The Aryskum Depression in the South Turgay Basin has shown improving exploration prospects for subtle reservoirs, due to investment in the exploration workload and more comprehensive geological research. Among them, lithologic stratigraphic reservoirs have gradually become one of the focuses of oil and gas exploration. At present, deduction of the sedimentary characteristics of the target layer through core wells using artificial exploration has become an urgent problem to be solved. We selected 16 artificially interpreted coring wells in the Aryskum Graben for this study. Using the parameters of the gamma-ray (GR) curve of coring wells and support vector machine (SVM) classification algorithms, we developed an automatic identification model of sedimentary facies in the study area. The application of the SVM includes the following steps: Firstly, using the GR curve of 16 coring wells, six quantitative indexes defined as standard deviation, relative gravity, curve amplitude ratio, average median, average slope, and mutation amplitude, are selected to quantify the logging curve in the study area, thus realizing the description of the logging curve form. Secondly, training samples are selected to establish an SVM classification model. Finally, a quantitative discrimination model based on the SVM algorithm is established to realize the classification of depositional facies. Field application shows that this solution can be effectively used in uncored wells to identify depositional facies with a rate of accuracy approaching 70%. Our results provide new methods for the identification of sedimentary facies in the study area. The results will also provide a theoretical basis, as well as data basis, for further fine division of microfacies in the study area.

A variety of unconformity types are commonly developed during the rifting of a continental basin. Identifying their origin and evolution is a prerequisite to understanding the complex tectono-sedimentary evolution of the basin and to evaluate the basin’s oil and gas resources. Based on the 2D/3D seismic, geophysical logging, and subsurface lithological data, the unconformities within the rift layer of the Lishu Depression in the Songliao Basin are identified as disconformities, nonconformities, and four “types” of angular unconformities. Their evolution and origin are analyzed by associating the unconformities with the basin’s tectonic evolution. The results show that the rifting of the Lishu Depression was not a continuous process. Instead, several regional tectonic episodes influenced the basin’s evolution. Episodic compressional events and a phase of extension along the main faults determined the basin configuration and sedimentary fill characteristics of different sub-rifting stages. The tectonic history and related paleogeomorphology changes are the dominant factors in the formation of these different unconformity types. During the rifting process, the type and distribution of unconformity varied. In the initial rifting stage, the basin developed a nonconformity and four types of angular unconformities as the result of both regional uplift and fault block tilt. Rotation and tilting of the fault blocks during the intensive rifting resulted in two types of angular unconformities. Finally, in the recession rifting stage, a different form of angular unconformity and disconformity developed, mainly as a result of the regional uplift and subsequent subsidence.

The uplift-and-depression pattern of the Bozhong Depression represents a shallow tectonic response to the multiple-sphere interactions and plays a critical controlling role in sedimentary filling, tectonic evolution, and hydrocarbon accumulation in the Bohai Bay Basin, East China. However, its Mesozoic-Cenozoic tectonic evolution and formation mechanism remain unclear. Integrating drill core data and high-resolution 3D seismic data, this study systematically analyzes the structural framework and evolutionary history of the western Bozhong Depression. Seven regional unconformities are identified, dividing the strata into eight tectono-stratigraphic units. Balanced cross-section restoration delineates eight evolutionary stages from the Late Triassic compression to the Neogene thermal subsidence. The Late Triassic compression produced a maximum shortening of ca. 6.14 km, while the Early Cretaceous extension yielded a stretching of ca. 17.66 km. These results indicate that the Paleogene normal faulting, driven by reactivation of pre-existing faults and development of new faults, controlled the present uplift-and-depression pattern with differential evolution of the Chengbei, Shaleitian and Shijiutuo uplifts. The Chengbei uplift originated from Cenozoic overall northeastward tilting, the Shaleitian uplift represents a long-term inherited paleo-uplift, and the Shijiutuo uplift exhibits gradual west-to-east uplift. By linking Mesozoic fault reactivation directly to Cenozoic structural patterns, this study demonstrates that the structural preform inherited from earlier compressional epochs dictates the kinematics of subsequent extensional phases. Furthermore, these findings establish a new tectonic model and geodynamic framework applicable to similar intracratonic basins worldwide that exhibit pronounced tectono-sedimentary differentiation, shifting basin analysis from homogeneous extension models to those incorporate structural inheritance. Thus, understanding the formation mechanism of the uplift-and-depression framework is crucial for elucidating basin evolution and predicting hydrocarbon distribution.