Study On Mechanism Of Increasing Production And Injection By Hydra-Slotting And Technical Parameter Designing In Oil-Water Well

The eastern region of Yan Chang Oilfield is charaterized by “three-low” reservoir inOrdos basin as low-pressure,low-porosity,low-permeability,and it develop beddingfractures.For prolonged water flooding,the questions of injection lower than distribution orhard injection,low production and water-cut raising rapidly are occurred,if adopt HydraulicFracturing transformation,it maybe occur watershot because of widespread fractures,soHydra-Slotting is suitable for transformation while it has characteristics of miniaturecrack,few pollution characteristics and avoiding watershot.But it also exist some problemsof Hydra-Slotting technology:first,the mechanism of increasing production and injection isnot clear.Second,the factors which are affect the transformation results are not quantized,soit can not practice for real application.Third,the design of technical parameter and technicalprocess are imperfection.So the paper systematic study the Hydra-Slotting technology frommechanism,influencing factors to designing method of parameters and technical process.The paper study the effect of percolation resistance,anisotropy,seeping area on theseepage,combining liquid-solid-coupling theory,model deformation equation of near borerock and permeability constitutive equation which is be connected with strain,qualitativeanalyze the mechanism of increasing production and injection.Production well is choiced tostudy object,according to whether the crack depth penetrating the damage zone,there aretwo cases:un-penetrated and penetrated,then the two cases equivalent to equivalent calipervertical well and vertical well with horizontal hole in accordance with the principle of theequality of seepage volumes,and the seepage is divided into two parts:seepage of the liquidseeping into the crack and wellbore through the damage zone,seepage of liquid not throughthe damage zone,after this,the method of conformal transformation and equivalent seepageresistance is adopted to modeling the seepage model,and the reasonable is verified.Thepaper study mechanism of increasing production and injection further more while analysing the influencing factors of seepage on the basis of seepage model,the results demonstrate thatpercolation resistance dropping,permeability increasing near wellbore and anisotropydropping are the dominant mechanism of increasing production and injection,the effect ofseeping area varition is very small,in the other hand,the influencing factors of seepage areanalyzed.Through ground test,optimizing the slotting parameters while viewing thepenetrating time as objective and the designing method of parameters are given,finally,thepaper conclude the principle to select the well and layer and design technical process.Theresults and method can provide scientific guidance for hydra-slotting on oilfield.