Sedimentary Facies Analysis Of The Second Section Of Qingshankou Formation In Daqingzijing Area

Da Qingzijing oilfield, a large-scale lithologic reservoir group with over a hundred million ton, is located in the centre of Changling sag depression which is located in centralsag in the southern songliao basin, due to higher oil strata,enormous workload, low level study on sedimentary facies of the target layer,sedimentary structures and lithological characteristics,it is unable to appply an comprehensive study on sedimentary disciplinarian in the entire working area.As a result,it has bacome a bottleneck which restricts the development of lithologic oil and gas exploration in the region.Through the observation and description of core, integrated with the use of seismic, well logging, etc., this paper makes analysis of trace elements, mudstone color value, heavy mineral ZTR index, ancient flows and the maturity of sandstone composition, meanwhile, ancient sedimentary environment and source directions of each layer were identified and Da Qingzijing oilfield's sedimentary facies types were clarified, are time and space distribution characteristics of sedimentary facies and reservoir sands were clarified, sedimentary evolution model was established and the dominant geological factors controlling the reservoir is defined combined with macro and micro facies, comprehensive study of sand microfacies.According to mudstone color value, rare earth elements, heavy minerals and paleocurrent analysis,material source of the second member in Qingshankou sections is mainly west and south, during the period,the climate was warm and humid, the scale of basin water is large, so the sendimentary condition is underwater oxygen free environment.Through the study of the core, drilling and logging data, in combination with depositional environment and provenance analysis, IV type delta depositional system of qinger member is firstly proposed by Green Erduan, the type of delta is affected by the storm seriously,river and estuarine sand bar sandbody is damaged by storm which is not conducive to the formation of the same thickness of sand body of channel sand body and finger-like sand body. The sand body is migrated by waves and then deposited the barrier bar in the front of sand bar approximately parallel with the coast line. The drilled sedimentary facies are mainly mouth bar,barrier bar, frontal sand sheet and underwater distributary channel, distributary.Through the core, drilling and logging data, in combination with depositional environment and provenance analysis, first proposed by Green Erduan IV delta depositional system, the type of delta waves affected by the storm seriously, river and estuarine sand bar sand by storm damage, is not conducive to channel sand body and finger-like sand body thickness of bar sand body formation. The transformation of sand transport by waves and then deposited in the estuary sand bar formed in front of approximately parallel with the coast shoreline outside the sand bar sand. The drilled sedimentary facies are mainly mouth bar, Bin outside sand bar, sand front seats and underwater distributary channel, distributary.At the basis of single well facies, this paper analyses log-facies and FMI-facies. This paper does statistical analysis of the statistics characteristic parameters which extracted through the log of core section and corresponded with the core description. At the result of statistical analysis, this paper establishes distinguishing expressions of log-fcies and achieves the automatic identification of log-facies by program. The dummy resistivity curve extracted from FMI overcomes the difficulty of facies identification of siltstone.On the basis of analysis of sandstone of layers graphs about each layer and sedimentary model are drawn in order to study the reservoir distribution rules and evolution characters.