CO2Method for blocking rock stratum microcrack permeation by mineralized nano silica gel grouting material
阅读说明：本技术 Co2矿化纳米硅胶注浆材料阻断岩层微裂隙渗透的方法 (CO2Method for blocking rock stratum microcrack permeation by mineralized nano silica gel grouting material ) 是由 马立强 吴乙辉 翟江涛 王洋洋 于 2021-08-31 设计创作，主要内容包括：本发明公开一种CO-(2)矿化纳米硅胶注浆材料阻断岩层微裂隙渗透的方法,适用于煤矿井下使用。确定采矿活动扰动围岩导致的上行微裂隙发育高度和下行微裂隙发育深度,根据工作面采深及空隙压力梯度计算最大孔隙压力；将硅基材料与水按质量比1:100～50:100混合得到基液；将纳米颗粒与基液按质量比1:1000～100:1000混合得到纳米流体；将纳米流体通过注浆管道与顶底板注浆钻孔分别注入上行微裂隙发育区和下行微裂隙发育区中,压力不再变化时停止注入,最后将CO-(2)气体分别注入上行微裂隙发育区和下行微裂隙发育区中形成原位纳米硅胶,从而封闭微裂隙。其步骤简单,使用方便,具有广泛的实用性。(The invention discloses a CO 2 The method for blocking the permeability of rock stratum microcracks by using the mineralized nano silica gel grouting material is suitable for being used in coal mines. Determining the ascending micro-fracture development height and the descending micro-fracture development depth caused by the disturbance of the surrounding rock by mining activities, and calculating the maximum pore pressure according to the mining depth of a working surface and the pore pressure gradient; mixing a silicon-based material and water according to a mass ratio of 1: 100-50: 100 to obtain a base solution; mixing the nano particles with a base liquid according to a mass ratio of 1: 1000-100: 1000 to obtain a nano fluid; injecting nanometer fluid into the upstream micro-crack development area and the downstream micro-crack development area through the grouting pipeline and the top and bottom plate grouting drill hole respectively, stopping injecting when the pressure is not changed any more, and finally, injecting CO 2 Gas is respectively injected into the upstream microcrack development zone and the downstream microcrack development zone to form in-situ nano-siliconGlue, thereby sealing the microcracks. The method has the advantages of simple steps, convenient use and wide practicability.)
1. CO (carbon monoxide)2The method for blocking the permeability of the rock stratum microcracks by using the mineralized nano silica gel grouting material is characterized by comprising the following steps of:
step one, sampling and testing aquifer water of a mining area to be constructed, and determining the concentrations of sodium ions, calcium ions, bicarbonate ions, magnesium ions and sulfate ions in the aquifer water;
calculating and determining the ascending micro-fracture development height and the descending micro-fracture development depth caused by disturbance of surrounding rock by mining activities through parameters such as mining height, mining depth, filling rate and influence degree coefficient of filling rate on overburden rock fracture development, coal seam inclination angle and working face length, and further determining construction parameters such as angle, depth, aperture and interval of grouting drilling;
step three, calculating the maximum pore pressure according to the mining depth of the working face and the pore pressure gradient;
step four, mixing the silicon-based material and water according to the mass ratio of 1: 100-50: 100, and fully stirring to obtain a base solution;
mixing the nano particles with a base liquid according to the mass ratio of 1: 1000-100: 1000, and performing ultrasonic dispersion and stirring to obtain a nano fluid;
constructing a grouting drill hole (14) according to the construction parameters determined in the second step, and respectively injecting a nanofluid (3) into the upstream micro-crack development area (10) and the downstream micro-crack development area (12) through a grouting pipeline (6) and the top and bottom plate grouting drill hole (14) by utilizing a mineralized nano silica gel grouting system, wherein the injection pressure does not exceed the maximum pore pressure, and the injection is stopped when the pressure is not changed any more;
seventhly, utilizing a mineralized nano silica gel grouting system to drill the CO through the grouting drill hole (14) of the top and bottom plates2Gas is respectively injected into the ascending microcrack development zone (10) and the descending microcrack development zone (12), the injection pressure does not exceed the maximum pore pressure, and the injection is stopped when the pressure is not changed any more, because of CO2Good gas permeability to CO2The gas reacts with the nano fluid (3) injected into the micro cracks in the micro crack development area to form in-situ nano silica gel, thereby sealing the micro cracks.
