Study Of Sedimentary Microfacies In One Setion Of Nantun Group In Wuerxun Hollow

This topic is intended to use sequence stratigraphy, petroleum geology, sedimentology, tectonic stratigraphy, reservoir geology and basin analysis studies and other subjects of the new theory, new methods, integrated with logging,well logging,core, particle size,heavy minerals, etc.,and based on the results of previous research,to divide sequenceof one section about nantun group and build regional comparative framework for isochronous sequence and conduct the study area characteristics of the distribution of sedimentary facies. Clarify the sedimentary facies, microfacies within the depositional system, the control factors of distribution between sequences and sedimentary facies.Through research we found that: the region boundary fault-controlled subsidence is wuxi fracture. It is a typical Graben of "West-off East super, West steep east slow". has "brought East and West, North and South sub-block" feature. The fracture and erosion frequentiy and have difficult to contrast formation.Based on the characteristics of seismic profiles, well logging curves, lithological characteristics to define the sequence boundaries, according to the principle of "cyclic comparison, hierarchical control"to division the purpose of layer into 4 four sequences.By source analysis, we know that there are two main material source during the deposition , one NE direction to extend the deposition of body axis, and second, south and west of work area . Through a large number of observation, we have a conclusion that:the main facies developed in this area islacustrine facies, braided river delta facies and fan-delta facies, only some areas have lake floor fan phase.As to the reservoir lithology,,the main sand is thin sandstones,,conglomerate,,sandy conglomerate less, the heterogeneity of reservoir permeability is strong and not favorab to oil exploitation.Studies have shown that: the most favorable reservoir facies is lake floor fan phase, followed by the outer braided delta front, fan-delta front outside the second, and followed by the braided delta front, fan -delta front, and the last is shore-shallow lake facies. Recommends the deployment of well location as far as possible to find the location of lake floor fan phas and outer braided delta front.