Abstract
Intracratonic strike-slip faults are pivotal in controlling hydrocarbon migration and accumulation within deep carbonate reservoirs, yet their multi-phase reactivation histories and spatio-temporal coupling with hydrocarbon charging remain poorly constrained. This study integrates calcite U-Pb geochronology, fluid inclusion microthermometry, and fluorescence spectroscopy to resolve the evolution of the F117 and F119 strike-slip fault systems in the ultra-deep (>7,000 m) Ordovician strata of the Tarim Basin. The F117 fault records five reactivation phases, from Middle Caledonian (453.1 ± 3.2 Ma) to Himalayan, while the F119 fault exhibits four phases, terminating at the Indosinian but with intensified Late Hercynian–Indosinian activity (268 ± 45 Ma, 263 ± 24 Ma). Hydrocarbon charging occurred in three distinct episodes: Middle–Late Caledonian (442.2 ± 4.3 Ma, 445.3 ± 2.5 Ma, 437.3 ± 7.2 Ma, and ca. 440–420 Ma) migration of low-maturity oils (λmax: 520–480 nm), Late Hercynian–Indosinian (ca. 290–210 Ma, ca. 350–250 Ma, 281.4 ± 3.1 Ma, 268 ± 45 Ma, 263 ± 24 Ma, and ca. 310–210 Ma) recharging of high-maturity oils (λmax: 480–435 nm), and a unique Indosinian–Himalayan phase methane influx (ca. 212–18 Ma) in F117. Critically, fault segment architecture governs reservoir heterogeneity: linear segments (e.g., F117–HD32, F119–MS7-H4) preserved Caledonian oils due to structural stability; extensional segments and intersections (e.g., F117–MS5, F119–MS701) experienced post-Caledonian leakage and Hercynian–Indosinian recharging; contractional segments (e.g., F117–MS2, F119–MS702) retained hydrocarbons only during late-stage (Hercynian–Indosinian) fault reactivation.
Paper Information:
Zhuo Liu, Jinqiang Tian, Fang Hao, Xianzhang Yang, Ke Zhang, Yongquan Chen, Xiaoxue Wang, Feifei Yuan, Li, Quan, Ping Wang, Fuyun Cong, 2025, Differential (re-)activation and hydrocarbon enrichment of segments of intra-cratonic strike-slip faults in the central Tarim basin, northwestern China. AAPG Bulletin, doi: 10.1306/04302523125.
https://archives.datapages.com/data/bulletns/aop/2025-05-15/aapgbltn24042aop.html
