砂砾岩潜山边底水复合油藏见水特征分析

ANALYSIS ON WATER BREAKTHROUGH CHARACTERISTICS OF EDGE BOTTOM WATER COMPOSITE RESERVOIR IN GLUTENITE BURIED HILL

渤海X油田由古近系东二段底部的孔隙型砂砾岩储层和太古界潜山基岩储层构成。潜山储层特征非常复杂,下部底水能量活跃,储集空间类型有孔隙、溶洞、裂缝三种。采用水油比导数图版判别法、见水特征无因次判别法、数值模拟法综合分析了油田水平井见水特征。油井见水特征为潜山裂缝沟通底水快速锥进,且含水率随潜山裂缝储量的增加而减小,拟合敏感性分析结果表明X油田潜山裂缝储量较小。油井压力波及至潜山后,潜山裂缝储量快速采出,并沟通底水,引起含水快速上升。对于这类裂缝性底水油藏,生产压差应控制在0.5MPa以内,油井高含水后适当关井压锥可以取到较好的效果。研究成果对于类似油藏合理开发具有一定的指导意义。

The X oilfield in Bohai Sea is composed of porous glutenite reservoir and Archean buried hill bedrock reservoir.The characteristics of buried hill reservoir are very complex.The energy of bottom water in the lower part is active.There are three types of reservoir space:pore,karst cave and fracture.The water breakthrough characteristics of horizontal wells in oil⁃field are comprehensively analyzed by means of water oil ratio derivative plate discrimination method,dimensionless water breakthrough feature discrimination method and numerical simulation method.The water breakthrough characteristics of oil wells are that the fractures of buried hill connect with the bottom water rapidly,and the water cut decreases with the increase of fracture reserves in buried hill.The results of fitting sensitivity analysis show that the fracture reserves of buried hill in X oilfield are small.After the oil well pressure reaches the buried hill,the fracture reserves in the buried hill are rapidly pro⁃duced,and the bottom water is communicated,resulting in the rapid rise of water cut.For this kind of fractured bottom water reservoir,the production pressure difference should be controlled within 0.5MPa.After the oil well has high water cut,proper shut in and pressure cone can achieve good results.The research results have certain guiding significance for the reasonable development of similar reservoirs.