Water well drilling construction methods and technical measures

Well drilling construction methods and technical measures

I. Well construction process

Measurement and positioning - site leveling - equipment installation and debugging - diameter drilling - through hole - slurry change - pipe change - slurry - gravel throwing - cementing - well washing - pumping test - acceptance inspection - exit.

II. Construction method

1. Well construction preparation

1.2 Measurement and positioning

The measurement team composed of managers of the whole process of measurement and construction shall lay out the lines uniformly. The hole position shall be planned according to the construction plan and accurately measured with a level. The horizontal coordinates and elevation of the hole position shall be determined. Wooden stakes shall be driven into the well position for marking. After verification, it shall be reported to the registered supervisor for acceptance by the whole process management personnel of the construction.

1.3 Equipment selection, site entry and installation

(1) According to the well structure and stratum conditions, a drilling rig shall be selected to adopt the positive circulation method for construction.

(2) The equipment shall be installed horizontally, straight, stable and in place. The electrical appliances shall be placed in a rainproof and moisture-proof position. The power lines, lighting lines and lighting fixtures, electrical appliances and installation shall comply with the safety production regulations and be well grounded.

(3) The base of the drilling rig should be rammed and leveled. Other foundations should be flat and solid, the supporting parts should be evenly stressed and avoid being soaked by rain and mud.

(4) The drilling rig should be installed to keep the three points in a straight line and the turntable level. The drilling pressure gauge should be shockproof and water-proof. The mud pipeline is sealed, pressure-resistant, and the high-pressure pipe is fixed in the appropriate position on the external tower. If leakage or damage is found, it should be repaired or replaced in time.

(5) The construction site should be compact, neat, and reasonable. Pipes, tools and auxiliary facilities should be placed neatly. All materials should not be piled up randomly.

(6) After the equipment is installed, it can only be drilled after being accepted by the owner and relevant departments of the company.

1.4. Material preparation

Under the guidance of the owner and the registered supervisor of the whole process of construction management, determine the material supplier and report to the owner and the registered supervisor of the whole process of construction for approval. After the raw materials arrive at the site, they should be inspected and accepted in time. Only materials that pass the inspection can be put into use.

2. Well completion technology

2.1. Drilling method and requirements

(1) Drilling method: Use e three-wing drill bit to drill the hole to the designed hole depth in one time.

(2) Drilling parameters: drilling pressure is the weight of the drill bit, speed, pump volume.

(3) The hole diameter meets the design requirements, the hole body has no excessive over-diameter or under-diameter, and the same diameter drill bit should pass through the hole unobstructed. The hole depth error is less than %°.

(4) Drilling precautions

1 Reasonably grasp the drilling parameters according to the formation conditions, and blind pressure is prohibited. The drilling pressure shall not exceed the weight of the drill bit and shall not exceed the critical pressure value of the first bend.

2 Carefully operate and feed the drill evenly. The operator should pay attention to observe the drilling pressure meter to avoid fluctuations in drilling pressure and artificial intermittent pressure.

3 During the drilling process, the operator should pay attention to the following situations: drilling pressure meter and pump pressure gauge. Whether the footage speed is normal. Whether the drill jumps, the car is stuck, or the pump is stuck. Mud displacement and cuttings return. Mud performance changes and consumption and leakage. Whether the turntable operates normally. If any abnormality is found, the drilling tool should be lifted immediately and corresponding measures should be taken in time.

4 It is forbidden to start the turntable with pressure to avoid damaging the drill bit and twisting the drilling tool.

5 Under no circumstances should the drilling tool be left stationary in the hole. When drilling is stopped for some reason, try to keep the circulating fluid circulating, and assign a special person to move the drilling tool. The upper and lower movable drilling tools should be greater than meters, and the original hanging weight should remain unchanged, and the rotating drilling tools should exceed the circle.

6 Control the upper and lower drilling speed to avoid long-term punching in the sand layer hole section.

7 When the upper and lower drilling encounters resistance, the hard pier should not be pulled hard, and the pump should be turned on to cut the eye to eliminate the obstruction.

8 Insist on recharging the drilling hole, and keep the mud full of the drilling hole under any circumstances.

9 During the drilling process, the mud performance should always meet the design requirements, maintain sufficient pump pressure and pump volume, and keep the bottom of the hole clean.

10 For each single root, the eye should be cut and the punching should be minutes.

Do a good job of checking the drill bit before and after entering the well. Before entering the well, carefully check the thread, cone, teeth, wheel palm, bearing, water hole, and pressure transmission hole. If any problems are found, the drill bit shall not enter the well.

