Detection of gas reservoirs by the joint use of P- and PS-waves: A case study on the Ordos basin, China
Xiucheng Wei1, Xiangyang Li2, Yang Liu3, Songqun Shi4, Weidong Jiang5
1 Petroleum Exploration and Production Institute, China Petroleum and Chemical Corporation, Beijing 100083, China 2 Edinburgh Anisotropy Project, British Geological Survey, Edinburgh EH9 3LA, UK 3 Faculty of Resources and Information, China University of Petroleum, Beijing 102249, China 4 Changqing Research Institute, China National Petroleum Corporation, Xi’an 710021, China 5 Changqing Institute of East Geophysical Company, China National Petroleum Corporation, Xi’an 710021, China
Detection of gas reservoirs by the joint use of P- and PS-waves: A case study on the Ordos basin, China
Xiucheng Wei1, Xiangyang Li2, Yang Liu3, Songqun Shi4, Weidong Jiang5
1 Petroleum Exploration and Production Institute, China Petroleum and Chemical Corporation, Beijing 100083, China 2 Edinburgh Anisotropy Project, British Geological Survey, Edinburgh EH9 3LA, UK 3 Faculty of Resources and Information, China University of Petroleum, Beijing 102249, China 4 Changqing Research Institute, China National Petroleum Corporation, Xi’an 710021, China 5 Changqing Institute of East Geophysical Company, China National Petroleum Corporation, Xi’an 710021, China
摘要We present an example of using converted-waves for characterizing onshore gas reservoirs in the Ordos basin in Northwest China. The Ordos basin is the largest gas province in China. The main gas reservoirs (about 3 300 m in depth) are in upper Paleozoic sandstone that has low or reversed P-wave impedance and is immediately above a coal seam. This makes it very difficult to image the gas reservoirs using conventional P-wave data. Analysis of core, log and VSP data shows a weak PP reflection but a relatively strong PS-converted wave reflection, or both strong PP- and PS-reflections but with opposite polarity from the gas bearing sands, which indicates the potential of using PS-waves to image the gas reservoirs in the Ordos basin. Subsequently, thirteen seismic lines were acquired, processed and interpreted to verify the PP- and PS-responses, and two corresponding attributes (PP- and PS- amplitude ratio and polarity ratio) are used to map the reservoirs through joint PP and PS analysis.
Abstract:We present an example of using converted-waves for characterizing onshore gas reservoirs in the Ordos basin in Northwest China. The Ordos basin is the largest gas province in China. The main gas reservoirs (about 3 300 m in depth) are in upper Paleozoic sandstone that has low or reversed P-wave impedance and is immediately above a coal seam. This makes it very difficult to image the gas reservoirs using conventional P-wave data. Analysis of core, log and VSP data shows a weak PP reflection but a relatively strong PS-converted wave reflection, or both strong PP- and PS-reflections but with opposite polarity from the gas bearing sands, which indicates the potential of using PS-waves to image the gas reservoirs in the Ordos basin. Subsequently, thirteen seismic lines were acquired, processed and interpreted to verify the PP- and PS-responses, and two corresponding attributes (PP- and PS- amplitude ratio and polarity ratio) are used to map the reservoirs through joint PP and PS analysis.
Xiucheng Wei, Xiangyang Li, Yang Liu, Songqun Shi, Weidong Jiang. Detection of gas reservoirs by the joint use of P- and PS-waves: A case study on the Ordos basin, China[J]. 《地震学报》英文版, 2009, 22(3): 307-313.
Xiucheng Wei, Xiangyang Li, Yang Liu, Songqun Shi, Weidong Jiang. Detection of gas reservoirs by the joint use of P- and PS-waves: A case study on the Ordos basin, China. Earthquake Science, 2009, 22(3): 307-313.