塔河奥陶系油藏沥青质沉淀形成机理研究

A studying on the formation mechanism of heavy hydrocarbon stemming in Ordovician Reservoir of Tahe oilfield

塔河缝洞型碳酸盐岩油藏储集体非均质性严重,流体充注的成藏过程中,早期稠油与后期轻质油在同一缝洞体内共存,开采过程中,先后有36口井因沥青质堵塞井筒无法生产。开展沥青质沉积机理研究,通过凝析油与稠油混合的沥青质沉积实验,结合典型井生产特征研究,确定了沥青质堵塞形成的主要原因是凝析油与稠油混合和井筒温度下降。该研究成果为井筒解除沥青质堵塞提供了理论基础。

Through the production performance analysis of well that the heavy hydrocarbon stemming have occurred in ordovician reservoir of Tahe oilfield,the distribution of stemming well is found,then the formation mechanism of heavy hydrocarbon stemming are initially deduced,and the mechanism is verified by laboratory experiments.The flocculation point tests are implemented for the first time by using the condensate oil and heavy oil from the same reservoir.The results shown that the asphalt flocculation point of mixed oil is at 55% of mass ratio of condensate oil under experiment condition;the main cause of formation stemming is the mixture of heavy oil and condensate oil inTahe oilfield.Understanding the mechanism,there can be some benefit for the oilfield production.