Subsea Telemetry System for MWD Data Transmission
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Solution Overview
Problem
Conventional offshore MWD systems face limitations in data transmission rates and quality, requiring the removal and reinsertion of drilling assemblies for wireline logging, which is time-consuming and costly, and existing telemetry systems like mud pulse, acoustic, and EM systems struggle with data transfer efficiency in offshore drilling operations.
Innovation Solution
A subsea data communication system that measures and transmits L/MWD data from a bottomhole assembly to the seafloor using a telemetry signal, processed by a signal processor, and then transmitted to the surface via a communication link, allowing for improved data quality and increased transmission rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireline logging is used to obtain downhole measurements, then measurement precision is improved, but loss of time and loss of cost increase due to removal and reinsertion of drilling assembly
Solution Approach 1:
The patent applies preliminary action by installing MWD/LWD tools and sensors in the drill string before drilling operations begin. This allows continuous measurement and communication during drilling, eliminating the need to remove and reinsert the drilling assembly for wireline logging, thus resolving the contradiction between measurement precision and time loss
Solution Approach 2:
The patent replaces the mechanical wireline logging system with an integrated MWD/LWD system that uses electromagnetic or acoustic telemetry embedded in the drill string. This substitution eliminates the mechanical process of removing and reinserting the drilling assembly while maintaining measurement capabilities
2Loss of information
If conventional telemetry systems (mud pulse, acoustic, EM) are used for data transmission, then data communication is achieved, but data transfer rate and transmission quality are limited
Solution Approach 1:
The patent merges multiple telemetry transmission methods (mud pulse, acoustic, and electromagnetic) into a hybrid system that operates simultaneously or sequentially. This combination allows the system to overcome the limitations of individual methods and achieve higher data transfer rates and improved transmission quality by utilizing the strengths of each method
Solution Approach 2:
The patent introduces a new dimension to data transmission by using the drill string itself as a transmission medium for electromagnetic or acoustic signals, in addition to the traditional mud pulse method. This multi-dimensional approach to communication enables simultaneous data transmission through multiple pathways, increasing overall productivity
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 data transmission efficiency and quality by processing signals at the seafloor before transmission to the surface, reducing the need for costly assembly removal and optimizing drilling operations.
Implementation Method 1
communicating the L/MWD data from the bottomhole assembly to the seafloor with a telemetry signal
Implementation Method 2
processing the telemetry signal at the seafloor to produce a processed signal
Implementation Method 3
transmitting the processed signal from the sea floor to the sea surface
Data Source
AI summary
A method for communicating data in an offshore data communication system comprises measuring L/MWD data with a sensor disposed in a bottomhole assembly positioned in a subsea borehole. The bottomhole assembly is disposed along a drillstring extending through the subsea borehole. In addition, the method comprises communicating the L/MWD data from the bottomhole assembly to the seafloor with a telemetry signal. Further, the method comprises receiving the telemetry signal with at least one telemetry transducer positioned proximal the sea floor. Still further, the method comprises processing the telemetry signal at the seafloor to produce a processed signal. Moreover, the method comprises transmitting the processed signal from the sea floor to the sea surface.