Chemo‐Mechanical Solid Production in Deep Carbonate Gas Reservoirs: A Mineralogical Classification and Exploratory Intensity Evaluation (Case Study From the Eastern Sichuan Basin, SW China)

ABSTRACT Solid production and blockage in deep carbonate gas reservoirs can impair flow assurance and wellbore integrity. The term solid production is used here as an umbrella term covering (i) mechanically released reservoir‐derived particles, (ii) chemically precipitated or scale‐like solids, and (iii) mixed chemo‐mechanical products; the term sanding is reserved for mechanically released particles or for comparison with conventional sandstone studies. Blockage and solid‐production samples were collected from 11 representative wells in the Eastern Sichuan Basin and characterized using x‐ray diffraction (XRD), scanning electron microscopy with energy‐dispersive spectroscopy (SEM–EDS), thermogravimetric analysis/loss on ignition (TGA/LOI), acid‐solubility analysis, and particle‐size measurements. A diagnostic framework was established using carbonate minerals (calcite + dolomite) and acid‐insoluble silica as mineralogical endmembers, with LOI and SEM–EDS used as an auxiliary diagnostic route for biogenic and organic/sulfide‐bearing materials. Four nonoverlapping diagnostic modes were defined: Type I, carbonate‐rich chemically precipitated solids; Type II, mixed carbonate–silica chemo‐mechanical solids; Type III, biogenic or organic/sulfide‐bearing solids identified by ancillary evidence; and Type IV, silica‐rich mechanically released particles. A bounded Combined Solid‐Production Index (CSI) is proposed as an exploratory mineralogy‐based indicator. The available data support mechanism‐based diagnosis and screening of well‐control options, but the small sample set and incomplete replicate‐level records do not provide independent predictive validation of CSI.