That it empirical matchmaking is actually one particular successful estimator for 20% pounds percent clay posts; the most famous condition on sandstone reservoirs
It can be inferred from this analysis you to, brand new Shurijeh reservoir Formation is placed on marine ecosystem since the Th/U proportion ranged anywhere between step one.8 and 23.2 in the gasoline creating well and ranging from step one.2 and you can 5.six about non-creating better. All of the studies issues in both wells understand Th/U ratios below ten showing one, the depositional ecosystem had an aquatic nature. The better Th/You proportion from the gas promoting really might possibly be on account of much more oxidizing conditions or to increased concentration of almost every other radioactive nutrition for example K-feldspar otherwise heavier nutritional elements about sand dimensions small fraction. The fresh new intermediate Th/You proportion regarding dos–7 about non-creating better exhibited a minimal amount from weathering and you will leaching regarding uranium, otherwise it could be inferred as the a sign of mixtures out of information off lowest and you may large proportion environments.
The brand new cross-plots research managed to make it obvious that the Shurijeh isn’t good brush reservoir once the line of class investigation factors just weren’t alongside the origin during the none of your cross-plots of land shown from the Fig. 11; these were the clustered on the down leftover-hand area of every cross plot. Reduced differences in this wells rather than anywhere between wells, ideal certain health-related transform including other diagentic histories ranging from wells. The data situations of one’s fuel creating really was indeed less better discriminated but the demonstrated relatively moderate potassium and you may thorium into get across plot marked An off Fig. 11. For both wells, the knowledge points on the clay typing get across-plots of land decrease from inside the a specific town you to exhibited all round products of your clay nutritional elements in the region. But not, certain studies regarding one another wells was basically managed to move on from the pattern. Even in the event, there’s no contract to the clay sizes introduced by the for each cross-area, but in accordance with the overall performance considering of all of them, the clay mineralogy in the development under investigation would be concluded because merely regarding glauconite/smectite/muscovite/Illite designs. Such efficiency weren’t in arrangement with that of XRD laboratory training achieved on the core types of each other wells. New kaolinite, chlorite, plus the mixed layer clay vitamins was in fact as well as remained unrecognized because of the so it petrophysical strategy.
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 https://datingranking.net/pl/lds-singles-recenzja/ 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.