Near-bit Test Oblique Gamma Short Section Study

In recent years, the Rotary Steerable System (RSS) Drilling Technology has been more and more widely used in horizontal well, large displaced well and complex well, but the RSS technology is only monopolized by few word-wide oil field services companies. So a few in-country companies started to research and develop their RSS technology based on the applicable global RSS technology, and achieved fruitful progress, but the RSS tools made by these companies are weak in reliability and life during operation comparing with foreign tools.Because of the above problem, this article focuses on the functional module At the Bit Inclination Gamma of RSS tool?The main research content includes:(1) By researching overseas and domestic RSS tool research status, summarize the RSS tools'principles of each large oil field services companies, and analyze the measuring wellbore inclination mechanism and main function of ABG tool.(2) For the mechanical structure of ABG tool, by FEA, study material and size etc. of ABG main body, pressure sleeve, cover and seal part. Performance analysis of O-ring seal at high temperature and ambient temperature, and determine the reasonable structure.(3) By means of performance analysis of sensor for gamma ray, study the appropriate gamma ray sensor for ABG tool, further calculate the attenuation of gamma ray on the way to sensor. By studying gamma ray interaction mechanism with matter, determine selection and alignment of gamma-ray sensor.(4) Study and analyze principle and equation of gravity accelerometer and fluxgate for wellbore inclination, tool face and azimuth. By performance comparison, further add fluxgate for ABG tool, enable ABG tool measure wellbore inclination, tool face, as well as wellbore azimuth, avoid the limitation of gravity accelerometer for small angle, and make ABG tool be able to work independent of MWD tool.The research of the article design a reasonable structure of At the Bit Inclination Gamma module ABG tool, material and sensor alignment solution, and is significant important for RSS tool research and development of our country.