-
-
-
-
Honor
-
-
-
-
-
Contact
-
Basic knowledge of drilling
Release time:
2018-08-14
Author:
Source:
1. drilling structure 1. Definition: refers to the change of hole diameter and length from opening to final hole. That is, the technical profile of the borehole. 2. Contents: including drilling diameter, number of diameter changes, number of layers of casing, pipe diameter, length and depth of diameter change, water sealing method at the bottom of casing, etc. 3. Requirements: Under the premise of ensuring the quality and safety of drilling, high-quality mud, cement slurry or chemical slurry shall be used as much as possible to protect the wall and plug the leakage, and strive to reduce the diameter change, reduce the casing or not, and simplify the drilling structure to the greatest extent. 4. The purpose of running casing: to isolate complex formations. 5, in the following cases, often need to change the diameter and into the casing: ① drilling loose gravel
1. Definition: refers to the change of bore diameter and length from opening to final hole. That is, the technical profile of the borehole.
2. Contents: including drilling diameter, number of diameter changes, number of layers of casing, pipe diameter, length and depth of diameter change, water sealing method at the bottom of casing, etc.
3. Requirements: Under the premise of ensuring the quality and safety of drilling, high-quality mud, cement slurry or chemical slurry shall be used as much as possible to protect the wall and plug the leakage, and strive to reduce the diameter change, reduce the casing or not, and simplify the drilling structure to the greatest extent.
4. The purpose of running casing: to isolate complex formations.
5, in the following cases, often need to change diameter and run into the casing:
① When drilling into loose gravel layer and flowing sand layer, the mud hole protection is invalid due to the influence of groundwater.
② When it passes through the fractured zone with developed thick joint fissure, the collapse is serious, and mud or other hole protection methods are ineffective.
③ When the water-bearing structure and large fissure are connected through the borehole, serious water leakage occurs, and other methods of water stop are ineffective.
④ After the drilling reaches a certain depth, the drilling can be changed in order to adapt to the capacity of the equipment load.
6. Selection factors of drilling structure
Rock properties, hydrogeological conditions, final hole diameter, drilling depth, drilling method, drilling purpose, hole protection measures, construction equipment, etc.
7. Drill tool grading: matching relationship between drill pipe diameter and drill hole diameter (drill bit diameter). It reflects the size of the hole wall gap, the working state of the drill pipe, the flow of flushing fluid, the size of the drilling tool rotation resistance has an important impact.
Basic knowledge of 2. drilling
1. Drilling method: the general term of the method and technical measures for crushing the rock at the bottom of the hole when drilling underground.
2. Drilling technology: how to use certain equipment and tools to break the rock (soil layer), create a smooth drilling with a certain diameter and depth in the formation, and take certain technical measures to ensure the smooth progress of the drilling work.
3. Classification of drilling methods
① According to the different external force and mode of broken rock, it can be divided into rotary drilling, percussion drilling and percussion rotary drilling, etc;
② according to the broken rock tool (abrasive material) is different, divided into hard alloy drilling, steel grain drilling, diamond drilling and so on;
③ According to different flushing circulation methods, it is divided into positive circulation, reverse circulation and local reverse circulation drilling at the bottom of the hole.
④ According to whether the core drilling is divided into core drilling and full drilling.
How to choose the drilling method: the drilling method is mainly selected according to the physical and mechanical properties of the rock.
① For soft and part of medium-hard rock stratum, cemented carbide shall be selected for drilling;
② For some medium-hard to hard rock formations, use acicular alloy, diamond composite sheet or steel particles for drilling;
③ For medium-hard to hard rock formation, diamond, steel grain or down-the-hole hammer shall be selected for drilling.
5. What preparations should be made before drilling
① Adequate number of drill pipes, casings, directional pipes, drill bits, steel particles, oil, flushing fluid, screwing and unloading tools, special coring tools, necessary short core pipes, core boxes and various reports shall be prepared before drilling.
② The drilling equipment and installation quality must be fully inspected, and repair and adjustment should be carried out if they do not meet the requirements. It can be reinstalled if necessary, and must not be improvised.
③ When the deep hole is drilled into the opening, in order to prevent the hole from being inclined, a pit can be dug in the orifice when necessary, and the directional pipe can be embedded, and then the casing can be drilled into the bedrock. Mud shall be used to protect the shallow hole. In case of serious collapse, artificial wall-making method can be used to drill, and the casing can be drilled into the bedrock after drilling.
6. Matters needing attention when drilling
The core tube shall be gradually lengthened during drilling, and shall be drilled with light pressure, slow rotation and appropriate pump capacity. When changing the diameter, comprehensive guide drilling tools shall be used to prevent the drilling hole from bending.
When drilling the hole, it is often covered, and the flushing fluid is easy to leak, which reduces the stability of the hole wall. Attention should be paid to prevent the occurrence of in-hole accidents such as sticking, buried drilling, paste drilling and burning drilling.
Casing shall be placed on intact bedrock. Before running the casing, put a clay ball into the hole and tamp it to insert the casing into the clay to seal the bottom of the casing. The upper end of the casing shall be fixed with a wooden wedge and closed with clay, and may be closed with cement if necessary. Before fixing the casing, the active drill pipe is connected to the casing to check whether the casing is correct and whether the center of the hole is in line with the center of the casing.
Key words:
Previous Page
Previous Page:
