Sequence Stratigraphic Study On The Fuyu Reservoir In The Chao1-Chaoqi3 Block

To solve the realistic problems caused by the uncertainty of the heterogeneity of thereservoir during the middle or late stage of oil-field development in the low-permeability andlow-porosity district in the east of the Daqing placanticline, this article have a systematichigh resolution sequence stratigraphic study on the Fuyu reservoir in the Chao1-Chaoqi3block,Chaoyangou oil fields by using the principles and methods of high resolution sequencestratigraphy and modern sedimentology and petroleum geology and latest research results ofreservoir characteristics for the first time. The main results are listed below:1. In combination with regional standards layer, 2 long-term base-level cycles aredistinguished. According to the data of rock cores, 41 short-term base-level cycles aredistinguished. 7 mid-term base-level cycles are distinguished within the framework oflong-term base-level cycles by using rock cores to demarcate logging curve and by using thelogging curve stacking patterns of the short-term base-level cycles, then the high resolutionsequence stratigraphic framework are established and the detailed description to thecharacteristic of the short-term and the mid-term and the long-term base-level cycles arecarried on separately. The identification methods to short-term and mid-term and long-termbase-level cycles in this article are significant to similar sedimentary environment.2. 15 kinds of logging's microfacies models have been established. We made a deliberatesedimentary microfacies study on the 41 sedimentary units, corresponding to the stratum ofshort-term base-level cycle, and analyzed the relationship between sedimentary macrofaciesof the 41 sedimentary units with the changing mid-term and long-term base-level cycles. It ispointed out that the braided river develops mainly in the early stage of the uprising periods ofthe long-term base-level cycle, and the energetic meandering river develops mainly in themiddle stage of the uprising periods of the long-term base-level cycle.3. By using the physical property of the coring, the predict model of porosity andpermeability are established. We made secondary interpretation to all the wells in theresearching field and analyzed the relationship between porosity and permeability of the 41sedimentary units with the changing mid-term and long-term base-level cycles. The porosityand permeability are much higher in the sedimentary units in the early stage of the uprisingperiods of MSC5 and MSC6 than others.4. Analyzed the characteristic of the intercalation of the 41 sedimentary units and itsrelationship with the changing mid-term and long-term base-level cycles in details bydifferent microfacies.5. Analyzed the macro heterogeneity characteristics including in-layer heterogeneity andthe interlayer heterogeneity and planar heterogeneity of every sedimentary units and itsrelationship with the changing mid-term and long-term base-level cycles in details.6. Using the research results mentioned above, we take 12 parameters in 5 categoriessuch as reservoir size parameters and physical property parameters and permeabilityheterogeneity parameters and intercalation parameters of the reservoir and oil bearingproperties parameters into the quantitative comprehensive evaluation, and classify thereservoir into â… or â…¡ or â…¢ or â…£ rank. The calculation results are consistent with thecharacteristics of mid-term and long-term base-level cycles and the distribution of sand bodiesand the distribution of sedimentary facies. The evaluation results are instructive to thecomprehensive adjustments during the middle or late stage of oil-field development. Theevaluation methods are significant to the similar reservoir.