Marker selection method for oil field logging

Abstract

The invention discloses a marker selection method for oil field logging. The method comprises the following steps of (a) selecting elements capable of participating in neutron activation treatment, and calculating element factors S of the selected elements according to the following formula (1): S=[theta]*[sigma]*[beta]*[gamma] / M(1); and (b) sorting the elements in a sequence from large S factors to small S factors according to the determination result in the step a, and primarily selecting the elements which are sorted in the front; then performing gamma ray interference elimination in the primarily selected elements, i.e., only remaining the elements with the large S factors in the elements with the characteristic gamma ray signal mutual interference; and regarding the finally left elements as marked elements. The invention provides a brand-new marker selection method; and through cooperation with the trace analysis, the flow rate of produced liquid in each target position under a well and the proportion of water to crude oil in the produced liquid can be accurately reduced. Meanwhile, the normal operation state of a horizontal well cannot be damaged, system errors can be effectively reduced, and the accuracy and reliability of the measurement result are improved.

Description

technical field [0001] The invention relates to the field of oilfield exploitation, in particular to the field of underground measurement of oilfield exploitation, in particular to a method for selecting markers for oilfield well logging. This application provides a new method for selecting markers for oil field logging, which provides a new idea for the selection of markers. Based on the markers for oil field logging obtained by the selection method of this application, and the use of trace analysis, it is possible to accurately restore the ratio of water and crude oil in the fluid produced at each target location downhole. Background technique [0002] Fluid production profile testing of horizontal oil wells is a difficult problem in the field of petroleum logging, which involves the following aspects: [0003] 1) Accessibility problem [0004] Traditional instruments go downhole by their own gravity, and it is difficult for the instrument string to continue moving after...

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Problems solved by technology

[0004] Traditional instruments go downhole by their own gravity, and it is difficult for the instrument string to continue moving after reaching the vicinity of the deflection; for this reason, Schlumberger specially designed the MaxTRAC crawler, which drags the signal cable and power cable, and carries the instrument The string enters the horizontal section; but once the horizontal section is relatively long, or the wellbore trajectory is tortuous and undulating, or there is casing deformation, it is easy to cause the crawler to be blocked, or even get stuck in the horizontal section, causing accidents;

[0005] 2) Problems with production testing

[0006] Traditional instruments go downhole with cables. Due to the existence of instruments and cables, it is necessary to use unconventional methods such as gas lift to lift the production liquid to the surface, causing the liquid to flow, thereby measuring parameters; these measures have objectively changed the entire horizontal section. The flow environment is easy to cause deviations between the test data and the real data in normal production, resulting in inaccurate test conclusions;

[0007] 3) Adaptation to harsh underground conditions

With this method, when replacing ordinary markers, well shutdown operations are required, which affects the normal operation of the oil well, and the cost of manpower and replacement is high

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