激光扫描共聚焦技术在录井储集层评价中的应用及展望

Application and prospect of laser scanning confocal technique in reservoir evaluation of mud logging

激光扫描共聚焦技术是20世纪80年代初兴起的一项显微测试方法,是当今世界最先进的显微分析技术之一,它可对样品逐点、逐线、逐层扫描并三维重建成立体图。将该技术引入录井行业,通过激光波长、强度及不同岩性穿透性等实验分析与研究,认为激发波长为488nm时,荧光强度最大,对岩石的穿透性最佳;在激光强度为75%时穿透效果最好;提出了应用不同物镜扫描成像所需的扫描分辨率以及部分参数优选值;重复性和一致性实验结果约为99%。阐述了激光扫描共聚焦技术对岩石骨架、微孔隙和流体的识别方法;进行了基于岩心、岩屑等岩石样品的物性参数分析测试,讨论了基于该技术的储集层岩石孔隙度、孔隙结构参数分析方法;并就该技术的应用优势及拓展方向进行了展望。基于实验及相关理论分析论证,认为激光扫描共聚焦技术可以对现代钻井技术条件下的细碎岩屑样品进行孔隙度、孔隙结构参数的快速准确获取,较好地解决了录井定量评价油气的难题。

Laser scanning confocal technology is a microscopic test method developed in the early 1980 s.It is one of the most advanced micro-analysis techniques in the world.It can scan the samples point by point,line by line and layer by layer,and rebuild three-dimensional stereogram.The technology is introduced to mud logging industry,through the laser wavelength,intensity and different lithology penetrance and other experimental analysis and research, when the excitation wavelength is 488 nm,the fluorescence intensity is the largest and the penetrability of rock is the best,the penetration effect is best when the laser intensity is 75%.The authors proposed the scanning resolution and some parameter preferred values of scanning imagery with different objectivelens,the repeatability and consistency experiments show that the results are about 99%.The identification methods of rock matrix,micro-pores and fluid by laser scanning confocal technique were also described.The physical properties of rock samples based on core and cuttings are analyzed and tested.The parameter analysis method of the porosity and pore structure of reservoir rock based on this technique was discussed.The application advantages and development direction of the technology were also prospected.Based on the experiment and related theoretical analysis and demonstration,it is concluded that the laser scanning confocal technique can obtain the rapid and accurate acquisition of the porosity and pore structure of fine cuttings under modern drilling technology,the problem of quantitative evaluation of oil and gas by mud logging is solved well.