Using 3-D technology, seismic information is transformed from raw data into a unified analysis of potential reserves. Although it is utilized primarily to bring clarity to previously identified prospects, it can also define previously unrecognized, high-quality locations. In prospects that have already been identified, 3-D technology serves as a sifting tool, separating the good from the bad. Our objective is to perfect the data in order to minimize the number of dry holes drilled and increase the number of productive wells. The following is a brief description of advanced reprocessing techniques currently in use for prospect generation and analysis.
Proprietary high frequency imaging techniques developed by GeoTrace recover usable high frequencies from seismic data that was previously considered unintelligible. HFI®-processed data provides increased resolution for structural and stratigraphic interpretation.
This technique combines a high frequency relative acoustic impedance volume with the low frequency velocity trend estimated from non-seismic sources. The resulting acoustic impedance volume is an excellent tool for imaging thin producing beds, detecting subtle stratigraphic changes and pinpointing optimal porosity in zones.
3D Kirchhoff PSDM is rapidly evolving to become the standard for accurately imaging complex geological structures such as salt domes, faults, overthrusts, etc.
3D Kirchhoff PSTM is the industry's most widely used advanced imaging technique for accurately imaging complex geological structures, allowing higher quality images and increased data angles for AVO/AVA analysis.
This methodology detects anomalies that arise as a result of beds with very low Q, such as gas sands, which absorb high frequencies at a much faster rate than low frequencies. This greatly increases the reliability of the results and makes FAR an excellent tool to further high-grade AVO anomalies.
Often called "Bright Spot Analysis", AVO reveals significant anomalies, or bright spots, when sound waves reflect off a gas-bearing formation. Properly imaged relative amplitudes are a key component of this process and are attained using fully prestack migrated gathers from Geotrace's proprietary Kirchhoff time and depth migration programs. Gathers are further prepared using ANVEL and radon filtering to attenuate multiples and ambient noise, generating information regarding angle stacks, Product Gradient and Fluid Factor. Bright Spot Analysis has been applied with great success in the shallow Miocene gas trend along the Gulf Coast.
Reservoir Characterization focuses on defining the parameters related to porosity, permeability and compartmentalization; including the rock matrix, micro-fractures, macro-fractures, stratigraphy, pressures, fluid contacts and faulting.
A finite element model is created using reservoir information. The model includes permeability barriers such as faults and stratigraphic boundaries. Dual porosity systems such as fractured matrix can also be analyzed. The simulation model is run repeatedly until there is a reasonable match to the production history of each existing well. When the history match is successfully completed, a simulation is run to predict the performance of future development plans.
For more information on this topic, visit the experts at www.geotrace.com.
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