1. School of Petroleum Resources, Xi'an Shiyou University, Xi'an 710065, China; 2. Geological Department,  Northwest University, Xi'an 710069, China; 3. State Key Laboratory of Continental Dynamics, Northwest University, Xi'an 710069, China; 4. Geological Research Institute of Shengli Oilfield Co. Ltd. , SINOPEC, Dongying 257015, Shandong, China

Lacustrine turbidite of Chang-7 Member in the studied area consists of siltstone and fine sandstone with respect to grain size, which is feldspathic lithic sandstone, syrosem arkose and arkose with respect to mineral constitution affected by provenance. There are such apparent signatures as lithology, sedimentary structure, sedimentary sequence and well logs, to recognize turbidite. During the paleogeographic evolution of Chang-7 Member, lake basin and deep lake are both at their maximum extent during Chang-7₃ stage, resulting in the deposition of Zhangjiatan shale with widesp read extent and of turbidite with fragmental2like. Deep lake line is gradually moving toward lake center and turbidite sand bodies are gradually turning better with better lateral continuity, connectivity and more thickness, from stages of Chang-7₃ , Chang-7₂ and Chang-7₁ , which can be favorable reservoir in deep-water.