Th/You ratio mix-area is made toward cored times of every really to take a look at towards depositional environment (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 AldosO3/(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
Conversation
Considering the insignificant contribution of your own potassium-free clay nutrition regarding Shurijeh Formation, the sheer gamma ray, potassium and thorium signing analysis were used with full confidence to get prices regarding Shurijeh clay posts. Discover an effective linear correlation within weight % clay as well as the sheer gamma beam journal data based randki collarspace on the Pearson’s relationship coefficient. According to the XRD abilities, the low-promoting better was a lot more shaly with a great clay amount of you to definitely and a half purchase from magnitude larger than which was inside the brand new gas creating better. The new clay articles calculated in the modified sheer gamma ray journal and its spectral parts investigation, exceeded the true key-measured on the parameter, probably by the almost every other low-clay radioactive vitamins and you can/and/or sized testing.
It is obvious your borehole signing means measures brand new natural radioactivity in a big part of material consider many kilograms, weighed against the latest center attempt and that is short for just a little part of a kilogram. This really is referred to as dimensions sampling effect. With the density in place of gamma ray mix-area (Fig. It actually was investigated out-of Fig. In line with the mediocre per cent relative error, certainly all of the previously advised changes in the Shurijeh Development, men and women put by Dewan, Bhuyan–Passey, and you can Larinov met with the extremely extensively overestimations. Dewan picture produced the most significant estimation mistakes, by great value of 3 with its materials, which had been a knowledgeable guess there was zero measured investigation on the books to help with they. Buhyan–Passey amendment made seemingly erroneous estimations, considering the non-sensible expectation out of identical characteristics for clay vitamins regarding the clastic reservoirs in addition to adjacent shales.
Larinov equation to your very consolidated rocks provided overestimations too and also the reason for that it inapplicability you will lie on the standard presumption found in their materials. It is are created in line with the undeniable fact that the newest earlier rocks exposed to strong burial contain much more illitic nutrition as compared to most other stones as a result of the illitization away from smectite since the a features out-of burial depth. Because there are of many exceptions to this generalization, in the event that clay articles is actually chose from Larinov elderly material contour, such as for example what is actually revealed in Fig. New amendment suggested by Clavier is actually an excellent compromise amongst the tertiary and you can old stone equations to own estimate of one’s clay content material throughout the reservoirs; however, they appeared to some overestimate the new clay blogs of your own Shurijeh tank Creation (Fig.
Total, they looked your generalization function of your empirical non-linear calibration matchmaking is much better than the earlier calibrations and you may the brand new installing mistake of the model was faster
The new contract amongst the XRD data as well as the Stieber prices is satisfactory; although estimations supplied by the empirical calibration increased the accuracy of the estimations better than you to. On the clay content estimation purpose, the effective use of the brand new empirical matchmaking are found a whole lot more reputable than just the latest previously recommended modifications of the sheer gamma ray record, simply because of its signal viewpoints and reasonable estimate errors. Brand new estimate mistakes of all of the previously advised changes were relied towards the log form of (the latest gamma beam, potassium or thorium logs), unlike the newest empirical low-linear calibration which in fact had approximately equivalent problems for everybody of your different kinds of logs.
