Research and Application of High-Precision Real-Time Imaging Technology with Near-Bit Gamma

The measurement point of the conventional MWD tool is far distant from the bit, and the lithology and dip angle of the formation around the bit cannot be accurately judged in time. This result in a low success rate for drilling formation and a failure to meet the requirements of accurate reservoir description. Therefore, a gamma-ray dynamic formation scanning imaging technology under high-speed conditions, which can realize real-time judgement of the formation lithology under sliding and compound drilling conditions, was studied. In addition, the calculation method realizing the accurate calculation of formation dip angle at the bit was also studied. The high-precision real-time imaging technology with near-bit gamma can image and measure the parameters of near-bit gamma, dynamic well deviation, temperature, and rotation speed in real time, and provide data source for the accurate control of the bit in reservoirs. The field application shows that this technology could meet the needs of geosteering drilling for measurement data, and timely adjust the drilling trajectory through the accurate description of the drilled formation, thus improving the drilling ratio of high-quality reservoirs. The result suggests that the geosteering drilling technology based on domestic near-bit gamma imaging tools deserves wide applications in drilling thin oil layers and those formations with quick dip changes.