Premium
Fluid Inclusion Re‐equilibration in Carbonate Rock Caused by Freezing during Microthermometric Analysis
Author(s) -
YANG Peng,
LIU Keyu
Publication year - 2020
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 - 10.1111/1755-6724.14524
Subject(s) - china , petroleum , inclusion (mineral) , library science , geochemistry , oceanography , geology , geography , mineralogy , archaeology , paleontology , computer science
Fluid inclusions are minute sealed fluid droplets in minerals, often less than 10 μm in diameter. They are commonly trapped in diagenetic cements or coalesced fractures in minerals, such as quartz, feldspar and calcite (Roedder, 1984). Following the basic norm for fluid inclusion analysis, the ―Roedder's Rules‖ (Roedder, 1984), fluid inclusions have been widely used in reconstructing paleofluid evolution history within a reservoir in petroliferous basin (Bourdet et al., 2012). Numerous studies, however, have shown that fluid inclusion reequilibration is a fairly common phenomenon in sedimentary rocks (Goldstein, 1986; Burruss, 1987; Prezbindowski and Larese, 1987), which could alter or erase the original information of fluid inclusions entrapped. This may render the information preserved useless or misleading with incorrect inference or conclusions drawn without a careful discrimination. Microthermometry is the primary method for fluid inclusion analysis and offers essential physical and geochemical parameters that can be used to identify the compositions of the fluid inclusion, and conduct PVT modelling (Goldstein and Reynolds, 1994). Commonly, it is recommended that homogenization temperature (Th) of fluid inclusion should be measured first, followed by measuring initial melting temperature and final ice melting temperature (Tm) during a microthermometric analysis (Goldstein and Reynolds, 1994). However, this measurement sequence is often not strictly followed in practice and many people would re-measure Th after Tm measurements under some circumstances. Here we carried out a quantitative analysis of fluid inclusion microthermometry and PVTx modeling to raise awareness on the correct microthermometric measurement sequence and the corresponding consequences if an incorrect measurement procedure was used. The primary objective of this study is thus to quantify the differences in microthermometric data generated using different measurement sequences and to highlight possible erroneous interpretation or conclusions caused by improper human operation. Methods