近钻头伽马高精度实时成像技术研究与应用

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

  • 摘要: 常规随钻测量工具的测点离钻头较远,无法及时准确判断钻头处的地层岩性和倾角,储层钻遇率较低,也不满足储层精确描述的要求。为此,研究了高转速条件下地层伽马射线动态扫描成像技术,以及时判断滑动和复合钻进状态下的地层岩性;研究了地层倾角的计算方法,实现了钻头处地层倾角的准确计算。研究认为,近钻头伽马高精度实时成像技术可以实时测量近钻头伽马、动态井斜角、温度及转速等参数,并进行成像,为实现钻头在储层内的精确控制提供数据。现场应用显示,该技术可以满足地质导向钻井对测量数据的需求,通过对所钻储层的精确描述及时调整钻井轨迹,从而提高优质储层钻遇率。研究结果表明,基于国产化近钻头伽马成像工具的地质导向钻井技术在薄油层、倾角变化快地层等具有较好的推广应用价值。

     

    Abstract: 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.

     

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