A method for quickly determining downhole transmission power of multi-frequency nuclear magnetic resonance logging tool

A technology of transmission power and nuclear magnetic resonance, which is applied in the direction of borehole/well components, measurement, earthwork drilling and production, etc., can solve the problems of inaccurate search power, increase logging risk, reduce logging quality, etc., and solve the problem of long search time , improve security and timeliness, and ensure the effect of data quality

Active Publication Date: 2018-09-04
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Abstract
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  • Claims
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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem of long logging time and inaccurate search power caused by manual determination of the downhole transmission power of the existing multi-frequency NMR logging instrument, which indirectly increases the logging risk and reduces the logging quality.

Method used

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  • A method for quickly determining downhole transmission power of multi-frequency nuclear magnetic resonance logging tool
  • A method for quickly determining downhole transmission power of multi-frequency nuclear magnetic resonance logging tool
  • A method for quickly determining downhole transmission power of multi-frequency nuclear magnetic resonance logging tool

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Embodiment Construction

[0052] The present invention will be described in further detail below with reference to the accompanying drawings.

[0053] refer to figure 1 Shown, concrete steps of the present invention are as follows:

[0054] Step 1: In the process of lowering the multi-frequency NMR logging tool downhole, measure the gain of the surrounding formations according to the logging tool, search for the corresponding water tank workshop calibration data, and determine the 90-degree chamfering angle under the transmission power corresponding to each working frequency. Required pulse magnetic field strength maximum value B 1max .

[0055] Load the workshop scale file, read the power value GA of each frequency scale and the pulsed magnetic field strength B' of each frequency measured during the workshop scale 1 and other parameters, B measured at each frequency when passing the workshop scale 1 and the echo amplitude Amp, according to the quadratic curve to fit the relationship:

[0056] ...

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Abstract

The invention discloses a method for quickly determining downhole transmitting power of a multi-frequency nuclear magnetic resonance logger. The method includes: (1), determining a pulse magnetic field intensity maximum B1max under a calibration transmitting power which each operating frequency corresponds to; (2), carrying out a first test according to each frequency calibration transmitting power value GAcal; collecting a pulse magnetic field intensity measured value B1 and a formation temperature T for each frequency transmission; (3), calculating a pulse magnetic field intensity measured value B1mod; (4), judging whether an error between the pulse magnetic field intensity measured value B1mod collected in real time and a workshop calibration pulse magnetic field intensity maximum B1Max meets requirements or not; (5), according to the pulse magnetic field intensity measured value B1mod of a formation collected in real time, calculating a power value GAnext of each frequency until the requirements are met. The problems that manual use of an existing logger to determine downhole transmission power takes long time, determination is inaccurate and logging quality is low are solved. Formation information is fed back in real time, and the transmitting power is determined quickly. The method is easy to implement and allows automatic accurate finding.

Description

technical field [0001] The invention relates to the technical field of petroleum exploration well logging, and relates to a method for quickly determining the downhole transmission power of a multi-frequency nuclear magnetic resonance logging instrument. Background technique [0002] Nuclear magnetic resonance logging is a method to detect the characteristics of formation pores and fluids by using the nuclear magnetic resonance phenomenon of hydrogen nuclei in a known magnetic field. NMR logging measures the decay time and amplitude of the free precession process of hydrogen nuclei after nuclear magnetic resonance occurs. The amplitude information is proportional to the number of hydrogen nuclei in the detection area, and the formation porosity information can be obtained through the scale, which is not affected by radioactive sources and lithology. [0003] The multi-frequency nuclear magnetic resonance logging tool is a central measurement nuclear magnetic resonance loggi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B49/00E21B47/12E21B47/08
Inventor 陈江浩汤天知陈宝余春昊李梦春余卫东朱万里杨居鹏钟剑王雷侯学理孙佩师光辉曹先军
Owner BC P INC CHINA NAT PETROLEUM CORP
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