Disclosure of Invention
In order to overcome the problems of the prior measurement technology means, the invention provides a device and a method for rapidly measuring the saturation of a pressure-maintaining hydrate core sample by a microwave method. The device has small volume, low manufacturing cost and simple and convenient operation, can be suitable for pressure-maintaining continuity test of the pressure-maintaining hydrate core, can rapidly measure the saturation of the pressure-maintaining hydrate core along with the ship on site, and provides guidance of the hydrate content for the hydrate exploitation and exploration process. The saturation of the hydrate is measured by adopting a definition method, so that the saturation of the hydrate in the sediment can be accurately and truly obtained.
Another object of the invention is to provide a method for rapidly measuring the saturation of a pressure maintaining hydrate core sample by a microwave method.
The object of the invention is achieved by at least one of the following technical solutions.
The device comprises a hydrate sediment pressure-maintaining transfer storage kettle, a microwave decomposition kettle, a gas-liquid collection kettle, a first large-diameter ball valve and a second large-diameter ball valve;
The hydrate deposit pressurize is shifted the top of storage kettle and is connected with first big latus rectum ball valve, and the bottom is connected with the big latus rectum ball valve of second, the big latus rectum ball valve of second links to each other with the microwave decomposition cauldron, hydrate deposit pressurize is shifted storage kettle and microwave decomposition cauldron are equipped with the business turn over pipeline and link to each other with the gas-liquid collection cauldron through pipeline and tee bend ball valve respectively at the cauldron body.
Further, a first temperature sensor and a first pressure sensor are arranged in the hydrate sediment pressure-maintaining transfer storage kettle, and a first refrigerating sheet is arranged outside the kettle body.
Further, a glass window is arranged on the kettle wall of the microwave decomposing kettle, and a microwave generating device is connected to the outer side of the glass window; the inner wall of the microwave decomposing kettle is of a corrugated structure and is used for reflecting microwaves and uniformly distributing the microwaves so as to reduce the influence of standing waves; and a second refrigerating sheet is arranged outside a pipeline connected with the microwave decomposing kettle and the gas-liquid collecting kettle.
Further, the gas-liquid collecting kettle is connected with a vacuum pump, and a second temperature sensor and a second pressure sensor are arranged in the gas-liquid collecting kettle.
Further, the first temperature sensor, the first pressure sensor, the second temperature sensor and the second pressure sensor are respectively connected with the data collector.
Further, the first refrigerating sheet and the second refrigerating sheet are connected with the refrigerating sheet controller.
Further, the microwave generating device is connected with a microwave generating controller.
A method for rapidly measuring the saturation of a pressure maintaining hydrate core sample by a microwave method comprises the following steps:
Step 1, butt joint sampling: the method comprises the steps of connecting a first large-diameter ball valve connected with the top of a hydrate sediment pressure-maintaining transfer storage kettle with a pressure-maintaining cylinder of a coring device, closing the first large-diameter ball valve and a second large-diameter ball valve, opening the second ball valve, injecting constant-pressure water into the second ball valve, balancing the pressure between the inside of the hydrate sediment pressure-maintaining transfer storage kettle and the pressure-maintaining cylinder, closing the second ball valve, simultaneously opening a first refrigerating plate through a refrigerating plate controller to cool to a temperature equivalent to that of the pressure-maintaining cylinder, opening the first large-diameter ball valve, cutting a section of sample core with a length smaller than 20cm, transferring the sample core into the hydrate sediment pressure-maintaining transfer storage kettle, and closing the first large-diameter ball valve;
Step 2, vacuumizing: closing the first ball valve and the fourth ball valve, opening the three-way ball valve and the fifth needle valve, starting a vacuum pump to pump air, keeping the air pumping time for 15-30 min, and closing the fifth needle valve;
step 3, pressure relief: opening a second ball valve, discharging partial pressure-maintaining water in the hydrate sediment pressure-maintaining transfer storage kettle, and enabling the pressure of the first pressure sensor to be close to normal pressure;
step 4, transferring and decomposing: opening a second large-diameter ball valve to enable the hydrate sample core to fall into a microwave decomposing kettle under the action of gravity, controlling a microwave generating device through a microwave generating controller, and sending out microwaves with power of 600-1000W to heat the hydrate sample core to decompose the hydrate sample core; a three-way valve is opened, a microwave decomposing kettle and a gas-liquid collecting kettle are communicated, and a second refrigerating sheet is opened through a refrigerating sheet controller to cool to about 0 ℃;
And 5, recording temperature and pressure: reading the readings of the second temperature sensor and the second pressure sensor after the readings of the first temperature sensor, the first pressure sensor, the second temperature sensor and the second pressure sensor are stable;
Step 6, liquid discharge volume measurement: and opening the fourth ball valve, immediately closing the fourth ball valve after discharging the liquid in the gas-liquid collecting kettle, and measuring the volume of discharged liquid.
Compared with the prior art, the invention has the advantages that:
1. the design pressure of the hydrate sediment pressure-maintaining transfer storage kettle is 0-30 MPa, the design temperature is-10-200 ℃, and the on-site rapid test of the saturation degree of the hydrate sediment in the frozen soil layer and the seabed can be satisfied;
2. the two large-diameter ball valves are arranged at the upper end and the lower end of the hydrate sediment pressure-maintaining transfer storage kettle, so that the pressure-maintaining transfer of the hydrate sample core can be realized, and a real fidelity test is performed;
3. The ball valve on the kettle body of the hydrate deposit pressure-maintaining transfer storage kettle is used for pre-releasing pressure, and then the sample core is transferred into the microwave decomposition kettle, so that the problem that the microwave generator cannot resist high pressure is solved, and the hydrate can be rapidly decomposed by utilizing the advantage of microwave heating
4. The measuring device can realize rapid measurement of the saturation of the hydrate in the sediment containing the hydrate, and the saturation of the hydrate can be accurately and truly obtained by measuring the saturation of the hydrate by adopting a definition method, so that rapid and accurate guidance is provided for mining a natural gas hydrate mine.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto, and may be performed with reference to conventional techniques for process parameters that are not specifically noted.