2. CO according to claim 12The method for blocking the permeability of rock stratum microcracks by using the mineralized nano silica gel grouting material is characterized in that the mineralized nano silica gel grouting system comprises: CO22A tank (2) and a nano-fluid tank (3), wherein the nano-fluid tank (3) is connected with a high-pressure pump station (1) for providing grouting power, CO2The outlets of the tank (2) and the nano fluid tank (3) are connected with a grouting pipeline (6) through a three-way switching valve, and the grouting pipeline (6) is provided with a monitoring device (5) comprising a pressure gauge and a flow meter.
3. CO according to claim 12The method for blocking rock stratum microcrack permeation by mineralized nano silica gel grouting material is characterized in that in the first step, sampling test is carried out on aquifer water in a mining area, wherein the concentration of sodium ions in the aquifer water suitable for nano silica gel is 0-5000 mug/L, the concentration of calcium ions is 0-1000 mug/L, the concentration of bicarbonate ions is 0-2000 mug/L, the concentration of magnesium ions is 0-1000 mug/L, and the concentration of sulfate ions is 0-2000 mug/L.
4. CO according to claim 12The method for blocking the permeability of the rock stratum microcracks by the mineralized nano silica gel grouting material is characterized in that in the second step, the ascending microcrack development height caused by the mining activity disturbance of the surrounding rock is as follows:
in the formula, HfM is the ascending micro-crack development height; m is the mining height M;is the filling rate; and lambda is the influence degree coefficient of the filling rate on the development of the overlying strata fracture.
5. CO according to claim 12The method for blocking the permeability of the rock stratum microcracks by the mineralized nano silica gel grouting material is characterized in that in the second step, the development depth of the downward microcracks caused by the disturbance of the surrounding rock by mining activities is as follows:
h＝0.0187H+0.2278α+3.4858M+0.0435L-8.2539
in the formula, h is the development depth of the descending microcracks, m; h is the mining depth m; alpha is the coal bed inclination angle, °; l is the working face length, m; m is the mining height M.
6. CO according to claim 12The method for blocking the permeability of the rock stratum microcracks by using the mineralized nano silica gel grouting material is characterized in that in the fourth step, the pH value of the base liquid is 8-14, and the initial viscosity is 2-80 mPa.s.
7. CO according to claim 12And the method for blocking the permeability of the rock stratum microcracks by using the mineralized nano silica gel grouting material is characterized in that in the fifth step, the particle size of the nano particles is 5-500 nm, the nano particles are non-metal nano particles, semi-metal particles or magnetic nano particles, and the nanofluid is prepared by adopting a two-step method, wherein the stirring time is 5-120 minutes, the stirring speed is 100-2000 r/min, and the ultrasonic dispersion time longer than 20kHz is 5-120 minutes.
8. CO according to claim 12The method for blocking the permeability of the rock microcracks by mineralized nano silica gel grouting material is characterized in that in the sixth step, in order to ensure that the injection pressure can not cause secondary permeation to the microcracked rock massFracturing, the injection amount of the nano fluid is 0.1-500 m3/d。
9. CO according to claim 12The method for blocking the permeability of the rock stratum microcracks by using the mineralized nano silica gel grouting material is characterized in that in the seventh step, CO2The gas flow is 0.1-100L/min, the viscosity of the formed nano silica gel is 100-5000 mPa.s, and the pH value is 4-12.
