The Characteristics Of Accumulation Controlled By Faults Of Shizigou-yingdong Structural Belt Of Qaidam Basin

Shizigou-YingDong structural belt is located in the southwestern qaidam basin, in recentyears, have achieved significant discoveries and proved reserves of over one hundred milliontons, that the tectonic belt exploration potential is tremendous. But structural belt experiencedmultiphase tectonic activities, and complex fractures and structures developed internally ofstructural belt, under the control of complex structure and sedimentary evolution, thehydrocarbon accumulation process and distribution regularity of oil and gas need furtherresearch. These problems restrict the further exploration of structural belt, increasing the riskof exploration.This article through to tectonic subsidence history simulation of the tectonic beltdifferent position, and formation shortening rate calculation combined with the technology ofbalanced section considering tectonic evolution characteristics of tectonic belt was dividedfour stages: Lulehe formation—lower Xiaganchaigou formation, initial weak faulted period;upper Xiaganchaigou formation, quick subsidence period; Shangganchaigouformation—lower Youshashan formation, depression period; upper Youshashanformation—now, tectonic uplift period. Two times of the peak of tectonic movement: in theupper Xiaganchaigou formation period, tectonic movement controlled the evolution of themain source rock. In the late of upper Youshashan formation, tectonic deformation controlledthe formation and the deformation regularity of the trap.Using microscope observation analysis the characteristics of reservoir fluid inclusions,found that structural belt developed two major kinds of hydrocarbon inclusions, Respectively,the yellow fluorescence inclusions with low maturity and the blue fluorescent inclusions withhigh maturity. Mainly developed at the edge of the quartz increase and in the healing offractures, and combined with quantitative grain fluorescence technique to determine thestructural belt of typical reservoir filling process and period, make it clearly that there weremainly two periods of reservoir-forming in the structural belt; Using the method of inclusionshomogenization temperature, combined with the burial history of single well by numericalsimulation, clearly typical oil and gas accumulation periods in the study area.Through the characteristics of geometry, kinematics about the faults in western ofQaidam basin, comprehensive research on faults in western Qaidam basin, and divided classesand different levels of faults in the role at the process of hydrocarbon accumulation.Summarizes the structural belt combination mode of fault-cover,and the control features of it, and systematic evaluation of fault sealing for YingDong reservoirs of the Shizigou-YingDongtectonic belt, combining with the analysis of hydrocarbon accumulation process, make itclearly that the characteristics of the faults controlling hydrocarbon accumulation, establishedthe accumulation mode of YingDong structural.