In order to study the local mechanical properties of pipeline's defects, taking X70 pipeline as the research object, based on the knowledge of elasticplastic mechanics, ANSYS is applied to simulate the distribution near defects of Von Mises stress and plastic strain under the action of high temperature. Then the variation tendency of the maximum stress and plastic strain of key parts near defects with the increase of internal pressure is analyzed. Also, the variation trend of the maximum Von Mises stress with the corrosion depth under the specific operating pressure is discussed. Finally, the Von Mises stress distribution and variation considering and without considering the temperature expansion are compared. The results show that there is a greater stress along the circumferential direction in the corrosion zone at high temperature. With the increase of internal pressure, the maximum Von Mises stress decreases first and then increases, and the greater stress also becomes axial distribution. ASME B31G1984,ASME B31G1991,PCORRC and DNVRPF101 methods are still suitable for evaluating the residual strength of pipelines under high temperature. 

A borefild in Sulige gas field, as the development experimental zone of this block, has built 1 billion square production after more than two years' pilot development. In this area， a set of effective thinking and method of research has formed about the fine geologic research. On the one hand, according to the characteristics of low porosity, low permeability and fluvial facies sand body developed, synthesizing all kinds of static and dynamic development data. The fine reservoir 3D visualized geological model was established and the areal channel sand body distribution was carved, which provide geological guarantee for the overall development of horizontal well and horizontal well geologic trace and implementation. Meanwhile, the regional distribution rule of remaining gas was gained, providing the reference for implementing horizontal wells step by step. On the other hand, based on unstructured grid used for depicting fracture system, through the gas reservoir numerical simulation, deployment parameters of horizontal well pattern, well spacing etc., are optimized and demonstrated, and reasonable values of parameters are gained, which provides reference to similar other fields for overall development.

The technology of composite perforation for the crude bedding is increasingly studied and developed in recent years. When the technology was applied for the well 59 of Nanbaxian gas field and Ma well 8-1 of Mabei 1 in the north marginal area of Qaidam basin, the procedure can successfully remove the pollution obstruction in the single well reservoir resulted from the well killing liquid. The results show that the technology can be widely used for removing obstruction in area of cold lake oil field.