Genetic Types of Tertiary Lacustrine Algal(Cyanobacteria) Limestones Reservoirs in Western Qaidam Basin
ZHAO Xian-zheng~ 1CHEN Zi-liao~ 2CHEN Hong-de~ 2SHOU Jian-feng~ 3SHI Ze-jin~ 2 1(Petroleum University, Changping, Beijing102249) 2(Chengdu University of Technology, Chengdu610059) 3(Hangzhou Institute of Petroleum Geology, Hangzhou310023)
Genetic types of tertiary lacustrine algal(cyanobacteria) limestones reservoirs in the western Qaidam basin mainly include:algal(cyanobacteria) flat limestones in littoral lake and algal(cyanobacteria) mound limestones in shallow lake.There are of completely different sedimentation characteristics,lithological types and reservoir featares.Tertiary algal(cyanobacteria)limestones reservoirs in the western Qaidam basin are characterized by widespread distribution and being the most important in the carbonate reservoirs.Tertiary algal(cyanobacteria)limestone reservoirs in the western Qaidam basin have been found in Yuexi, Yuedong,Qigequan, Shizigou, Huatugou, Jiandingshan, Nanyishan and Dafengshan regions etc., and distributed from E~2 3 to N~2 2. Algal(cyanobacteria)limestones reservoirs in E~2 3 and N 1 distributed mainly in the west(southwest) region of Yingxionglingdepression, those in N~1 2 and N~2 2 distributed mainly in east(northeast) region of Yingxionglingdepression. Distribution of algal(cyanobacteria)limestones in the western Qaidam basin is mainly controlled by lake level changes,migration of sedimentation center and basin evolution.Reservoir spaces of algal(cyanobacteria)flatlimestones in littoral lake are predominant with secondary disolution pores and disolution fissures .They are possibly controlled by atmospheric water leaching.Reservoir spaces of algal(cyanobacteria)moundlimestones in shallow lake are predominant with secondary disolution pores and disolution fissures,and also developed primary algal tube pores.They are possibly controlled bydisolution along rupture zones and organic acid disolution.
【CateGory Index】： P588.245