CALCULATION OF MILL RIGIDITY BY THREE DIMENSION CONTACT BOUNDARY ELEMENT METHOD

Vertical rigidity of the space self adaptive 530 high rigidity mill is calculated by applying the boundary element method (BEM) of three dimension elastic contact problem,which can update the existed deforming separation calculating theory and corresponding methods of material mechanics,elastic mechanics and finite element method.The method has less hypotheses and stronger synthesis in contact type calculating model.The advantages of the method are high calculating rate,high calculating accuracy,etc..

Connotation analysis, source-reservoir assemblage types and development potential of unconventional hydrocarbons in China

Through analysis of the connotation of unconventional hydrocarbons,the source-reservoir assemblages of unconventional hydrocarbons are divided into three types,i.e.,source-reservoir neighboring type,source-reservoir integration type,and source-reservoir separation type.The source-reservoir neighboring type resources mainly include tight oil and tight gas with the following formation conditions and characteristics:(1)efficient near-source accumulation close to high-quality source rocks with the pressure difference between source and reservoir as the dynamic force;(2)large-area tight reservoirs with certain porosity,dominated by micro-nanopores of inorganic origin;(3)distributed in depressions and slopes with large hydrocarbon-bearing area and great resource quantity,low abundance and local development of“sweet spots”;(4)weak tectonism.The source-reservoir integration type resources mainly include coalbed methane,shale gas,shale oil and oil shale.The formation conditions and characteristics are:(1)high abundance of organic matter,different types of organic matter and thermal evolution grades leading to formation of different resources types;(2)organic-rich sections are distributed continuously in the reservoiring space which is dominated by nanometer organic pores,interparticle pores and microfissures;(3)hydrocarbons mainly occur in free or adsorbed state,varying much with resource type;(4)the resources are self-conserved,and enriched in depressions and slopes,the conservation conditions are controlled by tectonics,temperature and pressure;(5)the production per well can be enhanced by volume fracturing,which increases the permeability of the reservoirs.The source-reservoir separation type resources are more special,mainly including(1)transformed conventional resources such as oil sand and heavy oil;(2)unsteady resources formed under special conditions of temperature and pressure,among which natural gas hydrate is a representative.These three types of resources in China are different in both development prospect and current situation:(1)the source-reservoir neighboring type is most practical and will develop fast in the next 5 years;(2)the source-reservoir integration type needs continuous exploration and technical breakthrough,and is expected to develop rapidly in the coming decade;(3)in the source-reservoir separation type resources,natural gas hydrates have the greatest development potential,on which technical tests are being conducted.