In-hole television imaging method for solving problems of water turbidity and hole wall breakage through film attachment

Abstract

The invention discloses a method for completing in-hole television imaging under the conditions that in-hole water turbidity and hole wall collapse and chipping are solved through hole wall film attachment, and belongs to the technical field of in-hole television imaging in the geophysical prospecting industry. The technical problem of television imaging in the hole under the condition that water in the hole is turbid and cannot be turned to be clear is fundamentally solved through a method of attaching the transparent film to the hole wall and the like; the technical problem that in-hole accidents are caused due to the fact that a camera is prone to being stuck under the conditions that hole wall collapse, chipping and breaking zones exist in drilling is solved. The technical problem that hole washing is difficult in arid and water-deficient areas is solved; the method has the advantages of high test efficiency, low cost, environmental protection, no pollution and the like.

Description

Technical Field

[0001] The present invention relates to a geophysical prospecting method for assisting in-hole television imaging, which mainly solves the technical difficulties of in-hole television imaging when the water in the borehole is turbid and cannot be clarified, or when the borehole wall collapses and blocks fall off, making it impossible to lower a camera. Background Art

[0002] In-hole television imaging, also known as borehole television imaging, is a device used to detect the interior conditions of boreholes and deep wells. It primarily consists of a camera, transmission cables, and a host computer. During operation, the camera is lowered into the borehole and, using optical imaging principles, captures real-time image information of the borehole wall. This image data is then transmitted to the host computer's display screen via a transmission cable. This allows for clear, real-time observation and storage of information such as the color, bedding, fractures, and fracture zones of the borehole wall. This aids in determining stratigraphic and geological structures, providing a basis for mineral resource exploration and geological hazard assessment. It is an important geological survey tool.

[0003] Turbid borehole water makes in-hole television optical imaging impossible. This problem is typically addressed by flushing the borehole with clean water. However, in arid, water-scarce areas or areas with developed joints and fissures, it is difficult to clean the borehole to achieve the water transparency required for in-hole television imaging. This necessitates the use of another in-hole purification method: chemical methods. Commonly used chemical methods include precipitation (flocculant method), oxidation, and acid-base neutralization. Chemical methods first require indoor testing to understand the type of water turbidity, and then select the appropriate chemical reagent for clarification based on the type of turbidity. The experimental process is complex, time-consuming, and labor-intensive, delaying project schedules and increasing production costs. Furthermore, the treatment effect of turbid water is often unsatisfactory for various reasons, resulting in in-hole television imaging quality failing to meet technical requirements. This can easily lead to water pollution and damage to the groundwater ecosystem.

[0004] When a fault zone is present in a borehole, turbid, moving underground water is often present. Because this turbid, moving underground water continuously seeps into the borehole from the strata, neither hole washing nor chemical methods can clear the turbid water, making in-hole television imaging impossible and preventing the acquisition of relevant survey data.

[0005] When the borehole wall is unstable and prone to collapse and debris (which is extremely difficult to handle), the camera can easily get stuck by the debris. In addition, the in-hole imaging system is extremely weak in handling camera jams, which can easily cause in-hole accidents. This can make in-hole TV imaging impossible and even result in a failed borehole.

[0006] Turbid borehole water, which is difficult or impossible to clean, and problems such as borehole wall collapse and debris have long plagued in-hole television imaging. Purifying turbid water and addressing these issues are time-consuming and labor-intensive, delaying surveys, sometimes for months, and often resulting in no results. This increases project costs, delays the project schedule, and compromises the overall quality of the survey. Summary of the Invention

[0007] The present invention provides a method for completing in-hole television imaging in situations where the water in the borehole is turbid and difficult or impossible to clear, and where the borehole wall collapses and blocks fall off, thereby solving the technical problems that have long plagued in-hole television imaging.

[0008] For situations where turbid water in a borehole is difficult or impossible to clear, the guiding principle of the present invention is to lower a customized transparent membrane bag that runs the length of the borehole into the borehole. When the membrane bag reaches the bottom of the hole, clean water is injected into the membrane bag, and the water column pressure in the membrane bag is maintained slightly higher than the water column pressure in the hole. Under the action of pressure difference and capillary phenomenon, the clean water in the membrane bag gradually discharges the turbid water in the hole through the membrane bag or the cracks in the hole wall, and squeezes the transparent membrane bag tightly onto the hole wall and fits together with the hole wall. At this time, the entire hole is completely filled with the injected clean water. Then, a camera is lowered into the membrane bag to perform in-hole television imaging in the clear water. Due to the good transparency of the membrane bag, it will not affect the quality of the in-hole television imaging. The specific content and operation steps are as follows:

[0009] Step 1: Film bag customization

[0010] a) Length of membrane bag: The length of a single membrane bag should be greater than the maximum hole depth;

[0011] b) Diameter of membrane bag: should be 1-2mm larger than the hole diameter. The smaller the hole diameter, the smaller the diameter; the larger the diameter, the larger the diameter.

