In Romania, rendering the oil structures evident in the deep strata （= 6,000 m） is conditioned by the penetration of some salt deposits of appreciable thickness （500-3,000 m） situated above the structures with pet...In Romania, rendering the oil structures evident in the deep strata （= 6,000 m） is conditioned by the penetration of some salt deposits of appreciable thickness （500-3,000 m） situated above the structures with petroleum potential. Crossing by the drilling of these salt deposits constitutes a major risk factor both in achievement （drilling, cementing） and afterwards, to ensure the stability-reliability of the wells. Based on these reasons, the researches have been focused on： the study of salt behavior deformation, establishment of the required parameters to ensure the stability of the drillings until the bore-hole lining （especially the secondary stress state around the drilling, the density of the drilling fluid in correlation with the temperature and respectively the depth） and also after casing （type of the cement pastes, the nature, the quality and the dimensions of pipes）, namely the reliability of the wells.展开更多
The paper deals with the mechanical origin and rules of en echelon folds and their secondary fractures by means of elastic stability theory and nonlinear fracture criterion.Obtains the quantitative relations among en ...The paper deals with the mechanical origin and rules of en echelon folds and their secondary fractures by means of elastic stability theory and nonlinear fracture criterion.Obtains the quantitative relations among en echelon angles of en echelon folds,ratios of boundary stresses and en echelon pitches of shear zone under an action of general boundary forces(tension shear,pure shear or compression shear).As an applied example,the paper researches the displacement field,stress field,distortion energy distribution, state of secondary fractures and energy released by fracturing of en echelon fold structure developed at the east foot of Taihang Mountain.The results of research show that maximum principal (compressive) stresses,maximum shear stresses,high value area of distortion energy are in the nuclear parts of en echelon folds.In these parts compressive fractures were easily developed in approximately parallel with fold axis.So it is verified that the secondary fracture of en echelon folds is a mechanism controlling a strong earthquake.展开更多
文摘In Romania, rendering the oil structures evident in the deep strata （= 6,000 m） is conditioned by the penetration of some salt deposits of appreciable thickness （500-3,000 m） situated above the structures with petroleum potential. Crossing by the drilling of these salt deposits constitutes a major risk factor both in achievement （drilling, cementing） and afterwards, to ensure the stability-reliability of the wells. Based on these reasons, the researches have been focused on： the study of salt behavior deformation, establishment of the required parameters to ensure the stability of the drillings until the bore-hole lining （especially the secondary stress state around the drilling, the density of the drilling fluid in correlation with the temperature and respectively the depth） and also after casing （type of the cement pastes, the nature, the quality and the dimensions of pipes）, namely the reliability of the wells.
文摘The paper deals with the mechanical origin and rules of en echelon folds and their secondary fractures by means of elastic stability theory and nonlinear fracture criterion.Obtains the quantitative relations among en echelon angles of en echelon folds,ratios of boundary stresses and en echelon pitches of shear zone under an action of general boundary forces(tension shear,pure shear or compression shear).As an applied example,the paper researches the displacement field,stress field,distortion energy distribution, state of secondary fractures and energy released by fracturing of en echelon fold structure developed at the east foot of Taihang Mountain.The results of research show that maximum principal (compressive) stresses,maximum shear stresses,high value area of distortion energy are in the nuclear parts of en echelon folds.In these parts compressive fractures were easily developed in approximately parallel with fold axis.So it is verified that the secondary fracture of en echelon folds is a mechanism controlling a strong earthquake.
