Method for time lapse reservoir monitoring
AssigneePGS Data Processing, Inc.
InventorsChristopher Philip Ross, Mehmet Suat Altan
Life of this patent
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Abstract
A method of comparing multiple seismic survey data sets of a reservoir, is provided, wherein a first seismic survey data set is taken at a first time and a second seismic survey data set is taken at a second time, to detect changes in the reservoir between the first time and the second time. Generally, the method comprises design of a crossequalization function for the second data set based on a comparison of unchanging portions of the two data sets. Also provided is a processing method for preparing each survey according to similar processing steps with information taken from each survey.
Claims45
A method of comparing multiple seismic survey data sets of a reservoir, wherein a first seismic survey data set is taken at a first time and a second seismic survey data set is taken at a second time, to detect changes in the reservoir between the first time and the second time, the method comprising:
- providing a first reflection event in the first seismic survey data set having a corresponding second reflection event in the second seismic survey data set,
- wherein the first reflection event and the second reflection event represent an unchanged portion of geologic structure in or near the reservoir and
- wherein the first reflection event is represented by a first set of event parameters and the second reflection event is represented by a second set of event parameters;
- providing an acceptance threshold difference function between the first set of event parameters and the second set of event parameters;
- determining a crossequalization function to apply to the second set of event parameters, the crossequalization function being characterized in that, upon application of the crossequalization function to the second set of event parameters, whereby a crossequalized set of event parameters is defined, and the difference between the first set of event parameters and the crossequalized set of event parameters is below the threshold difference function;
- applying the crossequalization function to a third reflection event, the third reflection event being related to the second data set,
- wherein a crossequalized third reflection event is defined,
- wherein the third reflection event has a corresponding fourth reflection event in the first data set, and
- wherein the third and fourth reflection events represent a changing portion of the reservoir;
- comparing the crossequalized third reflection event to the fourth reflection event by subtracting the crossequalized third reflection event from the fourth reflection event.
A method of deconvolution of multiple sets of seismic data from the same geographic area is provided, the method comprising:
- designing of a deconvolution operator dependent upon data from at least two of the sets of seismic data, wherein the at least two sets of seismic data were recorded at different times;
- applying the deconvolution operator in a deconvolution process to both of the at least two sets of data;
- and
- conducting further time-lapse processing to form a difference record.
A method for performing time-lapse seismic survey, signal processing, having at least a first survey and a second survey, wherein each survey has a set of seismic data, the method comprising:
- performing a set of processing steps on the first survey;
- performing the set of processing steps on the second survey;
- wherein the set of processing steps is dependent upon a set of seismic signal parameters;
- choosing at least one of the set of parameters by a selection process dependent upon data from both the first survey and the second survey;
- and
- applying the at least one of the set of parameters in the at least one of the set of processing steps to both the first survey and the second survey.
Dependencies are inferred from the claim text.