| As an important booster of modern industry and economic growth, oil and gas resources have the irreplaceable status and significance in the economic globalization, and have become the main sign of comprehensive national strength and national security and stability all over the world. The drilling engineering is the most efficient and accurate method for understanding the underground geological conditions directly and the discovery and development of oil and gas resources in exploration and development of oil and gas resources. In the 21 st century, the trend of the development of the oil and gas resources exploration drilling technology is tobefaster, deeper, cleaner and cheaper. Now, a large number of different forms of research for improvement and machine system of oil-gas exploration drilling technology have been taken, and many effective fast drilling technologies have been put forward, and the corresponding drilling machines have been developed.Along with the expanding proportion of deep well, ultra deep well, horizontal well and directional well in complex surface and strata conditions, the risk of encountering complicated geological conditions, such as low permeability or deep buried strata, is increasing. So as to solve the problems above, including low drilling efficiency, borehole accident, long drilling time and high drilling cost, increasing production of single well and recovery efficiency, and promoting the development of domestic oil-gas exploration fast drilling technology, a new drilling technology for closed-cycle air hammer drilling with multiple techniques and mediums, which is together with the matched drilling system and sets three characteristics in one is present as follows: effectively rotary impact drilling with air hammer; compressed air closed cycle independently; chip removal and protect the security of the stability of hole wall using drilling mud. The corresponding calculation formulas, numerical simulation analysis andlaboratory tests have been taken for the key links. The research contents and conclusions of this paper are mainly including:1. Develop a new type of closed-cycle air hammer drilling tool and three-channel drilling tool system, including: BQ-190 closed-cycle air hammer with a special mechanism preventing falling; a specially designedbutton bit; the coaxial TSB-146 three-wall drill pipe and three-channel square kelly.2. This closed-cycle air hammer drilling tool with three-channel system will realize a new kind of compound drilling technique with multi-process and multi-medium, such as the following: when the closed-cycle air hammer works with conventional cemented carbide button bit, it can achieve the “rotary impact drilling with air hammer & drilling mud chip removal and counterfort by normal circulation or reverse circulation” technology; when the hammer works with jet bit, it can achieve the “rotary impact drilling with air hammer & rock broken by jetting high-pressure mud” technology; when the hammer works with gas lift reverse circulation drill bit, it can achieve the “rotary impact drilling with air hammer & chip removal by air lift reverse circulation” technology.3. Conclusions can be get by ANSYS-LSDYNA that the stress in the mating connection region of fall-prevention cover and drill bit is much less than the stress in the tail or neck of bit, so the possibility of the occurrence of fracture drill where cooperate with fall-prevention cover will be reduced obviously, to prevent the malignant accident effectively that drill bit crown fell into the well when the tail or neck of bit is fractured.4. Through the related knowledge of the stress wave theory and elastic-plastic theory, it can be inferred thatthe magnitude of interference of tooth hole is mainly influenced by such factors as the final speed when piston impacts the drill bit(vc), the material performance of bit ontology and alloy button(E、ρ、γ、σs), the diameter of alloy tooth(d), the depth of tooth hole(h), and the distance of adjacent tooth hole wall(l).5. Conclusions can be get through the dynamic analysis of interference fit between alloy tooth and tooth hole by ABAQUS software of finite element analysis: 1) Under the condition of the same interference quantity and dynamic friction coefficient, the lager the diameter of alloy tooth, the smaller stress value and displacement of tire body will be present around the tooth hole; 2) Under the condition of the same tooth diameter and dynamic friction coefficient, the larger the amount of interference, the greater stress value and displacement of tire body around the tooth hole will be, and the more obvious extent of variation; 3) Under the condition of the same tooth size and interference quantity, the larger the dynamic friction coefficient, the greater stress value and displacement of tire body around the tooth hole will be, and the more obvious extent of variation.6. Conclusions can be get through analysis of closed loop air hammer dynamic system: 1) For the round center holebottom type, the stress valves in stress concentration area and the stress between it and bottom surface of drill bit are significantly less than the flat type and sharp bottom type, and its influence on the stress valve of each variable cross-section under the drill bit is better than those; 2) When the depth of round bottom type center hole on the bit is 340 mm, the stress around its neck, crown and between the center hole and bottom surface is the minimum.7. Through the related theory of fluid mechanics, the calculation formula of the TSB-146 three-wall drill pipe can be deduced and the conclusions can be get: 1) When the structure size of inlet and exhaust passage in the three-wall drill pipe, its frictional pressure loss is proportional to the volumetric flow rate of air compressor(Q0) of the power of 1.75, and it is inversely proportional to the air supply pressure(p) of the power of 0.75; 2) The local pressure loss of inlet and exhaust passage in the three-wall drill pipe is proportional to the local pressure loss coefficient(ζ) and the square of the volumetric flow rate of air compressor(Q0), and it is inversely proportional to the air supply pressure(p).8. Through the pressure drop analysis for TSB-146 three-wall drill pipe and the inlet and exhaust passage of three-channel square kelly separately by Flow Simulation, conclusions can be get as fllow: 1) When the inlet and exhaust passage in the three-wall drill pipe take the structure design that the end face of guide boss highlight on the bottom of the joint face a certain distance, the pressure drop and wave amplitude of compressed air flow rate it caused can be minimum. 2) Either three-wall drill pipe or three-channel square kelly can make a case that the pressure drop of inlet and exhaust passage increases with the increase of air flow, and decreases with the increase of air pressure, in addition, the pressure drop of exhaust passage is always less than that of inlet passage.9. The test pipe line pressure drop is monitored by the method of simulation experiments, and the following conclusions are obtained: 1) The pressure drop increases with the increase of the pipe length. 2) The pressure drop decreases with the increase of the flow area ratio. 3) In the air and water mixing fluid, the pressure drop increases with the increase of the liquid phase content.The innovation of this paper is mainly as follows:1. For the first time develop a type of closed-cycle air hammer drilling tool and coaxial three-channel drilling tool system that can be applied to oil-gas exploration drilling, including: BQ-190 closed-cycle air hammer with a special mechanism to prevent falling and form a complete set of button bit; the coaxial TSB-146 three-wall drill pipe and three-channel square kelly.2. Combining the structural features of closed-cycle air hammer and three-channel drilling tool system, a compound drilling technology with multi-process and multi-medium for the first time is put forward, which sets multiple characteristics in one: effectively rotary impact drilling with air hammer; compressed air closed cycle independently; chip removal and protect the security of the stability of hole wall using drilling mud.3.Based on stress wave theory and elastic-plastic theory, the theoretical calculation formula for the magnitude of interference of tooth hole is deduced through static perspective, and finite element software is used to carry out the dynamic numerical simulation analysis for the interference fit between alloy tooth and tooth hole, to research the influence of different diameter of alloy tooth, magnitude of interference and dynamic friction coefficient on the stress value and displacement of tire body around the tooth hole.4. Research is carried out for the intensity of drill bit with three different types of center holes(the flat bottom type, the sharp bottom type and the round bottom type) and the influence on the intensity in the lower part of drill bit caused by depth of center hole, and the optimal structure parameters can be get finally.5. Through the related theory of fluid mechanics, the calculation formula of the TSB-146 three-wall drill pipe can be deduced, and the pressure drop analysis for TSB-146 three-wall drill pipe and the inlet and exhaust passage of three-channel square kelly are taken by Flow Simulation, to research the values of pressure drop and their variation trend under the condition of different air flow and air pressure... |
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