Research On Mechanisms Of Steamflooding And The Influencing Factors In Daqing Light Oil Reservoir

Zhaoyuan oilfield is low permeability, low reserves abundance and low single well productivity light oil reservoir in Daqing. The oil layers in Zhaoyuan block are at the depth of 1519.8m to 1826.2m. No mature experience about this kind of reservoir can be learned.This paper research oil recovery mechanism, analysis steam/crude oil movement laws and their factors for the driving effect. The result can give us the basis for changing the development style of the light oil reservoir.The light oil layer characteristic has been researched of experiment district, while it can give the basis for manufacturing the artificial core in the steam driving simulation experiment in the lab. Based on the features of Zhaoyuan oilfield, the experiment set has been reformed and made with the reservoir pressure, temperature and the operation parameter in the stage of changing the driving style taking into account, which have the oil, gas, water three phases auto-metering systems. The experiment set have the function with auto collecting the data and controlling. The research of indoor simulation steam driving experiment is in this set.Through experiments, oil displacement efficiencies of water flooding and steam flooding have been analyzed. The result shows that: steamflooding is more superior to hot-water, and hot-waterflooding is more superior than conventional waterflooding. The saturation of the immobile water increase and the saturation of residual oil by the water drive and the steam drive drop as the increase of the temperature. The oil and water relatively permeability curve about the hot water drive will turn right with the increase of temperature. The oil and gas relatively permeability curve about steam drive will be better about the curve shape and the point of inter section will increase.The research result about the steam distillation ratio shows steam distillation is the primary mechanism of enhancen oil displacement efficiencies, which is affected by the porous medium, and the original oil quantity, steam temperature, steam pressure and the steam injection velocity, while the steam pressure and temperature affect the distillation ratio most.This paper has discusssed the applicability of steam flooding in watered reservoirs.The result shows: the increasing water saturation due to water injection has no great influence on the swept volume of the injected steam, heat loss of the steam zones to top and bottom cap formations decrease; while it has great effect on development index of steam injection. Oil displacement efficiencies will induce greatly.