随钻方位伽马数据成像处理方法

Image processing method of LWD azimuthal gamma data

利用随钻方位伽马曲线和伽马图像可以更准确地确定储集层边界的位置,进而更好地指导水平井地质导向施工。介绍了方位伽马仪器结构及测量原理,针对随钻伽马测井存在井周测量数据少、扇区数据相关性高的特点,通过插值处理得到井周连续变化的伽马数据,优选RGB与HSI颜色空间转换方法和特定色谱的静、动态色度映射方法,使得伽马图像更加符合地质图像特点。通过现场随钻测井资料处理,获得了效果较好的伽马成像测井图像,对地层特征的观察和识别更加清晰,降低了打穿油层的风险。

Using LWD （Logging While Drilling） azimuthal gamma curves and gamma images can more accu- rately determine the location of reservoir boundaries, and can guidance geosteering construction of horizontal wells better. This paper first introduced the structure of two sectors and basic principles of LWD azimuthal gam- ma measurement instrument. During drilling, the gamma tool is responsed by rotary speed, and generally can on- ly measure up to 16 azimuthal sectors data. The circle borehole measuring range is limited, and the real-time data uploading to surface, due to the influence of downhole signal transmission rate, uploading up to no more than eight sectors. At the same time, the data correlation between different sectors is relatively high, and mutual influ- ence is relatively large. In use of the periodic cubic spline interpolation process, a continuous variation gamma data along the borehole was obtained. Through applying RGB and HSI color space conversion method and specif- ic chromatography static and dynamic color mapping method, the gamma image is more in line with the charac- teristics of the geological image. Through LWD data processing, better gamma images can be obtained, and the observation and identification of stratigraphic characteristics are clearer. It directly shows the wellbore formation lithology changes in different directions, and reduces the risk penetrated reservoir.