Compensated Surface WOB Control During Tool Joint RCD Passage
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Solution Overview
Problem
Conventional drilling technologies struggle to accurately measure weight-on-bit (WOB) due to deviations between surface weight-on-bit (SWOB) and downhole WOB, particularly in non-vertical boreholes, leading to inefficiencies and potential damage from incorrect WOB adjustments.
Innovation Solution
A drilling system that determines a compensated SWOB by accounting for intermittent axial forces applied by the rotating control device (RCD) and other factors, using sensors and a computer system to improve accuracy and control drilling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface weight-on-bit (SWOB) is used as a surrogate for downhole weight-on-bit (WOB), then drilling operations can be controlled without direct downhole measurement, but measurement precision deteriorates due to deviations caused by non-vertical boreholes and tool joint passage through rotating control devices
Solution Approach 1:
The system continuously monitors hook load variations and tool joint position, using this feedback to dynamically calculate compensated SWOB values that account for RCD forces and directional borehole effects, thereby maintaining measurement precision while enabling surface-based control
Solution Approach 2:
The system changes the parameter being measured from simple hook load to compensated SWOB by introducing correction factors for RCD axial forces, borehole inclination, and tool joint positioning, transforming the measurement to reflect true downhole WOB conditions
2Adaptability or versatility
If tool joints pass through the rotating control device (RCD), then the drill string can be rotated and controlled, but intermittent axial forces are applied to the drill string causing artificial deviations in SWOB measurements
Solution Approach 1:
The system performs preliminary identification of tool joint passage through the RCD by monitoring hook load variations and position data, then pre-calculates the axial resistance forces that will be applied during passage, allowing for compensated SWOB calculation before the actual measurement is affected
Solution Approach 2:
The system introduces an intermediary calculation layer between the raw hook load measurement and the final WOB value, using compensated SWOB as an intermediate parameter that mediates the effects of RCD forces, borehole inclination, and tool joint passage to produce accurate WOB values
3Productivity
If WOB is increased to improve rate of penetration (ROP), then drilling speed increases, but the drill bit, BHA, and drill string may be damaged due to excessive forces
Solution Approach 1:
The system uses real-time monitoring of compensated SWOB, hook load, and drill string position to provide feedback control, allowing WOB to be optimized for maximum ROP while automatically adjusting to prevent forces that would cause damage to the drill bit, BHA, or drill string
Data Source
AI summary
Drilling systems and methods determine a compensated SWOB that accounts for forces applied by a rotating control device. A method of drilling a borehole includes tracking movement of a drill string relative to a rotating control device (RCD) and determining a compensated SWOB that accounts for passage of a tool joint through the RCD. The compensated SWOB is based on a difference between a weight of the drill string and the hook load minus an axial resistance force during passage of a tool joint through the RCD.