The resistivity method is widely used to address long-term monitoring challenges in fields such as environmental protection, ecological restoration, seawater intrusion, and geological hazard assessment. However, external environmental changes can influence monitoring data, resulting in inversion results that fail to accurately reflect subsurface variations. Furthermore, the data volume required for such monitoring is several times larger than that for conventional single-point observations, leading to excessively long inversion times and low computational efficiency. To address these issues, we develop a three-dimensional inversion algorithm for the resistivity method that incorporates time-lapse constraints. Additionally, MPI parallelization is integrated into the program to increase computational efficiency. Through the design of theoretical models and the synthesis of data to test the algorithm, the results show that, compared with those of separate inversion, the shapes and values of time-lapse inversion results at different time points are more consistent, maintaining temporal continuity, and the computational efficiency of MPI parallel inversion is greatly improved. Particularly in high-noise environments, time-lapse inversion effectively suppresses background noise interference, reduces false anomalies, and produces results that closely align with the true model, thus confirming the algorithm’s effectiveness and superiority.

The resistivity method is widely used to address long-term monitoring challenges in fields such as environmental protection, ecological restoration, seawater intrusion, and geological hazard assessment. However, external environmental changes can influence monitoring data, causing inversion results that fail to accurately reflect subsurface variations. Furthermore, the data volume required for such monitoring is several times larger than that for conventional single-point observations, leading to excessively long inversion times and low computational efficiency. To address these issues, we develop a three-dimensional inversion algorithm for the resistivity method incorporating time-lapse constraints. Additionally, MPI parallelization is integrated into the program to enhance computational efficiency. Through the design of theoretical models and the synthesis of data to test the algorithm, the results show that, compared to separate inversion, the shape and values of time-lapse inversion results at different time points are more consistent, maintaining temporal continuity, and the computational efficiency of MPI parallel inversion is greatly improved. Particularly in high-noise environments, time-lapse inversion effectively suppresses background noise interference, reduces false anomalies, and produces results that closely align with the true model, thus confirming the algorithm’s effectiveness and superiority.

This study is based on field observations and sample collections from the Panjinbulak, Qiongbulak, and Qunjisayi outcrops in the Yining Sag of the Ili Basin. Using organic geochemical analysis methods, the characteristics and hydrocarbon generation potential of the Permian Xiaoshansayi Formation (P₂x) and Tamqisayi Formation (P₂t) source rocks in the Yining Sag were compared and analyzed. The results indicate that the Permian source rocks in the Yining Sag of the Ili Basin exhibit high organic matter abundance and good types, among which the P₂t source rocks are overall superior to the P₂x. The P₂t source rocks in the Panjinbulak outcrop section on the northern margin are dominated by Type II₁-II₂ kerogen, while those in the Qunjisayi and Qiongbulak outcrop sections on the southern margin show a transition to Type II₂-III kerogen. The maturity of Permian source rocks presents a pattern of “higher in the south and lower in the north”, and all have reached the hydrocarbon-generation threshold. The northern margin is in the oil window, mainly dominated by oil generation; the southeastern margin has higher maturity, mainly producing oil/condensate gas. The Permian source rocks were deposited in a saline-reducing environment, with mixed input of aquatic organisms and terrestrial plants. During the deposition of P₂t source rocks in the northern margin, the water salinity was higher, and plankton such as cyanobacteria made prominent contributions. The P₂t source rocks in the Panjinbulak outcrop section on the northern margin have relatively better organic matter abundance and type, making it the main hydrocarbon-generation-potential area. The source rocks in the Qunjisayi outcrop section on the southeastern margin are slightly poorer, but their maturity is higher, currently in the main oil window, representing a secondary hydrocarbon-generation-potential area.

The exploration level of the Bogda Mountain front belt is relatively low, and the research on hydrocarbon accumulation is limited, resulting in unclear sources of discovered oil. To further investigate the geochemical characteristics and sources of crude oil in the Bogda Mountain front belt, this study conducted geochemical experimental analysis and oil–source correlations on crude oil and hydrocarbon source rock samples from the Permian Lucaogou Formation in the Yongfeng sub-sag and surrounding areas of the Bogda Mountain front belt. By using gas chromatography–mass spectrometry technology, the geochemical characteristics of saturated hydrocarbons and aromatic compounds were analyzed. Combined with stable carbon isotopes of saturated hydrocarbons and aromatic hydrocarbons, the organic matter source, maturity, and sedimentary environment were determined. The research results indicate that the crude oil from Well Xyd 1 exhibits mature characteristics, and the source material was deposited in a reducing to weakly oxidizing, weakly reducing environment. The source rocks of the Lucaogou Formation in Well Xyd 1 were formed in a reducing, semi-saline–saline sedimentary environment, while those from the Gjg and Dhs outcrops developed in a weakly oxidizing–weakly reducing, non-high-salinity, weakly stratified sedimentary environment. Carbon isotope, terpane, and isoalkane characteristics confirm a significant genetic relationship between the crude oil from Well Xyd 1 and the local Luzhaogou Formation source rocks. The source rocks of the Luzhaogou Formation in the Yongfeng sub-sag exhibit strong heterogeneity, with significant differences in sedimentary environments and parent materials in their spatial distribution. Maturity analysis indicates that the Luzhaogou Formation source rocks in Well Xyd 1 have reached a mature stage, whereas those from the Gjg and Dhs outcrops are at a relatively low maturity level.

The Ulungu Depression, located in the northeastern Junggar Basin, adjacent to the Altai Orogenic Belt, exhibits distinctive tectonic relationships and evolutionary mechanisms. Through integrated interpretation of seismic and electromagnetic data, a composite transect was established to characterize the deep-to-shallow geological architecture of the Altai Orogenic Belt–Ulungu Depression system. The tectonic evolution since the Late Paleozoic was reconstructed, revealing three distinct phases: (1) Late Paleozoic peripheral foreland basin development, (2) Mesozoic intracontinental foreland basin formation, and (3) Cenozoic intracontinental foreland basin reactivation. The Late Paleozoic phase records the formation of a peripheral foreland basin in the northeastern Junggar Basin, driven by the Altai-Junggar collision orogeny. During the Mesozoic, intracontinental orogeny along the Altai Belt controlled the development of an intracontinental foreland basin in this region. Paleogene tectonic quiescence facilitated regional subsidence and stable sedimentary deposition. From the Neogene to Quaternary, the Ulungu Depression experienced weak compressional deformation dominated by minor thrust faults, with intermittent regional extensional structures, attributable to the far-field effects of the India-Eurasia collision. This distant tectonic stress primarily localized intracontinental orogeny in the North Tianshan, while the Ulungu Depression, situated farther north, exhibited attenuated strain partitioning. Reconstruction of this multi-phase tectonic evolution provides critical insights into the accretionary orogenic processes of Central Asia. Furthermore, it offers practical implications for hydrocarbon exploration in the Ulungu Depression, particularly regarding structural traps and reservoir distribution patterns.