The newest finding was a student in agreement with cored durations of one’s Shurijeh depositional ecosystem described from the Moussavi-Harami and Brenner

It empirical matchmaking is one particular productive estimator for approximately 20% lbs per cent clay posts; the best condition about sandstone reservoirs

It is also inferred from this analysis you to, the fresh new Shurijeh reservoir Creation try transferred from the marine ecosystem as Th/You proportion varied ranging from step one.8 and you will 23.dos in the gas generating really and you can anywhere between 1.dos and 5.6 regarding the non-creating well. All of the study activities both in wells discover Th/You percentages lower than ten exhibiting one, new depositional environment had an aquatic nature. The better Th/You ratio about energy promoting well could well be because of a lot more oxidizing requirements or even a top intensity of almost every other radioactive nutritional elements such K-feldspar otherwise big nutrition throughout the sand dimensions small fraction. The latest intermediate Th/U proportion from the dos–seven regarding low-promoting really presented a minimal degrees away from weathering and you can leaching away from uranium, or it could be inferred due to the fact an indication of mixtures away from material out-of reduced and you may higher proportion surroundings.

The newest cross-plots of land testing managed to get obvious your Shurijeh isn’t a brush reservoir given that collection of class investigation issues just weren’t near to the origin inside not one of the cross-plots shown regarding Fig. 11; they certainly were all the clustered throughout the straight down kept-give place of each get across plot. Reduced distinctions contained in this wells in the place of anywhere between wells, recommended some clinical alter such as for instance additional diagentic records ranging from wells. The content things of your own fuel generating well was basically less better discriminated but every presented relatively average potassium and thorium into the cross patch designated A from Fig. 11. For wells, the information issues to your clay typing mix-plots dropped inside a certain city you to definitely shown the overall versions of one’s clay minerals in the area. But not, some studies out of each other wells was indeed moved on from the development. Regardless of if, there is no contract on clay types introduced because of the for each cross-spot, but in line with the overall performance considering out of them, the brand new clay mineralogy regarding development not as much as study is ended due to the fact only from glauconite/smectite/muscovite/Illite versions. This type of results just weren’t within the agreement thereupon of XRD research degree accomplished with the center samples of each other wells. The kaolinite, chlorite, plus the combined covering clay minerals was basically also stayed unrecognized of the this petrophysical method.


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.