Abstract:
International petroleum industry has learnt the necessity and significance of wellbore integrity establishment and application from the oil and natural gas development and many accidents. The definition of wellbore integrity is described in the Norway standard NORSOK D-010, and this definition is appraised highly and applied in international petroleum industry and is widely recognized as the wellbore integrity standard. In this paper, the wellbore integrity was analyzed and illustrated by using the "four properties" and diagrams of integrity. Wellbore barrier is the key to the realization of wellbore integrity. The wellbore barrier and its components were studied thoroughly from the aspects of structure and function. It mainly has two functions. First, it can prevent the risk that the uncontrolled formation fluid drains or channels into another formation. And second, it can protect oil and gas resources, underground water and environments. The functions and structures of wellbore barrier were illustrated based on two typical diagrams. The main problems that wellbore integrity and wellbore barrier tend to suffer during the safe operation were pointed out. In order to solve these problems, it is necessary to complete the standardization and normalization of wellbore integrity and wellbore barrier, enhance the integrated design on each operation in the full life cycle from the aspects of technology, operation and organization management, improve technical level and engineering quality, implement all-around monitoring and organization in the whole process, etc.