The Structural Features And Lower Paleozoic Of Black Shale Fracture Characteristics And Distribution In Qianbei Area

The regional tectonic evolution of the Yangtze platform and the Qianbei areahave consistency, however, due to Qianbei farther away from the edge of platemovement, so overall a little lag behind the evolution of the Yangtze platform stage;Tectonic evolution in the region have obvious stages, and can be divided into the lateProterozoic to Silurian development stage, Devonian to the middle of late Triassicstages and in-Cenozoic (from the Late Triassic since the late) stage of development.Qianbei region folds, faults are well developed, the overall folds with NE or NNEtrending, mainly in the main compartment trough folds. Can also be seen everyblock-type folds. Single fold often show "S" shape or reverse "S" shape, reflecting theregional tectonic deformation Qianbei main squeeze, with a strike-slip properties.Guizhou region folds are widely developed across the trough. Anticline zoneassociated with the fracture common development. Since differences in lithology andstructural conditions, often syncline into mountains into the valley landforms anticline.Type of fault distribution and folds affect regional stratigraphic distribution ofGuizhou.Qianbei area faults are very developed, with multiple sets of fault systems,including the north-east, north-north-east, north-south, north-west, east-west,5sets ofbroken, mutual cut, joint, interference, is very complex. Fault dip generally larger,mostly in the50°-80°, and some sections upright, or even reversed..In the Cenye-1well Niutitang cores, the longer the crack length, width, morewide angle steeper sections of the layer, the higher the gas it contains. Contrastfracture line density, toc, brittle minerals and gas content shows: these three basic apositive correlation, while the maximum flooding surface1441m in the vicinity, thesethree are basically reached the maximum.The black shales target layer depth of Lower Cambrian and Upper Ordovician-Lower Silurian changes by folding, faulting distribution influence. Synsedimentary fault footwall In syncline, depth generally higher, while in the anticline area, depthis generally small; within the same fault footwall sedimentary layer depth purposessignificantly increased.In Qianbei region,Niutitang and Longmaxi black shale crack distribution ismainly controlled by the fault zone, While east-north and the NNE-trending faultsystem has the most significant impact for the distribution of crack.With the trend offault isolation distribution, Main distribution location are the intersection of faultlocation, fault ends and turning parts and different parts between faults, and theseparts are generally stress concentration area which is conducive to the formation ofcracks. In addition, the steep part of the anticline, but also conducive to the formationof cracks.