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Research Of Characteristics Of The Faults In The Baiyun Depression Of The Pearl River Mouth Basin

Posted on:2009-11-14Degree:MasterType:Thesis
Country:ChinaCandidate:J ChenFull Text:PDF
GTID:2120360242993020Subject:Mineral prospecting and exploration
Abstract/Summary:PDF Full Text Request
Baiyun depression is part of large depositional basin on the edge of extensional continent in Cenozoic. It is early faulting and late rifting, together with structural reverse and wrenching strike slipping, especially its well developed sub-fractures. Geological structural characteristics in the depression is very complicated because of stacking of multi structural movement. So study on relationship between structural faulting and reservoir is of great importance for further exploration in this depression.Regarding multicycle structure and basin evolution,taking basis on 2D seismic data with comprehensive analysis, focusing on historical occurrence, characteristics, strata deposition and development evolution of the depression, combining recent drilling and exploration and development data, this article has comprehensively analyzed this depression consisting of its type, fault and structural evolution,grasped its reservoir formation and distribution, built the evolution model and consequently found its exploration target and potential.Study shows fractures of Baiyun depression mainly trend NWW and nearly EW, and NW, NNW, NE and NEE as well. NWW and nearly EW striking fractures have long distance and closely spaced. On type, the fractures appear normal fault, strike-slip fault and so on. While on the structural style the factures are like fault block, broom, flowers and so on. Early tension fracture, middle shear strike slipping or normal overturning occurred during the movement.Present structure was developed in a complicated and various stress field environment. The depression was faulted to be a basin caused by early NWW-SEE stress, while in the late period NEE-SWW compression happened to cause wrenching strike slipping and reverseg. 2D seismic data shows most of the structures in the depression are of expanding style, consisting of listric slipping fault block, horst and grabon expanding fault block, vertical and lateral faulted nose or fold and so on, but overturning and shearing strike slip structures are also developed in local area. Southwest area in the depression and northeast area are big nose structure developed on basal uplift, which is an important adjustment belt for EW striking structures. Between of their sides deposited very thick sandy mudstone formation.Development evolution provides the depression good geologic condition for reservoir formation. Southwest of the depression is the most important area for petroleum migration and accumulation. While northeast structural trap is mainly developed when rifting and reverse happened. Current discovered reservoir is controlled by structure for the most time. Reservoir formation is greatly relative to fracture and structural movement. Various structures and structural-lithologic trap are favorable places for hydrocarbon accumulation.Analysis suggests faulted belt and structural adjustment belt are advantageous to find oil and gas accumulation. Depression belt has weak structural movement with good preservation so it is an important area to seek subtle reservoir and even production increasement as well.
Keywords/Search Tags:Baiyun Depression, Fracture, Structural Evolution, Structural Style, Reservoir
PDF Full Text Request
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