Drilling process bit pressure modeling method considering uncertain damping coefficient

Abstract

The invention aims at the field of geological drilling engineering, and discloses a drilling process bit pressure modeling method considering an uncertain damping coefficient, which comprises the following steps of: firstly, modeling a drilling machine lifting system, a drill column system and a drill bit-rock action mechanism, constructing a drill column longitudinal motion equation, and obtaining a state space model depending on the uncertain damping coefficient; and solving model parameters by using on-site drilling tool parameters and historical data, and finally setting an uncertain feeding damping coefficient. The characteristic that an actual drill string system is composed of discrete units is considered, and a high-degree-of-freedom model with the degree of freedom equivalent to the number of actual drilling tools is invented based on a finite element method. The introduced damping model can reflect the drill-rock action in the current environment by setting a damping coefficient, so that a drilling process bit pressure dynamic model suitable for different environments is established. On-site data shows that the model can better fit the dynamic response from the winch rotating speed input to the above-well bit pressure output.

Description

technical field [0001] The invention relates to the field of geological drilling engineering, in particular to a drilling weight modeling method in the drilling process considering uncertain damping coefficients. Background technique [0002] The drilling process is an important way to explore deep resources and energy. The WOB is one of the key operating parameters in the drilling process. During the drilling process, it is necessary to control and maintain the WOB at the pre-designed expected value, so as to ensure the smoothness of the entire drilling process. Safe and efficient. Since the WOB is the longitudinal stress on the drill string, it is closely related to the longitudinal movement of the drill string. Deep geological drilling often needs to go through a variety of complex formations to reach the target area and obtain complete cores. During this process, the diameter of the drill string is usually tens or even hundreds of centimeters, while the length has to b...

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Problems solved by technology

[0004] The invention discloses a method for modeling pressure-on-bit in the drilling process considering uncertain damping coefficients

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