Recent research from the Sinopec Geophysical Research Institute has unveiled a sophisticated method for predicting thin sand reservoirs associated with coal seams, particularly in the PB area of the Xihu Sag in the East China Sea. This study, led by Pan Luo, aims to enhance the identification techniques of these reservoirs that are often obscured by the complexities introduced by coal seams.
In an environment influenced by river-tidal bidirectional flow, thin coal seams are embedded within oil and gas-bearing strata of the Pinghu Formation. These coal seams significantly alter the seismic amplitude, phase, and frequency, making accurate reservoir identification a complex challenge. “Understanding how coal seams affect seismic responses is crucial for effective reservoir characterization,” Luo stated, emphasizing the practical implications of the research.
The study meticulously analyzes both seismic and logging data to evaluate the response characteristics of the reservoirs before and after the coal seams are removed. By employing poststack seismic forward modeling based on wave equations, the researchers are able to clarify the seismic response characteristics of the reflection coefficient. This innovative approach not only sheds light on the impact of coal seams but also leads to a more refined understanding of reservoir dynamics.
One of the key findings reveals that when the reservoir thickness falls below the tuning thickness, the seismic data can be rotated by 90 degrees, thereby minimizing the coal seam’s influence on the reservoir’s seismic signature. This insight is pivotal for geoscientists and engineers who rely on seismic data for exploration and production decisions, as it could significantly improve the accuracy of reservoir predictions.
To further enhance the identification process, Luo and his team introduced a three-step high-quality reservoir prediction methodology. This involves broadband spectrum inversion and prestack Vp/Vs and AVOG analysis, which collectively provide a more precise description of the distribution of aerated sand bodies within the study area. Such advancements hold substantial commercial value for the construction sector, particularly in optimizing resource extraction and minimizing operational risks.
The implications of this research extend beyond the immediate findings; they signal a transformative shift in how thin sand reservoirs with coal seams are approached in the industry. By refining predictive techniques and enhancing the understanding of seismic responses, this work paves the way for more efficient exploration strategies, ultimately leading to better resource management and reduced costs.
This groundbreaking research was published in ‘地质科技通报’, which translates to ‘Geological Science and Technology Bulletin’. For more information about the research and its commercial applications, you can visit the Sinopec Geophysical Research Institute’s website at Sinopec Geophysical Research Institute Co. Ltd..