The looking for was a student in arrangement having cored durations of Shurijeh depositional environment revealed of the Moussavi-Harami and Brenner

Which empirical dating was by far the most effective estimator for up to 20% pounds % clay posts; the most used situation throughout the sandstone reservoirs

It can also be inferred from this data one to, the newest Shurijeh reservoir Creation try deposited on aquatic ecosystem once the Th/U ratio ranged anywhere between step 1.8 and you will 23.dos regarding gas producing better and you will ranging from step one.2 and 5.six regarding low-producing well. All of the studies things in both wells see Th/You rates less than 10 proving you to, the depositional ecosystem had an aquatic characteristics. The higher Th/You ratio from the gas generating well is on account of even more oxidizing requirements or to a top intensity of most other radioactive nutrition eg K-feldspar otherwise heavy vitamins on the mud dimensions tiny fraction. The fresh new intermediate Th/You ratio from the 2–7 regarding the low-creating really showed the lowest amount out-of weathering and you may leaching off uranium, otherwise it can be inferred while the a sign of mixes off material out of reduced and large ratio environment.

New mix-plots of land evaluation managed to make it clear your Shurijeh is not a great brush tank as the type of people study issues just weren’t near to the foundation during the not one of the mix-plots of land found throughout the Fig. 11; these were most of the clustered in the straight down remaining-hand area of each and every get across patch. Quicker differences contained in this wells in lieu of ranging from wells, advised particular systematic alter such as some other diagentic histories ranging from wells. The information and knowledge things of energy generating really were shorter really discriminated but all the demonstrated seemingly reasonable potassium and you may thorium toward mix plot noted A from Fig. eleven. For wells, the knowledge things towards the clay entering cross-plots of land fell in the a particular town you to definitely displayed the overall products of your own clay nutrition in your neighborhood. However, certain data regarding both wells was in fact moved on off the trend. Even in the event, there was no arrangement into the clay systems introduced from the per cross-area, but according to research by the results considering out-of all of them, brand new clay mineralogy on formation significantly less than study will be ended due to the fact only from glauconite/smectite/muscovite/Illite models. These types of abilities just weren’t inside the contract with this of XRD laboratory knowledge achieved to your core types of both wells. New kaolinite, chlorite, together with combined coating clay nutritional elements was indeed along with stayed unrecognized of the which petrophysical technique.

Conclusions

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 (I_GR) 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 blackfling 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.