Structure Evolution And Dynamic Complex Accmulation

BaChu-Maigaiti area undergone multiply structureal evolution phase,especially Caledonian, hercynain indosinian,yanshannian and himalayan movement. So ,for many kinds of plant structural mechanisms ,a plenty of prototype basins experienced modify and formed some new stacking basins. Based on structural dynamics ,kinematics and petroleum system theory ,the author systematic studied the relative relationship between basin style and structural unit's change and poll forming. Contraposing to multiply accumulation system in this area, the studying of structural evolution must be put the first place, applying the analysis way of "the line radition theory" guided by four dimension conceive way,that is ,dependenting on analysis the relation of "point-line- plane-time", using the many interactive subjective knowledge to resolve critical problem in petroleum geology not only brings the new energy ,but also expend the space of basin analysis in conceive way and research.In the process of analysis basin construction and modifying ,the author studies the BaChu-Maigaiti area and put forward some new ideals:(l)seven structural evolution stage,that is, late Simian-Ordovician passive continent marginal basin, Silurian-middle Devonian peripheral foreland basin,late Devonian-early Permain craton marginal depressionan craton rift, late permain-early Triassic rear arc foreland basin, and Mesozoic-Paleogene rift basin ,Neogene-Quaternary foreland basin.(2)five main basin modified stage;(3)eleven unconformity: point out, among them ,the T_2O,T₅₀,T₅₂,,T₆₀,T₇₀,T₇₄ are main unconformities,which affecting the wholearea, the unconformity ,lies between weathering crust of upper Cambrian-lower Ordovician and Carboniferous, has the efficiency action to control petroleum migration. (4) systematically analysize forming andevolution of the uplift in BaChu-Maigaiti area compartmentalize five main phase: forming and expending of uplift in early lower Paleozoic, evolution period in later lower Paleozoinc, and in early upper Paleozoinc,uplift enter the alteration time, while in later upper Paleozoinc coeixt time, Mesozoic-Cenozoic is the finally forming period, indicate buried paleohigh of Cambrian-Ordovician stable exist all the time before hercynain movement and the all explored oil-gas fields liein the north slope of buried paleohigh, further point out the control action of craton paleohigh to petroleum.During the dynamic multiply accumulation system and cycle analysis, emphasis on studying factors of petroleum accumulation and each single link is the very difference from the former studying,and point out there are many kinds of time-space matching relation in critical time of this area: (1) there are direct and indirect relationship between trap forming and petroleum generative and migration;(2) among channel net syetem consisting of faults, unconformities and fractures,during Caledonian-hercynain period^ is main the fracture and cuve;before middle hercynain-late hercynain period, channel syetem is main consisted of fault, unconformities and fractures;in later hercynain-himalya , fault, unconformities and fractures is the main pathway, but there exist different in each action of it There are many kinds of channel among petroleum migration mam pathways:(a) unconformity(before later hercynain period):(b)fault -unconformity in trapflater hercynain period and after it);(c) unconformity-fault- unconformity in trap Himalayan;(d) pore-cave-fracture system ;(3)main migration channel and accumulation area lie in north-east in of this area before later hercynain period,while after it, locate upper Paleogene unconformity of BaChu-Maigait slope and margin fault belts in south-west of Bachu uplift;(4)three accumulation cycle: Cambrian-middle Devonian,later Devonian-Mesozoic and Cennozoic accumulation cycle.There are six kinds of predominant pathway and basic channel model. Among the episodic migration and accumulation theory analysis, besides stable episodic migration and accumulation ,the"embroil"migration model is put forward the first time. According to nantomy seismic interpretation of th trap and oil play study, index there are five geometry styles and seal styles^urther point out there exist two stacking pattern, two assemblage stytles and two dynamic Transform stytles , which very useful for analysis trap's efficiency and accumulation...