Claims
- 1. A method for 2D inversion of true resistivity from dual laterolog tool measurements, using a pre-calculated look-up table, comprising the steps of:deriving an initial layered earth model; dividing the earth model into intervals; calculating a 2D tool response in each interval from the earth model; checking whether the 2D tool response and the tool measurements substantially match; and iterating the following steps until the match is satisfactory: deriving a 1D radial tool response in each interval using the pre-calculated look-up table; calculating shoulder bed effects in each interval by subtracting the 1D radial tool response from the 2D tool response; and applying a non-linear least square optimization at boundaries of the intervals and local maximum and minimum values in the intervals to update the earth model.
- 2. The method of claim 1, wherein the step of deriving an initial earth model comprises the further step of:pre-processing the initial earth model to honor geological and geophysical constraints.
- 3. The method of claim 1, wherein the number of selected intervals equals the number of layers in the derived earth model.
- 4. The method of claim 1, wherein the step of calculating the 2D tool response involves 2D finite element forward modeling.
- 5. The method of claim 1, wherein the step of deriving a 1D radial tool response comprises the step of:interpolating values from the pre-calculated look-up table.
- 6. The method of claim 1, wherein the step of updating the earth model comprises the further step of:post-processing the updated earth model.
Parent Case Info
This application claims the benefit of U.S. Provisional Application No. 60/237,749 filed Oct. 3, 2000.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4484278 |
Edmundson |
Nov 1984 |
A |
5675147 |
Ekstrom et al. |
Oct 1997 |
A |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/237749 |
Oct 2000 |
US |