地球物理学进展 ›› 2017, Vol. 32 ›› Issue (5): 1967-1972.doi: 10.6038/pg20170514

• 应用地球物理学Ⅰ • 上一篇    下一篇

过钻杆中子孔隙度测井的蒙特卡罗模拟

陈前1, 张锋1,2, 张泉滢1, 刘军涛1, 郭洪波3, 鲁明宇4   

  1. 1. 中国石油大学地球科学与技术学院, 青岛 266580;
    2. 海洋国家实验室海洋矿产资源评价与探测技术功能实验室, 青岛 266071;
    3. 中国石油塔里木分公司勘探开发研究院, 新疆库尔勒 841000;
    4. 中国石油集团测井有限公司塔里木事业部, 新疆库尔勒 841001
  • 收稿日期:2017-01-15 修回日期:2017-07-23 出版日期:2017-10-20 发布日期:2017-10-20
  • 通讯作者: 张锋,男,1970年生,教授,博士,从事核测井方法、核测井数据处理及蒙特卡罗模拟研究.(E-mail:zhfxy_cn@upc.edu.cn) E-mail:zhfxy_cn@upc.edu.cn
  • 作者简介:陈前,男,1992年生,硕士,从事核测井方法、核测井数据处理及蒙特卡罗模拟研究.(E-mail:chenqian20112015@163.com)
  • 基金资助:

    国家自然科学基金项目(41374125,41574119)、国家重大油气专项(2017ZX05019005-004)和中央高校基本科研业务费专项资金资助(15CX06008A)联合资助.

Monte Carlo simulation of neutron porosity loggingin the logging while fishing

CHEN Qian1, ZHANG Feng1,2, ZHANG Quan-ying1, LIU Jun-tao1, GUO Hong-bo3, LU Ming-yu4   

  1. 1. School of Geosciences, China University of Petroleum, Qingdao 266580, China;
    2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China;
    3. Research Institute of Petroleum Exploration and Development, Tarim Oilfield Company, CNPC, Xinjiang Korla 841000, China;
    4. CNPC logging Tarim Business Division, Xinjiang Korla 841001, China
  • Received:2017-01-15 Revised:2017-07-23 Online:2017-10-20 Published:2017-10-20

摘要:

过钻杆存储测井是评价水平井、大斜度井地层参数的一种重要的测井方式.本文针对过钻杆中子孔隙度测井中源和探测器相对钻杆的位置开展研究,并与电缆、随钻中子孔隙度测井响应进行了对比.利用蒙特卡罗方法建立了过钻杆、电缆及随钻中子孔隙度三种仪器模型,模拟研究了热中子分布及近、远探测器计数比值与孔隙度的响应关系,分析了孔隙度测量精度和相对灵敏度以及井眼尺寸的影响.结果表明:源在钻杆内探测器在钻杆外的测量方式近探测器计数率和孔隙度测量精度高;且低孔隙度时相对灵敏度高,同时防止测量过程中放射源的脱落.随着孔隙度增大,随钻仪器近探测器计数率增加,而电缆与过钻杆仪器计数率降低;随着井眼尺寸增加,近、远热中子计数率比值率增大,过钻杆和电缆近探测器计数率降低,随钻近探测器计数率增加.源在钻杆内探测器在钻杆外的测量方式在保证孔隙度测量精度及灵敏度的同时,提高了放射性源测井的安全性.

Abstract:

Logging While Fishing(LWF) is an important logging method for the evaluation of porosity and other formation parameters in horizontal wells and high deviated wells.The responses of LWF with the different positions of the source and the detector relative to the drill pipe are studied and compared with the responses of Compensated Neutron Logging(CNL), Logging While Drill neutron porosity(LWD-CNL).The distributions of thermal neutron and the Models of CNL, LWD-CNL and LWF are built using Monte Carlo simulation to study the responses of near and far detector to porosity.The effects of porosity measurement accuracy, relative sensitivity and borehole size were analyzed. The results indicate that the counting rate of near detector and measurement accuracy are high by the measurement method of source in the drill pipe and detectors outside the drill pipe.The relative sensitivity of porosity measurement is enhanced under the low porosity conditions.At the same time, the loss of radioactive sourcesis prevented. With increase of porosity, the counting rate of near detector of LWD-CNL increases, and the counting rate of near detector of CNL and LWF decrease,and the ratio of the near to far thermal neutron counting increases.With the increase of the borehole size, the count rate of LWF and CNL are reduced, and the counting rate of LWD-CNL is increased. The ratio of the near to far thermal neutron counting of the three measurement modes increases.The measurement method with source in drill pipe and detectors outside drill pipe both to ensure the porosity measurement accuracy and sensitivity, while improves the safety of radioactive logging sources.

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