碳酸盐岩-H_2S平衡体系原位溶蚀模拟实验及其地质意义

In-situ Simulation Experiment of Carbonate-Hydrogen Sulfide Equilibrium System and Its Geological Significance

利用自主组装的水热金刚石压腔设备,结合激光拉曼光谱,原位连续观察封闭条件下碳酸盐岩与H2S溶液反应的升温(室温→230℃)和降温(230℃→室温)过程。实验结果表明,从室温升温至140℃,碳酸盐岩矿物大量沉淀,继续升温至230℃,沉淀较少。随着温度、压力的升高,碳酸盐岩整体趋于沉淀,且白云石比方解石、白云岩比灰岩更稳定。随着温度、压力的降低,碳酸盐岩少量溶蚀。根据实验结果推测,在深部封闭条件下,随着埋深增加,碳酸盐岩整体趋于胶结,原始孔隙度较好的储层经过快速封闭埋藏及缓慢抬升,有利于形成优质储层。断裂、岩浆热液等活动可能打破封闭体系,其改造作用需进一步研究。

The interactions between carbonate and H2 S saturated acid fluid at various temperatures and pressures in-situ conditions were simulated using hydrothermal diamond-anvil cell equipment combined with Raman spectroscopy. The heating process is from room temperature to 230℃ and then the system is cooled to room temperature again. Experimental results clearly demonstrate that carbonate minerals present much precipitation from room temperature to 140℃ and little precipitation from 140℃ to 230℃. Carbonate trends to precipitate with the increase of temperature and pressure, and dolomite is more stable than calcite and limestone. But in the cooling process carbonate suffers from little dissolution. So in the burial process, carbonate trends to precipitate, and the rapid closed burial and slow uplift process is beneficial to form high quality reservoirs in the deep closed condition. Fault and magmatic hydrothermal activities may break the closed system, which needs further study.