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. 2. Petrological features of three types of early low-temperature dolomite. (a) Intergranular pores, bioclastic dolomite, Miocene Xuande Formation, Well Xike 1, Shidao Island of Xisha Islands; (b) Intergranular pores and bioclastic moldic pores, partially filled by dolomite cements, bioclastic dolomite, Miocene Xuande Formation, Well Xike 1, Shidao Island of Xisha Islands; (c) Microbial mat (Desulfovibrio brasiliensis) on the surface of the lower part of intertidal zone, Sabkha Coast, Abu Dhabi (according to reference [22]); (d) Algal framework pores, algal lamina or algal laminated dolomite, dolosparite cement, 5 067.35 m, Forth Member of Dengying Formation, Well Moxi 17, Sichuan Basin; (e) Spherical dolomite in algal lamina and algal laminated dolomite, 5 108.07 m, Forth Member of Dengying Formation, Well Moxi 8, Sichuan Basin; (f) Honeycomb or rice-granular gypsum-moldic pores, yellowish gray gypsiferous mud-sized crystalline dolomite, Middle-Lower Cambrian, Well YaHa 10, Tarim Basin; (g) Intergranular dolomite cement and residual intergranular pores, dolograinstone, 5 833.00 m, Middle Cambrian, Well YaHa 7 X - 1, Tarim Basin; (h) Tubular gypsum moldic pore, filled by a small amount of quartz, micritic-fine crystal dolomite, Majiagou Formation, 3 629.00 m, Well Shan 30, Ordos Basin; (I) Algal framework pores and intergranular pores, dolomite cement, algal framework dolomite, Leikoupo Formation, 3134.02 m, Well Zhongba 80, Sichuan Basin.