10. Use of the CO of claim 22The detection method of the method for blocking the permeability of the rock stratum microcracks by the mineralized nano silica gel grouting material is characterized by comprising the following steps: the device comprises a sealed core holder (16) for holding a measured core, wherein one side of the core holder (16) is provided with an injection end (15), the other side of the core holder is provided with an output end (17), the injection end (15) is connected with a grouting pipeline (6) of a mineralized nano silica gel grouting system through a pipeline, the output end (17) is connected with a fractionating tower (18) through a pipeline, and a valve (4) and a monitoring device (5) are also arranged on the pipeline connected with the fractionating tower (18);
the method comprises the following specific steps:
s1, firstly, preparing a standard sandstone test piece for testing, and manufacturing micro-cracks in the sandstone test piece in a mode of uniaxial compression of the sandstone test piece, wherein the sandstone test piece has micro-cracks and porous medium pores for permeability testing;
s2, installing the sandstone test piece in a rock core holder (16), displaying pressure change during liquid and gas injection by using a monitoring device (5), testing initial permeability before grouting by using pressure difference between two ends, testing initial permeability by using advanced injection flow (less than 0.5 and more than 1.5mL/min), wherein each advanced injection flow is carried out until no pressure fluctuation exists in the process, and the permeability is calculated by the following formula:
in the formula: q is the flow, m3/s；KabsAs permeability, m2(ii) a μ is the solution viscosity, Ns/m2(ii) a A isCross sectional area, m2(ii) a Δ P is the pressure difference, Pa; l is the length, m.
S3, taking out the sandstone test piece from the clamp holder (16), drying at high temperature, and cooling the dried sandstone test piece to normal temperature to prepare for grouting;
s4, preparing base liquid from the silicon-based material and water according to the mass ratio of 10:100, dispersing nano particles in the base liquid to prepare nano fluid, injecting the nano fluid into the sandstone test piece in the core holder until the sandstone test piece is saturated, and judging that the sandstone test piece is saturated when bubbles appear in the fractionating tower (18);
s5 closing the outflow end (17) and then injecting CO through the injection end2Gas, CO injection2The flow control is changed into pressure control, and CO is injected into the sandstone test piece saturated by the nano fluid2Stopping CO until the desired pressure2Injecting, closing the injection end (15), observing the injected CO2Reacting with the nano fluid in the rock core, observing pressure change through the monitoring devices (5) at the two ends, and indicating CO when the pressure of the monitoring devices (5) at the two ends is balanced2Reacting with the nano fluid in the rock core to form nano silica gel;
s6, after the nano silica gel is formed, the injection end (15) and the outflow end (17) are opened, and the step S2 is repeated to detect the permeability change of the sandstone test piece filled with the nano silica gel.
Technical Field
The patent aims to invent a method for blocking the permeability of rock stratum microcracks, which is particularly suitable for coalCO in the technical field of carbon mining2A method for blocking permeability of rock stratum microcracks by using mineralized nano silica gel grouting material.
Background
After coal mining, the instability of the top plate and the bottom plate rock stratum of the goaf causes deformation and damage of surrounding rocks, rock stratum disturbance and fracture development change underground seepage field distribution, and an underground water funnel which takes the goaf as a water collecting area and a water guide fracture as a seepage center is formed, so that a large amount of underground water and surface water are lost, and the problems of environmental damage, such as plant withering, desertification and the like, are caused. If not, water will permeate into the goaf, finally causing water burst and causing safety accidents.
In the past decades, ecological problems in coal mining have come to be of great concern, water resource protection and utilization are major challenges in green mining, and in order to prevent and treat aquifer and surface water loss and environmental damage caused by mining, damage before and after mining is pretreated. Wherein, the formation of crack has obvious influence to the direct infiltration of aquifer, uses the grout or chemical grout slip casting can effectively block the infiltration. The micro-cracks have small influence on early-stage water seepage, but when the micro-cracks are contacted with a water-bearing layer for a long time, mineral substances in rocks are decomposed under the action of water (formula 4), so that the micro-cracks develop to form large cracks, and a series of problems after the water seepage and the cracks develop can be effectively prevented and treated by researching micro-crack pretreatment.
Conventional cement slurries are suitable for large fractures in the upper layers of the goaf, but during production there are also micro-fractures above the fractured zone, these micro-fractures having an average width of less than 0.15 mm. The cement slurry is distributed with particles with larger diameters, has higher initial viscosity (100-1200 mPa.s), can not be effectively injected into micro cracks, can generate secondary fracturing when the injection pressure is increased, can expand the micro cracks into large cracks, can not be injected for reinforcement, and can form a water guide channel. There is therefore a need to develop a slurry that can penetrate into microcracks and effectively block the path of water seepage.
