Genetic types and distinguished characteristics of dolomite and the origin of dolomite reservoirs

Wenzhi ZHAO,Anjiang SHEN,Zhanfeng QIAO,Liyin PAN,Anping HU,Jie ZHANG

Fig. 4. Petrological characteristics of the three types of burial, hydrothermal dolomites in late stage. (a) Intergranular pores, residual oolitic texture, very fine - fine crystalline dolomite, Feixianguan Formation, 5 626.00 m, Well Longgang 2, Sichuan Basin; (b) Residual intergranular pores, pebble texture, fine crystalline dolomite, Feixianguan Formation, 3 243.97 m, Well Luojia 2, Sichuan Basin; (c) Intergranular (dissolved) pores and organism pores, residual grain texture, fine crystalline dolomite, Changxing Formation, 5 976.00 m, Well Longgang 28, Sichuan Basin; (d) Pinhole-like intercrystalline pores, saccharoidal fine - medium crystalline dolomite, Qixia Formation, 2 423.00 m, core from Well Kuang 2, Sichuan Basin; (e) Intergranular (dissolved) pores, fine crystalline dolomite, 2 423.55 m, Qixia Formation, Sichuan Basin, Well Kuang 2, Sichuan Basin; (f) Organism pores and dissolved pores, bioclastic stone is the primary rock, same visual area with e; (g) Intergranular (dissolved) pores, medium - coarse crystalline dolomite, Qixia Formation, 7 328.60 m, Well Shuangtan 8, Sichuan Basin; (h) Some solution pores in dolomite filled by saddle dolomite, Qixia Formation, Chejiaba Section, Guangyuan, Sichuan Basin; (I) Some fractures filled by saddle dolomite, Maokou Formation, outcrop section, Sichuan Basin.