Fluid Inclusion Evidence for Oil Charge and Cracking in the Cambrian Longwangmiao Dolomite Reservoirs of the Central Sichuan Basin, China

Figure 3

The Longwangmiao Formation in Well MX22 (4941.83-4943.88 m). Photos of cores and thin sections with accompanying petrological observations. (B1) 4941.83 m, the core petrology is powdery crystal dolomite with dissolution pores and cavities. (B2) Thin-section scans show asphalt partially filling intercrystalline pores and dissolution pores. (B3) (-) and (B4) (CL) Dissolution pore partially infilled with asphalt and residual pores. (B5) (-) and (B6) (UV) Dissolution pore fill suite: a small amount of dolomite → solid asphalt → residual pores. (A5) (-) and (C1) 4943.72-4943.88 m, the core petrology is a fine-grained powder crystal dolomite with bedding parallel dissolution pores. (C2) Observation of thin sections shows rims of asphalt filing dissolution holes. (C3) (-) and (C4) (CL) Dissolution pore fill suite: a small amount of dolomite → solid asphalt → residual pores. (C5) (-) and (C6) (UV) Pore fill types identified in intercrystalline pores in powder crystal dolomite dissolution pores included the following: dolomite → solid asphalt → residual pores. (-): plane polarized light; CL: cathodoluminescence; UV: fluorescence.