Exploration of oil reservoirs using activation of materials by gamma rays with the help of Monte Carlo method

In the field of nuclear physics, the use of gamma rays is an important and practical method. This method is used in various industries such as oil and gas production, mining and quarrying, environmental monitoring and so on. The technology of using gamma rays is based on the interaction of the beams with materials. The three main phenomena are the interaction of gamma rays with photoelectric material, Compton scattering, and pair- production phenomena. Due to its very high sensitivity, activation analysis has become an important and applicable tool in various fields ranging from science and engineering to industry, mineral exploration, medicine, etc. One of the biggest advantages of analyzing by this activation method is that it can detect most isotopes with very high sensitivity. In this research, different simulations have been carried out on sedimentary rocks in order to find a suitable method for exploration of oil reservoirs. These simulations are performed in three different states and by comparing the results obtained in each case, the best results are selected to explore the oil reservoirs. 

Methodology and Approaches:

The Monte Carlo method is a class of computational algorithms that rely on random iterative sampling to calculate their results. To use this method, a structured input file must be provided, including problem information such as geometry, material type, source, output type, and so on. The code, based on this method, solves the problem using input file information and the crosssection library and generates the results in an output file. In the simulations by this code, a cubic block of about 2 meters is considered to be a type of sedimentary rocks, oil, gas, water and a combination of these rocks with water, gas or oil. The simulated cavity has a depth of 180 cm and a radius of 7.62 cm. A 2-inch NaI (Tl) detector is inserted into the specified hole.

According to the obtained results, it is possible to detect and identify the oil reservoirs and to separate the oil reservoirs from the gas and water reservoirs. The advantage of using this method is that due to the minimal amount of energy required for carbon interactions of 18.7 MeV, there is no need to investigate existing sources in nature, since the maximum energy emitted by these sources is less than 18.7 MeV. Thus, the sources in nature do not cause any disruption in the measurements.