杨家坝油田裂缝发育规律及对开发效果的影响

杨家坝油田砂岩储层裂缝以水平缝和低角度倾斜缝为主,裂缝发育密度受岩性、厚度和构造位置影响明显。粉砂岩中裂缝密度最大,薄砂层中裂缝密度大于厚砂层,边界断层对裂缝的形成具有控制作用。靠边界断层附近,裂缝密度高,沿鼻状构造轴部裂缝密度大于翼部。结合动态资料分析了裂缝对开发效果的影响:裂缝的存在提高了油层的产量,但边水和注入水突进严重,含水率上升速度快,导致油藏采收率低;薄砂层裂缝发育,水淹严重;杨家坝油田开发后期的挖掘潜力仍在厚油层上。

Fracture distribution and its influences on the development of Yangjiaba oilfield

Fractures of sandstone reservoir are chiefly horizontal fractures and dipping fractures of low angle in Yangjiaba Oilfield. Fracture density is obviously influenced by lithology, thickness and structural location. Fracture density in siltstone is higher than other lithology. There is higher fracture density in thin sand than thick sand. Fracture formation is controlled by boarder fault. The result shows that Fracture distribution density is high nearby boarder fault and on the axis of structural nose than the alar part. Combined with the dynamic documents, influences of fractures on development effect are analyzed. Because of fractures, oil layer production is high, but edge and injection water invade seriously , escalating rate of water cut is rapid and recovery factor is low. As a result, fracture developed in thin sand, and serious water flood, the potential tapping is still in thick oil layers for the later stage of Yangjiaba oilfield development.