Study On Influence Factors And Thermal Management Method Of Gravity Fire-flooding Effect

In-situ combustion technology has the characteristics of high heat wave efficiency and low energy consumption.It is often used as a replacement development mode after steam stimulation.Gravity fire-flooding is an improved in-situ combustion technology.At present,the gravity fire-flooding technology has not been widely used.The main reason is that there is no clear impact of reservoir geological factors and development engineering factors on the production effect.Secondly,there is insufficient research on the thermal management of the gravity fire-flooding technology,which can not protect the production safety and improve the heat utilization efficiency as much as possible.In this paper,CMG numerical simulation software is used to study the influence of reservoir geological factors and development engineering factors on the development effect of gravity fire-flooding.The grey correlation method is used to study the reservoir geological factors,and the primary and secondary order is viscosity>permeability>reservoir thickness>oil saturation>porosity>K_v/K_h.The orthogonal experimental design method is used to study the influence of development engineering factors,and the primary and secondary order is gas injection speed>perforation location of gas injection well>distance between horizontal section and gas injection vertical well>length of horizontal section.The gravity fire-flooding process is divided into three stages:ignition start,radial expansion and forward propulsion.According to the characteristics of different stages,the corresponding thermal management measures are studied,the quantitative and qualitative suggestions are given,and the thermal management decision-making process of gravity fire-flooding is established.According to the actual production problems and well pattern characteristics in the mine,a thermal management method of sidetracking gravity fire-flooding in vertical wells with reverse nine point pattern is proposed.The characteristics and thermal management measures of different stages of gravity fire-flooding are fully considered,and the inherent production increasing mechanism is revealed by CMOST sensitivity analysis.Generally,the sidetracking length is 1/2 of the well spacing.With the increase of sidetracking length,the main influencing factor changes from geological factor to development factor.The multiple linear regression equation between influencing factors and recovery factor is established,which can effectively predict the field production effect(error<15%)and guide the actual production.