| Wuerxun-Beier Depression is located in the central fault zone of the Hailaer Basin.They are the largest two depressions in the basin which are full of oil in the basin.After two times of reserve increasing of the end of eleventh Five-year and twelfth Five-year,the 13 th five-year period is still the key exploration target area.But the main exploration targets in Wuerxun-Beier Depression has changed from structural oil-gas reservoirs to lithologic oil-gas reservoir,the remaining targets burys deeper,the reservoir is thinner,and the scale is smaller,the existing theories and techniques can not meet the requirements of the current fine exploration,so to carry out the fine geological reunderstanding research is needed.Therefore this page is based on the comprehensive analysis and research with the actual data of the Wuerxun-Beier Depression,to establish the high resolution sequence stratigraphy of Nantun Formation and to study the sequence structure,the type of the sedimentary facies,the distribution of sedimentary system and its evolution law,with the guidance of source-sink theory to analyze the distribution law and the control factors of sand body,then combine with oil-gas combination conditions,a favorable zone for the next exploration is predicted.It has a certain practical significance for the further exploration of Wuerxun-Beier Depression.At the same time,it is of great theoretical significance to apply the theory of source-sink space-time coupled sand controlling to the oil and gas exploration in the continental faulted lake basin.The main achievement of the thesis obtains the following achievements:1.On the basis of the newest theoretical progress of the high resolution sequence stratigraphy,to do the comprehensive research on the data of drilling,logging,core and earthquake of Wuerxun-Beier Depression,five kinds of sequence boundary in Nantun Formation is identified.According to the characteristics of the sequence interface,the Nantun Formation is divided into 3 long-term base level cycles and 14 medium-term cycles.A high resolution isochronous stratigraphic framework covering the whole area has been established,and the characteristics of sequence development of different tectonic zone in this area are summarized.2.Under the control of the isochronous frame,to study and analyze the various sedimentary facies marks,four mainly sedimentary system in Nantun Formation can be ensure: fan delta,braided river delta,sublacustrine fan and lake sedimentary.At the same time,the data of palaeogomorphology,heavy minerals,sand dispersion system,seismic attribute and pre-Product reflection are also used.To adopt the method of “element analysis,multielement judgment “ to describe source system of Wuerxun-Beier Depression finely.It is thought that the source is mainly from the slope zone around the depression and the low bulge in the basin.The source direction in different sedimentary periods has inheritance.3.Guided by the idea of dynamic sources,it's thought that different sequence in source areas owns different ranges.Even though in the same sequence,the size of the source area at different depositional periods of the system is also different.The palaeoggeomorphology controls the distribution of the main valleys,while the valley controls the distribution and deposition thickness of the sand body.According to the differences in development position and tectonic style of the structural slope break zone,the slope zone in Nantun Formation of Beier Depression can be divided into five types: steep slope fracture type,steep slope in the same direction fault-step type,gentle slope in the same direction fault-step type,slow slope reverse fault-step type and dustpan trough type.Different types of depositional system are controlled by different tectonic parts and different types of slope break zones.4.Guided by the theory of “source-sink” and the three ancient geomorphologic elements to be the researching objects,to analyze sand controlling mechanism in Nantun Formation which based on the whole process of the “source area-transport-deposition”,according to the development degree of palaeognomy elements,8 coupling ways of “source”(source system)+ gully system(gully system)and "slope"(slope break system)are put forward.It is considered that “source” is dynamic and the most important,if there's not enough source supply,no matter how the valley and slope break develop,there will not be large amount of sand bodies deposition.While there's enough source supply,valley develops and the sand body extends,the slope break develops and the sand body distributes widely.5.On the basis of sequence stratigraphic analysis,and the study of sedimentary microfacies,combines with the analysis of lithology,physical property,oiliness and structure-sedimentation analysis,to choose the selection of sedimentary facies belts;to adopt target lithology with fine descriptions in multi-level and multi-angle;to do synthetic evaluation and optimize the queue to lock the drilling target,which effectively supports the oil reserves of 9 million 140 thousand tons in blocks such as Huo 12,Bei 70. |
PDF Full Text Request