Damage Analysis Of Oil Field Casing Under Soil Moving

At present, casing damage occurred in more than 1000 wells in our country, the amount and speed of casing damage increased gradually. As the analysis of casing damage when soil layer displaced is not systemic and deep, these problems cannot be instructed and solved well in time, and now there are not effective measures to prevent and relieve the casing damage. The analysis of these problems should be carried on in a new scientific way and tried for academic meaning. This paper took the casing in displacement soil as target, the work done as follows:The casing damage situation and some related technologies of our country and abroad are listed in the paper. The reasons and influence factors are disgusted,and a mechanical analysis model is brought up in the paper: casing-cement ring-soil model.Finite element analysis software ADINA is used to make the casing-cement ring-soil model into finite elements come true,and construct the three-dimensional finite element model in displacement soil layer. Considering the action among cement ring, casing and surrounding soil,So simulate the casing into four-node shell elements, and the cement ring and soil are simulated into three-dimensional eight-node solid elements. The simulated three-dimensional soil is used precise Mohr-Coulomb material. And interaction between cement ring and soil is simulated by contact element.Casing and cement ring are fixed.Using the verified finite element mode to simulate a specific example, through the analysis of results compares the casing diameter, stuff, thickness, cement ring thickness, displacement distance between soil layers and influence on soil.Finally, in order to improve the wrong strength casing,the casing system design recommendations presented.