The carbonate gas reservoir is one of the most important gas formation types; it comprises a large proportion of the global gas reserves and the annual gas production rate. However, a carbonate reservoir with weathering crust formation is rare, and it is of significant interest to illustrate the geological characteristics of this kind of formation and present the emerging problems and solution measures that have arisen during its exploitation. Therefore, in this research, a typical carbonate gas reservoir with weathering crust formation that is located in Ordos Basin, China, was comprehensively studied. In terms of formation geology, for this reservoir, the distribution area is broad and there are multiple gas-bearing layers with low abundance and strong heterogeneity, which have led to large differences in gas well production performance. Some areas in this reservoir are rich in water, which seriously affects gas well production. Regarding production dynamics, the main production areas in this gas reservoir have been stable on a scale of 5.5 billion cubic meters for more than a decade, and the peripheral area has been continually evaluated to improve production capacity. Nevertheless, after decades of exploration and development, the main areas of this reservoir are faced with several problems, including an unclear groove distribution, an unbalanced exploitation degree, low formation pressure, and increases in intermittent gas wells. To deal with these problems and maintain the stability of gas reservoir production, a series of technologies have been presented. In addition, several strategies have been proposed to solve issues that have emerged during the exploration and exploitation of peripheral reservoir areas, such as low-quality formation, unclear ancient land and complex formation-water distribution. These development measures employed in the carbonate gas reservoir with weathering crust formation in the Ordos Basin will surely provide some guidance for the efficient exploitation of similar reservoirs in other basins all over the world.

The Ediacaran Dengying Formation in the Sichuan Basin exhibits well-developed microbial mound–shoal complex (MMSC) sedimentation. Its abundant outcrops, core samples, and thin section data provide advantageous conditions for sedimentary architecture studies. Based on these data, this study elucidates typical lithofacies, identifies sedimentary architectural elements, summarizes MMSC stacking styles, describes sedimentary evolution characteristics, and explores the controlling factors of different stacking styles and the reservoir development conditions of architectural elements. Research indicates that MMSC primarily develops five lithofacies, namely, thrombolitic dolomite, undulate stromatolitic dolomite, laminar stromatolitic dolomite, granular dolomite, and micritic dolomite. MMSC sedimentary architecture is categorized into composite MMSCs, single MMSCs, and lithofacies. Three stacking styles of MMSCs are observed, namely, superimposed MMSCs, which represent aggradational sedimentation; migratory MMSCs, which depict progradational sedimentation; and isolated MMSCs, which denote a single parasequence depositional cycle. The stacking styles of MMSCs are fundamentally controlled by the relationship between MMSC sedimentation rates and variations in accommodation space, with the latter predominantly influenced by fluctuations in sea level. Superimposed MMSC sedimentation rates are comparable to accommodation space change rates, while migratory MMSC sedimentation rates exceed accommodation space change rates, and isolated MMSC sedimentation rates are lower than accommodation space change rates. Various composite MMSCs are isolated from each other by sediments formed under low hydrodynamic conditions, constituting distinct connectivity units. Compared to isolated MMSCs, superimposed and migratory MMSCs exhibit superior reservoir conditions. Within individual MMSCs, different lithofacies lead to high-quality reservoirs in mound cores and flanks due to variations in physical properties, while mound bases, flats, and caps form non-reservoirs.