Wellbore Stratigraphic Depth Likelihood for Real-Time Steering
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Solution Overview
Problem
Conventional drilling technologies face challenges in accurately steering a wellbore into geological targets due to uncertainties in stratigraphic vertical depth, as they fail to effectively integrate and process data from downhole sensors and surface control systems in a timely manner, leading to errors that can result in increased costs and reduced well output.
Innovation Solution
A computer system that generates a misfit curve between stratigraphic vertical depth of an offset wellbore and a measured depth of the subject wellbore, calculates likelihoods of target measured depths, and adjusts drilling parameters to improve steering accuracy, using a processor-enabled system that accesses memory media storing executable instructions for stratigraphic analysis during drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional drilling technologies are used to steer wellbore into geological targets, then drilling operations can be performed with standard equipment and procedures, but accuracy in determining stratigraphic vertical depth is insufficient due to inability to effectively integrate and process data from downhole sensors and surface control systems
Solution Approach 1:
The system segments the wellbore into multiple depth intervals and processes survey data from downhole sensors at different depths independently. Each depth interval is analyzed separately to determine stratigraphic vertical depth, allowing for more precise local measurements while managing overall system complexity through modular data processing
Solution Approach 2:
The system implements feedback loops where survey data from downhole sensors is continuously transmitted to surface control systems, processed to determine stratigraphic vertical depth with improved accuracy, and then used to adjust drilling parameters in real-time. This closed-loop feedback mechanism enhances measurement precision while systematically managing the complexity of data integration
2Reliability
If real-time data processing from downhole sensors is implemented to improve wellbore steering accuracy, then drilling errors can be reduced and well output improved, but the system complexity and computational requirements increase significantly
Solution Approach 1:
The system performs preliminary processing of survey data from downhole sensors immediately upon acquisition, before the drilling operation continues. By pre-processing and analyzing the data in real-time to determine stratigraphic vertical depth, the system ensures accurate wellbore steering decisions are made based on current information, enhancing reliability while managing computational complexity through timely data reduction
Solution Approach 2:
The system introduces an intermediary processing layer between downhole sensors and surface control systems that aggregates, filters, and pre-analyzes survey data before transmitting to the main control system. This intermediary layer reduces the computational burden on the overall system while maintaining real-time processing capabilities for improved steering accuracy and reliability
3Measurement precision
If conventional well planning methods are used assuming fixed geological target depths, then well plans can be created with simple spatial coordinates, but errors occur because desired geological targets are not exactly at the assumed depths due to unknown lateral variations and uncertainties in geological stratigraphy
Solution Approach 1:
The system continuously monitors survey data from downhole sensors and compares actual geological formations against the well plan in real-time. When deviations in stratigraphic vertical depth are detected, the system automatically adjusts the well plan spatial coordinates to account for lateral variations and geological uncertainties, ensuring the wellbore remains on course for the actual geological target location while minimizing time loss through automated adjustments
Solution Approach 2:
The system transforms the static well plan with fixed spatial coordinates into a dynamic plan that continuously adapts based on real-time survey data analysis. The well plan is updated on-the-fly to reflect actual geological conditions, allowing the drilling operation to respond dynamically to lateral variations and stratigraphic uncertainties, improving target depth accuracy while managing adjustment time efficiently
Data Source
AI summary
Stratigraphic analysis includes determining misfit values between stratigraphic vertical depth of an offset wellbore, SVDow and measured depth of a subject wellbore. A likelihood that the target measured depth is equal to or within a tolerance of stratigraphic vertical depth of the subject wellbore, SVDsw, for sequences of stratigraphic vertical depth is calculated. A probability weighted average and an uncertainty that the target measured depth for the subject wellbore, TMDsw, is equal to or within a tolerance of stratigraphic vertical depth of the subject wellbore, is calculated. A continuous probability function over a range of measured depth that the target measured depth for the subject wellbore, TMDsw, is equal to or within a tolerance of stratigraphic vertical depth of the subject wellbore, SVDsw, is calculated. The likelihood, the probability weighted average, the uncertainty, and the continuous probability function are used to make drilling decisions