Analysis Of Thermal Effect Of In Situ Combustion

In-situ combustion is a kind of oil recovery technology with high efficiency and wide application range,which can replace enhance the recovery of heavy oil reservoir after steam soaking.However,due to the variety of physical and chemical reactions,the complex energy transfer and the influence of various oil displacement mechanisms,the success rate of oilfield operation is not high.At present the in-situ combustion parameters set only on the basis of the semi empirical formula,it is difficult to consider the combustion and formation heterogeneity.To solve this problem,based on the energy balance principle of in-situ combustion,using CMG numerical simulation software to analyze the W block of reaction rate,heat dissipation of heat of in-situ combustion;discuss the influence of reservoir heterogeneity on the thermal effect of connectivity between injection wells and production wells,and analysis the thermal connectivity of W block.The results show that with the increase of gas injection rate,heat production increased first and then decreased,the heat loss continued to increase;Increase in layer heterogeneity will lead to combustion front spread unevenly,and will cause the production reduced of single layer;Increase of interlayer permeability of the reservoir would cause the increase of suction difference,and cause the reservoir recovery efficiency decreased;During the process of in-situ combustion,with the increase of the thermal sweep coefficient,the recovery rate is increasing,but there is no linear relationship under the two different gas injection rates.Finally,according to the analyzing energy of in-situ combustion,the energy balance equation is established,the formula of the optimum gas injection rate is derived,and the correction is made based on the analysis of reservoir heterogeneity.The caculated results and numerical simulation are close.Based on the energy balance,this formula is more reasonable than the previous semi empirical formula method,and it has a guiding significance for the adjustment of injection production parameters of different types of in-situ combustion reservoirs.