foams used in oil fields need to maintain stability in the reservoir environment for a long time and cannot rupture quickly or lose their performance after contacting oil to ensure their effective function during the oil displacement or profile control process. Therefore, the quality of foams used in oil fields needs to be strictly controlled. At the same time, during oil and gas well operations, three-phase foams are more widely used. After adding solid components, the difficulty of foam generation further increases. Therefore, the quality of the generated foam becomes a key indicator for evaluating the performance of foam generators. When conventional foam generators prepare foams, the foams are mainly generated by the gas-liquid flow passing through the spiral structure, orifice plate structure, or turbulence structure arranged in the generator. The residence time of the gas and liquid flowing through the above structures is too short, resulting in insufficient shear stirring of the foam by these structures, and often an uneven foaming phenomenon of "one section of foam and one section of liquid" occurs, leading to low-quality foams prepared by existing foam generators.

[0014] In the present invention, a crankshaft reciprocating stirring device is arranged in the foaming cavity. Through the rotation of the crankshaft, the stirring shaft and the porous spiral plate can be driven to reciprocate left and right in the foaming cavity, enabling the gas-liquid fluid or gas-liquid-solid fluid entering the foaming cavity to be fully mixed to form foam during the reciprocating stirring process of the porous spiral plate, increasing the residence time of the fluid in the foaming cavity, and thus improving the quality of foam generation.

[0015] In the present invention, two relatively independent chambers, chamber I and chamber II, are arranged in the foaming cavity. Check valves I and II are respectively arranged at the front ends of chamber I and chamber II, and stirring shafts I and II with opposite movement directions at the same moment are respectively arranged in chamber I and chamber II, so that while the stirring shafts I and II perform reciprocating movements, they do not interfere with the liquid inlet of the liquid inlet pipe.

[0016] The check valves I and II, the crankshaft reciprocating stirring device, and the sieve plate in the present invention form two relatively closed spaces, enabling the gas-liquid-solid fluid entering the foaming cavity to fully form foam during the reciprocating stirring process of the porous spiral plate, increasing the residence time of the fluid in the foaming cavity, and improving the quality of foam generation. The setting of the sieve plate increases the resistance of the fluid passing through the foaming cavity, preventing the incompletely generated foam from being discharged prematurely, enabling the generated foam to uniformly enter the liquid outlet pipe, and ensuring the stability of the foam flow rate. However, the setting of this structure will undoubtedly increase the resistance for the generated foam to be discharged from the foam generator. In addition, during on-site oil field operations, there may also be a situation where the injection pressure is equivalent to the formation pressure, which will lead to difficulties in foam injection. The present invention solves this problem well through a linkage turbine system. The inlet turbine rotates under the combined impact of gas and liquid, and drives the outlet turbine to rotate through a connecting shaft to generate negative pressure, which is beneficial to the discharge of the generated foam and enables the foam to be smoothly injected into the formation.

[0017] Meanwhile, in the prior art, due to uneven solid-liquid mixing during the generation of three-phase foam, situations such as solid particle blockage of the conveying pipeline and the conveying port are likely to occur. In the foam generator of the present invention, first, the solid and liquid to be mixed are pre-mixed evenly, and then enter the liquid inlet pipe by impacting the inlet turbine in the form of jet through an input pump, ensuring the uniformity of 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 shears the foam through the reciprocating motion of the porous spiral plate. 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.

[0018] Further, the crankshaft includes a main shaft, a crank I and a crank II. The crank I and the crank II are respectively located in chamber I and chamber II. The stirring shaft I and the stirring shaft II are respectively connected to the crankshaft through connecting rod I and connecting rod II. The main shaft is installed on the foaming chamber through bearings. The crank I and the crank II are provided on the main shaft. A connecting rod journal I is provided on the side of the crank I away from the main shaft. A connecting rod journal II is provided on the side of the crank II away from the main shaft. The connecting rod journal I and the connecting rod journal II are respectively located on both sides of the main shaft. One end of the connecting rod I is connected to the connecting rod journal I through 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 journal II through a bearing, and the other end is rotatably connected to the stirring shaft II.

[0019] Further, the porous foam generator of the present invention further includes a foam monitoring system. The foam monitoring system includes a controller and a conductivity electrode, a pressure sensor I, a pressure sensor II, a clamp-on flowmeter and a foam outlet electric valve that are signal-connected to the controller. The pressure sensor I, the pressure sensor II and the clamp-on flowmeter are provided on the liquid outlet pipe in front of the outlet turbine. The conductivity electrode is provided on the foaming chamber behind the screen. The foam outlet electric valve is provided on the liquid outlet pipe behind the outlet turbine; there is a fluid channel between the outlet turbine and the inlet turbine.

