Perpustakaan Digital ITB

Understanding the status and the relative content of water in shale is of great significance for shale gas and oil reserve estimations and production predictions. In this work, a facile and efficient method to quantitatively determine the status and relative content of water in shale is proposed. As shale composition significantly influences the distribution and status of water, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis were conducted; the results showed that shale composition is very complex, thus suggesting that is rather difficult to efficiently analyze the water in shale. Because the weight loss during a TG experiment not only contains water but also complicated organic hydrocarbons, it is impossible to obtain the status and relative content of water in shale by TG. In the present investigation, thermogravimetry-mass spectrometry (TG-MS) technology was employed to solve this problem, and the water ion currents of MS were utilized to record the removal behavior of water in shale. The integral area of the water ion current curves within different temperature ranges corresponds to the status (free, bound and structural water) and relative content of water. The TG-MS results indicate that the structural water content in the six typical shale samples is all greater than 50% of the total water. Among the six shale samples, the structural water content varies from 71.24% to 57.37%. At the same time, free water is the least abundant, and most of the free water contents of the shale samples contribute less than 10% of the bound water contents. A retort method was utilized to verify the effectiveness of the TG-MS method, and the results indicate this method is efficient and reliable. The results show that TG-MS technology can efficiently determine the removal behavior of water in shale, and the different statuses of water can be qualitatively described by using this method. This work provides a simple and effective method to explore the status of water and its relative content in shale.