塔河油田S48缝洞单元流体分布及开发动态响应

Fluid distribution and dynamic responses to exploitation in fracture-cave unit S48 in Tahe Oilfield

为了研究塔河油田奥陶系油藏缝洞单元内不同部位油井出水特征与开发动态,以S48缝洞单元为例,分析了缝洞单元主体洞穴、分支洞穴及古岩溶低洼区油井产能及水化学动态特征.主体洞穴井投产初期产能较高,稳产期较长,见水后含水上升较慢,产出水矿化度一般呈现平稳、波动或上升;分支洞穴井投产初期产能较低,稳产期较短,见水后压力及产能下降较快,产出水矿化度一般呈现波动或平稳后缓慢下降;古岩溶低洼区域井产能低,稳产期很短,产量递减快,含水率较高,产出水矿化度一般呈现波动中较大幅度下降.研究结果为塔河油田油井开发方案的制定提供了指导性建议.

To investigate the variation in water-yield and oil well performance related to the cave system in the Ordovician reservoir of Tahe Oilfield, the well productivity and hydrochemical characteristics were analyzed for the main cave, branch cave, and the paleo-karst depression zone, taking fracture-cave unit S48 as an example. Wells in the main cave had high initial yield and long stable production period. The water content increased slowly and the salinity of the produced water usually remained eventually unchanged, sometimes fluctuanting or even rising,after the water breakthrough. Wells in the branch cave had relatively low initial yield and short stable production period. Water broke through quickly and then the pressure and flow potential dropped quickly while the salinity usually fluctuated or dropped slowly. Wells in paleo-karst depression zone had low productivity and short stable production period. The yield dropped quickly and the water content was high. The salinity usually fluctuated with a precipitous decline. The results of this study provided valuable insight guide for designing the exploration plan of the Tahe Oilfield.