Borehole fluid time spectrum evaluation method using PNT (pulsed-neutron tool)

An evaluation method and internal fluid technology, applied in the direction of earthwork drilling, wellbore/well components, etc., can solve the problems that the cased hole formation evaluation cannot be used, and the limitation of logging methods, etc., so as to eliminate the influence of the wellbore, simplify the construction, reduce the Overall investment effect

Inactive Publication Date: 2012-07-04
SHANDONG RONGXING PETROLEUM ENGINEERING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because of the physical properties of casing, many logging methods in openholes are limited and cannot be used for formation evaluation in cased holes

Method used

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  • Borehole fluid time spectrum evaluation method using PNT (pulsed-neutron tool)
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  • Borehole fluid time spectrum evaluation method using PNT (pulsed-neutron tool)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Embodiment 1: PNT application example in low salinity formation (such as Figure 5 ).

[0037] Logging can well calculate remaining oil saturation in low-salinity formations and effectively judge water-flooded formations. For example, the salinity of this well is 3000ppm, the perforated interval is 928-936 meters, the late production fluid is 6.3T, the oil is 0.1T, and the water content is 98.2%. According to the analysis of PNT well logging data, the perforated zone is obviously water flooded, and the well temperature measured by PNT also shows that this zone produces water.

Embodiment 2

[0038] Embodiment 2, PNT is applied example in low porosity formation (such as Figure 6 ).

[0039] The well is an oil well in Zhongyuan Oilfield, with a porosity of about 10%. After the PNT test, the well shows good oil saturation. After perforation and fracturing, the daily oil production is about 5 tons.

Embodiment 3

[0040] Embodiment 3, judge the example of water-flooded layer (as Figure 7 ).

[0041] The well is an old well with an initial production of more than 100T / d. The well was shut down in 2002 due to high water cut. After testing PNT, it was found that the first two of the three perforated layers had been seriously flooded, and the third layer The thickness is relatively thin, and the degree of water flooding is small. Party A discussed and decided to seal the first two layers, single-mining No. 5 layer, with an initial daily liquid production of 21T / d and a water content of 15%.

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PUM

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Abstract

The invention provides a borehole fluid time spectrum evaluation method using a PNT (pulsed-neutron tool), which includes specific steps: firstly, using a high-energy neutron generator to transmit high-energy neutrons into a stratum; secondly, using two detectors to simultaneously acquire number of low-energy neutrons at 60 intervals of from 36 microseconds to 2160 microseconds when the high-energy neutrons are transmitted from the high-energy neutron generator; thirdly, generating a neutron time spectrum according to the number of the neutrons at each time interval, converting the neutron time spectrum into a data base to be recorded, and generating imaging information according to data of the data base; fourthly eliminating impact of borehole size, a cement mantle and in-wall fluid through images according to corresponding relation of well influencing factors to thermal neutral decay so as to obtain objective stratum parameters; and fifthly outputting the stratum parameters to a display device to serve for high-quality reservoir evaluation. The data are effectively acquired, so that risks are lowered, total investment is lowered, projections of logging through casing and open hole logging are the same in type, and time shifting analysis can be performed.

Description

technical field [0001] The invention relates to a well logging method, in particular to a method for evaluating formations by neutron number. Background technique [0002] After the oil and gas wells in the oil field are put into production, the output will change with the change of oil and gas saturation in the formation, the output of oil and gas will decrease, and the water content will increase significantly. It is very important to monitor the oil and gas saturation of the formation in the well in time, and find the next production measures through well logging analysis. [0003] Before the oil well is produced, the casing will be run and cemented. Because of the physical properties of casing, many logging methods in openholes are limited and cannot be used for formation evaluation in cased holes. At present, the most used saturation logging methods in cased wells are based on the principle of neutron lifetime logging, and the analysis of saturation is carried out by ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B49/00
Inventor 李新民宋海滨张政
Owner SHANDONG RONGXING PETROLEUM ENGINEERING CO LTD
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