Methods and systems for estimating formation resistivity and porosity
US-8947092-B2 · Feb 3, 2015 · US
Dielectric tool-based formation porosity logging system and methods
US9335433B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9335433-B2 |
| Application number | US-201114110803-A |
| Country | US |
| Kind code | B2 |
| Filing date | Sep 26, 2011 |
| Priority date | Apr 18, 2011 |
| Publication date | May 10, 2016 |
| Grant date | May 10, 2016 |
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Abstract
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A method and system for calculating formation porosity is presented. The method includes calculating formation porosity of a borehole by obtaining complex dielectric constant measurements with a high frequency dielectric tool. Next, a dielectric constant of formation water is derived from the complex dielectric constant measurements. Finally, a formation porosity is determined based at least in part on the measured complex dielectric constant and the derived dielectric constant formation water.
First claim
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What is claimed is: 1. A formation porosity logging method, comprising: obtaining complex dielectric constant measurements with a dielectric tool; deriving a complex dielectric constant of formation water from the measured complex dielectric constant measurements; wherein deriving the complex dielectric constant of formation water comprises determining a loss tangent of formation water as a function of water dielectric loss, water dielectric constant and water resistivity, wherein the loss tangent of formation water is a ratio of an imaginary part of the complex dielectric constant over a real part of the complex dielectric constant; and determining a formation porosity, based at least in part on the measured complex dielectric constant and the derived complex dielectric constant of formation water. 2. The method of claim 1 , wherein said complex dielectric constant is expressed as ɛ = ɛ ′ + j ( 1 ω ɛ 0 R + ɛ ″ ) wherein ∈′ represents the lossless relative permittivity, ∈″ represents imaginary component of permittivity attributed to bound charge and relaxation phenomena, and R represents formation resistivity. 3. The method of claim 1 , wherein said loss tangent of formation water is expressed as ( tan δ ) w = 1 ω ɛ 0 R w ɛ w ′ + ɛ w ″ ɛ w ′ wherein ∈ ″ w /∈ ′ w represents water dielectric loss, ∈ ′ w represent water dielectric constant and R w represents water resistivity. 4. The method of claim 3 , wherein water dielectric constant (∈′) is a function of water resistivity and temperature. 5. The method of claim 1 , wherein determining a formation porosity includes simultaneously solving equations ∈ ′ w =ƒ(R w ,T) and 1 ω ɛ 0 R meas ɛ meas ′ = α ( 1 ω ɛ 0 R ω ɛ ω ′ + ɛ ω ″ ɛ ω ′ ) to determine formation water resistivity and dielectric constant, wherein ∈ ′ w represents water dielectric constant, R w represents water resistivity, T represents water temperature, R meas represents apparent formation resistivity, ∈ ′ meas represents formation's apparent complex dielectric constant, α is an environmental factor, and ∈ ″ w /∈ ′ w represents water dielectric loss. 6. The method of claim 5 , wherein α is an environmental factor obtained by calibration to account for discrepancies. 7. The method of claim 6 , wherein said discrepancies include the effect of mud cake, the matrix, and system parameter drifts. 8. The method of claim 1 , wherein said determining a formation porosity, further includes substituting said water resistivity and said dielectric constant into this equation ϕ Water = ɛ Meas - ɛ Matrix ɛ MF - ɛ Matrix , wherein ∈ meas represents complex dielectric consta
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- G01V3/30Primary
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- What does patent US9335433B2 cover?
- A method and system for calculating formation porosity is presented. The method includes calculating formation porosity of a borehole by obtaining complex dielectric constant measurements with a high frequency dielectric tool. Next, a dielectric constant of formation water is derived from the complex dielectric constant measurements. Finally, a formation porosity is determined based at least in…
- Who is the assignee on this patent?
- Li Jing, Kainer Gary, Rourke Marvin, and 2 more
- What technology area does this patent fall under?
- Primary CPC classification G01V3/30. Mapped technology areas include Physics.
- When was this patent published?
- Publication date Tue May 10 2016 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 1 related publication on this page (citations in our corpus or others sharing the same primary CPC).