In addition, China takes coal as a main energy source for a long time, and the coal uses CO discharged by the coal2Accounting for 72 percent of the total discharge of China and 28 percent of the whole world, and causing the problems of global warming, climate change and the like. In order to control the increasing CO in the atmosphere2Concentration, mitigation of climate change problems, CO2Efficient handling, containment and utilization of the same is already at issue.
Disclosure of Invention
Aiming at the technical problems, the invention provides the CO with simple steps and good using effect2A method for blocking the permeability of rock stratum microcracks by mineralized nano silica gel grouting material.
To achieve the above technical objects, the CO of the present invention2The method for blocking the permeability of the rock stratum microcracks by using the mineralized nano silica gel grouting material is characterized by comprising the following steps of:
step one, sampling and testing aquifer water of a mining area to be constructed, and determining the concentrations of sodium ions, calcium ions, bicarbonate ions, magnesium ions and sulfate ions in the aquifer water;
calculating and determining the ascending micro-fracture development height and the descending micro-fracture development depth caused by disturbance of surrounding rock by mining activities through parameters such as mining height, mining depth, filling rate and influence degree coefficient of filling rate on overburden rock fracture development, coal seam inclination angle and working face length, and further determining construction parameters such as angle, depth, aperture and interval of grouting drilling;
step three, calculating the maximum pore pressure according to the mining depth of the working face and the pore pressure gradient;
step four, mixing the silicon-based material and water according to the mass ratio of 1: 100-50: 100, and fully stirring to obtain a base solution;
mixing the nano particles with a base liquid according to the mass ratio of 1: 1000-100: 1000, and performing ultrasonic dispersion and stirring to obtain a nano fluid;
sixthly, constructing grouting drill holes according to the construction parameters determined in the second step, and respectively injecting nano fluid into the upward microcrack development area through a grouting pipeline and the top and bottom plate grouting drill holes by utilizing a mineralized nano silica gel grouting systemAnd in the downstream microcrack development zone, the injection pressure does not exceed the maximum pore pressure, and the injection is stopped when the pressure does not change. Seventhly, utilizing the mineralized nano silica gel grouting system to drill the CO through the grouting of the top and bottom plates2And gas is respectively injected into the ascending microcrack development area and the descending microcrack development area, the injection pressure does not exceed the maximum pore pressure, and the injection is stopped when the pressure is not changed. Due to CO2Good gas permeability to CO2The gas reacts with the nano fluid injected into the micro cracks in the micro crack development area to form in-situ nano silica gel, so that the micro cracks are sealed.
The mineralized nano silica gel grouting system comprises: CO22A tank and a nanofluid tank, wherein the nanofluid tank is connected with a high-pressure pump station for providing grouting power, CO2The outlets of the tank and the nano fluid tank are connected with a grouting pipeline through a three-way switching valve, and the grouting pipeline comprises a pressure meter and a flow meter monitoring device.
In the first step, the aquifer water in the mining area is sampled and tested, and the nano silica gel is suitable for the aquifer water with the sodium ion concentration of 0-5000 mug/L, the calcium ion concentration of 0-1000 mug/L, the bicarbonate ion concentration of 0-2000 mug/L, the magnesium ion concentration of 0-1000 mug/L and the sulfate ion concentration of 0-2000 mug/L.
In the second step, the ascending microcrack development height caused by the disturbance of the surrounding rock by mining activities is as follows:
in the formula, HfM is the ascending micro-crack development height; m is the mining height M;is the filling rate; and lambda is the influence degree coefficient of the filling rate on the development of the overlying strata fracture.
In the second step, the development depth of the descending microcracks caused by the disturbance of the surrounding rock by mining activities is as follows:
h＝0.0187H+0.2278α+3.4858M+0.0435L-8.2539
in the formula, h is the development depth of the descending microcracks, m; h is the mining depth m; alpha is the coal bed inclination angle, °; l is the working face length, m; m is the mining height M;
in the fourth step, the pH value of the base liquid is 8-14, and the initial viscosity is 2-80 mPa.s.
And fifthly, preparing the nanofluid by adopting a two-step method, wherein the particle size of the nanoparticles is 5-500 nm, the nanoparticles are non-metal nanoparticles, semi-metal particles or magnetic nanoparticles, the stirring time is 5-120 minutes, the stirring speed is 100-2000 r/min, and the ultrasonic dispersion time greater than 20kHz is 5-120 minutes.
