Retrievable Downhole Cable Antenna for EM Telemetry
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Solution Overview
Problem
Electromagnetic (EM) telemetry systems face challenges in receiving signals from deep wells due to EM unfriendly formations, which attenuate or limit signal output, making it difficult to decode signals at the surface, especially when drilling through multiple layers.
Innovation Solution
A retrievable cable antenna system is deployed in a nearby wellbore to receive EM signals from a transmitter in the well being drilled, eliminating the need for additional downhole devices and allowing for easy redeployment, reducing costs and increasing re-use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface antennas are used to receive EM signals, then the system is simple to operate, but signal reception deteriorates when drilling through EM unfriendly formations
Solution Approach 1:
The patent transitions the antenna from surface location to downhole location within the wellbore, changing the spatial dimension of signal reception. This allows the antenna to receive EM signals closer to the transmitter before the signal passes through EM unfriendly formations, thereby improving signal strength and reception reliability while maintaining operational simplicity through automated deployment and retrieval systems
2Reliability
If a secondary receiver is placed deeper in the wellbore, then signal reception is improved, but device complexity increases
Solution Approach 1:
The patent combines the antenna function with the cable system used for power and data transmission. The cable serves multiple functions: providing electrical power to the antenna, transmitting received EM signals to the surface, and enabling automated deployment and retrieval. This integration reduces device complexity compared to separate antenna and cable systems while improving signal reception through downhole placement
3Reliability
If downhole devices are left in the secondary wellbore, then signal reception is maintained, but cost and reusability are reduced
Solution Approach 1:
The patent implements a dynamic system where the antenna can be deployed into the wellbore when needed for signal reception and then retrieved back to the surface for reuse in other applications. The automated deployment and retrieval mechanism allows the system to transition between operational states, maintaining signal reception capability while enabling cost-effective reuse across multiple drilling operations and locations
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 enhances signal reception by bypassing EM unfriendly formations, allowing for reliable data transmission from deep wells without leaving equipment in the secondary wellbore, thus improving the efficiency and cost-effectiveness of EM telemetry systems.
Implementation Method 1
a cable antenna deployed in a second wellbore and configured as an antenna to receive signals from the EM tool independent of other receiver devices
Data Source
AI summary
This invention provides an improved system and method for receiving electromagnetic (EM) signals from a wellbore in spite of EM unfriendly formations by placing a cable antenna in a wellbore, drilling another wellbore nearby, and using the cable antenna downhole in the wellbore to assist in receiving signal from the transmitter in the wellbore being drilled. The EM telemetry system can include a bottom hole assembly with an EM tool for transmitting a signal positioned in a first wellbore; EM equipment provided at or near the surface; and a cable antenna coupled to the EM analyzer positioned in a second wellbore. The cable antenna does not require other downhole antenna devices for receiving EM signals and therefore is independent of other antenna devices. The cable antenna can be retrieved after drilling is completed and moved to another drilling site.