[0020] Further, the controller is used to monitor the detection data of the conductivity electrode, the pressure sensor I, the pressure sensor II and the clamp-on 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, the pressure sensor II and the clamp-on flowmeter. If it is unqualified, the controller controls the foam outlet electric valve to close.

[0021] The quality of the foam used in the oilfield is mainly reflected by the foam density and foam viscosity. The foam is divided into a gas phase and a liquid phase, where the liquid phase conducts electricity and the gas phase does not. The conductivity method for measuring the foam performance is based on this. In the present invention, the magnitude of the conductivity is used as a measure of the bubble density, and a change in the bubble density will cause a change in the conductivity. In actual work, according to the specific production and use requirements, a standard value of the foam conductivity is set. When the prepared foam does not meet the standard, the electric valve at the foam outlet closes, and the foam flows back from the fluid channel to the inlet pipe and the foaming chamber for re-foaming until the density of the foam meets the standard.

[0022] In the present invention, the viscosity of the foam is determined based on the detection data of pressure sensor I, pressure sensor II, and the clamp-on flowmeter, as shown in the following formula:

[0023] In the formula, η is the foam viscosity, Pa·s; △P - the pressure difference, Pa, △P specifically refers to the difference in the foam pressure detected by pressure sensor I and pressure sensor II; the value of g is 9.8 N / kg; D is the inner diameter of the liquid outlet pipe, m; L is the pipe 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-on flowmeter, m 3 / s.

[0024] The controller determines whether the foam viscosity meets the standard through the above formula. In actual work, according to the specific production and use requirements, a standard value of the foam viscosity is set. When the prepared foam does not meet the standard, the electric valve at the foam outlet closes, and the foam flows back from the fluid channel to the inlet pipe and the foaming chamber for re-foaming until the viscosity of the foam meets the standard.

[0025] Furthermore, the multifunctional foam generator further includes a mounting seat. The mounting seat is located between the inlet pipe and the outlet pipe. The connecting shaft is installed on the mounting seat through a bearing, and the fluid channel is located above the mounting seat; a one-way check valve III is provided on the fluid channel. When the fluid flows from the outlet turbine to the inlet turbine, the one-way check valve III is in an open state. By setting the one-way check valve III, when the electric valve at the foam outlet closes, the foam fluid can flow back from the outlet turbine through the fluid channel to the inlet turbine, while preventing the fluid from flowing from the inlet turbine to the outlet turbine direction. That is, the setting of the one-way check valve III enables the fluid in the fluid channel to flow only in one direction.

[0026] Furthermore, the inlet pipe is a rough inlet pipe with a protrusion I on the inner wall. A mixed fluid inlet is provided below the inlet turbine. The inlet pipe is detachably connected between the mixed fluid inlet and the foaming chamber, and a suitable inlet pipe can be selected according to the foaming medium.

[0027] Further, the multifunctional foam generator further includes a heating jacket and a temperature control system. The heating jacket is disposed outside the foaming chamber and is in signal connection with the temperature control system. The temperature control system is used to adjust the heating temperature. The temperature control system is of the existing type and will not be elaborated here. At the actual oil and gas well construction site, carbon dioxide is a commonly used injection gas. The heating jacket outside the foam generator can prevent the foam generator from freezing due to the vaporization heat absorption of the carbon dioxide injected into the oil and gas well.

[0028] Further, the linkage turbine system, the foaming chamber, the porous spiral plate, the crankshaft, the liquid inlet pipe and the liquid outlet pipe are all made of Hastelloy. It has the properties of high temperature resistance, acid and alkali resistance, and the pressure bearing capacity is up to 100 Mpa, and it can be applied to most oil and gas production enhancement operation sites.

[0029] Further, the porous spiral plate includes spiral blades and a plurality of rough holes uniformly distributed on the spiral blades. Through the multiple shearing actions of the rough holes on the porous spiral plate, the foam generation quality can be further improved. The rough holes can be realized by arranging protrusions II on the inner wall of the holes.

[0030] The present invention also discloses the application of the multifunctional foam generator described above, which is used to generate two-phase foam or three-phase foam in oil and gas well operations. The three-phase foam is any one of particulate foam, gel foam and solidified foam.

[0031] Further, the oil and gas well operation is any one of foam drilling, foam plugging, foam fracturing and foam flowback.

