Design method of PDC drill bit with conical teeth
阅读说明：本技术 一种锥形齿pdc钻头设计方法 (Design method of PDC drill bit with conical teeth ) 是由 刘伟 其他发明人请求不公开姓名 于 2019-10-14 设计创作，主要内容包括：本发明涉及一种锥形齿PDC钻头设计方法,属于油气井钻井工具属于油气井钻井工具的设计学领域。该方法主要是通过室内实验获取岩石的可钻性以及根据钻井设计要求确定钻井条件,再根据岩石可钻性确定钻头刀翼数量和切削齿直径,然后根据钻井条件确定钻头直径,最后根据岩石可钻性与钻头结构参数确定锥形齿与PDC齿的高度差。本发明将实验与数值计算相集合的方式来设计钻头结构参数,计算精度高,为锥形齿PDC钻头的设计提供支撑,提高钻头的破岩效率。(The invention relates to a design method of a PDC drill bit with conical teeth, belonging to an oil and gas well drilling tool and belonging to the field of design of the oil and gas well drilling tool. The method mainly comprises the steps of obtaining the drillability of rock through indoor experiments, determining drilling conditions according to drilling design requirements, determining the number of blades and the diameter of a cutting tooth of a drill bit according to the drillability of the rock, determining the diameter of the drill bit according to the drilling conditions, and determining the height difference between a conical tooth and a PDC tooth according to the drillability of the rock and structural parameters of the drill bit. The invention designs the structural parameters of the drill bit in a mode of integrating experiments and numerical calculation, has high calculation precision, provides support for the design of the PDC drill bit with the conical teeth and improves the rock breaking efficiency of the drill bit.)
1. A design method of a conical tooth PDC drill bit is characterized in that the drill bit is provided with conical teeth and PDC teeth, and the design method comprises the following steps: the design method comprises the following steps:
Technical Field
The invention relates to a design method of a PDC drill bit with conical teeth, belonging to the field of design of drilling tools of oil and gas wells.
Technical Field
PDC bits rely on high hardness, wear resistant, self-sharpening polycrystalline diamond compacts (referred to as PDC or cutter) as cutting elements to shear and break up rock. The PDC drill bit has high mechanical drilling speed, long service life and low drilling cost in soft to medium hard formations, so that the PDC drill bit is widely used in drilling of oil and gas wells.
In oil and gas drilling engineering, geological conditions of strata are often complex, mud shale, argillaceous sandstone and the like of deep strata increase the density and hardness under the conditions of overlying stratum pressure and high-density drilling fluid, the drillability is poor due to the transformation from brittle rock under normal pressure to plastic brittle rock or plastic rock, and the hydraulic energy of deep well sections is seriously insufficient, so that the hydraulic auxiliary rock breaking effect cannot be effectively exerted, and the drilling speed is quite low. The drill bit often traverses a variety of formations of different lithologies, including not only relatively easy-to-drill soft rock formations, but also hard formations, highly abrasive formations, plastic formations, interbedded formations with alternating hardness and hardness, heavily heterogeneous formations containing gravel, and high steep formations with large inclination angles. The complex stratum conditions easily cause the abnormal failure of the PDC drill bit, the conventional PDC drill bit is provided with the conical teeth, the rock breaking efficiency of the drill bit can be improved, and meanwhile, the impact resistance of the conical teeth is higher than that of the conventional circular PDC drill bit. In order to further improve the performance of the PDC drill bit with the conical teeth and widen the application field of the drill bit, it is very important to research a design method of the PDC drill bit with the conical teeth.
Disclosure of Invention
The invention provides a design method of a conical-tooth PDC drill bit, aiming at solving the problem that the design of the height difference between conical teeth and PDC teeth in the existing conical-tooth PDC drill bit is only designed by depending on experience, the number of blades and the diameter of cutting teeth of the drill bit are determined by the drillability of rocks, the diameter of the drill bit is determined by drilling conditions, and finally the height difference between the conical teeth and the PDC teeth is determined by depending on the drillability of the rocks and drill bit parameters.
The invention is realized by the following technical scheme:
the utility model provides a conical tooth PDC drill bit design method, is provided with conical tooth and PDC tooth on the drill bit, and conical tooth is the same with PDC tooth diameter, and conical tooth and PDC tooth are the same rail setting (radial radius is the same), and the PDC tooth is a little higher than the conical tooth, as shown in figure 2, the drill bit uses the PDC tooth to scrape and cuts as leading, and the conical tooth plows the broken rock mode as assisting, its characterized in that: the design method comprises the following steps:
In the above formulaKThe number of blades of the drill bit is expressed in units of one;d k is rock drillability; the unit is a level;
In the above formulad M Denotes the diameter of the cutting tooth in mm;d k is rock drillability; the unit is a level;
given rock drillabilityd k， Number of bladesKDiameter of cutting toothd M Diameter of drill bitDThe height difference between the conical tooth and the PDC tooth is obtained according to the formula 3h p ;
In the above formulad M Denotes the diameter of the cutting tooth in mm;d k is rock drillability; the unit is a level;Kthe number of blades of the drill bit is expressed in units of one;d isThe diameter of the drill bit is in mm;h p is the height difference between the conical teeth and the PDC teeth, and has the unit of mm.
The invention has the beneficial effects that:
according to the design method of the conical tooth PDC drill bit, the depth of the conical teeth and the PDC teeth penetrating into rock is deeply researched, the structural parameters of the drill bit are determined according to the rock drillability and drilling conditions, the height difference between the conical teeth and the PDC teeth is related to the diameter of the drill bit, the number of blades, the diameter of cutting teeth and the rock drillability, a formula is established, and the conical teeth and the PDC teeth are located at the position with the highest rock breaking efficiency, so that the rock breaking efficiency of the drill bit is improved, and the comprehensive performance of the drill bit is enhanced.
Drawings
FIG. 1 is a schematic diagram of a PDC bit with tapered teeth and a design method;
FIG. 2 is a schematic view of the height difference between the conical teeth and the PDC teeth;
1-drill bit, 2-blade, 3-water hole, 4-conical tooth, 5-PDC tooth
The specific implementation mode is as follows:
the technical solution of the present invention will be described in detail with reference to the accompanying drawings and specific embodiments,
the utility model provides a conical tooth PDC drill bit design method, is provided with conical tooth and PDC tooth on the drill bit, and conical tooth is the same with PDC tooth diameter, and conical tooth and PDC tooth are the same rail setting (radial radius is the same), and the PDC tooth is a little higher than the conical tooth, as shown in figure 2, the drill bit uses the PDC tooth to scrape and cuts as leading, and the conical tooth plows the broken rock mode as assisting, its characterized in that: the design method comprises the following steps:
passing chamberThe drillability of the rock is obtained by the internal drillability experimentd k (ii) a Obtaining rock drillabilityd k Is 8 grades.
In the above formulaKThe number of blades of the drill bit is expressed in units of one;d k is rock drillability; the unit is a level;
According to the drillability of the rock, the number of the blades of the drill bit is 6.
In the above formulad M Denotes the diameter of the cutting tooth in mm;d k is rock drillability; the unit is a level;
deriving bit cutting diameter from rock drillabilityd M Is 13.44 mm.
In the above formulad M Denotes the diameter of the cutting tooth in mm;d k is rock drillability; the unit is a level;Kthe number of blades of the drill bit is expressed in units of one;d isThe diameter of the drill bit is in mm;h p is the height difference between the conical teeth and the PDC teeth, and has the unit of mm.
The height difference between the conical teeth and the PDC teeth is 0.05mm according to the formula.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
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