柴达木盆地石炭系页岩吸水—饱水特性研究

发布时间：2018-08-03 20:02

【摘要】：页岩是成分复杂的沉积岩,具有多种特性,其特征由矿物成分和结构、阳离子交换能力、比表面积和水饱和度等来表征。页岩中蕴藏着潜在的碳氢化合物资源,它长期以来一直是能源和环境研究的重点。根据实验原理,利用课题组实验室自主设计的页岩吸水实验仪器,对取自柴达木盆地东部石浅1井和ZK1-1井的4个页岩岩样进行吸水饱水特性实验。实验通过测量计算不同饱水压力下各岩样的含水率,由此探究页岩吸水-饱水与时间和压力的关系,进而得出水测孔隙度。研究表明:页岩在饱水过程中其含水率先逐渐增加,升高到最高值时趋于平稳;达到饱和所需时间随饱水压力的增加而逐渐减少;吸水速率随时间而逐渐减小;绝对饱和吸水量随饱水压力的升高而逐渐增加。页岩水测孔隙度随饱水压力的增加而逐渐升高。页岩吸水能力的影响因素众多,包括压力、孔容大小、比表面积、有机碳含量、黏土含量、热成熟度和埋藏深度等不同影响因素。实验研究表明:压力显著影响页岩吸水-饱水能力,页岩吸水速率随饱水压力的升高而逐步增大,达到最大后出现下降的趋势;页岩吸水量随饱水压力的增加而增大,吸水量增大到一定数值后不再增加,页岩吸水能力随压力升高而增强,但也受到压力的限制;页岩的孔径分布范围很大,在有压吸水条件下,吸水量与微孔孔体积呈正相关;而在无压力吸水条件下,吸水量则与总孔孔体积呈正相关;页岩的总比表面积与其饱和吸水量呈正相关关系,总比表面积越大,页岩的饱和吸水量增加的也越多;页岩的黏土矿物含量与其饱和吸水量呈显著正相关关系,黏土矿物是影响页岩吸水的主要因素之一,页岩黏土矿物含量越大,页岩的饱和吸水量越多;有机质含量是影响页岩吸水的重要因素,页岩吸水量与有机碳含量呈正相关关系,相关系数大于98%,页岩吸水量随有机碳含量的升高而增加,具体关系为:y=0.03x-0.01,页岩TOC值越大,页岩吸水量越大;页岩吸水量随其镜质体反射率(Ro)的增加而增大,有机质热成熟度越高,吸水量越大;岩样吸水量随页岩埋藏深度的增加而减少,页岩吸水量与岩芯埋藏深度呈负相关关系,浅层页岩有较强的吸水能力。
[Abstract]:Shale is a sedimentary rock with complex composition. Its characteristics are characterized by mineral composition and structure, cation exchange ability, specific surface area and water saturation. Shale contains potential hydrocarbon resources, which have long been the focus of energy and environment research. According to the experimental principle, four shale rock samples from Shishen1 well and ZK1-1 well in eastern Qaidam Basin were tested by using the shale water absorption experimental instrument designed by our laboratory. Through measuring and calculating the water content of each rock sample under different saturated pressure, the relationship between shale water absorption and saturated water and time and pressure is explored, and the porosity of water measurement is obtained. The results show that the water content of shale increases gradually in the process of saturated water, and tends to be stable when it rises to the highest value, the time to saturation decreases gradually with the increase of saturation pressure, and the water absorption rate decreases with time. The absolute saturated water absorption increases gradually with the increase of saturated water pressure. The porosity of shale water increases with the increase of saturated water pressure. There are many factors affecting shale water absorption, including pressure, pore volume, specific surface area, organic carbon content, clay content, thermal maturity and burial depth. The experimental results show that the water absorption rate of shale increases gradually with the increase of saturated water pressure, and decreases after reaching the maximum, and the water absorption rate increases with the increase of saturated water pressure, and the water absorption rate increases with the increase of saturated water pressure, and the water absorption rate increases with the increase of saturated water pressure, and the water absorption rate increases with the increase of saturated water pressure. When the water absorption is increased to a certain value, the water absorption capacity of shale increases with the increase of pressure, but it is also limited by pressure, the pore size distribution of shale is very large, and under the condition of water absorption under pressure, the water absorption capacity is positively correlated with the pore volume of micropores. The total specific surface area of shale is positively correlated with its saturated water absorption, and the larger the total specific surface area is, the more the saturated water absorption of shale is increased, while under the condition of no pressure water absorption, the total pore volume is positively correlated with the total pore volume, and the total specific surface area of shale is positively correlated with its saturated water absorption. There is a significant positive correlation between shale clay content and saturated water absorption. Clay mineral is one of the main factors affecting shale water absorption. The larger the shale clay content is, the more saturated water absorption of shale is. Organic matter content is an important factor affecting shale water absorption. Shale water absorption is positively correlated with organic carbon content. The correlation coefficient is greater than 98. The shale water absorption increases with the increase of organic carbon content. The specific relationship is: 1. 0. 03 x-0. 01. The greater the shale TOC value is, the higher the content of organic matter is. The water absorption of shale increases with the increase of vitrinite reflectance (Ro), the higher the thermal maturity of organic matter, the greater the water absorption of shale, and the water absorption of rock sample decreases with the increase of shale buried depth. There is a negative correlation between shale water absorption and core burial depth, and shallow shale has strong water absorption ability.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE311

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