Types and Distribution of Tight Oil of the Lower Cretaceous in the Jiuquan Basin, Western China

Abstract

The Jiuquan Basin is a middle-minor scale continental petroliferous basin, which has been explored since 1930s and conventional oil and gas exploration is more and more difficult, With the development of the exploration and development technology, unconventional oil and gas exploration has been gradually paid attention to. After researching the poor-forming types and distribution of tight oil in Jiuquan Basin that based on logging, core, analytic and testing data, It is found that there are two types of tight oil in Jiuquan basin: argillaceous dolomite tight oil and glutenite oil. The former is mainly distributed in Liugouzhuang area in Qingxi Depression, and it formed when lower Cretaceous Xiagou Formation tight argillaceous dolomite reservoir directly captures the underlying muddy source rocks, oil and gas enriched in fracture developed area; the later was formed because of the direct contact between the tight glutenite reservoir of Fan delta front in the slope of Xiagou Formation of lower Cretaceous and the muddy source rocks in deep lake region, which widely distributs in the west of Yaerxia area in Qingxi Depression and Shida-Huahai sag. The local developed dissolution has good effects on the physical properties of tight sandy gravel reservoir, the oil and gas enriched in dissolution area. Through the application of engineering technology such as under-balanced drilling technology, horizontal well technology and massive fracturing technology, the two types of dense oil reservoir have made great prospecting breakthrough, it shows that tight oil has good exploration and development prospects in this area.

AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014