Using normalized full gradient of gravity anomalies to detect geological structures with mineral oil and gas potential

Abstract

In deep structural studies such as determining oil and ore deposits, the normalized full gradient (NFG) method is used with relatively high accuracy. In this paper, by using an algorithm combining the change of the coefficient N and the potential field expansion according to the Fourier series to determine the gravity documents were analyzed. The maximum normalized full gradient could be determined based on the found normalized full gradient values. The studied geological structure (or foreign body) was determined at the location with the maximum total gradient with a defined depth. The models were set up for the purpose of finding the results and verifying the accuracy in the geophysical problem. Therefore, two models were established representing two types of geological structures: solid minerals with δ > 0 and liquid minerals with δ < 0. Research results of the two modeling problems were equal. The exact position possessing the maximum normalized full gradient was determined. Application of these models on the actual gravimetric data measured on a measuring line in the Songkhla basin southwest of the Gulf of Thailand showed the presence of a liquid-mineral geological structure. According to the field information, there were a number of oil fields in this area that had been identified and are in the process of being exploited. Thus, this position would be the center of the oil field, because the obtained result is in full agreement with the published depth of the well.