Technical paper on geological drilling 1
Discussion on geological drilling technology
Abstract: Drilling structure refers to the change of drilling diameter from opening to final hole formation. The more times the diameter is changed, the more complicated the drilling structure is, and vice versa. The selection of drilling structure should fully consider the rock properties, hydrogeological conditions, final aperture, drilling depth, drilling method, drilling purpose and other factors in the mining area.
Keywords: geological drilling; Geological conditions; Technical discussion
Abstract: Borehole structure refers to changing the diameter of the final interval. The more times the size is changed, the more complex and simple the drilling structure is. In the selection of drilling structure, factors such as mining rock properties, hydrogeological conditions, final aperture, hole depth, drilling method and drilling application should be fully considered.
Keywords: geological drilling; Geological conditions; technical study
China Library Classification Number: TU74
Introduction: With the progress and development of science and technology, drilling technology has also made great progress and accumulated a lot of experience. Such as small hole drill, open hole drill, diamond drill, hydraulic screwdriver, mobile workbench and container transportation. It promotes the development of drilling engineering with high quality, high efficiency, safety and low consumption. In order to better develop drilling technology, it is necessary to make a feasible development plan based on reality. That is to say, from the existing technology and actual production needs, we should conscientiously do a good job in the use of drill bits, anti-deviation drilling tools and coring tools suitable for various geological requirements and the development of drilling equipment to promote the development of drilling technology.
I. Selection of drilling structure When exploring a metal deposit, the design hole depth is 700 meters, and diamond drilling is used. The geological profile includes the following horizons: (1)0 to 100 meters are drillable 1-7 rocks, which are completely lost and have no circulation; (3)100-700m is a stable rock with drillability of 9-10; (4) Geological sampling requires 59mm final hole. Try to determine the drilling structure. [Resolution] According to the known conditions, the hole is suitable for running all the way from160m to the bottom without casing. Through the analysis of geological profile, drilling pipe and a layer of casing are enough; To seal the plugging layer, run the casing to the depth of120-130m, and the casing shoe extends into the stable layer of10-20m. The casing diameter is 73mm, and a 76mm interval must be drilled. The length of orifice tube is 18 to 20m. The diameter is 89mm, so the opening is 9 1 or110mm. ..
Second, cemented carbide drilling
In the concept of 1, cemented carbide with certain strength and shape is fixed on the drill bit according to the drilling requirements, and under certain technical conditions, it is used as a drilling method for cutting tools to break rocks. 2 Requirements for cemented carbide in drilling Alloy drilling relies on cemented carbide fixed on the bit body to break rocks. All kinds of rocks have certain strength and abrasiveness, and the stress on the bit during drilling is also very complicated. Therefore, the cemented carbide used should have the following properties: ① high hardness and strong wear resistance. It is convenient for the drill bit to cut into or press into the rock effectively, and it can resist the wear of cemented carbide by the rock. ② High bending strength and good toughness. It is convenient to bear all kinds of loads in the process of rock breaking, and there will be no edge collapse and breakage. ③ Good thermal hardness and high thermal conductivity. High temperature will be generated at the bottom of the drilling hole, so it requires high thermal hardness and is easy to release heat in the washing liquid. (4) Good formability, easy to insert and weld on the bit body. Tungsten-cobalt alloy is the main cemented carbide used in geological exploration, and its properties meet the above requirements. Whether the structure of cemented carbide bit for drilling is reasonable directly affects drilling efficiency, bit life, drilling quality and material cost, so attention should be paid to the research and selection of structural elements of cemented carbide bit. Generally, it can be divided into two categories: coring bit and all-round bit. Generally speaking, only coring bits are used in geological exploration. ① Bit body: it is the matrix of embedded tool and is made of D35 or D45 seamless steel pipe. The inner and outer edges