Prefabricated Hole Casing Collapse Strength Computing Research And Application

pre-core casing well completion is laying down pre-core casing in the open hole on the basis of barefoot completion. This method not only satisfy the need of oil field, but also prevent blockage by barefoot hole wall collapse, in the meanwhile, can prevent sand to some extent. Casing crush resistense intention is a international active research field. API/ISO is organizing international cooperation and research at all times, but to pre-core casing, especially when core diameter exceeds 30 core/meter, the research is paucity.This paper make some research of pre-core casing of N80, establishing 3D model by using FEA , from theory of stretch, using FEA, make some dynamics calculation esearch of pre-core casing, the results is coincide with data from foreign literature. On this basis, this paper make some research about load distribution and crush resistense intention affection by pre-core casing parameter,and get some results as follows:1. Phase position is the main infection which affects load distribution in the condition of equality load, the next is core diameter, core density. So we suggest adopt low phase position, high core density, large core diameter casing, increase core number in the unit of length, increase flow area. Multi-spirality load distribution is better by signal-spirality.2. Phase position is the main infection which affects load distribution in the condition of equality load, the next is core diameter, core density. load distribution and crush resistense intention are in tightness relation. Crush resistense intention decrease when core diameter and core density increase; Phase position isn't monotone function of crush resistense intention.In view of un-equality load which not regulate definitely, but it existents for a certainty in actual condition. This paper establish four mechanical model, take deformation as judge criteria of pipe failure. We made study in depth about pre-core casing crush resistense intention in the condition of un-equality load, be emphasizes on the influence of difference model and un-equality coefficient. It reflects:1. In the condition of un-equality load, the crush resistense intention inside the pipe is decrease obviously, un-equality coefficient is the main factor which influence crush resistense intension.2. In the condition of un-equality load, pre-core diameter, core density and phase position make some influence on crush resistense intension, but of low extent, so we suggest use big core diameter, high density casing to increase flow area of unit of length; because phase position make little influence in the condition of un-equality load, we suggest change phase position from velocity of flow.3. In the condition of un-equality load, in the same of un-equality coefficient, the equivalent crush resistense intension of P110 excess N80, so we suggest use P110. to squeeze in this condition, the main method is increase steel class, the next is increase thickness of pipe.From findings of this paper, seven test well of Ken Ji Ya Ke oil field adopt pre-core casing...