【摘要】 选取塔中地区奥陶系海相碳酸盐岩样品进行了模拟实验,以研究其在表生岩溶作用下的溶解动力学特征。实验分别在30,50℃下,用pH值为3~6的盐酸溶液,恒温水浴加热进行。结果表明:4种样品溶解速率的相对大小依次为:灰白色灰岩>砂屑灰岩>粗晶白云岩>中粗-细晶白云岩,且溶解速率均随着温度的升高而增大,随着pH值的增大而减小。但随着外界环境的变化,溶解速率的变化略有差异。造成这种差异的原因可能是样品中的硅酸盐杂质、晶体颗粒的大小以及实验过程中产生的CO2的影响。由实验结果推测可知,对于塔中地区以表生岩溶作用为主形成的奥陶系海相碳酸盐岩储层,灰岩储层的储集性能可能优于白云岩储层;对于以埋藏岩溶作用为主形成的奥陶系海相碳酸盐岩储层,白云岩储层的储集性能可能优于灰岩储层。更多还原

【Abstract】 This paper discusses the dissolution kinetics of Ordovician marine carbonate reservoirs in central Tarim Basin.The experiment,performed at 30℃ and 50℃ in hydrochloric acid with pH ranging from 3 to 6,was conducted in constant temperature water-bath using four samples of calcarenite,off-white limestone,fine-megacrystalline dolostone,megacrystalline dolostone.The result indicates that,under the experimental conditions,the dissolution rate of off-white limestone is the highest,whereas that of fine-megacrystalline dolostone is the lowest.The rates of the sample dissolving tend to increase with increasing temperature and decrease with increasing pH.However,this tendency is diverse for different lithologies,especially for dolostone.The carbonate dissolution may be influenced by many factors,such as the silicates contents,crystal size,CO2 production in the experiments.Based on the result of experiments,it can be predicated that the capability of the limestone reservoirs,formed by epigeic diagenesis in the Ordovician in this area,may be prior to that of dolostone’s.Nevertheless,the opposite state could be found for the reservoirs,formed after the burial.更多还原