Dizhi lixue xuebao (Dec 2021)
A KronosFlow software-based preliminary study on the tectono-thermal evolution of thrust-nappe belt
Abstract
Basin modeling is an essential technical method for the exploration and assessment of petroleum basins. However, traditional 2D basin modeling technologies only apply to extensional basins. This makes the thermal history reconstruction in lateral direction of compressional basins an unsolved problem and thus restricts oil and gas exploration. The latest KronosFlow software developed by the French Beicip-Franlab company breaks through the above limitations of traditional softwares on complex structures such as thrust-nappe belts, salt structures, mud diapir structures, and precisely controls the lateral and vertical structural displacements. We restored the burial history, thermal history, hydrocarbon generation, expulsion history, and hydrocarbon migration and accumulation history of compressional basins, by tracking the continuous motion pattern of a single grid, restoring lateral deformation and seamlessly interacting with the TemisFlow software. We then used the KronosFlow software on the Kalpin and Kuqa thrust-nappe belts in the northern margin of the Tarim Basin for quantitatively inverting the tectonic-thermal evolution history of the thrust-nappe belts since the Cenozoic. The modeling results were consistent with the measured paleo-thermal indicator data, confirming the validity of the results of this software for the compressional basin. The Yimugantawu fault in the Kalpin thrust-nappe belt was reactivated during 40~30 Ma, and the temperature of the Silurian-Devonian near the fault was higher than 85℃. The Kepingtag fault was active during 15~10 Ma, and the formation temperature was lower than 70℃. The Cambrian (maturity of source rocks between 1.3%~1.7%) and Ordovician (maturity of source rocks between 0.7%~1.2%) source rocks have a high degree of thermal evolution and strong hydrocarbon generation ability. The temperature of the Jurassic strata in the Kuqa thrust-nappe belt ranges from 50 to 70℃ in the northern section and 210 to 230℃ in the southern section. The salt structure results in geothermal anomaly, among which the salt rock in the Qiulitage structural belt is the thickest and the cooling effect is the most obvious.
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