Study On The Technology Of Pushing Water Coning With Nitrogen Foam Fluid In Bottom Water Reservoir

There is bottom water reservoir in the oil field of every country. Thetechnology of artificial interbed and recovering water to remove the waterconing is restricted with unideal effect. The nitrogen can supply theproducing energyand increase the reservoir pressure with its non-condensatehigh compressibility and dilatabilityafter its entering into the formation. Thenitrogen foam can be used to seal the channel with its high stabilityand highflow resistance compared to water, so the technology is worth to study andintroduce.The research was done using theory, experiment and numericalsimulation including three parts: one is the study on the stability of nitrogenfoam in porous media, and it is critical to the pushing. It demonstrated thatthe stabilityand sealing characteristics are good and ratio of sealingis 91.7%after canningin thebarrel for90days. Thesecond is thestudyof mechanismfor the pushing. The volume expression was derived as the reference for thevolume of injecting while pushing the water by nitrogen foam. It indicatesthatthenitrogenfoam couldretrievepressuredepletionofimmediatevicinityofwellboreandrepressthewaterconingwithhighpressureanddisplacementneartheoil/water interface. It also couldseal offthechannel of bottom waterand slow down the coning as a result of the elastic energy of nitrogen and Jamin action of foam and the selective blockage of nitrogen foam. The thirdis the computational analysis of sensible factor using numerical simulation,including the injecting time, velocity and volume, the close time, the liquidproducing capacity after opening the well, the ratio between verticalpermeability and horizontal permeability and the position of interbed etc. Allthe law of the effect of increasing oil using nitrogen foam to push the waterconingwasobtainedinthispaper.By means of site test in the three thermal wells in Shengli Le-an field,it could be known that the crude output increased significantly compared tothe last production cycle, water ratio decreased or keep stability and therewas a good effect of decreasing the water and increasing the oil by pushingwatercorningwithnitrogenfoam.