Unstructured data occupies the proportion of total information amount more than structured data, which is valuable data asset during management of oil and natural gas information. How to manage the unstructured data is an important content for developing new oil and natural gas information management system. In order to realize efficient management and integration application of unstructured oil and natural gas data, this paper puts forward a new oil and natural gas information management system from application of metadata technology view. In the new information management system, the unstructured data is defined and described by metadata, and the system framework is designed based on metadata of database. The new system has good flexibility and extensibility, which not only can efficient manage unstructured data of oil and natural gas, but also can realize integration application of heterogeneous data sources.