With the development of oil well logging technology, higher requirements are put forward for the reliability, accuracy and real-time of downhole parameter monitoring in oilfield exploration. Due to the underground environment has high temperature, high pressure, chemical corrosion and strong electromagnetic interference and other characteristics, the traditional measurement sensor is difficult to adapt to the harsh environment underground. Logging is a kind of optical fiber sensor developed in the 1970s model based optical fiber sensor, compared with the traditional sensor, which has good electrical insulation properties, strong anti electromagnetic interference, high sensitivity, easy to realize the advantages of remote monitoring, the measured signal can withstand extreme conditions such as underground play a great advantage in. Downhole parameters measurement, and has broad market prospects.

In this paper, the patent applications of logging optical fiber sensors in the global scope are statistically analyzed.

Foreign enterprises dominate

The retrieval of patent documents found in the database as of May 31, 2015 DWPI, logging optical fiber sensor of global patent applications 429.

From the changing trend of global patent applications, the development of logging optical fiber sensors can be divided into two stages. 1975 to 1991 is the budding period. As a new sensing technology, optical fiber sensing technology has been developed rapidly with the advent of optical fiber communication technology, but the technical research in this stage is still in infancy, and the number of patents is less. 1991 is the period of development. With the advantages of optical fiber sensors gradually highlight, the world's major oil producing companies, logging companies, and optical fiber sensor research and development institutions and enterprises began the research and development of logging of optical fiber sensors, and expand the application fields, the number of patent application stage gradually increased in active development stage of technological innovation.

The author of the logging optical fiber sensor patent distribution statistics found that logging optical fiber sensor research mainly concentrated in the United States, Canada, Britain and other countries, among them, the number of patent applications in the United States ranked first, accounting for 24% of the total global patent application. As a powerful technology country, the United States has great advantages in the research and development of logging optical fiber sensors, and has more core patents.

In addition, the top ten patents in the field are mostly foreign enterprises, and the first patent holder is Schlumberger Corp (SCHLUMBERGER), with 77 patents of logging optical fiber sensors. The key technologies in the field are dominated by international large oil companies and technology service companies, which play a leading role in the development of logging optical fiber sensor technology.

The author through the patent statistical analysis found that the current hot research of optical fiber sensor logging mainly concentrated in the measurement while drilling and downhole data transmission, parameter monitoring, logging and so on, the number of patent technology accounted for about 42.6% of the total patent logging optical fiber sensor.

Technical problems to be solved

The patent application of logging optical fiber sensors in China started in the early twenty-first Century, mainly based on the independent research and development of enterprises, and supplemented by the research and development of universities. Although the research and development of logging optical fiber sensor in China started late, but after more than ten years of research and development, patent applications have been in a steady upward trend, has a broad space for development.

At present, optical fiber sensors are widely used in logging field, but there are still some problems to be solved. It is of great practical significance to improve the performance of the optical fiber sensor and improve the stability of the downhole optical fiber sensor due to the possibility of affecting the performance of the optical fiber in the process of contacting the fluid in the well with the optical fiber sensor. In addition, to further reduce the optical signal loss is on the focus of the research. At the same time, the design of the connection head of fiber connector and pipe hanger needs to be further optimized.

In recent years, the excellent characteristics of logging optical fiber sensor has aroused widespread concern in the industry, many scientific research units and enterprises have started to carry out technical research, development of domestic logging optical fiber sensor is in rapid development stage. However, due to the late start of related research, there are also some problems such as insufficient patent quantity and less patent conversion in this field. The author suggested that domestic enterprises should be combined with the market demand, targeted development of technical features, and increase efforts to improve the patent application, patent layout, to form a patent protection logging optical fiber sensor network as soon as possible, to enhance the international competitiveness of enterprises.