Experimental Research on Bit Side Force and Anti-deviation in Vertical Well
Based on dimensional method, the similarity criterion of simulation test was derived. The experimental apparatus was established in accordance with the similarity criterion. A series of experiments with different drilling parameter were carried out. The experimental results show that
with rotary speed rise, the bit side force fluctuation increased, however, the vibration energy at the dominant frequency decreased, at low rotary
speed, the dominant frequency of the bit side force is equal to rotation frequency of drill string, and at high rotary speed, the dominant frequency is
consistent with the backward whirl frequency of drill string, which is about 3 times of rotation frequency, moreover, as WOB rise, the vibration energy at dominant frequency increased, while the total wave energy decreased, and the critical rotary speed value at the jump process of the dominant
frequency increased. Furthermore, for the purpose of deviation controlled straight drilling, there is the problem of optimization grouping between
WOB and rotary speed.
Well deflection is a crucial indicator to evaluate the hole quality
in drilling, and bit side force is a key parameter judging the inclination control effect in the technique of inclination control. Therefore, many of scientists and engineers in the field of drilling have
done the massive theoretical research work for bit side force and
have established a number of mathematics calculation models. The
certain result obtained from the theoretical researches was applied
for field,1-4 however it is inaccurate to analyse side force at bit only
through the theoretical analysis. With the development of downhole logging while drilling technology and indoor measurement
technology, some progress is made on the research of bit side force
by analysing down-hole measured field data and conducting laboratory simulation experiments. In order to measure the bit side
force during drilling,5,6 Millheim7
, Maron8
and others designed a
short section of the test structure which can measure the axial force,
bending moment and shear force for derivation of the bit side force.
However, the high cost of measurements and the complex working
conditions on site are resulting in the incomplete measured data.
So in this paper, the laboratory simulation test has become an important mean to research the bit side force. To establish lab simulation test device, this paper derived the simulation test of similarity
criterion by using dimensional analysis method. According to the
principle of similitude, an experimental device for investigating the
bit side force was designed and set up. And a series of experiments
with different drilling parameter was carried out to study the influencing factor on the bit side force during vertical rotary drilling.
https://www.stephypublishers.com/tpe/pdf/TPE.MS.ID.000514.pdf
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