The Analysis Of Casing Mechanism Model Calculation

The casing can protect borehole wall,separate the hydrocarbon reservoir,produce from separate zones,adopt flood development measure and maintain oil well production. The casing failure will affect the regular field production. The well stimulation can raise the production. That will bring about stratum rock mass to generate movement and make the crustal stress coming to alteration. The casing working environment that is alternate will bring about bigger altering to the the crustal stress. When the altering crustal stress acts on casing, it will cause the casing damage. The casing-failure chiefly occurs on the rock salt formation. That results from stratum creepage, tectonic movement, fracture acidizing meassures in producing,it will cause a great quantity of casing coming into regional breakdown. Along with the field development, casing failure affect the enonomy and productivity. Hence, studing the casing producing mechanism will propose better building measures to rasie the casing intensity.The pore pressure of rock formation will be alteration in the production and it will alter the stress condition of the formation. The rock formation will be deformed and compresses casing, it makes the stress of casing rising. The cement sheath has an important contribution to the casing mechanics property. Establishing the casing finite element model will have a good arithmetical solution to analyse the casing stress and deformation and it can propose the measures to enhance the casing collapsing strength.This article is according to casing failure mechanism and combines rock mechanics theory to analyse the casing stress. According to theory analysis, this theme will establish casing mechanical model. From computational analysis, the crustal stress varies a lot owing to a long producing term. The casing that affects by the cement sheath in the layer and be exerted by the crustal stress and axial formation pressure will become deformed. That causes casing failure and decrease casing collapsing strength.According to analysis of casing mechanical model theory to establish casing and casing-cement sheath finite element model that is in the plane and air space. From finite element model calculation, there will be analysis of deformation and stress-strain relationship of casing on which the external pressure be acted. Accoding to the analysis of casing finite element model calculation, it can be proposed to effective measures to enhance casing collapsing strength.