Growth Structure And Petroleum Geological Condition Of Sangzhu Area, West Kunlun Mountain

Sangzhu growth structure zone lies in front of the west Kunlun orogenic belts. Because of the special structural position, the piedmont region is different in structural characteristics of oil and gas both from the internal orogen and the basin. The study of the region has important academic value and become a hot-spot to geologist. However, due to the complicated terrain in this region, it is very difficult to explore, so substantive breakthrough of exploration has not been made in a long time.This article is based on the elaborate geological cross section making, the refined seismic interpretation and the use of logging data. Connecting with Tiekelike nappe, taking structural geology, sequence stratigraphy, lithology and other related theories as the guide, this paper studied on the structural zone geometry, kinematic characteristics and structural deformation style of Sangzhu area, and in accordance with their unconformity, we use the growth strata theory to reserach the regional Cenozoic uplift.Sangzhu growth structure belt can be seen as an inclining-model folded groups which lies in the front of south Hetian overthrust nappe. The regional thrust nappe structure can be divided into the root zone, the middle zone and the front zone from south to north basing on structure, stratum assemblage and other characteristics of formation. The underground geological condition is complicated in this area, which has three tiers on the vertical structure: shallow level is the allopatry nappe system of the Sangzhu surface fault-propagation fold; middle level is the duplex and triangle zone deformation. There are three structural wedges which were composed of Paleozoic (especially the upper Paleozoic) and lower Tertiary strata; deep level is the in-situ deformational system, forming an imbricate-thrust fault. Because three Paleozoic wedge-shaped formations wedged, the strata uplift, forming a limb rotational fault-bend folding. At the same time deposits started, growth strata generated in Sangzhu anticline structure. The thickness and occurrence of strata under Anju’ an group of Miocene were not changed significantly: they are pergrowth strata. From Anju’ an group to Pleistocene western Regions group, the thickness of strata gradually increased from the core to the limb, and the obliquity became slow: they are growth strata. The thickness of stratum between Anju’ an and Pakabulake formation are rapidly thinning from the limb to the core (to south), then a synsedimentary wedge (growth strata-wedge) formed, which tip pointed to the crest of the anticline. It’s a off-lap sequence. Above Pakabulake formation there is an on-lap sequence. Sangzhu anticline controls the growth of strata from Anju’ an group and above, it shows that the uplift of Sangzhu growth structure zone started from the Anju’ an group of Miocene, and the uplift of west Kunlun orogenic belts could started from Miocene.The research area has good prospect for exploration of oil and gas. Oil source , reservoir and cap rocks are in good condition and formed several source-reservoir-cap assemblage. Triangle zone in research area formed a large-scale superimposed anticline, which is covered by lower Tertiary gypsum-salt rock as a good cap rock, it’s the first zone for the exploration.