of the needle-shaped alloy bit should be consistent with the corresponding diamond bit, and the length of the bit body should be not less than 95mm, in which the length of the threaded part is 40mm, and the wall thickness of the steel body of the bit is 7-9 mm. If it is too thick, it will bring a large area of rock and consume a lot of power, while if it is too thin, it will affect the strength and be easily deformed. Under the condition of ensuring sufficient strength and rigidity, the wall thickness should be reduced as much as possible to reduce the coring area and improve drilling efficiency. ② The number and arrangement of alloy mosaic welding: it should be determined according to rock properties, drill bit diameter, alloy quality, drilling tool strength, equipment power and other factors. When the bit has large diameter, deep hole, high rock hardness and high abrasiveness, the amount of alloy should be appropriately increased. The quantities commonly used in geological exploration are shown in the following table. Bit specification (mm) Alloy number (PCs) Rock properties 36 46 59 76 91130150 Strong abrasive strata 3-43-44-666-88-1kloc. (3) Cutting edge: There are three kinds of cutting edges: bottom, inside and outside. Among them, the bottom cutting edge plays the role of cutting into and breaking rocks, and the larger cutting edge is beneficial to the circulation of broken rocks and washing liquid, but it is easy to cause blade collapse and fracture if it is too large; The inner and outer blades mainly form an annular gap to ensure the circulation of washing liquid. Larger inner and outer blades will increase the rotary resistance of the drill bit, which is easy to collapse, but it is beneficial to discharge powder and reduce the chance of plugging. If it is too small, it is easy to block the core, affect the powder discharge effect, and even lead to bad phenomena such as paste drilling. Therefore, the size of the cutting edge should be considered according to the rock properties, and the following table can be referenced for selection in practical work. Rock properties Inner edge (mm) Outer edge (mm) Bottom edge (mm) Soft, weak to moderately abrasive rock1.5-2.5-3 moderately hard and strongly abrasive rock1-21-21.5-.
Three, alloy drilling technical parameters
The technical parameters of alloy drilling mainly include WOB, rotating speed and flushing fluid volume. They are directly related to drilling efficiency, drilling quality, abrasive consumption and construction safety. In the process of operation, it is necessary to reasonably grasp the physical and mechanical properties of rocks, bit structure, the possibility of drilling equipment and drilling tools, drilling quality requirements and other conditions, and make corrections in practice to sum up the best drilling technical parameters suitable for mining areas. ① WOB: A reasonable WOB should not only ensure the durability of the bit, but also obtain the maximum average ROP. When other conditions remain unchanged, within a certain range, with the increase of WOB, the proportion of drilling speed increases. Practice has proved that the improvement of ROP mainly depends on the improvement of WOB. However, excessive pressure will lead to accidents such as edge collapse, drilling tool fracture, borehole bending and easy burning of soft rock drilling. WOB can be calculated by the following formula: total pressure of drill bit = pressure to be added by each cutting tool (such as columnar alloy 70- 120kgf/ piece) x number of cutting tools on the drill bit. In practical work, the types of alloy cutters, the arrangement and quantity of drill bits should be preliminarily calculated according to the nature of the drilled rock strata, and the best WOB should be continuously summarized in construction. ② Rotational speed: There are two ways to express the rotational speed of drilling tools, one is the revolutions per minute (rpm) of the drill bit, and the other is the circumferential speed v (m/s) of the drill bit. V = [？ The production practice of (D+D 1)n ]/(2X60) shows that under certain conditions, increasing the bit speed can improve the ROP, but when it exceeds the optimal value, it will decrease with the increase of the speed. Generally speaking, when drilling in soft to medium hard rocks, a higher rotating speed can be used; When drilling in hard and abrasive rocks or rocks with uneven and developed cracks, the rotation speed should be reduced; Deep hole or large diameter drilling should also reduce the speed. ③ Flushing fluid volume: The flushing fluid volume should be determined according to factors such as rock properties and well diameter. Generally speaking, when drilling in soft rock, a large amount of flushing fluid is selected because of the large amount of rock powder produced by fast penetration; When drilling in a rock stratum with a large proportion of coarse particles and coarse particles, the flushing fluid should also be increased accordingly; When drilling large-diameter holes and deep holes, if the drill pipe and hole wall leak a lot, the amount of flushing fluid should also be increased; However, in order to prevent core erosion and hole wall erosion when drilling in loose and broken formations, a small amount of flushing fluid should be selected. The amount of rinsing liquid q is generally calculated by empirical formula: Q = KDK? Empirical coefficient (6? 