油井底水锥进与井筒积水特征对比分析及应用

CONTRAST ANALYSIS OF THE CHARACTERISTICS OF BOTTOM WATER CONING AND BOREHOLE HYDROCEPHALUS AND THEIR APPLICATIONS

塔河碳酸盐岩油藏缝洞发育、油水关系复杂、控水难度大，生产过程中部分油井出现井筒积水现象。由于井筒积水与底水锥进都会造成油井含水率上升，但二者控水方式截然不同，需加以区分。通过对比分析井筒积水与底水锥进的形成机理、表现特征（流压梯度、井底流压和生产动态）等方面的异同，明确了井筒积水是弱底水油藏的一类特殊的水体锥进现象。井筒积水呈井底流压正常下降、流压梯度上升，井筒流压梯度上升幅度底部大、顶部小；初期油压、含水率异常下降，后期含水率上升，放大油嘴直径后油压上升、含水率下降。底水锥进呈井底流压、流压梯度同时上升，井筒流压梯度均匀抬升；初期油压、产液量、含水率异常上升，下调油嘴直径后含水率有所下降。

It＇s difficult to control the water of the carbonate reservoir in Tahe 0ilfield, whose fissure caves are welldeveloped and the oil-water relation is very complex. And more serious, there are a certain wellbore hydrocephalus phenomena in the production process of partial oil wells. Although both bottom water coning and wellbore hydrocephalus can make the water cut of the wells rise, their water control＇s countermeasures are quite distinct, so they must be distinguished. Through the comparative analyses of the similarity and difference of the forming mechanism, performance characteristics （flowing pressure gradient, bottomhole flowing pressure and production performances） and so forth of the wellbore hydrocephalus and bottom water coning, it is clarified that the wellbore hydrocephalus is a special water coning phenomenon in weak bottom-water drive oil reservoir. The wellbore hydrocephalus is characterized by bottomhole flowing pressure drop, flowing pressure gradient ascent, and furthermore the increased magnitude of the bottom gradient is larger than that of the wellhead ; the oil pressure and water cut decrease abnormally at the early age, while the water cut rises at the late age of the wellbore hydrocephalus. After opening thenozzle, the oil pressure rises, but the water cut decreases on the contrary. The bottom water coning is featured by the simultaneous rise of bottom flowing pressure and flowing pressure gradient, in addition, the gradient of borehole flowing pressure rises evenly. Oil pressure, liquid production and water cut rise abnormally at the early age of the bottom water coning. After adjusting down the nozzle, the water cut decreases a little.