This empirical dating is the quintessential effective estimator for approximately 20% pounds percent clay articles; the most popular problem on sandstone reservoirs
It is also inferred using this investigation that, the fresh new Shurijeh reservoir Creation is transferred throughout the marine ecosystem once the Th/U proportion varied between 1.8 and you can 23.dos regarding gasoline promoting really and you can between step one.dos and you will 5.6 regarding the low-generating well. The analysis factors in wells see Th/You ratios below 10 proving you to, the new depositional environment had a marine character. The better Th/You proportion regarding the fuel generating better was because of so much more oxidizing conditions or even to a top concentration of most other radioactive vitamins for example K-feldspar otherwise heavier nutrition regarding the mud size small fraction. Brand new advanced Th/U proportion on dos–7 from the low-creating really showed a decreased degree out-of weathering and leaching from uranium, or it could be inferred as an indication of mixes away from material regarding lowest and high ratio surroundings.
The new get across-plots of land evaluation caused it to be obvious that the Shurijeh is not good clean reservoir because line of people analysis facts just weren’t next to the foundation in the none of one’s get across-plots of land found regarding the Fig. 11; these were all of the clustered about down left-hands spot of each mix spot. Reduced variations inside wells instead of between wells, suggested particular scientific change including some other diagentic records between wells. The info situations of your own fuel producing really was in fact shorter well discriminated however, all the shown relatively modest https://datingranking.net/pl/livejasmin-recenzja potassium and you will thorium with the mix plot designated A through Fig. eleven. For both wells, the knowledge points with the clay typing mix-plots decrease inside the a particular urban area one to showed the general products of the clay vitamins in your community. Yet not, certain investigation away from both wells have been moved on out of the pattern. No matter if, you will find no contract towards the clay brands put because of the for every cross-spot, however, according to research by the efficiency offered of all of them, the clay mineralogy in the creation less than investigation might be ended since only out of glauconite/smectite/muscovite/Illite versions. Such abilities were not into the arrangement with this of your XRD lab education carried out toward core examples of both wells. The fresh kaolinite, chlorite, plus the mixed covering clay minerals was together with stayed unrecognized from the that it petrophysical method.
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.