Logging-While-Drilling Tool with Look-Ahead Capability for Formation Characterization
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Solution Overview
Problem
Current methods for directional drilling and characterization of target earth formations during borehole drilling lack sufficient accuracy and resolution, particularly in predicting well placement and characterizing reservoirs, due to limitations in seismic surveys and resistivity measurements.
Innovation Solution
A method utilizing a bottom hole assembly with a controllable directional drilling subsystem and a logging-while-drilling directional measurement tool with look-around and look-ahead capabilities, which includes a knowledge base of earth formation characteristic models to determine and navigate based on formation parameters, enabling precise drilling and characterization of formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If seismic surveys are used to locate the well path in the formation, then the ability to probe far into the formation is improved, but the resolution and accuracy to sufficiently characterize a target formation deteriorates
Solution Approach 1:
The patent divides the formation characterization into multiple measurement zones using arrays of EM receivers at different positions (e.g., 4-foot intervals) to capture both deep and shallow formation properties. This segmentation allows simultaneous acquisition of deep probing capability and high-resolution local characterization.
Solution Approach 2:
The patent transitions from traditional single-point or limited-zone resistivity measurements to multi-dimensional EM field measurements using arrays of transmitters and receivers positioned at various orientations and distances. This enables characterization of formation properties in multiple spatial dimensions simultaneously, achieving both deep penetration and high resolution.
2Measurement precision
If EM propagation tools are used to measure formation resistivity, then the ability to determine formation properties is improved, but the depth of investigation and resolution trade-off deteriorates
Solution Approach 1:
The patent employs multiple EM receiver pairs at different spacings from the transmitter (e.g., 2-foot, 4-foot, 6-foot intervals) to simultaneously measure formation resistivity at multiple depths. Each receiver pair provides measurements at a specific investigation depth, creating a segmented depth profile that resolves both shallow and deep formation properties.
Solution Approach 2:
The patent changes the measurement parameters by varying the spacing between transmitters and receivers, as well as the orientations of EM fields. By adjusting these parameters, the system can optimize the depth of investigation and resolution for different formation zones, achieving both deep penetration and high measurement precision.
3Productivity
If directional drilling is used to increase borehole volume in the pay zone, then oil production is improved, but the accuracy of well placement and trajectory control deteriorates
Solution Approach 1:
The patent implements real-time feedback by continuously measuring formation properties using EM tools during drilling and comparing them against the planned well trajectory. The system provides feedback signals to the directional drilling control system, enabling real-time trajectory adjustments to maintain accurate well placement while optimizing production.
Solution Approach 2:
The patent performs preliminary formation characterization and trajectory planning before drilling by analyzing EM measurements and seismic data. This preliminary action establishes an optimized well path that anticipates formation boundaries and heterogeneities, improving both placement accuracy and eventual production.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of well placement and characterization of target formations by providing real-time measurement signals for controlling directional drilling, allowing for improved navigation and reservoir characterization, thereby increasing oil production and reducing drilling risks.
Implementation Method 1
Some EM logging tools use propagation techniques to measure the resistivity of the formation. A propagation tool measures the amplitudes, phase shifts, and attenuation of EM signals in the formation to determine the resistivity of the formation
Data Source
AI summary
A method for directing borehole drilling in a target earth formation includes the following steps: providing drilling equipment having a bottom hole assembly that includes a controllable directional drilling subsystem, and a logging-while-drilling directional measurement tool with a look-around and look-ahead capability; determining the presence of a predetermined type of formation characteristic in the target formation; and navigating a drill path in the target formation with the drilling equipment, including receiving measurement signals from the directional measurement tool, obtaining, from the received measurement signals, indications of formation parameters with respect to the formation characteristic in the target formation, and controlling the directional drilling subsystem to drill in a direction determined as a function of the obtained indication of formation parameters.