ZHU Wen-hui1,2, QU Xi-yu1, QIU Long-wei1, CHEN Yong1, GONG Fa-xiong2, WU Si-xuan1
1. School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, China;
2. Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China;
3. Jidong Oilfield Company, Petro China, Tangshan, Hebei 063004, China
Abstract: To investigate characteristics and erosion mechanism of carbonate in acid solutions, ten representative carbonate rock samples were collected from the Nanpu Depression and its surrounding outcrops to conduct dissolution experiments using acetic acid and hydrochloride acid solutions, and the characteristics of dissolution were observed under scanning electronic microscope (SEM). The results indicated that: ①Texture and composition-depended selective dissolution is the main mechanism of carbonate dissolution; ②Both calcite and dolomite have characteristic dissolution patterns, that is, "corroded cone" for calcite and "honeycomb" for dolomite, both of which are resulted from the selective dissolution; ③Under the supergene condition, the solubility of calcite increases when small amount of dolomite is found in limestone, and the critical content point of dolomite is 13%, if higher than this content point, the solubility of carbonate rocks will decrease as the dolomite content increases.
Keywords: carbonate rock selective dissolution "corroded cone" calcite "honeycomb" dolomite dissolution mechanism
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.3, 2015, page 619-625