Device for evaluating micro-effect of hydrate inhibitor and using method thereof
Technical Field
The invention relates to the technical field of oil and gas industry, in particular to a device for evaluating the micro-effect of a hydrate inhibitor and a using method thereof.
Background
During hydrate resource recovery and oil and gas transport, the components of the fluid comprise natural gas and water. In such a flow state, minute bubbles in the liquid phase and water droplets condensed in the gas phase may form hydrate particles due to low temperature and high pressure conditions in the pipe. Hydrate particles can accumulate and may adhere to the walls of the pipe during flow with the fluid, eventually plugging the pipe, causing a local pressure increase, reduced production efficiency and potential safety issues. Therefore, the research on the influence of the hydrate inhibitor on the growth and surface morphology of hydrate particles, particularly the influence on the adhesion force between the hydrate particles and the surface of a pipeline and the strength of a shell layer has very important promotion effects on the research on the action mechanism of the hydrate inhibitor and the reduction of the phenomenon that the hydrate blocks the pipeline. The adhesion force of the hydrate particles to the surface of the pipeline can quantitatively measure the difficulty of the hydrate particles attaching to the pipe wall; the properties of the hydrate particle shell layer also have important influence on the phenomena of aggregation, deposition and the like of hydrate clusters in the pipeline. If the shell of the hydrate particles is broken due to compression or shearing, the broken shell provides a plurality of additional nucleation sites, and the water contained in the particles is released, the hydrate can be rapidly generated, and the stronger adhesion force is generated among the particles to promote the occurrence of hydrate blockage.
The existing hydrate inhibitor performance evaluation technology is generally to observe the change of a hydrate generation process in the presence of a hydrate inhibitor from a macroscopic level in a large pipeline or a high-pressure reaction kettle, but the change of the physicochemical property of the hydrate in the process is difficult to measure, so that the effect of evaluating the hydrate inhibitor is not accurate enough.
Disclosure of Invention
Therefore, the invention provides a device for evaluating the microscopic effect of a hydrate inhibitor and a using method thereof, and aims to solve the problem that the existing hydrate inhibitor performance evaluation technology is not accurate enough for evaluating the effect of the hydrate inhibitor because the change of the hydrate generation process in the presence of the hydrate inhibitor is observed from a macroscopic level in a large pipeline or a high-pressure reaction kettle generally, but the physicochemical property change of the hydrate in the process is difficult to measure.
In order to achieve the above purpose, the invention provides the following technical scheme:
according to the first aspect of the invention, the device for evaluating the micro-effect of the hydrate inhibitor comprises a high-pressure reaction kettle, an aluminum cup, a nano-shifter, a movable cantilever and a fixed cantilever, wherein the aluminum cup and the nano-shifter are arranged in a cavity of the high-pressure reaction kettle, one end of the movable cantilever is mounted on the nano-shifter, the other end of the movable cantilever extends into the aluminum cup, one end of the fixed cantilever is fixed on the inner side wall of the high-pressure reaction kettle, and the other end of the fixed cantilever extends into the aluminum cup; a water bath coil pipe is wound on the outer wall of the aluminum cup; the device also comprises a controller, and the nanometer shifter is electrically connected with the controller.
Further, a pressure sensor is arranged at the bottom of the aluminum cup; the pressure sensor is electrically connected with the controller.
Further, the device also comprises a constant-temperature water bath which is arranged outside the high-pressure reaction kettle and is connected with the water bath coil pipe through a circulating pipeline; the temperature control precision of the constant-temperature water bath is +/-0.1 ℃, and the lowest temperature can reach-10 ℃.
Further, the fixed cantilever is Z-shaped.
Furthermore, the front end of the movable cantilever is provided with a carbon steel surface simulating the wall surface of the oil-gas pipeline.
Furthermore, the cavity of the high-pressure reaction kettle is cylindrical, the inner dimension of the cavity is phi 328mm multiplied by 148mm, the cavity is made of 316L materials, and the pressure resistance is 10 MPa.
Furthermore, the top of the high-pressure reaction kettle is provided with an air inlet interface, a temperature measuring interface, a pressure measuring interface and a plurality of high-pressure through interfaces, and the bottom of the high-pressure reaction kettle is provided with a circulating pipeline inlet and outlet interface.
Further, the device also comprises a pressurizing system, wherein the pressurizing system consists of a vacuum pump, a high-pressure gas cylinder and a gas inlet pipeline, the vacuum pump is connected with the high-pressure reaction kettle, and the high-pressure gas cylinder is connected with the high-pressure reaction kettle through the gas inlet pipeline.
