Th/You proportion get across-patch try produced on cored intervals of every better to look at the 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 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
Discussion
Due to the insignificant share of potassium-totally free clay vitamins regarding the Shurijeh Development, the sheer gamma beam, potassium and you can thorium signing investigation were used with certainty to locate prices regarding Shurijeh clay stuff. You will find a powerful linear relationship involving the weight percent clay and natural gamma ray diary studies in accordance with the Pearson’s correlation coefficient. According to XRD performance, brand new non-generating well is actually so much more shaly with a clay number of one and a half acquisition from magnitude larger than which had been for the new fuel promoting really. The brand new clay posts calculated from the modified pure gamma beam diary as well as spectral parts study, surpassed the actual core-measured on the factor, most likely from the most other low-clay radioactive minerals and/and/or sized sampling.
It’s clear that the borehole signing tool tips the fresh sheer radioactivity in the a massive percentage of stone weigh of numerous kilograms, compared to the newest core sample which stands for only a tiny part of a kilogram. This will be known as the dimensions testing impression. Towards density in place of gamma ray mix-area (Fig. It actually was investigated off Fig. Based on the average per cent relative error, among every in past times recommended modifications in the Shurijeh Development, the individuals produced from the Dewan, Bhuyan–Passey, and you will Larinov encountered the very commonly overestimations. Dewan equation put the most significant quote mistakes, by rapid worth of step three within the materials, that was an informed suppose there is actually no counted research about literary works to help with it. Buhyan–Passey modification produced apparently incorrect estimations, as a result of the low-realistic presumption away from similar functions for both clay minerals in the clastic reservoirs and the adjacent shales.
Larinov picture with the highly consolidated stones provided overestimations as well in addition to cause of so it inapplicability you’ll lie on the general assumption utilized in the foods. It is being conceived according to the fact that this new more mature rocks confronted with deep burial contain sigbificantly more illitic nutritional elements as compared to almost every other https://datingranking.net/pl/huggle-recenzja/ rocks due to the illitization from smectite because the a purpose off burial depth. Since there are many conditions to that particular generalization, in the event the clay contents try picked of Larinov older rock curve, for example what is actually shown for the Fig. The brand new modification proposed from the Clavier is actually a compromise between the tertiary and you will more mature rock equations to have estimation of clay content about reservoirs; although not, it did actually a bit overestimate brand new clay content of your own Shurijeh tank Formation (Fig.
Total, it looked the generalization element of the empirical low-linear calibration matchmaking are better than the prior calibrations and you will the brand new installing error of one’s model is faster
The newest arrangement involving the XRD studies together with Stieber estimates is satisfactory; although estimations supplied by the brand new empirical calibration increased the precision of your estimations better than you to definitely. For the clay articles estimation purpose, the usage the new empirical matchmaking is located alot more reliable than the brand new in earlier times recommended adjustment of the natural gamma beam log, due to its sign thinking and you can reasonable estimation mistakes. The fresh new quote errors of all before recommended adjustment was depended on log style of (this new gamma beam, potassium or thorium logs), unlike brand new empirical non-linear calibration which in fact had whenever equal errors for everybody of your different kinds of logs.