Induction Logging Antenna Non-Uniform Winding
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Solution Overview
Problem
Current induction array tools for formation resistivity logging lack sensitivity, particularly in high contrast situations and for thin or highly laminated beds, leading to inadequate tensor conductivity volumetric measurements and complicating the detection of hydrocarbon reservoirs and water/hydrocarbon boundaries.
Innovation Solution
The design of improved antennas with a hollow cylinder bobbin wrapped in a primary winding with more turns at the midpoint than at the ends, combined with a secondary winding, and a ferromagnetic core, enhances magnetic permeability and sensitivity, allowing for increased transmitter-receiver spacings and more accurate resistivity measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional solenoid-type antennas with uniform winding are used, then the antenna structure is simple and easy to manufacture, but the sensitivity and magnetic permeability are insufficient for detecting thin or highly laminated beds
Solution Approach 1:
The patent applies local quality by creating non-uniform winding distribution where the density of winding turns varies along the length of the antenna. Specifically, the winding density is higher at the ends and lower in the middle section, which optimizes the magnetic field distribution and enhances sensitivity for detecting thin or highly laminated beds while maintaining a manageable structural complexity
Solution Approach 2:
The patent changes the physical parameters of the antenna by introducing a magnetic core material with high permeability and by varying the winding density parameter along the antenna length. These parameter changes significantly enhance the magnetic permeability and sensitivity of the antenna, enabling accurate detection in challenging formation conditions
2Length of stationary object
If transmitter-receiver spacing is increased to improve depth of investigation, then the depth of investigation is improved, but the signal strength and measurement sensitivity decrease
Solution Approach 1:
The patent changes the magnetic properties parameter by incorporating a magnetic core material with high permeability in the antenna design. This parameter change amplifies the magnetic field strength and signal strength, allowing for increased transmitter-receiver spacing while maintaining adequate signal strength and measurement sensitivity for accurate resistivity measurements
3Measurement precision
If uniform winding distribution is used throughout the antenna, then the manufacturing process is simple, but the magnetic field distribution and sensitivity are suboptimal for deep induction measurements
Solution Approach 1:
The patent applies local quality by specifying different winding densities for different sections of the antenna. The winding density is higher at the end sections and lower in the middle section, which optimizes the magnetic field distribution for deep induction measurements. This localized variation in winding quality improves measurement precision while keeping the manufacturing process relatively simple through defined density zones
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
The enhanced antenna design increases the sensitivity and accuracy of induction logging tools, enabling better detection of hydrocarbon reservoir geometries and water/hydrocarbon boundaries, even in challenging formations, and provides stable performance under high-pressure and high-temperature downhole conditions.
Implementation Method 1
a ferromagnetic core, enhances magnetic permeability and sensitivity
Implementation Method 2
EM induction array tools work by using a transmitting coil or antenna (transmitter) to set up an alternating magnetic field in the earth formation. This alternating magnetic field induces eddy currents in the formation being evaluated.
Implementation Method 3
This alternating magnetic field induces eddy currents in the formation being evaluated. A plurality of receiving coils or antennas (receivers), disposed at varying distances from the transmitter antenna is used to detect the current flowing in the formation.
Data Source
AI summary
Improved receiver antennas are disclosed for long offset tensor induction army logging tools. The disclosed antennas include a bobbin which accommodates a ferromagnetic core. The outer surface of the bobbin is wrapped around a binding so that winding is thicker or includes more turns towards a center of the bobbin and is thinner or includes less turns towards the outer ends of the bobbin. The result is that the primary winding with a curved or parabolic profile that enhances the effective magnetic permeability and magnetic moment of the antenna. A secondary winding may also be utilized for flux feedback compensation. The elimination of winding turns towards the ends of the magnetic coil result in reduced DC resistance and the reduction in parasitic capacitance of the antennas. The disclosed antennas may be used in x-y-z receiver arrays.