[0032] Compared with the prior art, the beneficial effects of the present invention are: By setting the linkage turbine system, the present invention can make the inflow of fluid and the discharge of foam form a cycle. The inlet gas-liquid fluid drives the inlet turbine to rotate, and the outlet turbine generates negative pressure, so that the foam fluid can be smoothly discharged. A crankshaft reciprocating stirring device is arranged in the foaming chamber. The porous spiral plate in this device can promote the formation of uniform and stable foam through reciprocating motion and diameter reduction shearing actions, effectively avoiding the problems of uneven fluid mixing and poor foam generation effect caused by the lack of a stirring device in a conventional foam generator.

[0033] By setting the foam monitoring system, the present invention can detect the foam generation quality in real time after the foam is generated, and control the flow direction of the foam through the foam outlet electric valve to realize the recycling regeneration of low-quality foam, further ensuring the stability of the generated foam.

[0034] The multifunctional foam generator of the present invention can adapt to a variety of environmental and fluid conditions, so as to meet the oil and gas field production enhancement operations in different stages. Description of the Drawings

[0035] Figure 1 Schematic diagram of the overall structure of the multifunctional foam generator according to Embodiment 1 of the present invention; Figure 2 Cross-sectional view of the porous spiral plate in Embodiment 1 of the present invention; Figure 3 Schematic diagram of the structure of a single hole on the porous spiral plate in Embodiment 1 of the present invention; Figure 4 is Figure 1 Cross-sectional view taken along the dotted line AA' in; Figure 5 Schematic diagram of the structure of the crankshaft in Embodiment 1 of the present invention; Figure 6 Schematic diagram of the structure of the screen in Embodiment 1 of the present invention; Figure 7 Curve of the apparent viscosity of the foam generated in Examples 3 - 5 varying with the shear rate.

[0036] Wherein, 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 journal I, 8 - 5 - connecting rod journal 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 - one - way check valve I, 13 - 2 - one - way 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 passage, 21 - one - way check valve III, 22 - protrusion I, 23 - air inlet pipe, 24 - foam outlet. Detailed implementation manners

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0038] For the description of the required spatial relationship, three orthogonal directions of "front - back", "left - right", and "up - down (or vertical)" can be defined, and a spatial rectangular coordinate system is defined through the relative position relationship.

[0039] Embodiment 1 As Figures 1 - 6 shown, this embodiment discloses a multifunctional foam generator, including a gas nozzle 1, a liquid nozzle 2, a linkage turbine system, a liquid inlet pipe 3, a foaming chamber, a liquid outlet pipe 5, and a foam monitoring system.

[0040] The linkage turbine system includes an inlet turbine 6 and an outlet turbine 7. The inlet turbine 6 and the outlet turbine 7 are connected by a connecting shaft. An installation seat 19 is provided on the multifunctional foam generator. The installation seat 19 is located between the liquid inlet pipe 3 and the liquid outlet pipe 5. The connecting shaft is installed on the installation seat 19 through a bearing. A fluid passage 20 is provided above the installation seat 19. A check valve III 21 is provided on the fluid passage 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.

[0041] The gas nozzle 1 is located on the left side of the inlet turbine 6 at the rear end of the gas inlet pipe 23. The liquid nozzle 2 is located above the inlet turbine 6. 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.

[0042] 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 cavity, for example, by threaded connection.

[0043] The foaming cavity is located between the liquid inlet pipe 3 and the liquid outlet pipe 5. The foaming cavity includes a non-communicating chamber I 4-1 and a chamber II 4-2. A crank reciprocating stirring device is provided in the foaming cavity. The crank reciprocating stirring device includes a crank and stirring shafts I 9-1 and II 9-2 connected to the crank. The crank longitudinally penetrates the chamber I 4-1 and the chamber II 4-2 and is connected to the transmission shaft of a motor 10 provided outside the foaming cavity. The stirring shafts I 9-1 and II 9-2 are respectively arranged in the chamber I 4-1 and the chamber II 4-2. Porous threaded plates 11 are provided on the stirring shafts I 9-1 and II 9-2. By rotating the crank, the stirring shafts I 9-1 and II 9-2 respectively move left and right reciprocally in the chamber I 4-1 and the chamber II 4-2. At the same moment, the moving directions of the stirring shafts I 9-1 and II 9-2 are opposite. Check valves I 13-1 and II 13-2 are provided at the front ends of the chamber I 4-1 and the chamber II 4-2 respectively. A screen 12 is provided in the foaming cavity at the rear ends of the chamber I 4-1 and the chamber II 4-2.

