Guided Acoustic Wave Imaging Ahead of Drill Bit
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Solution Overview
Problem
Current drilling technologies face challenges in accurately controlling the direction of drilling due to limited capabilities in 'seeing ahead' of the drillbit, as existing methods like resistivity measurements lack the ability to provide reliable information at great depths, necessitating the development of a more effective method for real-time directional control during drilling operations.
Innovation Solution
The use of guided acoustic waves, specifically Stoneley waves or quadrupole waves, generated by transmitters activated at frequencies determined by the characteristic frequency of these waves, allows for the estimation of distance, dip angle, and azimuth of interfaces in the earth formation, enabling improved directional drilling control through wavefield separation and imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If resistivity methods are used for directional control, then the ability to see ahead of the drillbit is improved, but the measurement reliability at great depths deteriorates
Solution Approach 1:
The patent replaces electrical resistivity measurement methods with acoustic wave propagation methods. Acoustic transmitters generate guided waves that travel through the formation, and acoustic receivers detect these waves to determine formation properties and interface locations at great depths, providing reliable measurements where resistivity methods fail.
Solution Approach 2:
The patent changes the physical parameter used for measurement from electrical resistivity to acoustic wave velocity and attenuation. By measuring the propagation characteristics of acoustic waves (travel time, amplitude, frequency content) through the formation, the system achieves reliable depth measurements and interface detection that are not achievable with electrical methods.
2Productivity
If logging is performed on an unfinished hole, then directional control information can be obtained in real-time, but washouts occur that damage the drilling work
Solution Approach 1:
The patent performs logging measurements while the hole is still unfinished and before casing is set, allowing real-time directional control decisions to be made. The acoustic logging tool is deployed into the unfinished hole to obtain formation information and interface locations, enabling the drilling direction to be adjusted before the hole is completed, thus preventing washouts and damage to drilling work.
Solution Approach 2:
The system provides real-time feedback on formation properties and interface locations during drilling operations. The acoustic measurements are processed to generate information about the drilling environment, which is then used to immediately adjust the drilling direction and prevent harmful washouts, creating a closed-loop control system.
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 enables precise directional control during drilling by providing accurate distance and orientation information of subsurface interfaces, enhancing the ability to navigate drilling operations and optimize reservoir exploration.
Implementation Method 1
A guided acoustic wave is generated in the borehole by activating at least one transmitter
Implementation Method 2
A wave reflected from the interface is converted at the bottom of the wellbore to produce a reflected guided wave in the borehole
Implementation Method 3
A guided acoustic wave is generated in the borehole by activating at least one transmitter... A wave reflected from the interface is converted
Data Source
AI summary
A downhole acoustic logging tool is used for generating a guided borehole wave that propagates into the formation as a body wave, reflects from an interface and is converted back into a guided borehole wave. Guided borehole waves resulting from reflection of the body wave are used to image a reflector.