Seismic Electromagnetic Reservoir Property Mapping
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Solution Overview
Problem
Current seismic and electromagnetic survey methods struggle to accurately estimate subsurface reservoir properties beyond the limited area around wellbores, as local factors and varying petrophysical properties complicate the correlation of seismic and electromagnetic attributes with reservoir characteristics.
Innovation Solution
A method that correlates seismic and electromagnetic survey data from wellbores with petrophysical data to determine reservoir properties, using a calibration function to predict these properties at other geodetic positions, enabling the creation of detailed subsurface maps by converting depth-based data to time-based representations and matching electromagnetic data resolution with seismic data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If well log and core data are used to determine petrophysical properties, then measurement precision is improved, but the area of measurement is limited to around the borehole
Solution Approach 1:
The patent combines well log data, core data, and seismic data into an integrated system. By merging these different data sources, the method achieves both high measurement precision (from well logs and cores) and extended measurement area (from seismic data coverage), resolving the contradiction between precision and area.
Solution Approach 2:
The patent uses seismic attributes as an intermediary to bridge the gap between wellbore measurements and interwell regions. The seismic data acts as a mediator that transfers the high-precision petrophysical information from well logs to locations away from the borehole, enabling accurate property estimation in areas previously inaccessible to direct measurement.
2Area of stationary object
If seismic data is used to estimate subsurface properties in interwell regions, then the area of measurement is improved, but measurement precision deteriorates due to local factors and varying petrophysical properties
Solution Approach 1:
The patent transforms seismic data from raw waveforms to derived attributes (acoustic impedance, velocity, density) that have direct physical relationships with petrophysical properties. This parameter transformation enables the seismic data to maintain high measurement precision while covering large interwell areas, as the attributes are specifically designed to correlate with reservoir properties.
Solution Approach 2:
The patent applies location-specific calibration functions that are determined at each well location and then applied to surrounding seismic data. This local quality approach ensures that the relationship between seismic attributes and petrophysical properties accounts for local geological variations, maintaining high precision across different interwell regions despite varying petrophysical conditions.
3Loss of information
If electromagnetic survey data is acquired, then additional subsurface information is obtained, but data processing complexity increases due to resolution matching requirements
Solution Approach 1:
The patent applies resolution matching selectively only to the electromagnetic data that needs to be integrated with seismic data, rather than processing all electromagnetic data at full resolution. This partial action approach maintains the necessary subsurface information while reducing the overall processing complexity by focusing computational resources only where integration is required.
Data Source
AI summary
A method for mapping a property of a subsurface reservoir includes determining a value of at least one reservoir property from measurements obtained from a well drilled through the reservoir. A relationship is determined between the at least one property of the reservoir and at least one seismic attribute and at least one electromagnetic survey attribute at a geodetic position of the well. A value of the at least one reservoir property is determined at at least one other geodetic position from a value of the at least one seismic attribute, a value of the at least one electromagnetic survey attribute at the at least one other geodetic position, and from the determined relationship.