[0044] Further, 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 a chamber I 4-1 and a chamber II 4-2. The stirring shaft I 9-1 and the stirring shaft II 9-2 are respectively connected to the crankshaft through a connecting rod I and a connecting rod II. The crank I 8-2 and the crank II 8-3 are arranged on the main shaft 8-1. A connecting rod journal I 8-4 is provided on one side of the crank I 8-2 away from the main shaft 8-1, and a connecting rod journal II 8-5 is provided on one side of the crank II 8-3 away from the main shaft 8-1. The connecting rod journal I 8-4 and the connecting rod journal 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 journal 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 journal II 8-5 through a bearing, and the other end is rotatably connected to the stirring shaft II 9-2. Further, a heating jacket is also provided outside the foaming chamber, and the heating jacket is signal-connected to a temperature control system.

[0045] Further, the porous spiral plate 11 includes spiral blades 11-1 and a plurality of rough holes 11-2 uniformly distributed on the spiral blades 11-1. A projection II 11-3 is provided on the inner wall of the rough holes 11-2 to increase the roughness of the rough holes 11-2.

[0046] The foam monitoring system includes a controller and 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 that are signal-connected to the controller. The pressure sensor I 15, the pressure sensor II 16, and the clamp-on flowmeter 17 are arranged on a liquid outlet pipe 5 in front of the outlet turbine 7. The conductivity electrode 14 is arranged on the foaming chamber behind a screen 12. The foam outlet electric valve 18 is arranged 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 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-on flowmeter 17. If it is unqualified, the controller controls the foam outlet electric valve 18 to close.

[0047] The linkage 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.

[0048] The working process of the multifunctional foam generator in this embodiment is as follows: Gas and liquid (or solid-liquid mixture) respectively impact the inlet turbine 6 from the gas nozzle 1 and the liquid nozzle 2. 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 crank reciprocating stirring device, the mixed fluid moves reciprocally left and right in the foaming chamber and is sheared to form uniform and stable foam. Specifically, when the mixed fluid in chamber Ⅰ 4-1 flows to the right, the one-way check valve Ⅰ 13-1 opens, and the mixed fluid in the liquid inlet pipe 3 enters chamber Ⅰ 4-1. At this time, the mixed fluid in chamber Ⅱ 4-2 flows to the left, and the one-way check valve Ⅱ 13-2 closes to prevent the fluid in chamber Ⅱ 4-2 from flowing back into the liquid inlet pipe 3; when the mixed fluid in chamber Ⅰ 4-1 flows to the left, the one-way check valve Ⅰ 13-1 closes to prevent the fluid in chamber Ⅰ 4-1 from flowing back into the liquid inlet pipe 3. At this time, the mixed fluid in chamber Ⅱ 4-2 flows to the right, and the one-way check valve Ⅱ 13-2 opens, and the mixed fluid in the liquid inlet pipe 3 enters chamber Ⅱ 4-2. Due to the rotation of the outlet turbine 7, a negative pressure is formed at the liquid outlet pipe 5, enabling the generated foam fluid to pass through the screen and be smoothly discharged from the foam outlet 24.

[0049] 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 participates in the cycle again until the quality of the foam meets the standard.

[0050] Embodiment 2 This embodiment discloses a method for using the multifunctional foam generator of Embodiment 1, which is used to prepare three-phase foam. The specific steps are as follows: Step 1: Pre-dissolve the foaming surfactant and / or solid particles in the injection water, and connect the liquid nozzle 2 to the oil and gas well injection water pump; connect the gas inlet pipe 23 to the oil and gas well CO 2 or N 2 injection high-pressure pipeline.

[0051] Step 2: After connecting the pipelines, open the gas inlet valve (installed on the gas inlet pipe 23) and the liquid inlet valve (installed on the liquid nozzle 2), adjust the liquid flow rate at the oil and gas well injection pump end, and adjust the gas flow rate at the oil and gas well CO 2 or N 2 injection high-pressure pipeline end to meet the required injection gas-liquid ratio.

[0052] Step 3: Generation of foam: The high-pressure gas flow in the gas injection pipeline impacts the inlet turbine 6 through the gas nozzle 1. At the same time, the liquid nozzle 2 also impacts the inlet turbine 6. Driven by the dual impact of the gas-liquid fluid, the inlet turbine 6 rotates at high speed. The mixed fluid enters the foaming chamber through the liquid inlet pipe 3, and the motor 10 drives the porous spiral plate 11 to reciprocate and shear to form uniform foam. Finally, the linked outlet turbine 7 generates negative pressure during high-speed rotation, which is conducive to the smooth discharge of the foam fluid from the foam outlet 24.

