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公开(公告)号：US3890501A
公开(公告)日：1975-06-17
申请号：US35615073
申请日：1973-05-01
摘要： Apparatus and methods for verifying the validity of data derived at least in part by neutron logging of earth formations, and, where indicated, for affording neutron diffusion-corrected values of such data, are disclosed. In the illustrative embodiments described, an earth formation is irradiated with discrete pulses of high-energy neutrons, and a neutron characteristic of the formation is measured at a first location spaced from the neutron source by observing the neutron population decay at that location during a time period between pulses that is a function of a like earlier measurement of the neutron characteristic. The neutron population decay at a second location in the formation is also measured during a time period that is functionally related to a measured value of the neutron characteristic, conveniently the earlier measured value at the first location. An indication is then derived in response to the population decay measurement at the second location of the validity, specifically, of either the earlier or current value of the neutron characteristic measured at the first location as a measure of the intrinsic value of the neutron characteristic and, generally, of the validity of other neutron-logging derived data as well. Advantageously, the neutron characteristic measured is a thermal neutron absorption characteristic of the formation, such as the thermal decay time constant. In effect, apparent values of the neutron characteristic are observed at both measurement locations and a comparison of these observations made to determine the extent of correlation therebetween. Close agreement of the apparent values indicates an accurate measurement of the intrinsic formation characteristic. Substantial disagreement betweenthe apparent values evidences that perturbational effects have significantly influenced the neutron characteristic measurement and that appropriate correction of the measurement should be made.
摘要翻译： 公开了用于验证至少部分地球地球记录的数据的有效性的装置和方法，以及用于提供这种数据的中子扩散校正值的指示。 在所描述的说明性实施例中，用离散脉冲的高能中子照射地层，并且在与中子源隔开的第一位置处测量地层的中子特征，通过在一段时间内观察该位置的中子群体衰减 脉冲之间的时间间隔是早先的中子特性测量的函数。 在与地中海特征的测量值功能相关的时间段内，也可以在第一个位置的较早的测量值方便地测量地层中第二个位置的中子群体衰减。 响应于有效性的第二位置处的群体衰减测量，特别是在第一位置处测量的中子特征的较早或当前值作为中子特征的固有值的量度，得出指示，以及 一般来说，也是其他中子测井导出数据的有效性。 有利地，测量的中子特性是地层的热中子吸收特性，例如热衰减时间常数。 实际上，在两个测量位置都观察到中子特征的明显值，并且对这些观察结果进行比较以确定它们之间的相关程度。 表观值的紧密一致表明内在形成特征的精确测量。 明显值之间的明显不同意味着扰动影响显着影响了中子特征测量，并应进行适当的测量校正。
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2.发明授权
公开(公告)号：US3868505A
公开(公告)日：1975-02-25
申请号：US41118973
申请日：1973-10-31
CPC分类号： G01V5/102
摘要： Apparatus and methods are disclosed for investigating the quality of well logging data derived from a well tool of the type which repetitively irradiates an earth formation with pulses of neutrons, generates signals representative of the resulting neutron population in the formation between neutron pulses, derives a downhole measurement of a characteristic of the formation in response to the neutron population signals, and transmits to the earth''s surface signals representative of the formation characteristic measurement and of the generated neutron population signals. A representation of the quality of the downhole formation characteristic measurement and of signal transmission to the surface is obtained, either at the well site or remotely, from the neutron population signals received at the surface. In the illustrative embodiments described, the downhole measurement of the formation characteristic is made by comparing the background-corrected counting rates from two measurement intervals between neutron pulses and adjusting the times of occurrence and durations of the intervals until the two counting rates are in a predetermined relationship to each other. A like comparison of counting rates is formed at the surface from the transmitted neutron population signals, and deviations of this surface comparison from the predetermined relationship established between the downhole counting rates affords information as to the quality of signal transmission to the surface and of the accuracy of the downhole formation characteristic measurement. If desired, a separate measurement of the formation characteristic may be made at the surface and the quality representation obtained by comparing the downhole measurement and the surface measurement.
摘要翻译： 公开了用于研究从重复地用中子脉冲照射地球的类型的井工具得到的测井数据的质量的装置和方法，产生表示在中子脉冲之间的地层中产生的中子群体的信号，导出井下 测量响应于中子群体信号的地层的特征，并将表示地层特征测量的信号和产生的中子群体信号传输到地球表面。 从井表面获得井眼形成特征测量和向表面传输信号的质量的表征，无论是在井场还是远距离地面接收的中子群体信号。 在所描述的说明性实施例中，通过比较来自中子脉冲之间的两个测量间隔的背景校正计数率并调整间隔的发生次数和持续时间，直到两个计数率处于预定的时间 彼此之间的关系。 在透射的中子群体信号的表面形成类似的计数率的比较，并且该表面比较与井下计数率之间建立的预定关系的偏差提供了关于到表面的信号传输质量和精度的信息 的井下形成特征测量。 如果需要，可以通过比较井下测量和表面测量获得的表面和质量表现形成单独的地层特性测量。
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