14 Carbonate and Fracture Reservoirs（14碳酸盐岩裂缝储层）.pdf

Carbonate Reservoirs Carbonate Reservoirs and and Fractured Reservoirs Fractured Reservoirs 1 inch Carbonate Sidewall core Carbonate Reservoirs Outline • Carbonate Porosity • Porosity strongly controlled by post- – Primary vs. secondary porosity depositional processes • Reefs • High initial porosity • Karst (dissolution) • Dolomitization • Rapid cementation • Fracture systems • Dissolution creates secondary porosity • Healed Fractures vs open fractures • Fracture controlled production (example) • Usually due to acidic water Carbonate Porosity Types Intergranular Porosity Intergranular Porosity 1 Vuggy Moldic Porosity Vuggy Moldic Porosity Cretaceous Reefs Golden Lane Facies Water Drive, 33-40 API oil, 200 Million Barrels cum. production since 1915 Dissolution by Meteoric Water