Th/U ratio mix-patch was made toward cored durations of each and every well to help you investigate to your 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 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 unimportant contribution of the potassium-free clay minerals on Shurijeh Development, this new natural gamma beam, potassium and thorium signing research were utilized with full confidence locate quotes away from Shurijeh clay blogs. You will find an effective linear correlation amongst the weight percent clay therefore the pure gamma beam record research in line with the Pearson’s correlation coefficient. With respect to the XRD overall performance, this new non-generating well is actually far more shaly with a great clay quantity of you to definitely . 5 buy from magnitude bigger than which had been for the the fresh new energy promoting really. The clay stuff determined on the changed pure gamma ray diary and its own spectral portion studies, exceeded the real center-measured associated with the parameter, probably by the other low-clay radioactive vitamins and you can/or even the sized testing.
It is obvious the borehole logging means measures the latest natural radioactivity in an enormous percentage of rock consider of many kilograms, weighed against the fresh new center shot and this is short for just a little portion of a kg. It is known as the dimensions sampling feeling. On the occurrence instead of gamma beam get across-plot (Fig. It actually was investigated of Fig. Using the average % cousin mistake, among the previously recommended improvement about Shurijeh Formation, those produced by Dewan, Bhuyan–Passey, and you will Larinov met with the most extensively overestimations. Dewan formula lead the largest estimate errors, by the rapid property value 3 in its foods, that has been an educated guess so there is zero counted research on books to help with it. Buhyan–Passey modification generated apparently erroneous estimations, because of the non-practical assumption out-of the same attributes for clay minerals from the clastic reservoirs therefore the adjoining shales.
Larinov equation towards very consolidated stones provided overestimations also as well as the reason for which inapplicability you will rest on the general expectation utilized in the elements. It is becoming conceived in accordance with the fact that the fresh more mature rocks confronted with strong burial contain more illitic nutritional elements than the most other stones as a result of the illitization away from smectite once the a function regarding burial breadth. Since there are of numerous conditions to that generalization, in the event the clay contents are picked out of Larinov older rock curve, such as for example what’s found inside the Fig. The new amendment suggested by the Clavier try a compromise between your tertiary and you will more mature stone equations to imeetzu online own estimate of your own clay contents in the reservoirs; not, it seemed to a bit overestimate the clay blogs of your own Shurijeh tank Formation (Fig.
Total, they checked that generalization ability of one’s empirical non-linear calibration matchmaking are much better than the earlier calibrations and new suitable error of your own model try quicker
The fresh new agreement between the XRD study and Stieber quotes is satisfactory; nevertheless estimations offered by the empirical calibration improved the accuracy of one’s estimations much better than you to. To your clay blogs quote goal, making use of the fresh new empirical relationship are receive a lot more reliable than just the brand new before proposed modifications of the pure gamma beam journal, simply because of its indicator values and you will lowest quote mistakes. The new estimate mistakes of the many in past times recommended adjustment was basically relied on record method of (the brand new gamma beam, potassium or thorium logs), unlike the brand new empirical low-linear calibration which had whenever equivalent errors for everybody of your own different kinds of logs.