Method for estimating a logging tool response in a layered formation
AssigneeSchlumberger Technology Corporation
InventorsJosselin Kherroubi, Laurent Mosse, Ollivier Faivre
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Abstract
A logging method and a logging tool for approximating a logging tool response in a layered formation are provided. The method includes obtaining a first layered profile of at least one first measurement log provided by a logging tool using a squaring process, obtaining a filtered measurement log from the first layered profile using a forward physical model for the logging tool, and estimating an approximation of the forward physical model using a parameterized function so as to provide a first logging tool response.
Claims14
A method for estimating at least one logging tool response in a layered formation, the method comprising:
- obtaining a first measurement log representative of at least one first electromagnetic property of the formation with a logging tool, wherein the first measurement log is affected by shoulder bed effects
- obtaining a first layered profile of the at least one first measurement log using a squaring process;
- obtaining a filtered measurement from the first layered profile using a forward physical model for the logging tool, wherein the forward physical model is a function linking the first electromagnetic property of the formation to the first measurement log;
- and
- estimating a local approximation of the forward physical model using a parameterized function, wherein the approximation is determined based on the filtered measurement so as to provide a first logging tool response
- deconvolving the at least one first measurement log by using the approximation of the forward physical model to correct the at least one first measurement log from shoulder bed effects,
- determining the at least one first electromagnetic property of the formation based on the deconvoluted at least one measurement log.
A method for estimating at least one logging tool response in a layered formation, the method comprising:
- a) selecting at least one first measurement log representative of at least one first electromagnetic property of the formation taken at a first frequency;
- b) approximating a first forward model so as to provide a first logging tool response for the at least one first measurement log, wherein the first forward model is a function linking the first electromagnetic property of the formation to the first measurement log;
- c) deconvolving the at least one first measurement log using the approximation to correct the at least one first measurement log from shoulder bed effects;
- d) selecting at least one second measurement log representative of the at least one first electromagnetic property of the formation taken at a second frequency lower than the first frequency;
- e) approximating a second forward physical model so as to provide a second logging tool response for the at least one second measurement log using the deconvolved at least one first measurement log, wherein the second forward physical model is a function linking the first electromagnetic property of the formation to the second measurement log;
- f) deconvolving the at least one second measurement log using the approximation to correct the at least one second measurement log from shoulder bed effects;
- and
- g) when the at least one second measurement log comprises a plurality of second measurement logs, repeating d) to f) for the rest of the second measurement logs,
- h) determining the at least one first electromagnetic property of the formation based on the deconvoluted at least one first and second measurement logs.
Dependencies are inferred from the claim text.