[0012] c) Film bag thickness: The thickness of the single side should be 0.05-0.15mm, and the thickness should be selected according to the drilling and crushing conditions. The smaller the value, the better for a complete hole, and the larger the value for a broken hole.

[0013] d) Film bag material: It is advisable to choose materials with high transparency and good toughness such as polyethylene;

[0014] e) The air in the film bag should be completely evacuated to make the film bag in a near vacuum state, and then packaged into rolls.

[0015] Step 2: Install the membrane bag

[0016] a) Seal the bottom of the film bag, install the protective cap, and hang a 3-6kg counterweight. The weight of the counterweight should be selected according to the hole depth. The deeper the hole, the heavier the counterweight.

[0017] b) Slowly lower the film bag vertically from the center of the hole to the bottom of the hole through the guide frame. During the lowering process, measures should be taken to prevent the film bag from twisting or scratching;

[0018] c) After the film bag reaches the bottom of the hole, leave 1 to 2 meters of excess film bag above the hole mouth, cut off the excess film bag, and fix the film bag at the hole mouth to prevent it from falling into the hole.

[0019] d) When pressurized water returns to the borehole, the casing should be raised at the borehole to the height of the pressurized water head, and then the membrane bag should be lowered and installed according to the above steps.

[0020] Step 3: Fill the membrane bag with water

[0021] a) The water used to inject the membrane bag should be clear and transparent water, including well water, mountain spring water, etc.

[0022] b) The height of the water filling surface in the membrane bag should be kept about 1 to 2 meters above the groundwater level. It should be prevented that the water is injected too quickly, which will cause water sealing at the upper part of the borehole and form local high pressure to break the membrane bag;

[0023] c) The injected water gradually diffuses from the hole mouth to the hole bottom under the combined action of pressure difference and capillary phenomenon, and at the same time, the turbid water in the hole is gradually squeezed out of the hole through the hole mouth and formation cracks;

[0024] d) Determine the total water injection volume by calculating the borehole volume. When the injected water volume reaches the total water injection volume, the water injection can be stopped.

[0025] e) At this time, the membrane bag is tightly squeezed against the hole wall under the action of internal water pressure, and the entire hole is filled with clear and transparent water. In addition, the membrane bag has excellent transparency, and the visibility of the hole wall rock reaches an extremely ideal state.

[0026] Step 4: In-hole TV imaging operation process

[0027] a) When the water filling is completed, immediately lower the camera into the film bag slowly, and avoid scratching the film bag during the lowering process;

[0028] b) When the probe contacts the water surface in the membrane bag, real-time image information of the hole wall can be collected;

[0029] c) When collecting hole wall image information, if turbid water is found to remain between the membrane bag and the hole wall in some places, and the hole wall image is not clear enough, it is generally because the turbid water has not been drained out in time. At this time, you can leave it still for a while until the turbid water is completely squeezed out of the hole by the membrane bag under the action of the internal water pressure difference and the hole wall image becomes clear before continuing to collect.

[0030] Step 5: Remove the membrane bag

[0031] In order to prevent the film bag in the hole from affecting other in-situ tests and environmental protection requirements, the film bag should be removed after the TV imaging in the hole is completed. The steps are as follows:

[0032] a) When the in-hole TV imaging test is completed, first remove the probe;

[0033] b) Insert a special cutting tool into the film bag, go all the way to the bottom of the hole, and cut the film bag from the bottom;

[0034] c) Propose special tools;

[0035] d) Slowly pull the entire membrane bag out of the hole.

[0036] When the borehole wall is unstable and prone to collapse and debris (extremely difficult to handle), the in-hole TV imaging camera can easily become stuck. Furthermore, the in-hole TV test system is extremely weak in handling camera jams, which can easily cause in-hole accidents, making the test impossible or even causing the hole to be abandoned. Hole wall collapse and debris have long been a technical problem that has plagued in-hole TV imaging. We can solve this technical problem by utilizing the wall protection function of the membrane bag. The specific steps are as follows:

[0037] a) First, run the drill bit to sweep the hole to the intact section of the hole wall below the fracture zone;

[0038] b) Lower the membrane bag (preferably a thicker one) through the drill pipe and lower it to the bottom of the hole through the drill bit. Refer to "Step 2: Lowering and installing the membrane bag" for the lowering method;

[0039] c) Pull out the drill bit. During the process, measures should be taken to prevent the membrane bag from being taken out of the hole.

[0040] d) Immediately refer to step 3: Method of injecting water into the membrane bag to inject clean water, including well water or spring water, into the membrane bag;

[0041] e) Under the action of internal water pressure, the membrane bag will be tightly squeezed on the hole wall, which plays a good stabilizing role on unstable loose rocks and plays a good wall protection role for the entire hole, so that the entire hole forms a stable channel;

[0042] f) Then refer to "Step 4: Method of In-hole TV Imaging Operation Process" and "Step 5: Removal of Membrane Bag" to complete the in-hole TV imaging test of the entire hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Attachment Figure 1 This is a schematic diagram of TV imaging inside a hole with a film on the hole wall proposed by the present invention;

[0044] Attachment Figure 2 This is a TV imaging photo of the hole with turbid water and no film attached;

[0045] Attachment Figure 3This is a TV imaging photo of the hole after the film is attached.