15l/cm.min)D？ In actual drilling, the parameters of bit diameter (cm) are closely related. In order to achieve reasonable coordination, the coordination relationship is roughly as follows: the hard rock with high abrasiveness is large and small, the broken rock is small and correspondingly small, and the soft rock is small and correspondingly large. In the design, parameters can be selected within the data range of the following technical parameter table according to the lithologic characteristics of the mining area, and the optimal technical parameters suitable for the mining area can be explored in practical work. For the range of drilling technical parameters of different rock strata, see Table of Rock Grade Drilling Technical Parameters: WOB and rotational speed (rpm/min), pumping capacity (L/min), coring bit (kg/ grain), drag bit (kg/cm) 1 ~ 4, 50 ~ 60100 ~/kl. 20 200 ~ 350 >: The pumping capacity of some 805 ~ 6 and 7-level 80 ~12010 (2)100 rigs is given by the maximum effective displacement of the pump. (3) The cm (kg/cm) in the unit pressure of the bit refers to the bit diameter.
Four, alloy drilling matters needing attention
Using alloy drilling, in addition to reasonable selection of bit structure and drilling technical parameters, correct operation methods are needed to improve drilling efficiency and service life of bit. Therefore, we should pay attention to the following aspects: ① When the new bit enters the hole, it should be more than 0.5 meters away from the bottom of the hole, and gently press and slowly sweep to the bottom of the hole to prevent the new bit from being squeezed. When sweeping holes, the speed should be slow to avoid the alloy collapsing or being blocked by the core left at the bottom of the hole. ② Always keep the bottom of the hole clean. The rock powder and caving alloy in the hole must be fished out in time. When the residual core in the hole exceeds 0.5m or there are fallen cores, no new drill bit can be run. (3) In order to keep the aperture consistent, the drill bit should be used in a straight line. The principle is to use the one with large outer diameter and small inner diameter first, and then use the one with small outer diameter and large inner diameter. (4) The normal WOB should be uniform, drilling tools should not be lifted without reason, and the pressure should gradually increase as the alloy becomes dull. If the core is blocked, it should be handled in time. If it is ineffective, it should be lifted immediately to prevent accidents in the hole. ⑤ Grasp the footage time reasonably. In the process of alloy drilling, the diameter reduction and penetration rate gradually decrease because the abrasive becomes dull. Therefore, in order to avoid the next drilling and tripping time and improve the return efficiency, a reasonable return footage time should be determined, which is one of the effective measures to improve the ROP. It can be determined on site by calculation method or drawing method, and the strata in each mining area are different, so specific data cannot be given here.
Verb (abbreviation of verb) conclusion
In short, according to the actual situation, we should explore and summarize the reasonable cooperation of various parameters, accumulate experience, and gradually enrich and improve the drilling technical regulations in mining areas.
Geological drilling technology paper II
Research on the Development of Geological Drilling Technology
Based on the analysis of the demand for drilling technology and the present situation of geological drilling technology in China, the long-term, medium-long-term and short-term development goals of geological drilling technology in China are put forward, the focus and plan of recent research and development work are defined, and the importance of scientific and technological innovation, the popularization and application of new methods and technologies, and the strengthening of the role of professional committees of prospecting engineering are emphasized.
[Keywords:] geological work, geological drilling technology, development goals, technological innovation