In the sixth step, in order to ensure that the injection pressure can not cause secondary fracturing on the microcracked rock mass, the injection amount of the nano fluid is 0.1-500 m3/d；
In step seven, CO2The gas flow is 0.1-100L/min, the viscosity of the formed nano silica gel is 100-5000 mPa.s, and the pH value is 4-12.
CO (carbon monoxide)2The detection method of the method for blocking the permeability of the rock stratum microcracks by the mineralized nano silica gel grouting material comprises a sealed rock core holder for holding a tested rock core, wherein one side of the rock core holder is provided with an injection end, the other side of the rock core holder is provided with an output end, the injection end is connected with a grouting pipeline of a mineralized nano silica gel grouting system through a pipeline, the output end is connected with a fractionating tower through a pipeline, and a valve and a monitoring device are also arranged on the pipeline connected with the fractionating tower;
the method comprises the following specific steps:
s1, firstly, preparing a standard sandstone test piece for testing, and manufacturing micro-cracks in the sandstone test piece in a mode of uniaxial compression of the sandstone test piece, wherein the sandstone test piece has micro-cracks and porous medium pores for permeability testing;
s2, installing the sandstone test piece in a rock core holder, displaying pressure change during liquid and gas injection by using a monitoring device, testing initial permeability before grouting by using pressure difference between two ends, testing initial permeability by using advanced injection flow (less than 0.5 and more than 1.5mL/min), and calculating the permeability by using the following formula until no pressure fluctuation occurs in each advanced injection flow in the process:
in the formula: q is the flow, m3/s；KabsAs permeability, m2(ii) a μ is the solution viscosity, Ns/m2(ii) a A is the cross-sectional area, m2(ii) a Δ P is the pressure difference, Pa; l is the length, m.
S3, taking out the sandstone test piece from the clamp, drying at high temperature, and cooling the dried sandstone test piece to normal temperature to prepare for grouting;
s4, preparing base liquid from the silicon-based material and water according to the mass ratio of 10:100, dispersing nano particles in the base liquid to prepare nano fluid, injecting the nano fluid into the sandstone test piece in the core holder until the sandstone test piece is saturated, and judging that the sandstone test piece is saturated when bubbles appear in the fractionating tower;
s5 closing the outflow end and then injecting CO through the injection end2Gas, CO injection2The flow control is changed into pressure control, and CO is injected into the sandstone test piece saturated by the nano fluid2Stopping CO until the desired pressure2Injecting, closing the injection end, observing the injected CO2Reacting with the nano fluid in the rock core, observing pressure change through the monitoring devices at two ends, and indicating CO when the pressure of the monitoring devices at two ends is balanced2Reacting with the nano fluid in the rock core to form nano silica gel;
s6, after the nano silica gel is formed, opening the injection end and the outflow end, and repeating the step S2 to detect the permeability change of the sandstone test piece filled with the nano silica gel.
Has the advantages that: the invention develops a nano fluid with low initial viscosity by adopting a silicon-based material and nano particles to carry out micro-crack permeability blocking, and adopts a two-step injection method, namely, the nano fluid is injected firstly, and then CO is injected2Gas is dissolved and reacted, and the gel is formed in situ in the rock microcracks. The nanoparticles reduce gas-liquid surface tension and increase CO with their high surface area2The dissolution rate effectively reduces the permeability of the microcracks in the mining rock body, prevents the development of the microcracks and blocks a water seepage path. The method uses a grouting materialIn the form of a feedstock, CO2Mineralization is injected into the fractures of the subterranean formation to aid in the carbon neutralization process.
Drawings
FIG. 1 is a schematic structural diagram of a mineralized nano silica gel grouting system according to the present invention;
FIG. 2 is a schematic diagram of an experimental apparatus for the detection method of the present invention.
Wherein: 1. a high pressure pump station; 2. CO22A tank; a nanofluid tank; 4. a valve; 5. a monitoring device; 6. grouting pipelines; 7. a mining area; 8. a collapse zone; 9. ascending a large fissure development area; 10. ascending a micro-crack development area; 11. descending a large fissure development zone; 12. descending a microcrack development zone; 13. working face propulsion direction; 14. grouting and drilling; 15. an injection end; 16. a core holder; 17. an output end; 18; a fractionating tower.
