Diamondoids, biomarkers, and chemofacies: Uniting insights on hydrocarbon maturation and migration in the Cline Shale, Midland Basin

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Organic Geochemistry Pub Date : 2025-02-26 DOI:10.1016/j.orggeochem.2025.104953

Maram AlSaif , Ibrahim Atwah , Mauro Becker , J. Michael Moldowan , Alex Zumberge , Franco Marcantonio

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引用次数: 0

Abstract

Basinal mudrocks within the Wolfcamp Group of the Midland Basin, including the Cline Shale (Wolfcamp-D) interval, have proven to be prolific producers of oil and gas. However, predicting hydrocarbon distribution within the Cline Shale remains challenging due to its complex lithological heterogeneity and geochemical variability. In this study, molecular techniques and chemometrics were applied to address this challenge by: (1) characterizing the chemo-stratigraphically distinct depositional units of the Cline Shale, (2) understanding the role of lithological facies in hydrocarbon distribution, and (3) correlating produced-oil samples with the most productive zones within the Cline Shale.

Results reveal that the Cline Shale is dominated by marine-derived organic matter, with minimal terrigenous input. The sediments, currently in the peak-to-late oil window, exhibit distinct variations in redox conditions, paleoproductivity, and organic matter preservation across the Upper, Middle, and Lower intervals. Biomarkers such as terpanes, hopanes, and steranes highlight these variations. Further analysis using Quantitative Diamondoid Analysis (QDA) indicates notable differences in maturity and hydrocarbon cracking that cannot be explained solely by burial depth (∼300 ft difference). The highly mature oil in the Upper Cline appears to have been generated locally, whereas condensate in the Lower Cline is likely the result of lateral migration from deeper, more mature intervals. Quantitative Extended Diamondoid Analysis (QEDA) supports this by correlating oil samples from a nearby well to extracts from siliceous mudstones in the Upper Cline.

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来源期刊

Organic Geochemistry 地学-地球化学与地球物理

CiteScore

5.50

自引率

6.70%

发文量

100

审稿时长

61 days

期刊介绍： Organic Geochemistry serves as the only dedicated medium for the publication of peer-reviewed research on all phases of geochemistry in which organic compounds play a major role. The Editors welcome contributions covering a wide spectrum of subjects in the geosciences broadly based on organic chemistry (including molecular and isotopic geochemistry), and involving geology, biogeochemistry, environmental geochemistry, chemical oceanography and hydrology. The scope of the journal includes research involving petroleum (including natural gas), coal, organic matter in the aqueous environment and recent sediments, organic-rich rocks and soils and the role of organics in the geochemical cycling of the elements. Sedimentological, paleontological and organic petrographic studies will also be considered for publication, provided that they are geochemically oriented. Papers cover the full range of research activities in organic geochemistry, and include comprehensive review articles, technical communications, discussion/reply correspondence and short technical notes. Peer-reviews organised through three Chief Editors and a staff of Associate Editors, are conducted by well known, respected scientists from academia, government and industry. The journal also publishes reviews of books, announcements of important conferences and meetings and other matters of direct interest to the organic geochemical community.