The Study On Comprehensive Constrained Inversion Of Gravity And Magnetic Exploration And Research In Dayangshu Basin

The exploration and development of oil and gas reservoirs indicate Cenozoic volcanic rocks in the eastern volcanic reservoirs in various basins of a new reservoir type, is an important complement to oil and gas resources in eastern China. As a new type of reservoir, there are many volcanic reservoir exploration requires further study. Research and exploration of igneous reservoir basin exploration methods have far-reaching strategic significance.In order to accelerate the exploration and further deepen the understanding of the basin of Songliao Basin particularly the Dayangshu Basin, the geological characteristics of the study area to find out from the deep geological structure and contacts the base of the overlying strata control relationship, the project combines the methods of seismic, drilling, geological data, using advanced methods and techniques of integrated geophysical data (gravity, magnetic, electrical) to further the processing and interpretation. Based on the southern basin seismic and well data,9EMAP survey lines as the main constraint we carried out the gravity, magnetic, electrical joint inversion of multiple data effectively to improve the retrieval accuracy, improving the accuracy of geological research results. After these studies,we made the following findings:(1) The basin were divided into servral tectonic units:Dayangshu Basin showing the overall structure of the characteristics of the north and south block. From south to north the basin developed zone in southern depression, uplift in southern area, depression in central area, central uplift, northern tectonic unit area and the northern uplift depression; The second level of tectonic units were NNE banded distribution based features.(2) A large number of faults are developed, the direction for most of the faults are north-south and NNE. there is a small amount of fault for the North and North East, North West, NEE.(3)The basement depth of the basin is that deep in southern, central and northern light. Most areas are southern depression basement depth of about3000meters, the deepest is up to3800meters; the central depression region and the northern base deepest depression area up to3000meters.(4) The basement lithology:Based on the electrical properties of gravity and magnetic inversion results, combined with the geological outcropping deduction, the depression area in southern basin and the central uplift and the northern area are mainly ancient depression Paleozoic metamorphic basement, which places east and west sides of the main distribution Hercynian granites.(5) The inference of the depth and Jiufengshan group and the thickness of Ganhe group-Longjiang group:Using the gravity and magnetic inversion based on constraint-based shallow earthquake, we get Ganhe Basin group distribution and depth of change results. The Ganhe basalts dominated a large group of development, the thickest southern Depression is up to2500meters. Jiufengshan group-Longjiang group also distributed in this area, but there is a certain amount of the distribution is more fragmented, mainly distributed in the southern depression, the maximum thickness of2200meters.(6) The distribution of volcanic rocks:Large area of volcanic rocks were found in Dayangshu Basin, in the southern belt off concave depression area, the thickness of volcanic rocks up to about3000meters, in breaking with the central concave depression area, the thickness of volcanic rocks is up to2,000meters, the maximum thickness is up to1800meters above the volcanic rock, volcanic basin is the main reservoir of Dayangshu Basin.(7) The prospects of Hydrocarbon source rocks and exploration: Petroleum geological research shows that a large poplar Basin Jiufengshan group-Longjiang group argillaceous rocks is the main hydrocarbon source rocks in layers. Based on a comprehensive analysis, the delineation of hydrocarbon source rocks in the distribution of favorable areas, concludes16favorable exploration targets in the cell block, mainly in the southern depression Dayangshu Basin, which Yulin Tuen structure is the most favorable for oil and gas, etc. exploration zone.(8)We formed a techniques dealing with volcanic basin interpretation of comprehensive geophysical data for oil and gas exploration. Further study and improve methods are required to form targeted technical solutions.