Structure Design Of Porous Annulus Ring Jet Reverse Circulation Drill And Testing Research

With the development of human civilization and progress, Mineral resources have been an important factor in restricting the development and the survival of human society. Therefore, the exploration of mineral resources playes a decisive role at this time. Run-through DTH reverse circulation continuous sampling technique has been increasingly recognized and applied by the drilling workers. It is applicable to many other technology cannot solve complex formation, and the core of good quality, take high accuracy. In this system, the specific reverse circulation bits of reverse circulation is affecting the most fundamental factors effect.So, if you want to get faster and better drilling results, optimizing of reverse circulation bits structure continuously is particularly important.This paper accorded to DTH hollow structural features, considered the various factors to form reverse circulation, based on the ejector in the original, designes out several new reverse circulation bits structure. Aims to improve the effect of reverse circulation, reduce the cuttings and the contact with the stratum. Thereby increasing the purity of cuttings and drilling efficiency, to improve the drilling level of complex formation o furtherly.First, the study analyzed the necessity of reverse circulation drill structure, And considered the various factors what obstructed and promoted the reverse forming circulation, and designed porous ring jet reverse circulation drill in the original ejector principle, And introduced its principles and structure preliminarily.Secondly, to determine the structure parameters on the effect of the reverse circulation, the study designed the experimental platform of the reverse circulation bits compressed gas flow simulation, and took the mathematics test and simulation analysis to the new structure designed with the orthogonal principle and CFD flow analysis software. The study examined respectively the variation of annular clearance Ls, the nozzle diameter DE, the nozzle layer m, the nozzle height HE, the nozzle diameter DN, the diameter of the end nozzle mixing section DT,the distance of the nozzle to the bottom gush hole receiving section entrance LNT, the contraction angle of bottom nozzle receiving segmentθc, the depth of the diffuser groove LD, the elevation of the diffuser grooveθD, inlet air volume flow Qv, center channel back pressure Pcen and other factors to central air mass flow that representatives effect of reverse circulation. Preliminary deduced the primary and secondary order of various factors on reverse circulation effects, and provided a theoretical basis for the following entities test.Finally, a lot of room physical tests about many factors have done based on orthogonal principle to examine the feasibility of the new structure and the influence of annulus mass flow about Numbers of structural parameters. Firstly, large amount of test data were optimized and rejected to find out the combination of optimal structure of reverse circulation drilling. And then a lot of single factor tests were done by using the optimal structure of the bit to text single factor effect of cycling law, such as Inlet air volume flow Qv, Center channel backpressure Pcen. The results provide a reference for the actual drilling operation, and provide a theoretical basis for promotion and application of this structure.In addition, the thesis also designes a dome-style and pure suction-type anti-cyclic structure on the basis of this structure. And a brief theoretical analysis and experimental study were done about the two structure, the results provide the future development of reverse circulation drill bit.