Abstract:

Based on the comparative analysis of different thermal conduction models of magmatic intrusion, the thermal effect of magmatic intrusion to the organic matter maturity of country rock is simulated, which combined the Easy R_o% model and the reported vitrinite reflectance values (R_o). The numerical simulation results show that the improved Fjeldskaar model can be easy to simulate the thermal maturation of organic matter near the magmatic intrusion and has a good fitting effect. Further more, the alteration of the initial temperature and the thickness of magmatic intrusions have different thermal effects to the organic matter maturity of country rock. It shows that the thermal effect extent is in a limited range. However, this range (X/D, denoted by the ratio of intrusion thickness to the distance which is from the calculation depth to the contact surface) changes with the different geological conditions. Generally speaking, the higher of the initial temperature of the magmatic intrusion is, the broader of the range is, and so does the thickness of magmatic intrusion, but the X/D value is usually less than two (X/D<2). The preliminary application of the thermal conduction model shows that the thermal effect of volcanic process has an important effect to the hydrocarbon generation process, which can accelerate the organic matter maturation of the source rock and advance the hydrocarbon generation period.

Key words: magmatic intrusion, improved Fjeldskaar model, Easy R_o% model, hydrocarbon generation period, numerical simulation, petroleum gas