Carefully check the drill tools. Any drill rods that are bent, deviated, have bad threads, blocked water channels, have damage, or have foreign objects welded on them shall not enter the well. The threads shall be cleaned and thread oil shall be applied when drilling.

Salvage must be prepared on site.

Strictly implement the handover system. The drill tool assembly, the remaining length on the machine, the drilling parameters, the time of drilling operation, the situation in the hole, the operation of the equipment, the speed of the footage, and all the specified situations shall be clearly handed over.

When entering the water-taking layer section, rock sample salvage and drilling layer identification should be done well, and drilling records and simple hydrological observation records should be kept. And timely report to the registered supervisor and construction management personnel throughout the process.

Comply with the drilling safety operation procedures and do not violate regulations.

(5) Mud process

1. Design of mud performance indicators

2. Mud preparation. Prepare mud before drilling. Mix clay powder and clean water, add soda ash (the amount of soda ash added is about % of the weight of clay powder) to make a base slurry, and then add an appropriate amount to control water loss so that the mud performance meets the design requirements. During drilling, the natural slurry of the formation can also be used according to the situation, and clean water and treatment agent can be added for adjustment.

3. Daily maintenance and management of mud

4. Measure the mud performance every shift and keep records.

5. When the mud performance deteriorates, it should be adjusted in time to avoid the ups and downs of mud performance.

6. Daily maintenance and treatment should be carried out in the circulation tank during drilling, and clean water and treatment agent solution should be added slowly. The mud performance is adjusted while circulating to ensure that the mud on the surface and in the hole is adjusted synchronously.

7. Frequent maintenance and treatment, frequent slag removal, and regular treatment of sedimentation tanks to keep the mud clean.

8. The machine should establish and improve the mud management organization and rules and regulations, and the use, storage and maintenance of mud treatment agents, test instruments and related equipment should be designated by a designated person.

2.2 Drilling and brushing holes

(1) After the well location is located and the equipment is installed, and other equipment is ready for operation, the drilling is started and the holes are drilled one by one to the bottom of the hole. The hole should be unobstructed when it is drilled.

(2) After the hole is drilled, brush the hole. The length of the brush should be greater than meters, and the length of the wire rope should be greater than the diameter of the drill hole. The brushing section is from the water stop position to the bottom of the hole. The brushing speed is controlled at, and each single root is brushed repeatedly.

(3) The pump must be turned on and the drill bit must be rotated during brushing. After the brushing is completed, the hole depth should be corrected again.

Punch the hole to remove slag and adjust the slurry before lowering the pipe. Punch the hole to remove slag after brushing the hole to the bottom of the hole. Adjust the mud performance after the slag in the hole is thoroughly checked. Do not dilute the mud before the slag is completely removed.

The slurry should not be adjusted too quickly. Clean water should be added slowly (add treatment agent when necessary) to make the mud performance meet the requirements.

(4) Make all preparations before lowering the pipe: check the well materials, check the equipment and instrumentation tools, clean the site, lay the pipe according to the well plan, organize the labor and divide the personnel, etc.

(5) Pipe lowering method: lift the pipe at a time, wrap the mother-child joint with palm leather, and tie the pipes firmly without looseness.

(6) Ensure that the well pipe connection is vertical (using the hanging line method in two directions) and concentric, and the joint is tight.

(7) To prevent sand from gushing into the well, wrap the filter pipe with palm leather, and install a set of centralizers at each interval of the well section, with the centralizer height of about 1.5 meters.

(8) Appropriately control the speed of lowering the pipe and pay attention to the liquid level inside and outside the pipe.

(9) Careful operation and close cooperation should be carried out during the lowering process to prevent tools and other foreign objects from falling into the well.

(10) The well pipe must be seated at the bottom of the hole and must not be suspended in the air. It must be seated at about the bottom pressure of the hole and then fixed.

2.3. Punching holes to change slurry

(1) Punching holes outside the pipe is used to change slurry. When drilling, the drill rod should be tightened to ensure that slurry returns from the bottom of the hole from the outside of the pipe.

(2) Before starting the pump, the slurry pump should be fully inspected to ensure that the pump can be started successfully at one time.

(3) After starting the pump, circulate the original slurry for one week. After the pump pressure and slurry circulation are normal, add clean water and drain the slurry to make the slurry gradually thinner. Note that both adding clean water and draining the slurry should be kept up, and no delay or interruption should be allowed.

(4) The pump should not be stopped during the slurry change until the gravel filling is completed. If it must be stopped for special reasons, the valve on the high-pressure pipeline should be closed in time.

(5) At the end of the slurry change, the following requirements should be met: the slurry specific gravity is less than, the viscosity, the slurry flow state is completely transformed into turbulent flow, and a proper amount of sand is flushed out of the hole.

