Multipole Shear Wave Splitting Measurement System
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Solution Overview
Problem
Current downhole drilling systems face challenges in accurately measuring fast and slow principal shear wave slowness and anisotropy during drilling operations, especially in slow formations, due to limitations in dipole systems and the need for wireline measurements, which are time-consuming and complex.
Innovation Solution
The implementation of a multipole transmitter and receiver system configured to transmit and receive acoustic signals at various azimuthal angles, allowing for the determination of acoustic azimuthal anisotropy in real-time during drilling, using a bottomhole assembly with a multipole transmitter of order n≥2 and axially offset receivers to obtain accurate multipole data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dipole while-drilling systems are used to measure acoustic properties, then measurements can be obtained during drilling operations, but the systems cannot measure acoustic low frequency flexural modes and thus cannot measure true slow principal shear wave
Solution Approach 1:
The measurement system is segmented into multiple independent multipole receivers (first multipole receiver and second multipole receiver) with different axial positions. Each receiver captures specific acoustic modes, allowing the system to separately measure fast and slow principal shear waves by processing signals from multiple receivers independently
Solution Approach 2:
The system transitions from a single-dipole measurement configuration to a multi-multipole receiver array configuration with axial separation. This adds the axial dimension to the measurement geometry, enabling resolution of multiple acoustic modes including low frequency flexural modes that were previously inaccessible
2Measurement precision
If wireline systems are used to make accurate measurements of acoustic properties, then measurement precision is improved, but time and complexity considerations are worsened
Solution Approach 1:
The system merges the multipole transmitter and multiple multipole receivers into a single integrated bottomhole assembly that operates during drilling. This combination enables simultaneous drilling and measurement operations, eliminating the need to stop drilling for wireline measurements and thus reducing total measurement time
Solution Approach 2:
The measurement process continues uninterrupted during drilling operations. The multipole transmitter and receivers operate continuously as the drill string rotates and advances, maintaining measurement capability throughout the drilling process rather than requiring separate static measurement campaigns
3Measurement precision
If wireline systems are used to measure acoustic properties, then measurement accuracy is improved, but device complexity is increased
Solution Approach 1:
The bottomhole assembly integrates multiple functions into a single system: drilling capability, acoustic signal transmission, and multi-mode acoustic measurement. The multipole transmitter and receivers serve both as drilling components and as measurement instruments, eliminating the need for separate wireline measurement tools
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
Enables the precise measurement of fast and slow shear slowness and associated directions during drilling, eliminating the need for wireline operations and providing accurate data for seismic processing, well completion, and fracture characterization.
Implementation Method 1
a multipole transmitter configured to transmit acoustic signals into the formation
Implementation Method 2
a first multipole receiver and a second multipole receiver, wherein each of the first and second multipole receivers are azimuthally aligned with the multipole transmitter
Implementation Method 3
the controller is configured to determine acoustic azimuthal anisotropy of the formation from the acoustic multipole data
Data Source
AI summary
Downhole measurement systems and methods include deploying a bottomhole assembly having a multipole transmitter into a formation and transmitting acoustic signals into the formation. The multipole transmitter is of order n≥2. Acoustic signals are received at respective receivers that are circumferentially aligned with the multipole transmitter, and are axially offset from the multipole transmitter, and axially offset from each other. The order of the first and second multipole receivers are equal to the order of the multipole transmitter. A controller is used to obtain first and second acoustic multipole data from the first and second multipole receivers at one or more azimuthal angles of a rotation of the bottomhole assembly in a formation during a drilling operation. Acoustic azimuthal anisotropy of the formation is determined from the first acoustic multipole data and the second acoustic multipole data.