[0046] Advantages of this patent:

[0047] The main advantages of the present invention are:

[0048] a) It fundamentally solves the technical problem of in-hole TV imaging being impossible due to turbid water in the hole;

[0049] b) Solved the technical problem of cameras getting stuck easily and causing accidents in the borehole when there is a hole wall collapse and fragmentation zone;

[0050] c) This method uses very little water, solving the technical problem of borehole washing difficulties in arid and water-scarce areas;

[0051] d) After the drilling is completed, the branch can be used to immediately conduct in-hole television imaging, which shortens the construction period and reduces the overall construction cost;

[0052] e) No chemical reagents, no damage to the groundwater environment, environmentally friendly and pollution-free;

[0053] f) Customized film bag materials are cheap and low cost;

[0054] This patented technology fills a gap in the field of in-hole TV imaging, addressing issues such as turbid borehole water that cannot be cleared and borehole wall collapse and blockage. It represents a breakthrough in in-hole TV imaging and has broad practical applications for improving the quality of in-hole TV results, reducing construction costs, and shortening construction periods. DETAILED DESCRIPTION

[0055] Example 1: 100m deep exploration hole (hole diameter 100mm)

[0056] Film bag customization: LLDPE film bag, diameter 102mm × thickness 0.08mm, vacuum roll packaging;

[0057] Lowering: hole depth 102m, hanging 5kg counterweight, guide frame control vertical deviation <1°;

[0058] Water injection: inject 0.79m of clean water 3 , the liquid level is maintained at 1.8m above the groundwater level;

[0059] Imaging: The camera collects 30 frames per second, and the crushing section is left stationary for 20 minutes;

[0060] Recycling: After the cutter rotates 2 circles, the whole film is taken out, and the film bag breakage rate is less than 5%.

[0061] Example 2: Collapse treatment of sand and gravel layers

[0062] First, the borehole is swept through the fracture zone to the intact sandstone layer 3m below;

[0063] Lower the thick film bag (0.15mm) to the bottom of the hole;

[0064] Pull out the drill rod and drilling tools, and keep the membrane bag in the hole;

[0065] The water injection pressure is adjusted to a head difference of 2.2m, so that the hole wall forms a stable channel under the protection of the membrane bag.

[0066] After imaging, the cutter is lowered through the drill rod, the membrane bag is cut from the bottom, and then the membrane bag is lifted out.

[0067] This patent has been successfully applied to in-hole TV imaging in a survey project in Heihe, Heilongjiang Province. The borehole was 370 meters deep and 75 mm in diameter. Due to the presence of turbid underground water caused by borehole fragmentation, hole washing and chemical treatment failed to clarify the turbid water for over a month, making in-hole TV imaging impossible. The in-hole TV imaging was then successfully completed using the hole wall coating method.

Claims

1. A method for in-hole television imaging by film attachment to solve water turbidity and hole wall breakage, characterized in that The following steps are involved: S1. Customized full-length transparent film bag: The length of the film bag is greater than the maximum depth of the drilling hole, the diameter is 1-2mm larger than the hole diameter, the thickness of one side is 0.05-0.1mm, and it is made of high-transparency and toughness material. It is vacuum-packed and rolled. S2. Lowering and installing the membrane bag: Seal the lower end of the membrane bag and hang a 3-6kg counterweight, then lower it vertically to the bottom of the hole through the guide frame, leaving a 1-2m margin at the hole mouth and fix it; S3. Inject water into the membrane bag: Inject clean water into the membrane bag, keep the water column pressure inside the membrane bag 1-2m higher than the water column pressure in the hole, and squeeze the turbid water out of the hole or cracks through the pressure difference and capillary action, so that the membrane bag is close to the hole wall; S4, In-hole imaging: A camera is lowered into the borehole to collect real-time images of the borehole wall. The local turbid area is left to stand until it is drained and then imaging is continued; S5. Take out the film bag: insert a special cutting tool to cut the film bag from the bottom and then take it out as a whole.

2. The method according to claim 1, wherein: The film bag is made of polyethylene and is easy to unfold when vacuum packed.

3. The method according to claim 1, wherein: When the membrane bag is lowered, the return pressure water from the orifice needs to be raised by the casing to the pressure head height before operation.

4. The method according to claim 1, wherein: During the water injection process, the water injection volume is calculated and controlled according to the borehole volume, and the water injection height is dynamically maintained 1-2m above the groundwater level.

5. The method according to claim 1, wherein: Treatment of hole wall collapse includes: a. Sweep the hole to the complete section below the broken zone; b. Lower the thickened film bag to the bottom of the hole through the drill pipe; c. Pull out the drill rod and drill bit and keep the membrane bag in the hole. d. Inject water to squeeze the membrane bag to loosen the rock wall; e. After imaging is completed, cut the membrane bag and take it out.

6. The method according to claim 1, wherein: The cutting tool is a tubular tool with a cutting edge at the bottom. It reaches the bottom of the hole and rotates to cut the film bag.

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