Further, a temperature pressure gauge is also arranged on the high-pressure reaction kettle.
According to a second aspect of the present invention, a method for using the above apparatus, the method comprising the steps of:
starting the thermostatic water bath of the device, and precooling the aluminum cup; ice particles are fixed on the fixed cantilever, and the controller controls the nanometer shifter to enable the surface of the carbon steel at the front end of the movable cantilever to be close to the ice particles;
injecting required liquid into the aluminum cup, and adding a proper amount of hydrate inhibitor;
starting a vacuum pump in a pressurizing system of the device, and exhausting air in the high-pressure reaction kettle; closing the vacuum pump and opening the air inlet valve; adjusting the temperature of the constant-temperature water bath to be 1-2 ℃ higher than the stable existence temperature of the hydrate, keeping for 25-35 minutes to melt ice particles into water, and reducing the temperature to enable the water and the gas to react to generate hydrate particles;
the controller controls the nanometer shifter to enable the movable cantilever to gradually approach the hydrate particles until the surface of the carbon steel just contacts the hydrate particles; moving the movable cantilever upwards slowly, and recording the adhesion force when the surface of the carbon steel is separated from the contact with the hydrate particles; the movable cantilever is slowly moved downwards until the hydrate grain shell layer is crushed by the surface of the carbon steel, and the strength of the hydrate grain shell layer is recorded.
The invention has the following advantages:
according to the device for evaluating the microscopic effect of the hydrate inhibitor, the water bath coil pipe is introduced into the high-pressure reaction kettle, so that the problem of low refrigeration efficiency caused by soaking the whole high-pressure reaction kettle in water bath in the traditional design is solved, and the temperature of a test area can be controlled more accurately; the movable cantilever is controlled by the nanometer shifter to gradually approach the hydrate particles in nanometer-level micro step length, so that the whole testing process is in a quasi-static process, and the precision of microscopic measurement is ensured; the shell strength of the hydrate particles is accurately measured from a microscopic angle by simulating the wall of the oil and gas pipe by using the surface of the carbon steel, and taking the pressure change generated in the process that the surface of the carbon steel is close to the hydrate particles and is finally crushed as the shell strength of the hydrate particles.
The device for evaluating the microscopic effect of the hydrate inhibitor can accurately measure the adhesion force between micron-sized hydrate particles and the surface of a carbon steel pipeline and the anti-broken ring strength of a hydrate particle shell layer in different liquid environments (such as formation water and alkane) under the condition of adding the hydrate inhibitor, intuitively reflects the microscopic effect of different hydrate inhibitors on the hydrate particles, and takes the reduction of acting force and the strength change of the hydrate shell layer as quantitative indexes for judging the effect of the hydrate inhibitor to carry out multi-angle evaluation on the surface interface.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.
The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so that those skilled in the art can understand and read the present invention, and do not limit the conditions for implementing the present invention, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the functions and purposes of the present invention, should still fall within the scope of the present invention.
Fig. 1 is a schematic structural diagram of an apparatus for evaluating the micro-effect of a hydrate inhibitor provided by the invention 1.
Detailed Description
The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
The device for evaluating the micro-effect of the hydrate inhibitor as shown in fig. 1 comprises a high-pressure reaction kettle 1, an aluminum cup 2, a nano-shifter 3, a movable cantilever 4 and a Z-shaped fixed cantilever 5, wherein the aluminum cup 2 and the nano-shifter 3 are arranged in a cavity of the high-pressure reaction kettle 1, one end of the movable cantilever 4 is installed on the nano-shifter 3, the other end of the movable cantilever extends into the aluminum cup 2, one end of the fixed cantilever 5 is fixed on the inner side wall of the high-pressure reaction kettle 1, and the other end of the fixed cantilever extends into the aluminum cup 2; the cavity of the high-pressure reaction kettle 1 is cylindrical, the internal dimension is phi 328mm multiplied by 148mm, the 316L material is resistant to pressure of 10 Mpa; the top of the high-pressure reaction kettle 1 is provided with an air inlet interface, a temperature measuring interface, a pressure measuring interface and a plurality of high-pressure through interfaces, and the bottom of the high-pressure reaction kettle is provided with a circulating pipeline inlet and outlet interface. A water bath coil pipe 6 is wound on the outer wall of the aluminum cup 2; the bottom of the aluminum cup 2 is provided with a pressure sensor 7; the device also comprises a controller, wherein the nanometer shifter 3 and the pressure sensor 7 are electrically connected with the controller; the high-pressure through connector 12 is arranged on the high-pressure through connector and is used for transmitting data of the equipment such as the nanometer shifter 3, the pressure sensor 7 and the like in the high-pressure reaction kettle 1 to the controller through the high-pressure through connector 12; the front end of the movable cantilever 4 is provided with a carbon steel surface 40 simulating the wall surface of an oil-gas pipeline.
