That it empirical matchmaking is actually more successful estimator for approximately 20% pounds per cent clay articles; the most common condition about sandstone reservoirs
It is also inferred from this research you to, the Shurijeh reservoir Formation is deposited from the aquatic ecosystem just like the Th/U ratio ranged between step one.8 and you will 23.2 regarding energy promoting well and you may anywhere between 1.dos and you will 5.6 regarding non-producing really. All studies facts in both wells read Th/U rates lower than ten indicating you to definitely, the depositional environment had a marine nature. The greater Th/You ratio regarding the gas generating well would-be due to way more oxidizing requirements or to increased intensity of almost every other radioactive minerals such as K-feldspar or hefty vitamins regarding the sand size tiny fraction. Brand new intermediate Th/You ratio throughout the 2?eight on non-creating better presented the lowest level of weathering and leaching of uranium, otherwise it may be inferred given that an indication of mixes from content out of reduced and you may large ratio environment.
New cross-plots assessment managed flingster odwiedzaj??cych to get obvious your Shurijeh isn?t a great clean tank due to the fact line of cluster analysis activities weren't next to the origin from inside the not one of mix-plots of land shown from the Fig. 11; they were all clustered about lower kept-hand area of each cross spot. Less differences within this wells in place of ranging from wells, suggested particular systematic changes including some other diagentic histories between wells. The information facts of the fuel producing better was in fact smaller better discriminated however, all the presented seemingly average potassium and thorium on mix spot noted A through Fig. eleven. For both wells, the information and knowledge circumstances on clay entering get across-plots decrease inside a specific urban area that shown all round sizes of the clay nutrients in your neighborhood. However, particular investigation away from one another wells were shifted out of the trend. Regardless if, there can be no agreement toward clay sizes introduced by the per cross-plot, however, in accordance with the performance given regarding them, the clay mineralogy in the creation less than study will be concluded since merely out-of glauconite/smectite/muscovite/Illite brands. This type of abilities were not for the contract with that of the XRD lab degree accomplished with the core examples of both wells. The kaolinite, chlorite, and also the combined layer clay nutrition was basically along with remained unrecognized by the this petrophysical technique.
Findings
In this paper, all previously proposed modifications of natural gamma ray log and its spectral components data were reviewed and a new calibration equation for reliable assessment of the clay content in the Shurijeh reservoir Formation was presented. The quantitative XRD results showed a low average percentage of clay minerals for the gas producing well and moderate amounts for the non-producing well. The differences between the varying amounts of clay minerals in wells were attributed to the changes in the diagentic histories. In both wells, all the previously proposed modifications overestimated the weight percent clay indicating it is critical to calibrate petrophysically-derived weight percent clay to the laboratory data to find better estimations. The results also showed by using natural Steiber modified gamma ray values, more reliable clay contents could be obtained rather than all other previous modifications in this area. On the basis of minimum average percent relative error, the natural gamma ray and thorium curves were powerful tools to recognize the clay zones in a sandstone reservoir rather than potassium curve. In summary, the comparison of core clay contents from quantitative XRD data, estimated values using the previously proposed modifications and the empirical calibration, demonstrates that a simple nonlinear regression using the XRD data and natural gamma ray index (IGR) allows for the quantification of clay content with the least percent relative errors, i.e., lower than 12%, which is comparable to the values of the methodological errors associated with the XRD analysis. The excellent agreement between the locally calibrated natural gamma ray index and the clay quantitative XRD data showed it was well suited to provide reliable quantitative clay content estimates. The application of the proposed approach in this paper, will significantly improve the weight percent clay estimations from the gamma ray log in the Gonbadli field. The depositional environment can be correctly recognized from the spectral gamma ray logging ratio, however the safest method of reservoir clay typing is still based on the laboratory analysis of core samples. Overall, the natural gamma ray log and its spectral components data proved to be dependable qualitative and quantitative tools to diagnose clay minerals in sub-surface formation studies. In this paper, the broad scope of problem-solving capability of them was illustrated in the reservoir formation evaluation.
