核磁共振测井.ppt

文档介绍：核磁共振测井
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Why NMR Logging
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Why NMR Logging…?
Porosity f
Saturation Sw
Permeability K
f Neutron
f Density
Rt
Sw > 60% water
Sw < 40% oil
40% < Sw < 60% oil + water
Sw
Rw
Rt
=
f
2
What will the reservoir produce?
Formation
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Why NMR Logging …?
Neutron / Density log responses
Porosity
f
Solids
Complex mineralogy
Formation model
1. Less sensitivity to pore fluids than to solid matrix;
2. Radioactivity sources.
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Why NMR Logging …?
Resistivity log responses
Water porosity
fw
Formation model
Complex texture
1. No resolution to capillary bound water;
2. Difficulty to determine clay bound water;
3. No sensitive to hydrocarbon types
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Why NMR Logging …?
f Neutron
f Density
Resistivity Rt
Sensitive volumes are poorly defined
Bore hole fluids effects
Mud cake effects
Rugosity effects
Depth of investigation mismatch
Vertical resolution mismatch
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Total Porosity
Effective Porosity
Pore Size Distribution
Permeability
CBW / BVI / FFI
Rock
Properties
Fluid
Properties
Reservoir
Understanding
Hydrocarbon detection
Hydrocarbon typing
Why NMR Logging …?
Log Analyst
Where are the HC’s ?
How much HC ?
What type of HC ?
Petrophysicist
What are the fluids ?
What is the reservoir quality?
What will flow ?
Reservoir Engineer
What will produce ?
At what rate?
Which recovery strategy ?
The NMR logging provides answers for:
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NMR Physics
核磁共振是磁场中的原子核对电磁波的一种响应,原子核由质子和中子组成,质子带正电,中子不带电。质子与中子统称为核子。所有含奇数核子以及含偶数个核子但原子序数为奇数的原子核,都具有内秉角动量(或叫“自旋”)。这样的核,自身不停地旋转,犹如一个旋转的陀螺。由于原子核带有电荷,它们的自旋将产生磁场,象一根磁棒,该磁场的强度和方向可以用核磁矩矢量来表示,即:
μ=γp
式中μ—磁矩;p—自旋角动量;γ—比例因子,被称做旋磁比,是磁性核的一个重要性质,每一个核都有一个特定的值,由实验测定。γ可以为正,亦可以为负,所以核磁矩的方向可能与核自旋角动量的方向相同或相反。
当没有外加磁场时,单个核磁矩随机取向,因此,包含大量等同核的系统在宏观上没有磁性。
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S
ization
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The Origin of ization
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