OBJECTIVE To assess if the screw design (self-drilling/self-tapping) and the pilot hole tapping could affect the insertion torque and screw pullout strength of the screw used in anterior fixation of the cervical spine. METHODS Forty self-tapping screws and 20 self-drilling screws were inserted into 10 models of artificial bone and 10 cervical vertebrae of sheep. The studied parameters were th...

Rotary drilling belongs to the key methods of rock separation not only in mining, but also in wider areas of geotechnologies 1, 2 . The most efficient separation of rocks is in so-called volume area which can be achieved with the correct choice of work tool and work mode while taking into account the geomechanical properties of rock separation. Theoretical research of rock separation by rotary ...

At present there is a lack of an instrument to measure the trajectory up-holes in safe and efficient way with minor disruption underground production. To overcome this, mechanically operated probe equipped Inertial Measurement Units (IMU) centralisers integrated explosive charge-up unit, which allows operator start stop measurements from area, while he views records real time handheld PC. The s...

Multiplicity of the effective factors in drilling reflects the complexity of the interaction between rock mass and drilling bit, which is followed by the dependence of parameters and non-linear relationships between them. Rock mass or, in other words, the formation intended for drilling, as the drilling environment, plays a very essential role in the drilling speed, depreciation of drilling bit...

Experimental methods for determining a performance index of explosives are analysed: the ballistic pendulum, mortar, lead block, and according to volume soil explosion funnel. It is defined that determination emulsion (EE) involves set significant features connected with large critical diameter requiring experiments large-mass charges resulting in refusal from traditional index. Analytical calc...

SUMMARY Use and interpretation of wireline lookahead VSP combined with LWD seismic while drilling and LWD sonic log for base of salt prediction, a case study offshore Brasil deep offshore Campos. It aimed to assist drilling decisions by obtaining a more accurate prediction of Base of Salt depth. Setting the 9-5/8" casing point was key from a drilling perspective.

Abstract This paper establishes the risk assessment index system according to characteristics of oil and gas drilling engineering cooperation project. After modularizing risk indexes of oil and gas drilling engineering cooperation project into eight clusters, risks are evaluated on the basis of multi-level fuzzy comprehensive evaluation method. The study is to construct risk assessment indexes ...