The Structural Feature and Tectonic Evolution about Bachu -Awati Area in Tarim Basin
|Keywords||Tarim Basin Bachu Fault-Uplift Awati depression|
Tarim basin is located in west-north area of china , surround by Tianshan mo-untain ,Kunlun mountain .It is the biggest inland oil-gas basin with 560000km2 and is oil-gas exploration prospect area in china. The genetic potential is 15000×108t.The explored reserves and control reserves is only 10×108t,occupying 5 percent in total ,the number is far from the expect aim .The reason is bad earth’s surface and geography factor ,the geology of petroleum is not deep ,especially in Bachu upheaval–Awati sag of the basin ,the gains is not exact .so it is necessary to study geology petroleum depend on new two dimensional seismic dates .Tarim basin is large superposition compound croton basin ,reformed in different degree ,under went long time complex evolution (Z-Q),especially Indian plate collision since Cenozoic era ,Kunlun mountain and Tianshan mountain uplift speedily , two foreland basin in different direction formed in Tarim plate ,they are Kuche basin in north margin and south-west sag in south margin at the same site as Bachu upheaval and Awati sag ,The site is near by the Tumuxiuke fault zone. So, to make the structure evolution of the last three places clear is very important to study the Tarim basin further Before the thesis ,people can’t recognize the place (Bachu upheaval–Awati sag and Tumuxiuke fault zone) .importance in study Tarim basin structure evolution ,no suitable theory ,no suitable thinking ,so the gain is not compound the practice well in Fengnan1 well and Badong4 well. The people can’t notice the special position of the place in Tarim basin structure evolution .The new theory and method——thin structure ,transmission fault ,thrusting nappe have been put forward by studying Kuche sag recently years. That offers us a kind of new theory and help us to recognize the structure feature and evolution again in work area .That has important sense to Tiram basin. Tumuxiuke fault zone is a boundary fault between Bachu upheaval and Awati sag ,with difference structure both side of it .The sedimentary layer of Awati sag in north side is 1200m ,and it is 7000m in another .There is a set ofanticline in Bachu upheaval and Tumuxiuke fault zone .That is potential beneficial oil exploration area.The thesis relies on growth fault correlation fold ,and balance geological cross-section theory ,applying geology logging and seismic section to study Bachu upheaval, Awati sag and Tumuxiuke fault zone in aspect of geometry ,kinetics deeply ,to inquiry into the structure evolution ,to study the structure activity in different time ,to study the factors affecting structure open and close and to evaluate them .Above all ,the thesis gets four conclusion :1. Bachu upheaval began to form from early Paleozoic era to late Paleozoic era .That is Caledonian orogeny and early Variscan orogeny . That shows some flatter occurrence fault band fold in north–west direction near by Tumuxiuke fault zone are large and high ,and they break by the large high angular thrusting right fault later in Tumuxiuke fault zone.2. Tumuxiuke fault zone formed in Cenozoic era Tumuxiuke fault zone is the newest structure zone ,and it is to form following the axial plane of fore-limb or lateral–limb of the syncline in fault band fold or fault propagation fold .3.Regional dextral compression stress field appear and keep exist is the reason of the work area structure fixed form .The stress field is related to Plate an wedding north ,to Asia-plate and Tianshan mountain thrusting south.4.The thesis applies new method of structure sectional drawing to study structure conclusion first.