Detailed Description
Embodiments of the invention are further described below with reference to the accompanying drawings:
one kind of CO of the present invention2A method for blocking stratum microcrack permeation by mineralized nano silica gel grouting material is applied to a mining area 7, wherein a caving zone 8 exists in the mining area 7, an ascending large crack development area 9 exists above the caving zone 8, an ascending microcrack development area 10 exists above the ascending large crack development area 9, a descending large crack development area 11 exists below the caving zone 8, and a descending microcrack development area 12 exists below the descending large crack development area 11.
Which comprises the following steps:
step one, sampling and testing aquifer water of a mining area to be constructed, and determining the concentrations of sodium ions, calcium ions, bicarbonate ions, magnesium ions and sulfate ions in the aquifer water; the sampling test is carried out on the aquifer water in the mining area, and the nano silica gel is suitable for the aquifer water with the sodium ion concentration of 0-5000 mug/L, the calcium ion concentration of 0-1000 mug/L, the bicarbonate ion concentration of 0-2000 mug/L, the magnesium ion concentration of 0-1000 mug/L and the sulfate ion concentration of 0-2000 mug/L.
Calculating and determining the ascending micro-fracture development height and the descending micro-fracture development depth caused by disturbance of surrounding rock by mining activities through parameters such as mining height, mining depth, filling rate and influence degree coefficient of filling rate on overburden rock fracture development, coal seam inclination angle and working face length, and further determining construction parameters such as angle, depth, aperture and interval of grouting drilling; in the second step, the ascending microcrack development height caused by the disturbance of the surrounding rock by mining activities is as follows:
in the formula, HfM is the ascending micro-crack development height; m is the mining height M;is the filling rate; lambda is the influence degree coefficient of the filling rate on the development of the overlying strata fracture; the development depth of the descending microcracks caused by the disturbance of the surrounding rock by mining activities is as follows:
h＝0.0187H+0.2278α+3.4858M+0.0435L-8.2539
in the formula, h is the development depth of the descending microcracks, m; h is the mining depth m; alpha is the coal bed inclination angle, °; l is the working face length, m; m is the mining height M;
step three, calculating the maximum pore pressure according to the mining depth of the working face and the pore pressure gradient;
mixing the silicon-based material and water according to the mass ratio of 1: 100-50: 100, and fully stirring to obtain a base liquid, wherein the pH value of the base liquid is 8-14, and the initial viscosity is 2-80 mPa.s;
mixing the nano particles and a base liquid according to a mass ratio of 1: 1000-100: 1000, and performing ultrasonic dispersion and stirring to obtain a nano fluid, wherein the particle size of the nano particles is 5-500 nm, the nano particles are nonmetal nano particles, semimetal particles or magnetic nano particles, and the nano fluid is prepared by adopting a two-step method, wherein the stirring time is 5-120 minutes, the stirring speed is 100-2000 r/min, and the ultrasonic dispersion time greater than 20kHz is 5-120 minutes;
step six, respectively detecting a method 10 for detecting the ascending micro-crack development area from the edge of the caving zone 8 and a method for detecting the descending micro-crack development area according to the construction parameters determined in the step twoIn the detection method 12, an inclined construction grouting drilling detection method 14 is adopted, the trend of the grouting drilling detection method 14 is opposite to the advancing direction 13 of a working face, a mineralized nano silica gel grouting system is used for injecting a nano fluid detection method 3 detection method into an uplink micro-fracture development area detection method 10 and a downlink micro-fracture development area detection method 12 through a grouting pipeline detection method 6 and a top and bottom plate grouting drilling detection method 14 detection method respectively, the injection pressure of nano flow does not exceed the maximum pore pressure, and the injection is stopped when the pressure is not changed; in order to ensure that the injection pressure can not cause secondary fracturing on the microcracked rock mass, the injection amount of the nano fluid is 0.1-500 m3/d；
Step seven, utilizing a mineralized nano silica gel grouting system to perform grouting and drilling detection on the top and bottom plates by a detection method 142The gas detection method 4 is respectively injected into the detection method 10 for the ascending microcrack development zone and the detection method 12 for the descending microcrack development zone, and CO is2The gas flow is 0.1-100L/min, the viscosity of the formed nano silica gel is 100-5000 mPa.s, and the pH value is 4-12; the injection pressure does not exceed the maximum pore pressure, and the injection is stopped when the pressure is not changed any more; due to CO2Gas detection method 4 detection method good permeability, making CO2The gas detection method 4 is reacted with the nano fluid injected into the micro cracks in the micro crack development area by the detection method 3 to form in-situ nano silica gel, so that the micro cracks are sealed. The mineralized nano silica gel grouting system comprises: CO22A tank detection method 2 and a nano fluid tank detection method 3, wherein the nano fluid tank detection method 3 is connected with a high pressure pump station detection method 1 for providing grouting power, and a CO detection method2The outlet of the detection method of the tank detection method 2 and the detection method of the nano fluid tank 3 is connected with a grouting pipeline detection method 6 through a three-way switching valve, and the grouting pipeline detection method 6 comprises a pressure meter and flow meter monitoring device detection method 5.
