Downhole Torque Estimation Using Surface Drive Signals
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Solution Overview
Problem
Current borehole drilling technologies face challenges in accurately measuring and controlling downhole speed and torque in real-time, leading to inefficiencies and equipment damage due to vibrations and stick-slip phenomena, which require frequent retuning of speed controllers and rely on expensive and unreliable Measurement While Drilling (MWD) systems.
Innovation Solution
A method and device using a two-port spectral domain transfer matrix computational model to estimate downhole speed and torque by reducing spectral bandwidth and applying a time delay term, allowing for causal time domain solutions, enabling real-time calculation and automatic adaptation of drilling parameters to mitigate vibrations and stick-slip, without the need for expensive MWD equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Measurement While Drilling (MWD) systems are used to measure downhole speed and torque, then measurement capability is improved, but system cost and reliability deteriorate due to expense and unreliability
Solution Approach 1:
The patent uses surface-measured variables (top drive torque and speed) as intermediaries to indirectly determine downhole conditions through a transfer matrix model, avoiding the need for direct downhole measurement instruments that are expensive and unreliable
Solution Approach 2:
The patent replaces physical downhole measurement systems with a computational model that uses mechanical relationships and transfer matrices to calculate downhole speed and torque from surface measurements
2Measurement precision
If full spectral bandwidth is used in the transfer matrix calculation, then calculation accuracy is improved, but computational complexity and time increase
Solution Approach 1:
The patent extracts only the necessary spectral components (fundamental mode and selected higher-order modes) from the full spectral bandwidth, removing unnecessary computational complexity while retaining sufficient accuracy for downhole parameter estimation
Solution Approach 2:
The patent applies partial spectral analysis by including a limited number of higher-order modes rather than the complete spectral bandwidth, providing sufficient accuracy for practical applications without excessive computational burden
3Productivity
If real-time downhole data is obtained using MWD systems, then drilling optimization is improved, but equipment cost and downtime increase
Solution Approach 1:
The patent enables the drilling system to self-monitor and self-optimize by using the existing top drive control system to provide both drilling control and downhole measurement functions, eliminating the need for separate MWD equipment that would add cost and potential downtime
Data Source
AI summary
A method of and a device, borehole drilling equipment and a computer program product for estimating at least one of down hole speed and down hole torque of borehole drilling equipment while drilling a borehole in an earth formation. The borehole equipment comprising a rotational drive system, a drill string, a bottom hole assembly comprising a drill bit, a top end coupled to the rotational drive system, and a speed controller arranged for controlling rotational top end drive speed by commanding a top end drive torque. The method being performed in a computer based on a two-port spectral domain transfer matrix computational model of the borehole drilling equipment. While drilling, rotational top end drive speed and top end drive torque are obtained and down hole speed and down hole torque of the borehole drilling equipment are calculated by reducing spectral bandwidth of and applying a time delay term to the calculations enabling a causal time domain solution.