Analysis Of Sedimentary System In Xinxial Of Jiangling Sag Xingouzui Formation

Jiangling depression is located in the southwest of Jianghan basin. A cape to the east-new and channel and low bulge, ji shan fault sag and river to the north, YuanAn sag, apart from Jingmen graben, south eastern overlap on huarong uplift, and for the western Hunan dongting basin, north west fault is bounded and ZhiJiang sag is adjacent to greet temple, south to the section sells overlap in medieval living yidu reach the anticline belt and SangZhi Hefeng-Shimen synclinorium, is the largest cretaceous-paleogene in jianghan basin is a sedimentary sag, an area of 6500 km. At present, the Jiangling depression exploration degree is low, the resource discovery rate is low, has great exploration potential.At the same time, of xingouzui formation in Jianglin depression is a clastic mixed with evaporation sedimentary sag, oil, salt, symbiosis.Jingzhou anticline belt found rich oil and gas, with the deepening of the development.The understanding of the original sedimentary microfacies and sand body connectivity knowledge can’t satisfy the need of production. So on depositional system distribution research achievement into practice, and deepen the Jingzhou anticline belt of sedimentary microfacies and sand body connectivity.Provide the basis for the next step of rolling development.Based on the core logging data, through core observation and description, Zhamingyan electric relationship, to complete the core phase analysis;Find out from clastic sediments to chemical sedimentary types of sedimentary facies, establish logging facies model;Using log facies analysis result, the calibration by log facies, the distribution of sedimentary facies analysis.Through the phased, find out the distribution of sandstone, predicting favorable lithologic trap.We mainly draw the following conclusions.1. Jiangling depression sandstone grain size is so fine, it gives priority to with silt, fine sand, coarse sand is not developed in the gravel.The average particle size in a s-shaped curve shape that clastic particle size distribution on the whole for the delta front mouth bar after former delta distributary channel deposit types.2. Based on the analysis of log facies, delta plain subfacies mainly develops distributary channel, natural levee, crevasse splay microfacies. Distributary channel likes a bell-shaped curve or box and bell-shaped curve, natural levee located at the top of the distributary channel, the lithology is a kind of argillaceous siltstone, has the character of the Qu Zhong type. Splay microfacies in the delta plain subfacies, has a character of a funnel shape.Dark mudstone distribution, distribution of evaporite, complete the small layers of sedimentary facies in the study area figure 7;people think that Jingzhou to the north, inclined belt JingXi oilfield to the west, distributary channel leading edge;eight ridge oilfield to the east, located in the YuanAn stream delta front distributary channel area.3. On the basis of summarizing the predecessors’ achievements, through the analysis of heavy mineral, combined with the lithology of sandstone, and the analysis of granularity, confirmed that the Jiangling sag under the new period of development only YuanAn water system in northern and southern Jing drainage system, two sources of Yuanan water system in oil field and the region west of eight ridge, Nan jing water distribution in the oilfield, JingXi oilfield and the east of the garden;developed from the northern sag.4. Phase diagram, Through core observation,on the base on the analysisi of the phase diagram and logging data,combined with the data of grain size,to sum up the main sedimentary microfacies types in the study area include the following six kinds of microfacies types distributary channel front the delta, between tributary bay;shallow lake and sand dam, shallow lake of mud;salt lake.5. Epositional systems of Jaingling sag have three aspects of general characteristics:(1) northern paste mud, dark mudstones and facies zone in the center. (2) north sand are controlled by two drainages, east to the south Jing river, west to YuanAn drainage.(3) MeiHuai bridge sub-sag in the front of the YuanAn river, zifusi in front of Nan Jing river systems.Mainly two kinds of sedimentary system and lake basin evaporites system.6. Based on the sandstone distribution, structure figure, logging interpretation results figure and test results lamination figure, it analyzes and evaluates the lithologic trap, favorable area lamination, according to the lamination level, selection of lamination layers in the multi-layer area, totally choose two zones those are the most favorable.