Study On Oil-water Relationship Of Ordovician Reservoir In Block12of Tahe Oilfield

The fracture-cavity reservoir is the main reservoir of Ordovician inTahe Oilfield, and the pressure systems and the relationship between oiland water in different reservoirs are different, It’s difficult to reflect thecharacteristics of oil reservoir with oil-water distribution model of thefracture-cavity unit. The main research object is fracture-cavity reservoirof Ordovician in Block12of Tahe Oilfield in this paper. The oil andwater distribution and its main controlling factors is speculated bylogging, drilling, seismic, logging and testing data, base onunderstanding of reservoir geology and development dynamiccharacteristics. The Main achievements have been got as following:(1) The sources of the water body in the water breakthrough wellinclude the leakage fluid and the acid fracturing fluid remained, relicwater. Judge the truth of stratum water, to eliminate the influence by construction work on understanding of the distribution of oil and water.(2) The heterogeneity of the reservoir of Ordovician system isserious, and connectivity between reservoir of well in the samefracture-cavity unit is poor. Oil and water are universal coexistence inthe same fracture-cavity unit, in line with the law of “The oil’s elevationposition is higher than water’s “. Nether the whole area nor thefracture-cavity unit don’t have the uniform oil-water interface.(3) The types of producing water of developing well are mainlyincluded quick rising, slow rising, and degree with the enrichment of oil:The water’s producing time of high-yielding wells is later, watercontaining rate of the most rises slowly, and a few rises fast in laterdeveloped time. And most of the stripper well, is behaved for producingwater in early time, and the water containing rate rises fast, cause byacid fracturing treatment.(4) Karstification is important for development degree and range ofreservoir.(5) Due to the influence of tectonic movement, the karst in the eastof study area is most serious, the west gradually weak. So thedevelopment degree of the fracture-cavity reservoir in the east is betterthan the west.(6) The development degree of reservoir near Fault belt and largerfault zone, is good and easy to connective, is the area of crude oil enrichment; reservoir which is far away from the fault zone or in thearea where only small fault zone development, is poorer, and crude oilfilled poorly, and water breakthrough easily, cause by acid fracturingtreatment.