Experimental Methods And Effective Production Conditions Of Shale Oil And Gas

Shale oil and gas play an important role in easing the tension in oil and gas resources.Compared with conventional reservoir,shale oil and gas reservoir rich in organic matter is much more complicated in terms of mineral composition,pore types and liquid occurrence,which makes the mechanism of fluid flow in shale more sophisticated and cannot be characterized by traditional mechanism of fluid flow in porous media.Research on characterization of shale oil and gas reservoir and mechanism of flow is just beginning,most of which are focused on theoretical calculation,numerical simulation and molecular simulation.Experimental results are rarely reported due to the fact that it will be high-cost and time-consuming to conduct such an experiment and that the lack of feasible experimental methods.It deserves great effort to establish experimental methods of fluid flow in shale,providing theoretical analysis with data support.Combined with the knowledge of geochemistry,geology,petrophysics and mechanism of flow in porous media,the geochemical characteristics,petrologic feature,micro-pore structure,porosity and permeability characteristics are evaluated.Methods of evaluating physical properties and sensitivity of shale oil and gas reservoir are proposed,and experimental methods of fluid flow in unconventional reservoir are established.Methods of characterization of shale oil reservoir is discussed refer to the research on shale gas reservoir.With the help of such experiments,mobility and producing condition is analyzed.Results show that organic matter in shale oil and gas reservoir can have a significant influence on occurrence of fluid as well as the micro-pore structure and fluid flow pattern.Based on the different interaction between oil,gas,water and organic pore,inorganic pore,the method of fluid saturation is proposed to characterize shale oil reservoir.The organic saturation of shale of Jiyang Depression is about 20% to 50% and there is a positive correlation between organic saturation and total organic carbon(TOC).Adsorbed and dissolved oil is about 14%~43% of total oil,and 57%~86% for free oil instead.For the oil in organic material,70%~85% of oil is in adsorbed and dissolved state,and free oil occupies 15%~30%.Experiment results show that the behavior of pressure drop have a great influence on shale gas production.There exists a critical point of production pressure,above which free gas takes up most part of production and a little adsorbed gas will also be produced.Only when production pressure is below the critical point will adsorbed and dissolved gas be produced in great quantity,and the movability of adsorbed gas has no correlation with TOC.The saturation of movable fluid in shale of Jiyang is relatively low,for the average saturation is about 8.16%.Movable free oil mainly occupies pores which radius is more than 0.2?m and is controlled by throat.Results of experiment also show that the movability of shale oil can be great,and adsorbed and dissolved oil can also be produced except for elastic recovery.