Fluid Inclusions of Multi-Source Hydrocarbon Accumulation in Cambrian Dolomite Buried Hill and Its Significance for History of Hydrocarbon Accumulation: An Insight From Yaha Oilfield, Tarim Basin

Abstract

It has been confirmed that Cambrian dolomite buried hill of Yaha zone in Tarim Basin is an oil-gas enrichment area. However, with its particular position in tectonics, there exist the possibilities of multiple sources and multi-period accumulation, which could bring about an ambiguous history of hydrocarbon accumulation. The history of hydrocarbon charging could be inverted by the geological information contained in fluid inclusions. Using the characteristics of petrological analysis, microthermometry of saline inclusions coexisted with hydrocarbon, Quantitative Grain Fluorescence (QGF) fingerprints and Total Scanning Fluorescence (TSF) fingerprints of analyzing adsorbed hydrocarbons and non-hydrocarbons, intermediate and light hydrocarbon components were verified in the study area, which have the typical characteristics of two-phase hydrocarbon accumulation. According to the analysis results of hydrocarbon and source rock components extracted from hydrocarbon inclusions, two-phase hydrocarbon accumulation were both stem from Triassic-Jurassic terrestrial source rocks in the north part of Kuqa depression. Compared with the PT simulation method of saline inclusions coexisted with hydrocarbon, Electron Spin Resonance（ESR）quantitative dating analysis of authigenic quartz grains contained in hydrocarbon inclusions is more accurate. Thus, it can be measured that two-phase hydrocarbon charging time are 16.3-23.5Ma and 8.5Ma.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018