Study on Structure Parameters of Reverse Circulation Drill Bit Secondary Injector Device Based on Injector Coefficient

2016 ◽  
Author(s):  
Huang Yong ◽  
Zhu Lihong ◽  
Zou Deyong ◽  
Liao Hualin ◽  
Wang Jinying ◽  
...  
Keyword(s):  
Drill Bit ◽  
Structure Parameters ◽  
Reverse Circulation

scholarly journals Experimental and Numerical Study on Air Flow Behavior for a Novel Retractable Reverse Circulation Drill Bit of Casing-while-Drilling (CwD)

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bo Qi ◽  
Pinlu Cao ◽  
He Yang ◽  
Wenbo He ◽  
Mengke Wang ◽  
...  
Keyword(s):  
Numerical Study ◽  
Flow Behavior ◽  
Nozzle Diameter ◽  
Channel Structure ◽  
Entrainment Rate ◽  
Drill Bit ◽  
Structure Parameters ◽  
Channel Diameter ◽  
Gas Channel ◽  
Reverse Circulation

A reverse circulation Down-The-Hole (DTH) hammer drill bit in Casing-while-Drilling (CwD) processes is designed and applied to drilling under complicated formation. The drill bit is a special retractable drill bit with an exclusive reverse circulation gas channel. Using numerical simulations and experiments, the influence of the gas channel structure parameters of the drill bit, including the inner jet nozzles, flushing nozzles, suction channel, and other parameters, on its reverse circulation performance is analyzed, and the optimal gas channel structure parameters of the drill bit are determined to improve the reverse circulation effect. The results show that the flushing nozzles and inner jet nozzles have an important influence on entrainment performance. The entrainment rate η decreases as the flushing nozzle diameter increases and decreases as the inner jet nozzle diameter increases. An increase in the suction channel diameter can improve the reverse circulation effect of the drill bit. The spiral slot drill bit is more conducive to air being sucked into the central channel in the form of spiral flow, so it can improve the entrainment performance. The entrainment rate η can reach 23.4% with the optimum structured drill bit.

scholarly journals Orthogonal experimental research on the structural parameters of a novel drill bit used for ice core drilling with air reverse circulation

2019 ◽  
Vol 65 (254) ◽  
pp. 1011-1022 ◽  
Author(s):  
Pinlu Cao ◽  
Qi Zhao ◽  
Zhuo Chen ◽  
Hongyu Cao ◽  
Baoyi Chen
Keyword(s):  
Structural Parameters ◽  
Ice Core ◽  
Influential Factor ◽  
Dominant Factor ◽  
Orthogonal Experimental Design ◽  
Drill Bit ◽  
Entrainment Ratio ◽  
Core Drilling ◽  
Helical Angle ◽  
Reverse Circulation

AbstractA new type of ice core drill bit, designed with a vane swirler, was developed for ice core drilling with air reverse circulation. An orthogonal experimental design method was employed to investigate the effects of the swirler structure parameters on the reverse circulation performance of the drill bit including helical angle, number of blades, blade length and blade central angle, etc. The entrainment ratio was used to evaluate the reverse circulation effectiveness of the drill bit. The results show that the helical angle is the dominant factor regardless of whether or not the flushing nozzles are part of the design of the drill bit. The number of blades is the least important factor for the drill bit designed with the flushing nozzles (referred to as drill bit I), while the outlet area of the swirling slot is the least influential factor for the drill bit without flushing nozzles (referred to as drill bit П). In addition, the appearance of the ice core has a certain effect on the air reverse circulation for both drill bits. Within the ranges of this study, the optimal structure of the drill bit was determined based on the range analysis of the orthogonal design.

scholarly journals Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Cheng Yang ◽  
Jianliang Jiang ◽  
Bo Qi ◽  
Guoqing Cui ◽  
Liyong Zhang ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Structural Parameters ◽  
Flow Behavior ◽  
Experimental Tests ◽  
Maximum Error ◽  
Influential Factors ◽  
Drill Bit ◽  
Entrainment Ratio ◽  
Helical Angle ◽  
Reverse Circulation

A swirling drill bit designed with an integrated vane swirler was developed to improve reverse circulation in down-the-hole hammer drilling. Its entrainment effect and influential factors were investigated by CFD simulation and experimental tests. The numerical results exhibit reasonable agreement with the experimental data, with a maximum error of 13.68%. In addition, the structural parameters of the swirler were shown to have an important effect on the reverse circulation performance of the drill bit, including the helical angle and number of spiral blades, swirler outlet area, and the flushing nozzles. The optimal parameters for the swirling drill bit without flushing nozzles include a helical angle of 60°, four spiral blades, and the area ratio of 2, while it is about 30°, 3, and 3 for the drill bit with flushing nozzles. Moreover, the entrainment ratio of the drill bit without flushing nozzles can be improved by nearly two times compared with one with flushing nozzles under the same conditions.

