Diameter Taper Variable Structure Optimization And Mechanics Analysis

Caliper expansion tube technology compares with the traditional technology of the expansion pipe, It can significantly improve the deep well, ultra-deep well drilling process because of the complex formation pressure hole reduce problem which is caused by system factors,and Caliper expansion tube technology can improve and optimize the structure of well bore, reduce casing layer and reduce the exploration and development cost, reasonable exploitation of oil and gas storage.The administration of China petrochemical group Shengli drilling technology research institute completed independently research and development team who improves their ability of research and technology accumulation.They developed caliper variable diameter cone completion of downhole tools,but in the process of research and development of test, the expansion tool cannot be completely closed,and the tool appeared among the parts of cold welding and scratches.This thesis is proposed to solve the problems which the tool cannot be closed in the actual test and surface failure, then cooperated with sinopec drilling institute for caliper.Firstly, the author uses 3d software to complete the expansion of the original tool modeling. Secondly, finite element analysis of the original tool modeling is done and find out the original structure in the process of test, the fracture reason of variable diameter of the slider, and proposed methods of optimization of structure, the improved structure is made finite element analysis, in order to test stress condition of the improved structure.The original structure of caliper expansible tool was improved, and the experiment basicly can completely closed, but in the upper and lower the expansion of the tapered slide block surface and guide rail have been failed, For this problem, this paper proposed the phosphating treatment scheme of the surface modification of process, to reduce the friction coefficient, enhance its resistance to wear, so as to extend the upper and lower diameter changes the lifetime of the slider.After the structure and the surface modification of process scheme, field test has been successful, and expansion tool and closed the required load is greatly reduced, the expansion of 10 inch casing and wall thickness is 9 mm entities required the load from 150 t to 100 t.