Study On The Configuration And Heterogeneity Of Braided River Delta Sedimentary Sand Bodies

The 1st block of Tahe oilfieldis located at the junction of gangtai county and kuqa county in the north of tarim basin.At present,the recovery rate is only 32%,and the remaining recoverable reserves are 1.25 million tons.However,due to the lack of drilling,large well spacing,low seismic resolution,and insufficient precision of braided river delta sand body configuration characterization under sparse well pattern,the progress of exploration and development is restricted.Therefore,this thesis by Miall configurational theory as the instruction,under the 1st block of Tahe oilfieldis oil group on the basis of studying the sand body configuration,choose to have similar braided river delta sedimentary background of outcrop geological investigation and surveying and mapping,braided river delta sedimentary unit configuration and configuration mode,optimizing configuration unit scale,establishing the braided river delta sedimentary configuration parameters and geological knowledge base unit scale,guidance in tahe area 1 rare pattern under the condition of the braided river delta sand body configuration and fine geologic modeling,to provide geological basis for reasonable development adjustment scheme.Braided river delta plain and frontal deposition are developed in the lower oil formation of the 1st block of Tahe oilfieldis,and the main configuration units are braided distributary channel,heart beach,underwater distributary channel and estuary dam.Choice of shanxi's steak floor groove profile of shanxi formation,gansu,shanxi datong yungang group profile believed Rui water of river section,yanan GanGuYi yan profile such as a total of four of study on sand body configuration of outcrop section.The shanxi formation of baode tiaolougou formation in Shanxi Province has braided delta front deposition,which can be divided into five levels of configuration units,namely,laminar formation,laminar formation,estuary dam/subaqueous distributary channel proliferation body,estuary dam/subaqueous distributary channel,and single-phase subaqueous distributary channel.The sand body thickness of single-stage distributary channel is 0.9-4.5m,with an average thickness of 2.1m.Width 7~23m,average width 14.7m;The ratio of width to thickness is5.4~8,7.2 on average.The sand body of single period estuary dam is 1.5-2.1m thick with anaverage thickness of 1.7m.Width 11~22m,average width 17m;Width ratio 7.5~12,average 9.6.The cross section of the yungang formation in datong,Shanxi Province,shows the sedimentation in the upper reaches of braided river delta plain.There are four kinds OF horizontal splicing relationships OF sand body configuration units: CH/ACH--PB,CH--CB--CH,CH--OF--CH,CH/ACH--PB--OF.The braided channel sand body in single stage is 2.0-6.5m in thickness,50-180 m in width and 25-30 in width ratio.The thickness,width,width and width of the sand body are 2.5~7.0m,70~240m and 30~35 respectively.Believed in gansu Rui water river extend long group 8-6 section for shallow braided river delta front deposition.According to the consensus,there are four types of lithofacies in the 7types,namely,underwater distributary channel,estuary dam,underwater natural dike and distributary bay,and the vertical superposition mode of the configuration unit can be divided into superposed type,scour and fill type and isolated type.The changchang 2section of yanhe yanchang in gan gu,yan 'an is deposited in the lower reaches of the braided river delta alluvial plain with low curvature and rich sand.Seven main lithofacies types and three configuration units of channel,heart beach and flood plain were identified.The single-stage river course is 2.5~6.8m in thickness,60~180m in width and 25~30 in width ratio.The single-stage core beach layer is 2.8~7.5m thick,80~250m wide and 30~35 wide to thick.The main factors controlling the sand body configuration of braided river delta are tectonic movement,river flow,climatic conditions and changes of sedimentary datum level.Grilled prudential building of shanxi group profile and shanxi datong yungang ditch shanxi section andthe 1st block of Tahe oilfieldis under the oil reservoir with a similar set of sedimentary background and the hydrodynamic conditions,respectively,to build the braided river delta plain and front sand body configuration distribution patterns and to establish its unit parameter model,the results for residual oil in the 1st block of Tahe oilfieldis mining and dilute pattern under the condition of the braided river delta sand body configuration modeling has a certain reference significance.