The alteration of iron bearing minerals induced by hydrocarbon microseepage above oil/gas reservoirs has been evaluated using measurements of soil magnetic susceptibility κ , geochemical compositions (gas hydroca...The alteration of iron bearing minerals induced by hydrocarbon microseepage above oil/gas reservoirs has been evaluated using measurements of soil magnetic susceptibility κ , geochemical compositions (gas hydrocarbon and alteration carbonate Δ C ), and composition and concentration of iron bearing minerals. The analyses were performed along two profiles across the Qiangtang basin in Tibet, China: the Nuoermahu Xuehuanhu profile (C) and the Mugari Huochetoushan profile (E). Results show that three strong magnetic anomalies (C 1, E 1 and E 2 anomalies) are related to the distribution of Neogene volcanic rocks on the surface in the Gangmacuo Xiyaergang uplift. Two other anomalies (C 2 and E 4 anomalies), characterized by both moderately amplitude magnetic susceptibility and elevated soil gas hydrocarbons, occur near fault zones in the Cuoni Donghu synclinorium. These latter anomalies display characteristics of hydrocarbon microseepage anomalies commonly associated with oil and gas accumulations. Their presence in the Cuoni Donghu synclinorium suggests that parts of the Qiangtang basin may have significant petroleum potential.展开更多
文摘The alteration of iron bearing minerals induced by hydrocarbon microseepage above oil/gas reservoirs has been evaluated using measurements of soil magnetic susceptibility κ , geochemical compositions (gas hydrocarbon and alteration carbonate Δ C ), and composition and concentration of iron bearing minerals. The analyses were performed along two profiles across the Qiangtang basin in Tibet, China: the Nuoermahu Xuehuanhu profile (C) and the Mugari Huochetoushan profile (E). Results show that three strong magnetic anomalies (C 1, E 1 and E 2 anomalies) are related to the distribution of Neogene volcanic rocks on the surface in the Gangmacuo Xiyaergang uplift. Two other anomalies (C 2 and E 4 anomalies), characterized by both moderately amplitude magnetic susceptibility and elevated soil gas hydrocarbons, occur near fault zones in the Cuoni Donghu synclinorium. These latter anomalies display characteristics of hydrocarbon microseepage anomalies commonly associated with oil and gas accumulations. Their presence in the Cuoni Donghu synclinorium suggests that parts of the Qiangtang basin may have significant petroleum potential.
