Impact Of Minerals In Shale On Methane Adsorption Capacity

This paper systematically studied the brittle minerals,clay minerals and organic matter.we established the model of methane adsorption capacity of shale based on mineral composition.We validated the methane adsorption capacity model of marine,continental and transitional facies shale by analysising and comparing experimental data of shale samples from Laidi 1 well,Mouye 1 well,and DY-1 well.The following key findings were made:The development of pores on the surface of minerals has been studied by scanning electron microscope images of various minerals.It is found that the specific surface area of brittle minerals is much lower than the specific surface area of clay minerals,and a large amount of organic pores are developed on the surface of organic matter,which provides a lot of space for oil and gas;At 30 ? constant temperature conditions,the methane adsorption capacity of each mineral was measured and the order of methane adsorption capacity of minerals is organic matter> montmorillonite> illite/smectite mixed-layer> kaolinite> chlorite> illite> calcite> feldspar> quartz;Pure minerals of different particle size of isothermal adsorption experiments was conducted,the experimental results showed that there was a negative correlation between the methane adsorption capacity and particle size of pure minerals,i.e.the smaller the particle size,mineral methane adsorption capacity is higher,the larger the size of minerals,methane adsorption capacity is small;The isothermal adsorption experiments of methane on mixed pure minerals show that the methane adsorption capacity of mixed minerals is positively related to the proportion of minerals in mixed minerals;According to the different types of organic matter,the methane adsorption model of shale is divided into marine,continental and transitional facies shale methane adsorption model.The shale samples from Laidi 1 well,Mouye 1 well,and DY-1 well were chosen to verify three models and the results show that three models were suitable for these shale samples.According to the experimental results,the methane adsorption model of marine facies,continental facies and land sea transitional facies has high reliability.It can be used for prediction of methane adsorption capacity of shale samples.According to the mineral composition of shale samples,it is possible to predict the methane adsorption capacity of shale samples.