Th/U ratio mix-spot was generated for the cored times of each really to help you take a look at on 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 AldosOstep 3/(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
Dialogue
As a result of the unimportant contribution of your own potassium-totally free clay vitamins regarding the Shurijeh Formation, the latest sheer gamma ray, potassium and you may thorium logging analysis were utilized with certainty locate estimates out of Shurijeh clay content. There clearly was a robust linear relationship between the weight percent clay therefore the natural gamma beam log study according to the Pearson’s correlation coefficient. With respect to the XRD abilities, the brand new low-generating better are a great deal more shaly that have an excellent clay amount of one to and a half acquisition from magnitude bigger than which had been when you look at the the latest gas promoting really. Brand new clay stuff computed in the altered absolute gamma beam record and its own spectral section analysis, surpassed the genuine key-mentioned on the parameter, most likely because of the almost every other low-clay radioactive minerals and you may/and/or sized sampling.
It’s obvious that borehole signing appliance measures the latest absolute radioactivity from inside the a large portion of rock consider many kilograms, in contrast to the fresh center shot hence signifies merely a little percentage of a kilogram. This will be referred to as proportions sampling perception. To your thickness rather than gamma ray mix-spot (Fig. It had been investigated out of Fig. Using the average percent cousin mistake, among most of the prior to now recommended variations regarding the Shurijeh Development, those people put by Dewan, Bhuyan–Passey, and you will Larinov met with the most generally overestimations. Dewan formula put the largest estimate mistakes, of the rapid property value 3 within its elements, that has been an informed suppose there is no measured study regarding literature to help with it. Buhyan–Passey amendment produced apparently erroneous estimations, because of the non-practical assumption from the same services both for clay nutrients in the clastic reservoirs therefore przykЕ‚ady profili farmersonly the adjacent shales.
Larinov equation towards very consolidated stones given overestimations as well in addition to reason for so it inapplicability might sit regarding the general presumption utilized in the ingredients. It is being conceived according to the undeniable fact that the newest elderly rocks subjected to deep burial contain more illitic nutritional elements compared to most other stones considering the illitization away from smectite because the a function of burial depth. Because there are of numerous conditions to that particular generalization, if clay articles try picked from Larinov earlier material bend, particularly what’s shown in the Fig. The new modification suggested because of the Clavier is actually good compromise amongst the tertiary and you will older rock equations to have quote of your own clay content material regarding the reservoirs; although not, they did actually quite overestimate brand new clay blogs of your own Shurijeh tank Creation (Fig.
Overall, it searched that the generalization function of empirical low-linear calibration relationships are better than the prior calibrations and the newest installing error of the model are faster
New arrangement between your XRD analysis while the Stieber rates is actually satisfactory; although estimations supplied by the newest empirical calibration improved the accuracy of estimations better than you to definitely. On clay content estimate objective, using the newest empirical relationships is actually found even more reliable than simply the new before recommended modifications of sheer gamma beam journal, due to the indicator philosophy and lowest estimate problems. The latest estimation mistakes of all the previously advised improvement was relied to your log types of (the latest gamma beam, potassium or thorium logs), as opposed to the new empirical low-linear calibration which had up to equivalent problems for all of one’s different kinds of logs.