COMPARISON OF POLYNOMIAL, DEGREE AND LINEAR FORMULAS, DESCRIBING CHARACTERISTICS OF POSITIVE DISPLACEMENT MUD-MOTORS, BETWEEN THEM AND BENCH TESTS DATA
UDC: 622.243.922
DOI: 10.33285/0130-3872-2021-6(342)-10-17
Authors:
LEONOV EVGENY GRIGORIEVICH 1,
UBUSHAEV UBUSH BADMAEVICH 1
1 National University of Oil and Gas "Gubkin University", Moscow, Russian Federation
Keywords: positive displacement mud-motors, bench tests of PDM, recalculation of performance indicators of PDM, loss of fluid pressure in the motor, rotation frequency of the PDM rotor
Annotation:
The paper is relevant because it shows that there is not enough basic indicators of bench tests of positive displacement mud-motors for pressure drop determination and rotation frequency of the motor in operating environment in well-known catalogues and reference books. To bridge this gap typical performances of the bench tests of the D1-105 motor on the bench of PF VNIIBT have been described by two basic empirical performances of pressure drop of motors and rotation frequency against the moment of rotor and the mass flow rate. It is realized by the approximation of performances by polynomial, degree and linear functions. On this basis of comparison between them and bench tests data, it is established that using power (three-parameter) approximation is more exact and convenient for recalculation. New formulas have been obtained for recalculation of basic indicators in the working and corresponding individual conditions during motor operation in a well. A set of nine basic indicators have been revealed (density and mass flow rate of the fluid, pressure drop and rotation frequency both idling and under torque load, and powers αandβ), which should be mentioned in reference books. A method of choosing the shear force of the stem pin of the pressure relief valve of the mud pump based on the minimum pressure, which simultaneously prevents damage to the mud pump and the motor is proposed. Numerical tests such as the conversion of the basic data into operating data and the selection of the pressure relief valve of the mud pump is considered.
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