Study On Deep And Massive Heavy Oil Reservoir Converted To Fireflooding With Assisted Gravity Drainage

In this paper for the deep and massive heavy oil reservoirs of Liaohe oilfield afterCSS(cycle steam stimulation) development, the reservoir development condition was faced withthe high developed ratios in the plane and vertical oil zones and the existing heavy oil well withlow production, low OSR, low effect and high dispersed remaining oil,and moreover in theheavy oil reservoir the converted development pattern was not made true really, So the GravityFire Flooding(GFF) was put forward as the next development pattern converted.In this paper by the technology survey of the in-situ combustion and the GFF, the gravityfire flooding-THAI was mainly used in the matrix shallow ultra heavy oil reservoirs. So there aremany issues faced that the GFF was suitable or not for the deep and massive heavy oil reservoirsin Liaohe oilfield after CSS development which have very heavy heterogeneity in the reservoirsand how to optimize the development parameters was done in the DFF.In this paper by thereservoir adaptability study of the GFF, the property of the heavy oil reservoirs that was suitablefor the GFF was discussed from the oil zones thickness,the type of the reservoirs,the physicsproperty and heterogeneity of the reservoirs,the characteristics of the interlayers in the oil zones,and the screening criterion of the heavy oil reservoirs for the GFF was obtained. The numericalmodel of the GFF was build up by use of the methods of physics model and the thermalnumerical modeling combined,and the parameters optimimum and adjustment of the GFF wasstudied on basis of the indoors lab test research on the fire flooding. The result of the study wasshowed that the lateral GFF was more suitable than THAI technology for the deep and massiveheavy oil reservoirs after CSS development and furthermore in terms of the methods used bytrailing research of the numerical modeling, it was pointed out that the wet combustion sectionwas a better burning pattern than the dry combustion and at same time it was convinced that thehard coke combustion pattern could make the oil zones burned more completely during theheavy oil combustion.In term of the vertical wells fire flooding pilot evaluation on the deep and massive heavy oilreservoirs after CSS development, it was pointed that in the high heterogeneity heavy reservoirconverted to fire flooding development, the combustion front was pushed quickly along thedirection of good reservoir property, low well space and the lower formation pressure.The firefront pushed non uniform in the plane and the gas channeling and gas overlapped made the volume sweep coefficient lower which was showed that the GFF could be further utilized in thiskind of the heavy oil reservoirs.By the analysis on the lateral GFF pilot well group, the GFF pilot well groups got goodeffect in Gao3-6-18block with the average daily liquids7.3t and the average daily oil rate4.4tfor the horizontal production well and the monitoring technique of the GFF was studied. It wasconviced that it was a good development pattern for the deep and massive heavy oil reservoirsafter CSS development converted to the GFF development and it could improve oil wellsproduction and the block recovery.In general on the basis of the analysis on the existing technology of the GFF, the screeningcriterion of the heavy oil reservoirs for the GFF was bulid up and the parameters optimimumand adjustment of the GFF was studied by use of the methods of physics model and the thermalnumerical modeling combined which would be set on basis of the thick and massive heavy oilreservoir converted to the GFF after CSS development, and it would give more contribution onthe next heavy oil reservoir converted development pattern in Liaohe oil field.