Drilling Activity Detection Using Travelling Block Position
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Solution Overview
Problem
Existing drilling methods face challenges in accurately determining drilling activity due to noise in hook load measurements, which affects calculations of non-productive time and invisible loss time, especially when the drill string is gripped by the slips assembly.
Innovation Solution
A method that receives measurements of wellbore depth, drill bit depth, and travelling block position over time to identify connections and determine drilling activity by analyzing changes in these parameters, thereby distinguishing between drilling, non-drilling, and connection intervals without relying on hook load data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hook load measurements are used to determine drilling activity, then the drilling status can be monitored, but noise in the measurements adversely affects calculation accuracy of non-productive time and invisible loss time
Solution Approach 1:
The patent extracts the drill string position information from the noisy hook load measurements by using a separate sensor system (accelerometer or position sensor) mounted on the drill string. This separates the position detection function from the hook load measurement, allowing accurate position tracking independent of the noisy force measurements.
Solution Approach 2:
The patent introduces an intermediary sensor (accelerometer or position sensor) that directly measures drill string position without being affected by hook load noise. This intermediary measurement system acts as a mediator between the drill string and the control system, providing clean position data for activity detection.
2Length of moving object
If the drill string is gripped by the slips assembly to add segments, then the drill string length can be increased, but the hook load measurements become unreliable during these connection intervals
Solution Approach 1:
The drill string itself serves as the measurement platform by mounting sensors directly on it. This self-service approach allows the drill string to provide its own position information independent of the hook load measurement system, ensuring continuous reliable position data even when the slips assembly grips the drill string during connections.
3Difficulty of detecting and measuring
If traditional hook load-based methods are used to identify connections, then connection events can be detected, but noise causes incorrect identification of drilling activity intervals
Solution Approach 1:
The patent replaces the mechanical hook load measurement system with a sensor-based position measurement system. By using accelerometers or position sensors mounted on the drill string, the system substitutes direct force measurement with position tracking, eliminating the noise problem inherent in hook load measurements during connections.
Solution Approach 2:
The patent implements feedback by continuously monitoring drill string position and comparing it against expected drilling patterns. This feedback mechanism allows the system to identify actual drilling activity versus connection events based on real position data, correcting for any misidentifications and providing accurate activity detection despite connection interruptions.
Data Source
AI summary
A method of determining a drilling activity includes receiving a set of measurements at different times. The set of measurements includes a depth of a wellbore, a depth of a drill bit, and a position of a travelling block. The method also includes identifying a connection by determining when the position of the travelling block changes but the depth of the drill bit does not change. The method also includes determining when the depth of the wellbore does not increase between two different connections. The method also includes determining a direction that the drill bit moves between the two connections.