The device comprises a hydrate sediment pressure-maintaining transfer storage kettle K1, a microwave decomposition kettle K2, a gas-liquid collection kettle K3, a first large-diameter ball valve B1 and a second large-diameter ball valve B2; the hydrate deposit pressurize is shifted the top of storage cauldron K1 and is connected with first big latus rectum ball valve B1, and the bottom is connected with second big latus rectum ball valve B2, second big latus rectum ball valve B2 links to each other with microwave decomposition cauldron K2, hydrate deposit pressurize is shifted storage cauldron K1 and microwave decomposition cauldron K2 are equipped with the business turn over pipeline and link to each other with gas-liquid collection cauldron K3 through pipeline and tee bend ball valve V3 at the cauldron body respectively. The hydrate sediment pressure maintaining transfer storage kettle K1 is internally provided with a first temperature sensor T1 and a first pressure sensor P1, and a first refrigerating sheet C1 is arranged outside the kettle body. A glass window W is arranged on the kettle wall of the microwave decomposing kettle K2, and a microwave generating device M1 is connected to the outer side of the glass window W; the inner wall of the microwave decomposition kettle K2 is of a corrugated structure and is used for microwave reflection, uniform distribution and reduction of standing wave influence; and a second refrigerating sheet C2 is arranged outside a pipeline connected with the microwave decomposing kettle K2 and the gas-liquid collecting kettle K3. The gas-liquid collecting kettle K3 is connected with the vacuum pump M2, and a second temperature sensor T2 and a second pressure sensor P2 are arranged in the gas-liquid collecting kettle K3. The first temperature sensor T1, the first pressure sensor P1, the second temperature sensor T2 and the second pressure sensor P2 are respectively connected with the data collector E1. The first refrigerating sheet C1 and the second refrigerating sheet C2 are connected with the refrigerating sheet controller E2. The microwave generating device M1 is connected with the microwave generating controller E3.
Wherein the hydrate deposit sample volume is derived by measuring the hydrate deposit liner volume; the mass of the hydrate deposit sample is obtained through weighing the hydrate deposit; setting the density of sandstone in the sediment, and weighing to obtain the mass, so that the volume occupied by the sandstone in the sediment can be obtained, and the pore volume can be obtained; the water content of the hydrate deposit sample can be obtained by measuring the water volume discharged by the fourth ball valve V4 (combining the volume of the hydrate deposit sample and the volume of the hydrate deposit pressure-maintaining transfer storage kettle K1); the gas amount decomposed by the hydrate-containing sediment sample can be obtained through the change of the second temperature sensor T2 and the second pressure sensor P2 in the gas-liquid collecting kettle K3 and the water volume discharged by the fourth ball valve V4; calculating the volume of the hydrate according to the obtained gas quantity and water quantity; the hydrate saturation of the hydrate-containing sediment sample is obtained by comparing the hydrate volume with the pore volume.
The specific implementation steps are described below:
Step 1, butt joint sampling: the method comprises the steps of connecting a first large-diameter ball valve B1 connected to the top of a hydrate sediment pressure-maintaining transfer storage kettle K1 with a pressure-maintaining cylinder of a coring device, closing the first large-diameter ball valve B1 and a second large-diameter ball valve B2, opening a second ball valve V2 to inject constant-pressure water, balancing the pressure between the inside of the hydrate sediment pressure-maintaining transfer storage kettle K1 and the pressure-maintaining cylinder, closing the second ball valve V2, simultaneously opening a first refrigeration piece C1 through a refrigeration piece controller E2 to cool to a temperature equivalent to that of the pressure-maintaining cylinder, opening the first large-diameter ball valve B1, cutting a section of sample core with a length less than 20cm, transferring the sample core into the hydrate sediment pressure-maintaining transfer storage kettle K1, and closing the first large-diameter ball valve B1;
Step 2, vacuumizing: closing the first ball valve V1 and the fourth ball valve V4, opening the three-way ball valve V3 and the fifth needle valve V5, starting the vacuum pump M2 to pump air for 15-30 min, and closing the fifth needle valve V5;
Step 3, pressure relief: opening a second ball valve V2, discharging partial pressure-maintaining water in the hydrate sediment pressure-maintaining transfer storage kettle K1, and enabling the pressure of the first pressure sensor P1 to be close to normal pressure;
Step 4, transferring and decomposing: opening a second large-diameter ball valve B2 to enable the hydrate sample core to fall into a microwave decomposing kettle K2 under the gravity, controlling a microwave generating device M1 through a microwave generating controller E3, and generating microwaves with certain power to heat the hydrate sample core to decompose the hydrate sample core; opening a three-way valve V3, communicating the microwave decomposing kettle K2 with the gas-liquid collecting kettle K3, and simultaneously opening a second refrigerating piece C2 through a refrigerating piece controller E2 to cool to about 0 ℃;
And 5, recording temperature and pressure: reading the readings of the second temperature sensor T2 and the second pressure sensor P2 after the readings of the first temperature sensor T1, the first pressure sensor (P1), the second temperature sensor T2 and the second pressure sensor P2 are stable;
Step 6, liquid discharge volume measurement: and opening the fourth ball valve V4, immediately closing the fourth ball valve V4 after discharging the liquid in the gas-liquid collecting kettle K3, and measuring the volume of discharged liquid.
The above examples of the present invention are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.