The Study Of Improving Recovery Ratio By Water Injection In The Block12Tahe Oilfield

In this paper，water features and water distribution characteristics are analyzed inthe Block12of Tahe Oilfield by drilling、testing、logging、seismic、development ofdynamic data and so on; The overall effect and affecting factor of single well injectionare analyzed in the Block12Tahe Oilfield by development of dynamic data based onwater injection for oil single well fracture-cavity unit, the standard of select a singlewell injection is also derived; Analysis the oil groups which have effective by waterinjection flooding in the multi-well fracture-cavity unit obtained the effect and meansof displacement in flooding in the multi-well fracture-cavity unit of the Block12TaheOilfield. The study result indicates:(1) The wells in the Block12Tahe Oilfield have two main water features:moisture content slowly rising and the rapid increase, some of which may belong tothe transitional type. Water distribution characteristics have three types: low degree ofreservoir filling, main reservoir is oil in the whole oil field, the local development ofwater contiguous is poor; the reservoir oil filling conditions are good within80m ofthe scope of the erosion surface; the possibility of the reservoir development water isgreat below80m of the erosion surface，after water injection，the well produces water,(2)78wells have been injected water for oil in the wells in the Block12TaheOilfield, the overall effect of Water injection for oil is better mainly as: water injectionfor oil effectively add to the formation energy, the effect of increasing oil productionis significant; the effect of water injection for oil in cave reservoir is better; the effectof water injection for oil wells which are low‐containing or water free is better.Before the water injection the large of the remaining oil and low‐containing water arethe key factors for the better effect of water injection for the oil.(3) Injection failure of the wells are two major categories：the one is that the oil aqueous interface is close to the location of the borehole, do not play the purpose ofwater injection to improve oil recovery after water injection, gas injection in thesewells can enhance oil recovery; the other is that these wells have no liquid production capacity, also do not play the purpose of water injection to improve oil recovery afterwater injection, these wells can take a large acid fracturing to communicate a goodfracture-cavity unit in the order to enhanced oil recovery.(4)The water injection in a well or wells of a multi-well fracture-cavity unitwhich has connectivity can add to the formation energy, so that per well can increaseproduction in the entire fracture-cavity unit. The effect of this injection is like a singlewell injection for oil, so the well which did not appear water breakthrough also willcontinue to produce the pure oil and increase production.