CO (carbon monoxide)2Mineralized nano silica gel grouting material for blocking rock stratum microcrackThe detection method of the gap penetration method comprises a detection method 16 for a core holder used for holding a detected core and sealing the detected core, wherein one side of the detection method 16 for the core holder is provided with a detection method 15 for an injection end, and the other side of the detection method is provided with a detection method 17 for an output end, the detection method 15 for the injection end is connected with a detection method 6 for a grouting pipeline of a mineralized nano silica gel grouting system through a pipeline, the detection method 17 for the output end is connected with a detection method for a fractionating tower through a pipeline, and a detection method 5 for a valve detection method 4 and a detection method for a monitoring device are also arranged on a pipeline connected with the detection method for the fractionating tower;
example 1
For convenience of explanation, taking a laboratory scale as an example, as shown in fig. 2, a method for blocking the permeability of rock microcracks by using a CO2 mineralized nano silica gel grouting material is applied to low-permeability rock masses and rock masses which are mined to form microcracks, and the method comprises the following steps:
the method is characterized in that a standard sandstone test piece with the diameter of 50mm and the length of 100mm is used for testing, micro cracks and porous medium pores used for permeability testing exist in the test piece, and the specific implementation mode of the method is as follows:
and step one, manufacturing the micro-cracks in a mode of compressing the sandstone test piece by a single shaft.
And step two, the sandstone is arranged in the core holder, two ends of the sandstone are connected with pressure gauges to display pressure changes when liquid and gas are injected, and the initial permeability before grouting is tested through the pressure difference between the two ends. The initial permeability was tested by a three-step injection flow detection method of 0.5, 1, 1.5mL/min, during which each flow was carried out until there was no pressure fluctuation, and the permeability was calculated by the following formula:
in the formula: q-flow, m3/s；KabsPermeability, m2(ii) a Mu-solution viscosity, Ns/m2(ii) a A-cross-sectional area, m2(ii) a Δ P-pressure differential, Pa; l-length, m.
And step three, taking the sandstone out of the holder, drying the sandstone at 110 ℃ for 24 hours, and cooling the dried sandstone to normal temperature to prepare for grouting.
Dissolving the silicon-based material in water to prepare a base solution with the mass ratio of 10%, dispersing the nano particles in the base solution to prepare a nano fluid, and then injecting the nano fluid into sandstone at the flow rate of 1mL/min until the nano fluid is saturated, wherein the saturation point is based on that bubbles cannot be observed in the fractionating tower 18.
Step five in CO injection2Before the gas is injected, the outflow end is closed, and CO is injected2The flow control is changed into pressure control, and CO is injected into the sandstone saturated by the nano fluid2Stopping CO when the pressure reaches 2MPa2Injecting, closing the injection end, injecting CO2And (4) reacting with the nano fluid in the rock core, observing pressure change, and indicating that the reaction is finished to form nano silica gel by pressure balance.
And step six, after the formation of the nano silica gel is determined, opening the injection end and the outflow end, and testing the permeability change of the sandstone after grouting according to the step two.
