Telemetry Antenna Arrangement for Wellbore Communication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In directional drilling, the mechanical complexity and limited space around the bottom hole assembly (BHA) and mud motor hinder the placement of sensors close to the drill bit, leading to delayed awareness of deviations or unsafe conditions due to lag in communication between the drill bit and surface monitoring systems.
Innovation Solution
A transceiver sonde with a toroidal antenna and conductive element is positioned within a gap sub to enable short-hop wireless communication across mechanical obstructions, such as mud motors, allowing data transmission from sensors below the motor to the surface using alternating electromagnetic currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are placed above the mud motor assembly, then the MWD system can be positioned in available space, but the distance from the drill bit increases causing communication lag
Solution Approach 1:
The system divides the communication path into two segments: a lower antenna assembly near the drill bit that receives signals through the mud motor, and an upper antenna assembly above the mud motor that transmits to the surface. This segmentation allows sensors to be positioned close to the bit while maintaining reliable communication through the obstruction.
Solution Approach 2:
The mud motor assembly acts as an intermediary that the lower antenna penetrates to transmit electromagnetic signals from the near-bit location to the upper antenna. This mediator approach allows the signal to pass through the mechanical obstruction rather than requiring the entire system to be positioned above it.
2Loss of time
If sensors are placed below the mud motor near the drill bit, then communication lag is reduced, but the mechanical complexity and limited space around the BHA make placement difficult
Solution Approach 1:
The lower antenna assembly is positioned within the bore of the mud motor, utilizing the vertical space along the motor's length rather than requiring lateral space in the crowded BHA. This dimensional approach to positioning allows near-bit communication without adding to the horizontal mechanical complexity.
Solution Approach 2:
The lower antenna assembly serves multiple functions: it acts as both a receiving antenna for electromagnetic signals and as a structural component that can be integrated into the BHA design. This multi-functionality reduces the need for separate dedicated sensor mounting structures.
3Reliability
If a wireline connection is used for telemetry, then reliable communication is achieved, but the mechanical complexity and space requirements increase
Solution Approach 1:
The system replaces the mechanical wireline connection with an electromagnetic transmission system using antenna assemblies that communicate through electromagnetic fields. This substitution eliminates the need for physical wireline infrastructure while maintaining communication reliability.
Solution Approach 2:
The system changes the transmission medium from mechanical (wireline) to electromagnetic (radio frequency signals). This parameter change allows communication without the physical constraints and complexity of wireline connections while preserving reliability through the dual-antenna approach.
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 solution provides immediate and reliable communication of drilling data, reducing the lag between the drill bit and surface systems, enabling timely detection of deviations and ensuring safer drilling operations.
Implementation Method 1
a coil, the coil wrapped around the toroidal core and positioned to induce or receive alternating electromagnetic transmission currents
Implementation Method 2
a conductive element passing through the toroidal antenna core having a first end and a second end, the conductive element forming a current path
Data Source
AI summary
A sonde based antenna is used for communication within a wellbore. The sonde based antenna may include a toroidal antenna positioned about a conducting element. The sonde may be positionable within a gap sub. The sonde may be electrically connected to the first and second tubulars of the gap sub such that the tubulars are electrically coupled by the conducting element and are otherwise electrically insulated. The sonde may include a first and second structural member, the first and second structural members being electrically insulated except by the conducting element. The first and/or second structural element may extend through and/or around the toroidal antenna to, for example, add structural rigidity to the sonde.