于都－赣县矿集区科学钻探NLSD-1孔超声波成像测井响应特征及其深部找矿意义

Response Characteristics of Ultrasonic Imaging Logging in Hole NLSD-1 of the Scientific Drilling in Yudu-Ganxian Ore District and Their Implications for Deep Mineral Prospecting

NLSD-1孔是南岭地区第一口科学钻探孔，也是目前我国金属矿区最深的科学钻探工程之一，终孔深度达到2967．83 m。为了精细刻画矿集区深部结构框架、揭示深部矿化带分布特征和建立深部找矿地球物理解释标尺，提高对深部成矿规律的认识，该孔在钻进过程中实施了连续取芯，并且进行了多种地球物理测井和井中物探方法的测量。超声波成像测井是一种先进的测井技术，包含丰富的原位地质特征信息，在油气勘探中常用于井旁地质构造和地应力分析。本文将超声波成像测井应用于金属矿区科学钻探中，对NLSD-1孔采集到的超声波成像测井资料进行了研究，认为成像测井图像能够精细刻画孔壁裂缝、破碎带等地质特征，同样适合于金属矿勘查中的井旁构造解释；主要矿化层（409～429 m、430～446 m、621～641 m、655～666 m、679～691 m、696～706 m、744～759 m、776～788 m、907～921 m、1031～1042 m、1081～1090 m、1430～1439 m、1440～1448 m等）均发育裂缝或破碎带，表明测井结果对矿化层埋深具有指示作用，并且揭示钻孔附近矿化层具有西浅东深的空间展布特征；根据裂缝产状的垂向变化，推断F1断层过NLSD-1孔深度范围为1375．32～1380．79 m；此外，裂缝与孔斜关系的研究对钻孔纠斜具有指导意义。研究结果表明超声波成像测井在深部找矿中能够发挥重要作用。

The hole NLSD-1 is the first scientific drilling deep hole in the Nanling region,which also is one of the deepest scientific drilling projects in metallic ore districts of China,and its final depth is 2967.83 m.In order to characterize the deep structural frame of the ore concentration area,reveal the distribution characteristics of the deep mineralization belt,establish the geophysical interpretation rule of deep ore prospecting,and improve the understanding of the laws of deep mineralization of deposit,this hole was implemented continuous coring,and conducted the measuring of a variety of geophysical logging and borehole geophysical methods in the drilling process.Ultrasonic imaging logging is an advanced logging technology,which contains abundant in-situ geological characteristics information,often used to analyze the geological structure and in-situ stress near the hole in the oil and gas exploration.This paper applied ultrasonic imaging logging to scientific drilling in metallic ore districts,studied the ultrasonic imaging logging data of hole NLSD-1 ,considered that ultrasonic imaging logging images which can characterize the geological features of fractures and fracture zones of the borehole wall,are also suitable for the structural interpretation near the hole in the metal ore exploration.All the main mineralized layers （409~429 m,430~446 m,621~641 m,655~666 m,679~691 m,696~706 m,744~759 m,776~788 m,907~921 m, 1031~1042 m,1081~1090 m,1430~1439 m,and 1440~1448 m et al.）were developed fractures or fracture zones,which indicated that the logging results can illustrate the depth of mineralized layers,and explained the spatial extension characteristics of west light and east deep in the mineralized layers near the hole.Based on the vertical variation of the fracture occurrence,we inferred that the intersection depth range of the fault F1 and hole NLSD-1 is 1375.32~1380.79 m.Besides,the study of the relation between fracture inclination and well deviation has guiding significance for drilling hole straightening.The study results indicate that the ultrasonic imaging logging plays an important role in deep ore prospecting.