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The brand new depositional environment additionally the clay entering based on the spectral gamma beam percentages

The brand new depositional environment additionally the clay entering based on the spectral gamma beam percentages

Th/U ratio get across-plot is produced towards cored periods of each really in order to have a look at toward depositional ecosystem (Fig. 10).

The clay typing was later accomplished by a group of cross-plots (Fig. 11) with various combinations including thorium versus potassium, photoelectric (PEF) versus potassium, photoelectric versus Th/K ratio and thorium versus AldosOstep step three/(Al2O3 + SiO2). For generating the last one , the XRF data were used. The presence of clay minerals like illite, montmorillonite and glauconite are evident from Fig. 11, however chlorite and kaolinte are not detected by this method.

The results of log-derived clay typing: a Th (vs) K, from Schlumberger ; b PEF (vs) K, from Schlumberger ; c PEF (vs) Th/K, from Schlumberger ; d Th (vs) Al2O3/(Al2O3 + SiO2) from . Black circle Gas producing well data points, and black up-pointing triangle non-producing well data points


Considering the insignificant contribution of the potassium-100 % free clay nutrition regarding Shurijeh Creation, the latest natural gamma beam, potassium and thorium logging research were utilized confidently discover prices away from Shurijeh clay articles. There is certainly a robust linear correlation curves connect between your weight percent clay and the natural gamma beam diary study in accordance with the Pearson’s relationship coefficient. According to the XRD performance, the newest non-creating well are so much more shaly having a clay level of you to and a half acquisition regarding magnitude bigger than that was inside this new fuel generating really. This new clay content computed about changed natural gamma beam diary and its particular spectral areas analysis, exceeded the real core-measured of this parameter, most likely from the most other non-clay radioactive nutrition and you can/or the size of sampling.

It’s obvious that the borehole signing means strategies the brand new pure radioactivity inside a massive portion of stone weighing of several kilograms, compared to this new center test and this means only a small portion of a kilogram. This is known as the dimensions sampling feeling. Into the thickness in place of gamma ray cross-patch (Fig. It had been investigated from Fig. Based on the average per cent cousin mistake, certainly every before advised changes regarding Shurijeh Creation, men and women lead by Dewan, Bhuyan–Passey, and you may Larinov had the really commonly overestimations. Dewan equation put the most significant estimate problems, by great value of step three in materials, that was the best guess and there is actually zero mentioned analysis on the literature to help with they. Buhyan–Passey amendment produced relatively incorrect estimations, due to the low-sensible assumption from the same properties for both clay nutrition regarding the clastic reservoirs additionally the adjoining shales.

Larinov formula toward very consolidated rocks considering overestimations too while the cause of it inapplicability might rest in the standard presumption utilized in their foods. It’s becoming devised according to research by the fact that the latest old stones subjected to deep burial contain sigbificantly more illitic vitamins than the almost every other stones as a result of the illitization regarding smectite as the a purpose away from burial depth. Because there are of numerous exclusions compared to that generalization, if the clay information is actually chose out of Larinov more mature stone bend, for example what’s found in the Fig. The new amendment suggested from the Clavier are an excellent compromise involving the tertiary and you may older material equations to own estimate of one’s clay articles in the reservoirs; but not, it seemed to a bit overestimate new clay articles of your Shurijeh tank Creation (Fig.

Complete, it checked your generalization feature of empirical low-linear calibration matchmaking was much better than the last calibrations and you can the fitting mistake of your own model was less

New contract involving the XRD studies and also the Stieber prices is actually satisfactory; but the estimations provided by the empirical calibration improved the precision of one’s estimations better than one to. On clay posts quote purpose, making use of the newest empirical dating are receive way more reliable than just the newest in the past recommended variations of one’s natural gamma beam journal, due to the signal philosophy and you may reasonable quote problems. The latest estimate mistakes of the many in past times proposed variations were relied into log form of (this new gamma ray, potassium otherwise thorium logs), as opposed to the brand new empirical non-linear calibration which in fact had whenever equal problems for everybody of different types of logs.

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