| Based on the theory of sedimentology, Logging geology， reservoirsedimentology and petroleum geology, this dissertation take typical tight clasticreservoir-lower Shihezi formation in Daniudi gas field, Ordos basin. In the fullreference on the basis of predecessors’ achievements, macroscopic observation andmicro analysis combined, qualitative analysis and quantitative research combined, testanalysis and theoretical research combined, using field profiles and drilling cores andlogging curves and all kinds of test data, some content and achievements of theresearch are as follows:1.According to the stratigraphic division of the North China Branch of Sinopec,all levels of the sequence interface and the identification marks are studied in detail byusing field sections, drilling cores, well logging curves, etc. And the division schemeof the high-resolution sequence stratigraphy consists of four long-term (LSC1~LSC4),9mid-term (MSC1~MSC9) and dozens of short-term cyclic sequences in the lowerShihezi formation of the study area. A sequence stratigraphic framework is set up afterstudying all kinds of sequence developing characteristics and sequence stratigraphiccorrelation of well drilling.2.Identified marks of sedimentary facies that are rock colors, rock types,sedimentary structure, section structure and log facies is studied in detail.The writerargues that the lower Shihezi formation of the study area belongs to braidedriver-meandering river depositional system.He1member and He2-1sub-memberbelong to braided river deposition. He3member and He2-2sub-member belong tomeandering river deposition. And different subfacies and microfacies are divided.3. Based on detailed observation and description of drilling cores, a variety ofrock types and characteristics, as well as lithofacies system of gas-bearing sand bodies,are studied systematically.12lithofacies types and4lithofacies combinations of gas-bearing sand bodies are distinguished in lower Shihezi formation of Daniudi gasfield. A logging responsive template on different lithofacies types and combinations issetted up by studying responsive characteristics of Lithofacies-log facies-sedimentarymicrofacies from135cored well. These achievements have laid a solid foundation forresearching lithofacies paleogeographic evolution and drawing industrial plan oflithofacies.4. More than600logs of development well are inverted lithofacies andsedimentary microfacies by using responsive characteristics of Lithofacies-logfacies-sedimentary microfacies.4sand thickness and sedimentary microfacies diagramin lower Shihezi formation of the study area are drew in detail by adopting mid-termcycle sequence as a mapping unit. Based on the above results, the writer describes thelithofacies-paleogeographic characteristics and evolution detailedly and show surfaceexhibition about sand body of different causes in lower Shihezi formation. And adepositional model of He1member is setted up in the paper.5.Based on responsive characteristics of lithofacies-log facies, Relationship oflithofacies-log facies-sedimentary microfacies and reservoir,as well as productivity, isstudied innovatively for the first time. According to reservoir characteristics andproduction capacity, then, a correlative model is shaped.The results are asfollow:(1)the smooth box thick sandstone phase in main channel is the mostbeneficial.(2)the thick sandstone phase at the bottom of bell is of much capacity.(3)the others are bad.6. Based on all the above research results, those indicate differently favorablesand body how to form. And it is identified between differently favorable sand bodyand productivity.Lastly,4industrial lithofacies plans of He1member in lower Shiheziformation, Daniudi gas feild are innovatively drew in detail by adopting mid-termcycle sequence as a mapping unit for the first time. These plans could showeffectively the different small layers of favorable lithofacies plane distribution andvertically evolutive rule. Therefore,it is a good guidance to develop the gas field. |
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