Research And Application Of CO₂ Complicated Steam Huff And Puff Technology In Super Heavy Oil

Steam huff and puff is one of the main way of the super heavy oil developing in our company.In the late middle period of exploring,the formation pressure decreases obviously and the properties of reserved oil has changed.Meanwhile,the saturation distributed near the well has also decreased and the groundwater has increased.As result,it turns to be more and more difficult to explore the oil and the effect of cyclic steam stimulation turns to be worse and worse.So the water recovery period of oil well became longer and the ratio of oil and gas becomes lower,even it may below economic limited line.It is harm to the sustainable development of the oil field.From 2003,our super heavy oil began to develop,after about 10 years developing,the effect of steam huff and puff declined severely.Aiming at the worse of the stimulation and effect of exploring in the late middle period,through physical simulation experiments,we studied the oil increasing mechanism of CO₂ composite huff and puff technology,and found out the key factors affecting the effect of the measures.At the same time,combined with the characteristics of reservoir,we can optimize a series of technical parameters,such as the best injection way,injection volume and later production,to further improve the effect of super heavy oil CO₂ compound huff and puff process.The theory of CO₂+（surfactant）+ steam two（three）combined huff and puff technology is formed,which provides a theoretical basis and technical support for the popularization and application of this technology in heavy oil super heavy oil field.