Analytical and Numerical Simulation of Asymmetric Converging Flow of Gas under Drill Bits in Reverse Circulation Gas Drilling

2021 ◽  
pp. 1-11
Author(s):  
Xu Yang ◽  
Boyun Guo ◽  
Tamaralayefa Timiyan
Keyword(s):  
Numerical Model ◽  
Analytical Model ◽  
Gas Flow ◽  
Relative Difference ◽  
Structure Design ◽  
Drill Bit ◽  
Drill Cuttings ◽  
Gas Drilling ◽  
Reverse Circulation ◽  
Converging Flow

Abstract Reverse circulation gas drilling has been considered to solve engineering problems such as formation water influx, wellbore instability, and excess gas requirement in gas drilling. The performance of reverse circulation gas drilling depends to a large extent on the structure design of drill bit. An analytical model and a numerical model were developed in this study to simulate the asymmetric converging flow of gas under drill bit for reverse circulation gas drilling. The two models were compared and applied to the evaluation of a drill bit structure design for bottom hole cleaning capacity of gas flow. It was found that the pressure, velocity, and specific kinetic energy given by the analytical model are slightly lower than that given by the numerical model. The relative difference between the gas flow rates given by the analytical model and the numerical model is less than 5%. For the drill bit structure design considered in this study, the gas flow energy between the short blades is much higher than that between the long blades. A gas injection rate of 10 m3/min (360 ft3/min) is expected to clean the drill cuttings between the short blades, while a gas flow rate of 28 m3/min (990 ft3/min) is required to clean the drill cuttings between the long blades. Although the numerical model gives more accurate result than the analytical model in predicting hydraulics parameters, the analytical model is recommended for evaluating drill bit structure design because of its simplicity and conservativeness.

Disturbed Sampling Using Reverse Circulation

1986 ◽  
Vol 2 (1) ◽  
pp. 283-287
Author(s):  
M. R. Hurley ◽  
M. D. Lavender
Keyword(s):  
Water Table ◽  
Mineral Deposits ◽  
Drill Bit ◽  
Offshore Drilling ◽  
Reverse Circulation ◽  
Beach Sands ◽  
Sand And Gravel ◽  
Return Valve ◽  
Industrial Sand

AbstractThe exploration of unconsolidated and semi-consolidated strata is generally undertaken using shell and auger and continuous flight augering techniques. These methods have serious limitations, especially when accurate sampling is required below the water table.To improve the reliability of samples British Industrial Sand Ltd. have developed a drill bit for use with reverse circulation drilling. When used in combination with a non-return valve this method allows continuous drilling and sampling both above and below the water table.Comparisons with other drilling techniques show that the duo-pipe method is capable of delivering uncontaminated samples and recovering material of all anticipated size ranges.The system could be adapted for use in the exploration of other mineral deposits e.g. alluvial tin, beach sands, sand and gravel, or for offshore drilling programmes.

Finite Element Analysis of Flow Field in Drill Bit Design for Gas-Lift Drilling

2021 ◽  
Vol 143 (11) ◽  
Author(s):  
Yi Luo ◽  
Boyun Guo ◽  
Liehui Zhang ◽  
Dong Xiao
Keyword(s):  
Finite Element ◽  
Flow Field ◽  
Power Balance ◽  
Drill Bit ◽  
Hole Cleaning ◽  
Gas Drilling ◽  
Flow Stagnation ◽  
Reverse Circulation ◽  
Flow Power ◽  
Gas Lift

Abstract The hole cleaning issue in gas-lift drilling has been a concern and has not been previously investigated due to the difficulties of experimental studies and analytical modeling. The objective of this study is to deliver an assessment of hole cleaning capacity of drilling fluid in reverse circulation conditions for different bit designs. We use the finite element method (FEM) to target this issue and address a critical question in gas-lift drilling. The result of the theoretical investigation indicates that clean bottom hole can be achieved in gas-lift drilling through optimization of drill bit design to balance fluid energy (cleaning power) between tooth blades. Three drill bit designs were investigated in this study. The flow power balance between blades can be achieved with a 3-orifice bit design and a 2-orifice bit design, but there exist flow stagnation zones between these orifices, which are not desirable for bit tooth and borehole cleaning. The 1-orifice bit design with four cutter blades can eliminate flow stagnation zone and improve flow field to achieve a much better flow power balance between blades and thus bit tooth and borehole cleaning. Therefore, drill bits with one orifice are desirable for reverse circulation gas-drilling. This paper presents a novel technique of using FEM to evaluate bit hydraulics for hole cleaning in reverse drilling conditions. Future laboratory tests are desirable to obtain real data for further validating the model result.

Optimal Design of Novel Drill Bit to Control Dust in Down-the-Hole Hammer Reverse Circulation Drilling

2017 ◽  
Vol 43 (3) ◽  
pp. 1313-1324 ◽  
Author(s):  
Pinlu Cao ◽  
Yunwang Chen ◽  
Miaomiao Liu ◽  
Baoyi Chen
Keyword(s):  
Optimal Design ◽  
Drill Bit ◽  
Reverse Circulation
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