Research On The Storage Capacity And Flow Characteristic Of Shale Oil

Understanding the transport behaviors of oil through organic nanopores is important for shale oil reservoir development.Based on relevant MDS?molecular dynamics simulations?,experimental and theoretical studies,a mathematical model was derived to calculate the liquid permeability of organic nanopores in shale.The model can incorporate the mechanisms of boundary slip and physical adsorption,and the complicated structural properties of kerogen are included.By sensitivity analysis on the model,the flow regularities of organic pores are reached.On the other hand,the shape of the velocity profile is studied quantitatively.The analysis of the occurrence state of crude oil in shale rock is crucial for the formation evaluation of shale oil reservoirs.A method based on Gaussian Mixture Model for estimating the fractions of physically adsorbed,immobile?trapped in the pore space resulting from van der Waals?,and free oil while considering both organic and inorganic pores is established.A sensitivity analysis of the derived formulae is conducted to demonstrate the fractions and dominant factors of each state.A sensitivity analysis on the average pore radius demonstrates that the non-negligible,if not substantial,quantities of physically adsorbed and immobile oil in shale rock are very unique.Finally,comparisons are constructed to illustrate the superiority of the Gaussian Mixture Model in the depiction of the complicated and random porous structure of shale rock.The contribution of kerogen to oil flow in shale rock is not well understood but is crucial,and knowledge about the representative sizes is fundamental for upscaling studies.Based on a2D numerical model,the equivalent permeability and REA?representative elementary area?of shale oil rocks are explored in detail incorporating the effects of kerogen and the inorganic permeability heterogeneity.By sensitivity analysis,the impacts of the permeability contrast?ratio of organic permeability to inorganic permeability?,TOC?total organic carbon,volume fraction?,inorganic permeability heterogeneity,and kerogen geometric characteristics on equivalent permeability are investigated systematically.Based on sampling theory,the statistical method for estimating REA is derived.The REA is estimated to be no greater than10^-2 m.Starting from relative error?ratio of variance to average value?,the relationship among REA and the aforementioned factors is reached.Further understanding of the liquid storage characteristics of nanoporousgrains in shale,i.e.,kerogen or clay,will probably shed light on the efficient development of shale reservoirs.The expression for surface area belonging to kerogen and clay is derived based on Gaussian Mixture Model.Sensitivity analysis is conducted to demonstrate the relative importance of all the influencing factors.The frequency distribution of the referred surface area is obtained by calculation of random cases.Results show the importance of studying their storage regularities.Grounded on our previous work,the simplified models describing the storage properties of nanoporous particles are achieved.Analytical derivation or numerical method is employed to understand the impacts of each factor on the adsorbed and immobile content.