Quantitative Characterization And Application Of Organic Acid Generation And Its Dissolution To Reservoir

A kerogen mimic acid production experiment was carried out.Based on the kerogen generation kinetics principle and model summarized by previous researchers,combined with experimental data on kerogen production,a kerogen acid generation kinetic model was established on one hand for quantitative characterization.The acidogenic ability of source rocks,on the other hand,analyzed and summarized the main controlling factors of organic acid production mainly kerogen type,temperature,etc.The main organic acids generated were formic acid,acetic acid and oxalic acid.At the same time,the experiment of organic acid decarboxylation was carried out,and the thermodynamic model of decarboxylation of organic acid was established.The yield and stability of organic acid were summarized.The results showed that the stability of acetic acid was the best among the organic acids produced by the thermal evolution of kerogen.Formic acid Second,oxalic acid is the worst.Finally,the corrosion experiments of different organic acids and common minerals and core samples in the reservoir were conducted.The effects of organic acid dissolution on the mineral morphology and pore structure were qualitatively analyzed.The organic acid dissolution was quantitatively established by consulting the mineral thermodynamic database.Thermodynamic model of minerals.The above three models have a good agreement with the actual value.Using the established kinetic model for the generation of organic acids,the thermodynamic model for the decarboxylation of organic acids,and the thermodynamic model for mineral dissolution of organic acids,a dynamics and thermodynamics-based modeling method can be used to quantitatively characterize the history of dissolvable pore development in the study area.Formic acid and acetic acid,for example,have shown that with the approach of the geological age,the generation of organic acids,the amount of decarboxylation,and the newly-dissolved porosity all show a tendency of rising first and then slowly rising.According to the calculation results,it is known that The newly-added erosion porosity is greater than that of formic acid,but overall,the porosity of the new crucible resulting from the dissolution of organic minerals in the reservoir minerals is not significant.Therefore,organic acids do not have global significance for the dissolution of shale reservoirs.Fractures and other surrounding carbonates are less in the reservoir.Therefore,organic acids can be highly effective in the local dissolution of fractures in the reservoir,which is of positive significance for improving reservoir permeability.