公开(公告)号：US4136279A

公开(公告)日：1979-01-23

申请号：US815489

申请日：1977-07-14

申请人： Eric C. Hopkinson

发明人： Eric C. Hopkinson

IPC分类号： G01V5/10 ,  G01V5/00

CPC分类号： G01V5/102

摘要： A pulsed neutron generator in a well logging instrument is pulsed at a clock frequency of 20 KHz. Inelastic scatter gamma rays are detected during a first time interval coinciding with the neutron source being on and capture gamma rays are measured during a second interval subsequent to the end of each neutron burst. Only a single detected pulse, assuming detection occurs, is transmitted during each of the two detection intervals. Sync pulses are generated in the well logging instrument scaled down to a frequency of 200 Hz for transmission to the earth's surface. At the earth's surface, the scaled-down sync pulses are applied to a phase-locked loop system for regenerating the sync pulses to the same frequency as that of the clock frequency used to pulse the neutron source and to open the detection gates in the borehole instrument. The regenerated sync pulses are used in the surface instrumentation to route the pulses occurring in the inelastic interval into one section of a multichannel analyzer memory and the pulses occurring in the capture interval into another section of the multichannel analyzer. The use of memory address decoders, subtractors and ratio circuits enables both a carbon/oxygen ratio and a silcon/calcium ratio to be struck substantially free of background radiation and substantially unaffected by downscattering of high energy gamma rays.

公开(公告)号：US4316086A

公开(公告)日：1982-02-16

申请号：US172605

申请日：1980-07-28

申请人： Eric C. Hopkinson

发明人： Eric C. Hopkinson

IPC分类号： G01V5/10 ,  G01V5/00

CPC分类号： G01V5/102

摘要： A pulsed source of fast neutrons and a radiation detector system are utilized in a well logging instrument, the detector being responsive to the thermal neutron population decay rate. The inverse of the decay rate is proportional to the measured macroscopic neutron absorption cross-section (Sigma) of the surrounding formations. A first Sigma is measured by taking the natural logarithm of the ratio of the detected radiation counts occurring within two measurement intervals. A second Sigma is measured by taking the natural logarithm of the ratio of the detected radiation counts occurring within a second pair of measurement intervals. The first Sigma value is recorded when the Sigma value falls below a preselected limit and the second Sigma value is recorded when the formation Sigma value is above the preselected limit. Thus, the Sigma log is a composite of the two Sigma measurements.

摘要翻译： 快速中子的脉冲源和辐射探测器系统用于测井仪器中，检测器响应于热中子群体衰减速率。 衰变速率的倒数与周围地层的测量宏观中子吸收截面（Sigma）成比例。 通过采用在两个测量间隔内发生的检测到的辐射计数的比率的自然对数来测量第一Sigma。 通过采用在第二对测量间隔内发生的检测到的辐射计数的比率的自然对数来测量第二Sigma。 当Sigma值低于预选极限时记录第一个Sigma值，当形成Sigma值高于预选极限时记录第二个Sigma值。 因此，Sigma日志是两个Sigma测量的组合。

公开(公告)号：US4041309A

公开(公告)日：1977-08-09

申请号：US719758

申请日：1976-09-02

申请人： Eric C. Hopkinson

发明人： Eric C. Hopkinson

IPC分类号： G01T1/178 ,  G01V5/10 ,  G01V5/00

CPC分类号： G01T1/178 ,  G01V5/102

摘要： Neutron generator in well logging instrument is pulsed 100 times having a time between pulses of 1400 microseconds. This is followed by an off period of four cycles wherein 2800 microseconds is allowed for capture radiation to decay to an insignificant level and the remaining 2800 microseconds is used to measure background radiation. This results in the neutron source being disabled four pulses after every hundred pulses of operation, or approximately a 4% loss of neutron output. A first detector gate is open from 400 to 680 microseconds and a second detector gate is open from 700 to 980 microseconds. During the 100 cycles, each of the gates is thus open for 280 microseconds times 100 for a total of 28,000 microseconds. By scaling the gate count rate by a factor of 10, the background is subtracted directly.

摘要翻译： 测井仪器中的中子发生器脉冲100次，脉冲间隔为1400微秒。 之后是四个周期的关闭周期，其中允许2800微秒的捕获辐射衰减至微不足道的水平，并且剩余的2800微秒用于测量背景辐射。 这导致中子源在每百个操作脉冲之后被禁用四个脉冲，或大约是中子输出的4％的损失。 第一检测器门从400至680微秒打开，第二检测器门从700至980微秒打开。 在100个循环期间，每个门因此打开280微秒100次，总共28,000微秒。 通过将门计数率缩放10倍，直接减去背景。

公开(公告)号：US4596927A

公开(公告)日：1986-06-24

申请号：US469330

申请日：1983-02-24

申请人： Eric C. Hopkinson ,  Donald W. Oliver

发明人： Eric C. Hopkinson ,  Donald W. Oliver

IPC分类号： G01V5/04 ,  G01V5/10

CPC分类号： G01V5/101 ,  G01V5/045

摘要： In a neutron induced gamma ray well logging instrument, a neutron generator is pulsed at a preselected clock frequency. Each neutron burst produces inelastic scattering gamma rays and capture gamma rays. Inelastic scattering gamma rays are detected using a bismuth germanate scintillator during a first time interval coinciding with the neutron source being on. Capture gamma rays are detected by bismuth germanate scintillator during a second interval subsequent to the termination of each neutron burst. The detected pulses are converted into electrical pulses by a photomultiplier. The electrical pulses are coupled into processing circuitry. The use of address decoders, subtractors and ratio circuits enables measurements of the characteristic full-energy photopeaks of selected elements within the formations.

摘要翻译： 在中子诱导的γ射线测井仪中，中子发生器以预选的时钟频率脉冲。 每个中子爆发产生非弹性散射伽马射线并捕获伽马射线。 在与中子源接通的第一时间间隔期间，使用锗酸铋闪烁体检测非弹性散射γ射线。 在每个中子爆发终止之后的第二个间隔期间，由锗酸铋闪烁体捕获伽马射线。 检测到的脉冲由光电倍增管转换成电脉冲。 电脉冲耦合到处理电路中。 使用地址解码器，减法器和比例电路可以测量地层内选定元素的特征全能量光峰。

公开(公告)号：US4137450A

公开(公告)日：1979-01-30

申请号：US806050

申请日：1977-06-13

申请人： Eric C. Hopkinson

发明人： Eric C. Hopkinson

IPC分类号： G01V5/10 ,  G01V5/00

CPC分类号： G01V5/108

摘要： A logging instrument contains a pulsed neutron source and a pair of radiation detectors spaced along the length of the instrument. The radiation detectors are gated differently from each other to provide an indication of formation porosity which is substantially independent of the formation salinity. In the preferred embodiment, the electrical signals indicative of radiation detected by the long-spaced detector are gated for almost the entire interval between neutron pulses and the short-spaced signals are gated for a significantly smaller time interval which commences soon after the termination of a given neutron burst. The signals from the two detectors are combined in a ratio circuit for determination of porosity.

摘要翻译： 测井仪器包含脉冲中子源和沿着仪器长度间隔开的一对辐射探测器。 辐射探测器彼此不同地选通，以提供基本上独立于地层盐度的地层孔隙度的指示。 在优选实施例中，指示由长间隔检测器检测到的辐射的电信号被选通在中子脉冲之间的几乎整个间隔，并且短间隔信号被选通一个明显较小的时间间隔，该间隔在一个 给定中子爆发。 来自两个检测器的信号被组合在用于确定孔隙率的比例电路中。