Premium
Shale Oil Geological Characteristics and Resource Potential of Mesozoic Yanchang Formation in Ordos Basin, North‐Central China
Author(s) -
LI Qiyan,
YANG Zhi,
ZOU Caineng
Publication year - 2015
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.12304_16
Subject(s) - beijing , china , petroleum , geology , structural basin , oil shale , resource (disambiguation) , library science , geochemistry , archaeology , geography , geomorphology , paleontology , computer science , computer network
which is stored in organic-rich shale stratum with nanosized pore-throats, and is a very promising exploration field in future. Taking shale oil of Mesozoic Yanchang Formation in Ordos Basin for example. Shale oil occurs in the organicrich shale in the middle-lower seven member of Mesozoic Yanchang Formation in Ordos Basin, with the thickness 21-36m, burial depth 110-2900m and the exploration area 50 thousand square killometers. Shlae oil have five typical geological characteristics. (1) the organic-rich shale developped in the semi-deep ro deep lacustrine deposit, with I-type and II1-type kerogen, Ro 0.7-1.1% , TOC 1.425.6%, S1 1.2-11.6mg/g, chloroform asphalt A 0.2-1.2%, pyrite content 5.4-34.5%, and specially the hydrocarbon generation potential of shale is about five times of that of the mudstone; (2) laminated structure appeared commonly in the shale, pore-throats diameter are mainly 50-300nm, locally micro-sized pores, and nano-sized pore-throats and parallel bedding fractures are the main reservoir space; (3) higher brittle mineral content, with quartz, feldspar, calcite and dolomite 41%, and clay content lower than 50%; (4) lower formation pressure and lighter oil quality, with pressure coefficient 07-0.9, crude oil density 0.75-0.85 g/ cm, and viscidity 0.7-5mPa·s; (5) residual liquid hydrocarbon occurs in adsorption state and free state, with adsorption state in organic matters, adsorption state and free state in nano-sized pore-throats in pyrite, clay and brittle minerals, and free state in parallel bedding fractures. Organic-rich shale of Mesozoic Yanchang Formation in Ordos Basin, have “five higher” typical characteristics, respectively higher TOC, higher pyrite content, higher S1, higher chloroform asphalt A, and higher Gamma ray value. The beneficial shale oil distributiona area, with TOC higher than 2% and Ro higher than 0.7%, is about 20 thousand square killometers, and the preliminary resource potential is about 1 billion tons. LI Qiyan, YANG Zhi and ZOU Caineng, 2015. Shale Oil Geological Characteristics and Resource Potential of Mesozoic Yanchang Formation in Ordos Basin, North-Central China. Acta Geologica Sinica (English Edition), 89(supp.): 257.