Integration of NMR and NMRC in the Investigation of the Pore Size Distribution of Tight Sandstone Reservoirs: A Case Study in the Upper Paleozoic of Dongpu Depression

Figure 9

Diagenesis characteristic of tight sandstone samples. (a)–(b) SE2 images of sample #2. The dissolution of feldspar resulted in the formation of honeycomb pores. (c) Plane-polarized micrograph of sample #1. The dissolution of rock debris resulted in the formation of moldic pores. (d) Plane-polarized micrograph of sample #10. Authigenic kaolinite precipitated in the tuff dissolution space. (e) Backscatter image of sample #7. Authigenic kaolinite remained in intercrystalline voids. (f) SE2 image of sample #7. Kaolinites were tightly heaped. (g) Plane-polarized micrograph of sample #10. Authigenic kaolinite remained within intercrystalline voids. (h)–(j) Micrograph of sample #8. The quartz overgrowth that filled the primary and dissolution pores was easily observable in the matrix-poor samples. (k) Plane-polarized micrograph of sample #12. The sandstone sample had undergone intense compaction and was characterized by linear, concave, and convex contacts. (l) Crosspolarized micrograph of image A. The ductile fragments were deformed. R: rock debris; Fsp: feldspar; Qtz: quartz; Oq: overgrowth quartz; Diss. p: dissolution pores; Kao: kaolinite.

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