[0053] Example 3 The foam generator described in Example 1 was used to conduct tests on the foaming volume and stability of the foam. The following steps were included: Step 1: Dissolve the zwitterionic surfactant YL-3J (Dongying Hehui Chemical Co., Ltd.) and fly ash particles with a mass fraction of 15% (the addition amount here in the present invention refers to the mass ratio of fly ash in the total of injected water + surfactant + fly ash) in the injected water. The liquid nozzle 2 is connected to the injection pump. Connect the inlet gas pipe 23 to the 2 N gas cylinder.

[0054] Step 2: After connecting the pipelines, open the gas inlet valve and the liquid inlet valve, and adjust the flow rates at the injection pump and the 2 N gas cylinder ends to make the gas-liquid ratios 1:1, 3:1, and 5:1 respectively.

[0055] Step 3: After the generated foam is stable, taking 100 mL of the solution to generate foam as the standard, test the foaming volume and the foam half-life respectively; use the viscosity-shear module of the Anton Paar MCR302 type rotational rheometer to test the relationship curve of the gel foam viscosity changing with the shear rate. The foaming volume and half-life data of the foam obtained from the experiments in this example are shown in Table 1, and a comparison is made with the foam generated by the conventional gas flow method. The conventional gas flow method refers to the standard SY / T 7494-2020 "Experimental Evaluation Method for Foaming Agents Used in Oil and Gas Fields".

[0056] The relationship between the viscosity and shear rate of the foam obtained in this example is as Figure 7 shown, specifically referring to the Figure 7 YL-3J / 15% fly ash foam in it.

[0057] Table 1 Comparison of foam generation volume and half-life

[0058] It can be seen from Table 1 that both the foaming volume and the half-life of the foam generated by using the foam generator described in the present invention are higher than those of the foam generated by the conventional gas flow method, which indicates 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.

[0059] Example 4 The rheology and interfacial viscoelasticity of particle-stabilized gel foams were tested using the foam generator described in Example 1, including the following steps: Step 1: Dissolve polymer QC-6 (average relative molecular mass of 5 million, provided on-site by Northwest Branch of China National Petroleum and Chemical Corporation (Xinjiang, China)), zwitterionic surfactant YL-3J (Dongying Hehui Chemicals Company), and 10% fly ash by mass fraction in the injection water in advance to form a uniform polymer-surfactant solution (the polymer concentration and surfactant concentration are both 0.6%). Connect the liquid nozzle 2 to the injection pump and connect the gas inlet pipe 23 to the 2 N gas cylinder.

[0060] 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.

[0061] Step 3: Collect the generated mixed fluid at the foam outlet end, and use the viscosity-shear module of an Anton Paar MCR302 rotational rheometer to test the relationship curve of the gel foam viscosity with the shear rate. The relationship between the viscosity and shear rate of the gel foam obtained from the experiments of this example is as Figure 7 shown, specifically refer to Figure 7 YL-3J / QC-6 / 10% fly ash foam in.

[0062] Example 5 The rheology and interfacial viscoelasticity of two-phase foams were tested using the foam generator described in Example 1. Except for not adding fly ash, other steps were the same as in Example 3.

[0063] The relationship between the viscosity and shear rate of the two-phase foam obtained from the experiments of this example is as Figure 7 shown, specifically refer to Figure 7 YL-3J foam in.

[0064] Figure 7 It can be obtained that the foam generator described in the present invention can generate uniform and stable two-phase foams and three-phase foams (such as solid particle foams, gel foams, etc.). Particles or polymers are stably suspended in the foam system, increasing the viscosity of the foam liquid, thereby increasing the cohesion and adhesion of the foam and effectively preventing the foam from breaking.

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), 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 flow into the liquid inlet pipe (3) after impacting the inlet turbine (6) from the gas nozzle (1) and the liquid nozzle (2) respectively; 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) which 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 a transmission shaft of a 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), and the stirring shaft I (9-1) and the stirring shaft II (9-2) are both provided with a porous threaded plate (11), and the stirring shaft I (9-1) and the stirring shaft II (9-2) are driven to reciprocate left and right in the chamber I (4-1) and the chamber II (4-2) respectively through the rotation of the crankshaft, and 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 chambers I (4-1) and II (4-2) are both provided with one-way check valves I (13-1) and II (13-2), and the foaming chambers at the rear ends of the chambers I (4-1) and II (4-2) are provided with screens (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 arranged 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 arranged 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 comprises a foam monitoring system, wherein the foam monitoring system comprises a controller and a conductivity electrode (14) connected to the controller signal, a pressure sensor I (15), a pressure sensor II (16), a clamp-type flow meter (17) and a foam outlet electric valve (18). 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) via 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), and 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, the foaming chamber, the porous spiral plate (11), the crankshaft, the liquid inlet pipe (3) and the liquid outlet pipe (5) are all made of Hastelloy.

9. The 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.

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