Applying quantitative grain fluorescence techniques to investigate regular pattern of hydrocarbon migration and accumulation in Jurassic reservoirs in hinterland of Junggar Basin

Considering that the regular pattern of hydrocarbon migration and accumulation in Jurassic reservoirs in the hinterland of Junggar Basin is not clear, which makes petroleum exploration in this area more hindrance, grains containing oil inclusions (GOIs) and quantitative grain fluorescence (QGF and QGF-E) techniques were carried out to reveal the regular pattern of hydrocarbon migration and accumulation in Jurassic reservoirs in the hinterland of Junggar Basin. J1s22 and J1s212 in Jurassic reservoirs, where there exist effective lateral and vertical seal rocks, display very high GOI values and strong light oil QGF and QGF-E responses, greater than the generally accepted threshold value for an oil column, which suggests that J1s22 and J1s212 charged initially by massive light oil, and leaked. The GOI values and QGF and QGF-E responses drastically reduce with the increase of depth. Sandstones of J1s211 in Jurassic reservoirs are thick and their lateral distribution is stable and continuous. However, the GOI values and QGF and QGF-E responses of J1s211 only indicate an oil secondary migration pathway or water zone. The distribution of GOI values and QGF and QGF-E responses indicate that oil firstly moves up to J1s22 and J1s212 via J1s211 by the effect of buoyancy because of the lack of vertical closure rocks in J1s211.Then the oil migrates under the cap rock and is accumulated in the sand unites with effective lateral seal, showing that high-quality lateral seals have important implication for petroleum exploration in Jurassic in the hinterland of Junggar Basin. ©, 2014, Central South University of Technology. All right reserved.