2.4. Gravel filling

The filling material is layered according to the soil layer, and the filter material of the powder and fine sand layer is a qualified mixed sand material.

(1) When filling gravel with water, the mud should be returned from the bottom of the hole to the annular space outside the pipe and then to the surface mud tank. The pump should not be stopped in the middle and sufficient pumping volume should be maintained. During the gravel filling process, continue to add clean water and discharge the slurry.

(2) Appropriately control the speed of gravel filling. When filling gravel, use a wheelbarrow to deliver the gravel to the hole, and then use a shovel to slowly put it into the annular space. Do not pour the whole truck in to prevent the gravel from blocking.

(3) When filling gravel, pay attention to the changes in mud density, pump pressure, pump volume, and the sinking of gravel in the hole. When the mud density rises and exceeds, stop filling gravel, continue to add clean water to dilute the mud, and continue filling gravel after the mud density drops.

(4) Accurately record the amount of gravel filled. The actual gravel filling height and quantity should be consistent with the theoretical calculation. After the gravel filling is completed, stop for minutes and use a measuring rope to detect the gravel filling height. The over-throw height of the gravel is controlled above the ground, that is, to ensure that it exceeds the lower solid pipe position, and replace it with mud balls to fix the well pipe.

(5) When the pump is stopped after gravel filling, the valve should be closed in time.

2.5. Cementing

(1) After the mud ball is thrown, wait for 24 hours before starting cementing operation. The cementing is clay.

(2) After cementing is completed, the perforating drill is lowered from the well pipe to the bottom of the hole. The pump is turned on to pump clean water to replace the mud in the well pipe until it is flushed clean before drilling.

2.6. Well washing and pumping test

(1) Well washing

After cementing is completed, the submersible pump is put into the water to wash the well and test pump until the water is clear and the sand is removed.

During the well washing and pumping test, it is necessary to pay attention to the decline of the well sealing material. If there is any decline, it should be filled in time.

(2) Pumping test

The pumping test uses a deep well pump with a water output of not less than 10000.

The water volume is measured using a standard weir box. The weir box should be placed stably to ensure that the upper part of the overflow triangular weir is horizontal and the side is vertical.

From the beginning of the formal pumping test to the end of the water level recovery period after the test, the hydrogeological technicians should measure the water level in the well pipe and the water surface height of the overflow triangular weir according to the specifications and keep careful records.

During the pumping process, water samples should be extracted in accordance with the specifications and design requirements. The extraction of water samples should be clean and disinfected. The water samples should be sealed in time after extraction and sent to the owner's designated laboratory or a laboratory unit with metrological certification for testing within the specified time. The test items should be carried out according to the design requirements and specifications.

The entire pumping test process should be carried out strictly in accordance with the specifications. If the test route is stopped for some reason or anything that does not meet the specifications occurs, the test should be repeated.

2.7. Site cleaning and protection

When washing the well and pumping the water, strengthen the well protection. After the pumping test is successful, clean the site protection well and prepare to install the well.

2.7. Measures to prevent hole tilt

Before installing the drilling rig, level the site, compact the tower foot, reinforce the key stress-bearing parts with concrete, and dig drainage ditches around the site.

The installation of the drilling rig requires that the three points are in a straight line (i.e., the crane, the vertical axis, and the hole) and that they remain vertical.

During the drilling process, the parameters should be adjusted in time if the formation changes. Especially when the formation changes from soft to hard, it is necessary to press lightly and rotate slowly, and then use normal pressure and rotation speed to drill after drilling.

Do not use bent drilling tools.

When the designed hole depth is reached, the hole inclination is measured, and a type inclinometer is used to measure the inclination. If an out-of-tolerance phenomenon occurs, directional drilling should be used to correct the inclination.

2.8. Project acceptance and submission

The project acceptance is jointly accepted by the owner, the supervisor, the local administrative department and the company's technical department, or accepted in accordance with the method specified by the owner.

The project is first accepted in accordance with the single well acceptance method, and after the completion of all the projects, the overall project acceptance is carried out.

Before the project acceptance, the original construction records, water supply pipe well project report and other materials should be prepared. The water supply pipe well project report should include text description, drawings and materials (including pipe well plan location map and schematic diagram, pipe well comprehensive columnar diagram, soil sample or rock sample data, pumping test data and water quality inspection data, etc.), appendix (including pipe well acceptance form).

The acceptance content includes all the contents specified in the bidding documents and construction contract:

Whether the water inflow meets the contract requirements.

Whether the sand content meets the contract requirements.

Whether the water quality meets the contract requirements.

Whether the well depth meets the design requirements.

Whether the well platform and well cover are made in accordance with the specifications.