The testing system of the device consists of an aluminum cup 2 coiled by a water bath coil pipe 6, a nanometer shifter 3, a fixed cantilever 5 and a movable cantilever 4 connected with the nanometer shifter 3. When the micro-effect of the hydrate inhibitor is evaluated, liquid added with the hydrate inhibitor and a force measuring module provided with a pressure sensor 7 are filled in the aluminum cup 2, and the temperature required by the stable existence of the hydrate is maintained by cooling through a water bath coil pipe 6 surrounding the aluminum cup; the fixed cantilever 5 fixes the hydrate particles on a force measuring module in the aluminum cup 2; the front end of the movable cantilever 4 is provided with a carbon steel surface 40 simulating the wall surface of an oil-gas pipeline, the movable cantilever 4 is controlled through the nanometer shifter 3, so that the carbon steel surface 40 is gradually close to hydrate particles in a nanometer-level step length, when the carbon steel surface is just touched with the hydrate particles, the carbon steel surface can be lifted upwards or continuously pressed downwards to finally crush hydrate shell layers, the adhesion force of the hydrate particles and the surface of the carbon steel and the shell layer strength of the hydrate particles are respectively measured, the pressure sensor 7 respectively records the pressure change suffered in the two processes, and the reduction value of the pressure and the increase value of the pressure are respectively used as the adhesion force of the hydrate particles and the surface of the carbon steel and the shell layer strength of the hydrate particles.
The device also comprises a constant-temperature water bath 8, wherein the constant-temperature water bath 8 is arranged outside the high-pressure reaction kettle 1 and is connected with the water bath coil 6 through a circulating pipeline 9; the temperature control precision of the constant-temperature water bath 8 is +/-0.1 ℃, and the lowest temperature can reach-10 ℃. And cold energy is provided for the cavity of the high-pressure reaction kettle 1 through a circulating pipeline 9, so that the low-temperature condition required by the stable existence of the hydrate is maintained.
The device also comprises a pressurizing system, wherein the pressurizing system consists of a vacuum pump, a high-pressure gas cylinder and a gas inlet pipeline, the vacuum pump is connected with the high-pressure reaction kettle, and the high-pressure gas cylinder is connected with the high-pressure reaction kettle 1 through the gas inlet pipeline. When the experiment is started, firstly, the vacuum pump is utilized to exhaust the air in the high-pressure reaction kettle 1, and then the natural gas in the high-pressure gas cylinder is introduced until the high-pressure condition required by stable existence of the hydrate is achieved.
And a temperature pressure gauge 10 is also arranged on the high-pressure reaction kettle 1. The temperature and pressure of the autoclave 1 were constantly monitored by a temperature gauge 10.
Example 2
The method of using the device of embodiment 1 includes the steps of:
starting the constant-temperature water bath 8, circulating low-temperature water in the constant-temperature water bath 8 in the water bath coil 6 through a circulating pipeline 9, and pre-cooling the aluminum cup 2; ice particles are fixed on the fixed cantilever 5, and the controller controls the nanometer shifter 3 to enable the carbon steel surface 40 at the front end of the movable cantilever 4 to be close to the ice particles;
injecting required liquid into the aluminum cup 2, and adding a proper amount of hydrate inhibitor;
starting a vacuum pump, and exhausting air in the high-pressure reaction kettle 1; closing the vacuum pump, opening an air inlet valve, and introducing natural gas in the high-pressure gas cylinder into the high-pressure reaction kettle 1 through an air inlet pipeline until the required high-pressure condition for stable existence of the hydrate is achieved; in order to reduce the induction time of hydrate generation, the temperature of a constant-temperature water bath is adjusted to be 1-2 ℃ higher than the stable existence temperature of the hydrate and is kept for 30 minutes, so that ice particles are melted into water, and then the temperature is reduced, so that the water and gas react to generate hydrate particles;
controlling the nano shifter 3 through the controller to enable the movable cantilever 4 to gradually approach the hydrate particles 11 until the surface of the carbon steel just contacts the hydrate particles 11; slowly moving the movable cantilever upwards, and recording the adhesion force when the surface of the carbon steel is separated from the contact with the hydrate particles 11; the movable cantilever 4 is slowly moved downwards until the hydrate grain shell is crushed by the surface of the carbon steel, and the strength of the hydrate grain shell is recorded.
Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.