Experimental And Drill Bit Flow Field Analyze Of Run-through DTH Reverse Circulation Drilling Technique

The appliance of The DTH reverse circulation drillingtechnology in geography drilling engineer is gradually catchingpeople's eyes. It is looked as a new technology after diamonddrilling technology and is of abroad using fields. The technologyof chip continually removal by reverse circulation of DTH is oneof direction of DTH drilling technology development. Thistechnology centralizes three merits of drilling technology thatincludes DTH fracturing rock, fluent removal by reverse circulationand continually obtaining sample in drilling. This technology usesdouble-well drilling pole. The air-condensed is put into drillinghole through the gap of doubt-well drilling pole and the waste airafter DTH working is returned to ground carrying rock grain throughthe core of double-well drilling pole.Being an advanced drilling technical, run-through DTH drillingtechnical plays an important role in the case of exploiting WESTsolid mineral resources at present. When developing the WEST,exploiting mineral resources, it needs urgently to exploit mineralproducts. But the conditions of that strata and environment in theWEST is very formidable, as puts forward a new question: how DTHtechnical adapts to these formal conditions. At the same time, whendrilling hydrologic wells, there found some new questions, whichrequires run-through DTH to batter and improve with a great stride.The paper combine with the CGS's projects which is undertakenby The construction engineer academic of JiLin university, deeplyresearch on the technology of reverse circulation of DTH, which isused in solid mineral resources exploration. Through the fieldproductive experiment in the complex strata, research the drillingtechnology and drilling implements of this technique from severalaspects as follows.1. Further physical study on the reverse circulation mechanicsand compare the effects of reverse circulation discharging rock andexisting questions of reverse circulation drilling bit undercomplex strata condition. As a result, we may improve and perfectreverse circulation sample drilling bit's construct.2. Continually develop the DTH technology and co relationaldrilling implement construct through experiment that may improvethe reliability and working lives.3. combine with traditional fluid mechanics and CFD,analysethe problem which is discovered in field experiment, discuss thesettle scheme.4. thought experiment, research drilling parameter of seriesof run-through DTH is used in the fabricating yard, match of aerodynamical parameter.Though the representative complex strata experimental region——molybdenum and tungsten mine exploring in San daozhuang inLuanChuan in HeNan province. In the field productive experimentalcourse, obtain such conclusion and research produce as follow:1. The technical of run-through DTH chip removal by reversecirculation can settle drilling puzzle in the complex strata. suchas: bit block, collapse, loss create the problem of drill difficultySampling taking difficulty.2. there is same bug in the design of the complement drillingtool, and bring damage to the use. In the process of experiment,The kvetch destroy of lock ring of swivel, bring the result ofnon-revere circulation. The fabric of elbow pipe and cyclonesampler should be amendment, to improve working time and workingstability.3. cutting of bit easily pull-out.4. The bit play an important role in the effectiveness ofreverse circulation. We used different fabric bit in differentstrata, and generalize same rule, and supply practical foundationto the further optimization design of bit. In the future, We shoulddesign different fabric to improve effectiveness of reversecirculation in different strata.In the research of theory, applies Computational Fluid Dynamics, and applies liquid software, FLUENT, on analyzing and comparingflow field under the reverse circulation bit, and suppliesreference on the design of bit structure parameters. through theanalyze and analogue, We can find that the bit which have uprisingSpray-hole can distinctly Improve the effectiveness of reversecirculation, settle the problem of leakage in the complex strata,which is consistent with field experiment.As a advanced drilling technology, run-through DTH reversecirculation have some flaw and shortage, need further research,Do same improve and perfect against different condition and strata.