Study On The Basement Structure Characteristics Of The Paleo Central Uplift Belt

Songliao Basin ancient central uplift belt has found that the natural gas industry, but has not yet formed scale, and it is currently one of the key new areas to explore, but the complexity of the basin basement lithology, regional metamorphic rocks and granitoids mainly granite lithology, mylonite metamorphic conglomerate, phyllite, schist and gneiss in these rocks lithology, physical characteristics of the rock and reservoir seismic response characteristics of what is unclear; and the presence of structure interpretation of multiple solutions for basement insider lack of awareness; substrate insider reveals less drilling, drilling only the substrate surface, the insider is not clear what structural features; ancient central uplift belt has been submitted to the basement weathered crust reservoir zone, whether insider accumulation unclear. Therefore, to carry out the distribution of the ancient northern Songliao Basin in central uplift belt substrate gravity and magnetic, electrical, and seismic analysis of ancient central uplift belt substrate insider interpretation undertaken to study the structure inside for clear understanding of the ancient central uplift belt of gas reservoir, preferably better favorable risk targets provide a scientific basis. At the same time, to promote the realization of the magnificent goal oilfield century and 40 million tons oil companies continued stable production of great significance.The paper collected regional geological and geophysical data, and is based on previous studies and the periphery of the basin outcrop data, create sequence stratigraphic units of basement rocks; Songliao Basin by ancient central uplift belt structure interpretation 3D seismic data and research, the use of seismic stratigraphy, seismic and geologic interpretation techniques and other methods to identify the central uplift of Songliao Basin with the ancient tectonic style and in-depth analysis, the substrate structural styles have imbricate thrust tectonic style, broken Exhibition fold, tectonic wedge, sloping floor fault bend structural styles, detachment, strike slip compressional tectonic style; use the depth information acquired seismic data in the binding loose deep seismic profiles and three-dimensional seismic data base of insider explained, suggesting that the structure of the substrate insider feature.Utilization of District 43 and the surrounding drilling core outcrop data reveals Songliao basin basement lithologies development; the use of central uplift belt of seismic data, perform petrophysical analysis, seismic interpretation basement lithology various response characteristics, stochastic inversion using seismic stratigraphic get depends on the apparent density distribution and magnetic susceptibility distribution of all four, and the results were uncertainty analyzed; reasonably inferred Songliao Basin T5 top boundary of rock spread: overall in granite, followed Carboniferous Permian sedimentary + + schist slate, mylonite + phyllite and granite chipping tend to have a strong relationship with the fracture distribution on the whole south of the larger sets of granite distribution, while the northern distribution is broken, basically are distributed, not very different.The use of apparent density inversion method, reveals the apparent density change T5 interface. Depending on density loss in the study area and often it showed positive anomalies beaded strips and distribution, there is a close relationship with the T5 interface faults spread. Background-0.005-0.005 areal density, tensile fault fault, there is no gap between the faults, fracture rock fall between the gap, so in reality the fault of the density anomaly by density anomaly can be seen most of the fault Exhibition cloth wells exhibited by low-density anomaly; T5 apparent magnetic susceptibility interface with the same methods in dealing with the raw data, we used magnetic anomaly value parsed. In the study area showed significant magnetic susceptibility and beaded strip, and T5 and the top surface of the fracture have a strong correlation. Depending on the magnetic susceptibility can be seen as normal faults remanence magnetization direction randomly arranged, resulting in the apparent inversion becomes low magnetic susceptibility, along the direction of the fracture distribution, the situation appears alternating high and low, so-called "beaded" exception; through the study area Songliao basin valley in central uplift belt three-dimensional seismic tomographic slices 2676 and 3804 combined with a central uplift of Songliao Basin ancient three-dimensional survey lines Fangshen 3- Chang Chao-deep 9 4.3 arbitrary line, studies suggest that the main study area substrate the configuration can be made structurally divided into two layers, tectonic movement in the opposite direction of the upper and lower layers, the upper main push inverse structure to the north west, mainly the lower backstepping structure south east, separated between the detachment, detachment overall tilts to the south, not a detachment fault plane, is a group of nearly parallel to each other and downs of the fault plane; through T5 top surface fracture and apparent density and apparent magnetic susceptibility superposed, drawn abstract structural geology of the study area models can be both internal and external parts, ancient central uplift belt inside a multi-stage imbricated nappe structure is engineered, structural model of the substrate after the first squeeze slope floor structure pull structure; extremely tectonic evolution of the substrate, the Paleozoic end of Songliao Basin area began large-scale uplift and is accompanied by a large number of magmatic activity, Moho depth of occurrence and downs; the late Permian period, the basin is strongly compression south to north; early Cretaceous early, ancient both sides of the central uplift extremely tensional rift made into the period; the late early Cretaceous, the formation of a number of shallow inversion structure.