Example 2
For convenience of explanation, as shown in fig. 2, a method for blocking the permeability of rock microfractures by using a CO2 mineralized nano silica gel grouting material is applied to low permeability and mining to form microfracture rock bodies, and comprises the following steps:
the standard sandstone with the diameter of 50mm and the length of 100mm is used for testing, micro-cracks and porous medium pores exist in a test piece, and the method is used for permeability testing, and the specific implementation mode of the method is as follows:
and step one, manufacturing the micro-cracks in a mode of compressing the sandstone test piece by a single shaft.
And step two, installing the sandstone test piece in the rock core holder, connecting pressure gauges at two ends of the sandstone test piece to display pressure changes when liquid and gas are injected, and testing the initial permeability before grouting through the pressure difference at the two ends. The initial permeability is tested by a three-time advanced injection flow detection method of 0.5, 1 and 1.5mL/min, each flow is subjected to no pressure fluctuation in the process, and the permeability is calculated by a formula detection method 3.
And step three, taking the sandstone out of the holder, drying the sandstone at 110 ℃ for 24 hours, and cooling the dried sandstone to normal temperature to prepare for grouting.
Dissolving the silicon-based material in water to prepare a base solution with the mass ratio of 5%, dispersing the nano particles in the base solution to prepare a nano fluid, and then injecting the nano fluid into sandstone at the flow rate of 1mL/min until the nano fluid is saturated, wherein the saturation point is based on that bubbles cannot be observed in the fractionating tower 18.
Step five in CO injection2Before the gas is injected, the outflow end is closed, and CO is injected2Changing flow control to pressure control, injecting CO into the sandstone saturated with nanofluid2Stopping CO when the pressure reaches 2MPa2Injecting, closing the injection end, injecting CO2And (4) reacting with the nano fluid in the rock core, observing pressure change, and indicating that the reaction is finished to form nano silica gel by pressure balance.
And step six, after the formation of the nano silica gel is determined, opening the injection end and the outflow end, and testing the permeability change of the sandstone after grouting according to the step two.
Example 3
For convenience of explanation, as shown in fig. 2, a method for blocking the permeability of rock microfractures by using a CO2 mineralized nano silica gel grouting material is applied to low permeability and mining to form microfracture rock bodies, and comprises the following steps:
the invention uses standard sandstone with the diameter of 50mm and the length of 100mm for testing, and the test piece has micro-cracks and porous medium pores and is used for permeability testing, and the specific implementation mode of the method is as follows:
and step one, manufacturing the micro-cracks in a mode of compressing the sandstone test piece by a single shaft.
And step two, the sandstone is arranged in the core holder, two ends of the sandstone are connected with pressure gauges to display pressure changes when liquid and gas are injected, and the initial permeability before grouting is tested through the pressure difference between the two ends. The initial permeability was tested by a three-step injection flow detection method of 0.5, 1, 1.5mL/min, each flow was carried out until there was no pressure fluctuation in the process, and the permeability was calculated by equation (3).
And step three, taking the sandstone out of the holder, drying the sandstone at 110 ℃ for 24 hours, and cooling the dried sandstone to normal temperature to prepare for grouting.
Dissolving the silicon-based material in water to prepare a base solution with the mass ratio of 10%, dispersing the nano particles in the base solution to prepare a nano fluid, and then injecting the nano fluid into sandstone at the flow rate of 1mL/min until the nano fluid is saturated, wherein the saturation point is based on that bubbles cannot be observed in the fractionating tower 18.
Step five in CO injection2Before the gas is injected, the outflow end is closed, and CO is injected2Changing flow control to pressure control, injecting CO into the sandstone saturated with nanofluid2Stopping CO2 injection when the pressure reaches 1MPa, closing the injection end, and injecting CO2And (4) reacting with the nano fluid in the rock core, observing pressure change, and indicating that the reaction is finished to form nano silica gel by pressure balance.
And step six, after the formation of the nano silica gel is determined, opening the injection end and the outflow end, and testing the permeability change of the sandstone after grouting according to the step two.
TABLE 1 variation of microcrack permeability under different examples
Initial permeability
Permeability after grouting
Example 1
6.82×10-15m2
6.91×10-17m2
Example 2
7.21×10-15m2
15.8×10-17m2
Example 3
6.45×10-15m2
31.6×10-17m2
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