基于正则化约束的方位伽马成像测井分辨率提高方法

Resolution Improvement Method of Azimuth Gamma Imaging Logging Based on Regularization Constraint

随钻方位伽马测井可以用于地层放射性强度分析及地质导向、储层界面识别,但受到统计误差的影响非常大,曲线和成像分辨率不高,特别是在对比度不高的地层中,这种影响更明显。为了提高随钻方位伽马测井的成像分辨率,提出一种基于仪器响应特性对方位伽马数据进行正则化处理的方法,以获得更准确的地层放射性强度。首先根据探测器响应原理,采用数值模拟和实验方法得到方位伽马测井的响应灵敏函数,并验证得到的灵敏因子的准确性。然后,通过构造正则化计算公式、调整计算参数对测量的原始方位伽马数据进行处理。结果表明:经该方法处理后得到方位伽马曲线的聚焦性能、对比度得到提高,避免了过去使用线性求解方法所导致的过拟合问题,且伽马成像分辨率有显著增强,薄层识别能力也得到一定改善。该方法能够提供更加准确和清晰的成像结果,提高仪器的地质导向能力和储层钻遇率。

The azimuth gamma logging while drilling can be used for formation radioactive intensity analysis,geosteering and reservoir interface identification,but it is greatly affected by statistical errors,resulting in low resolution of curves and imaging.Especially in the formations with low contrast,this effect is more pronounced.In order to improve the imaging resolution of the azimuth gamma logging while drilling,a regularization method for potential gamma data is proposed based on instrument response characteristics to obtain more accurate formation radioactivity intensity.Firstly,according to the detector response principle,the response sensitivity function of azimuth gamma logging is obtained by numerical simulation and experiment,and the accuracy of the sensitivity factor is verified.Then,the original azimuth gamma data is processed by constructing regularization formula and adjusting calculation parameters.The result shows that the focusing performance and contrast of azimuth gamma curve obtained by this method are improved,which avoids the overfitting problem caused by the linear solution method in the past.Moreover,the resolution of gamma imaging is significantly enhanced,and the recognition ability of thin layer is also improved.As a result,this method can provide more accurate and clear imaging results,thereby improving the geo-steering ability of the instrument and reservoir drilling rate.