新疆风城油田SAGD井挤液扩容效果影响因素评价

Evaluation of the Influencing Factors of Dilatancy Effects by Squeezing Liquids in SAGD Wells in the Fengcheng Oilfield of Xinjiang Oilfield

新疆风城油田陆相稠油油藏主要采用蒸汽辅助重力泄油(SAGD)方式开采,但由于储层非均质性强、渗透率低,导致SAGD井预热周期长,使得蒸汽成本高,产出液处理困难,为此,提出了SAGD井挤液扩容储层改造技术和改造效果预测方法,分析了岩石物理性质、油藏几何参数和挤液施工排量等3类因素对扩容效果(表征为连通系数)的影响;并在这3类因素作用的92个有限元算例的基础上,建立了快速预测SAGD井挤液扩容连通系数的快速分析图版。风城油田3口SAGD井应用图版预测了连通系数,结果表明,预热周期的缩短幅度与连通系数呈较好的正相关性。研究认为,连通系数预测图版为现场施工时优化挤液压力和排量、进一步缩短SAGD井的预热周期提供了一种高效快捷的评价方法。

Steam assisted gravity drainage(SAGD)has been widely used in the exploitation of onshore heavy oil reservoirs in the Fengcheng Oilfield of Xinjiang Oilfield.However,due to high heterogeneity and low permeability of reservoirs,the preheating period of SAGD wells is long,resulting in high steam costs,making it difficult to treat the production fluids.Hence,the relative technologies have been put forward,including squeezing fluid and dilatancy in SAGD wells,and the reservoir stimulation prediction method.The three influencing factors on dilatancy effect(characterized as connectivity coefficient)were analyzed,i.e.petrophysical properties,reservoir geometric parameters and injection flow rate.Based on92finite element examples under the above three factors,an evaluation method for immediate prediction of injection and dilatancy effects in SAGD wells was proposed.The application of connectivity coefficient prediction chart in three SAGD wells in the Fengcheng Oilfield indicated that the shortening amplitude of the preheating period had a good positive correlation with the connectivity coefficient.The connectivity coefficient prediction chart has provided an efficient and rapid evaluation method for optimizing the injection pressure and flow rate and shortening the preheating period of SAGD wells in field operation.