The resistivity method and time-domain induced polarization (TDIP) method are two branches of electrical geophysical prospecting. In recent years, researchers have implemented time-lapse resistivity inversion and time-lapse TDIP inversion based on time-lapse constraint theory. Although time-lapse inversion ensures temporal continuity between inversion results obtained at distinct epochs, it may not only cause the results to deviate from the true subsurface conditions, but also result in significant structural discrepancies resistivity and TDIP inversion results, thereby reducing inversion accuracy. To address these issues, the joint inversion of time-lapse resistivity and TDIP data was implemented based on cross-gradient constraint theory and time-lapse constraint theory. Using synthetic data from the theoretical model, we conducted separate inversion, time-lapse inversion, and time-lapse joint inversion. Comparative analysis of the results from these inversion schemes reveals that, compared with separate inversion and time-lapse inversion, time-lapse joint inversion not only maintains the temporal continuity of inverted models across consecutive monitoring epochs but also enforces structural similarity among distinct physical property models. This approach significantly increases the accuracy of the inversion results and exhibits superior noise robustness. These findings confirm the stability, reliability, and superiority of the algorithm developed in this study, providing a novel approach for addressing geological monitoring challenges.

The Hexi Corridor Basin Group, renowned for its Carboniferous source rocks, has emerged as a pivotal target for oil and gas exploration. This study integrates fieldwork, drilling, and geochemical data to analyze the Carboniferous lithofacies and paleogeography of the basin group, which is marked by extensive transgressive deposits. The Hexi Corridor experienced three key evolutionary phases during the Carboniferous. During the Early Carboniferous (deposition stage of the Qianheishan and Chouniugou Formations), crustal subsidence formed the Qilian epicontinental sea. Marine water intruded from the southeastern Qinling Mountains, and clastic sediments were supplied by the Alashan and Ordos oldlands to the north, developing lagoon-tidal flat facies interbedded with coal seams. As marine transgression expanded during the deposition of the Chouniugou Formation, the marine domain of the South Qilian area connected with the Beishan Trough, resulting in sedimentary differentiation between barrier-lagoon and open-coast deposits within this region. In the Late Carboniferous (deposition stage of the Jingyuan to Taiyuan Formations), transgression peaked; the marine area extended northward to Jiayuguan and eastward to connect with the North China Sea. Sediment thickness in the Helan Aulacogen changed sharply due to fault movement. This area was dominated by littoral-neritic tidal flat deposits with extensively developed coal seams, and detrital materials were still sourced from the Dunhuang–Alashan and Longxi oldlands. The entire evolutionary process was marked by tectonic control on basin development, multi-directional marine transgression, and persistent terrigenous sediment supply.