塔中北斜坡富油气区油气分布规律与富集主控因素研究

Research on hydrocarbon distribution regularity and main accumulation controlling factors of Tazhong northern slope hydrocarbon-rich region

塔里木盆地塔中北斜坡奥陶系油气藏类型多样、油气性质变化大、油气水分布复杂。通过对塔中北斜坡大量单井及其生产动态的分析解剖,结合分析化验资料,深入探讨了富油气区的流体分布特征、断裂发育特征、储层差异性以及典型高产井和出水井的对比,揭示了油气分布规律与控制因素。鹰山组顶部的风化壳型不整合面在垂向上控制了储层的发育深度范围和储层质量;平面上储层的非均质性是导致油气分布差异的重要原因。断裂引起的局部高差对流体聚集存在明显影响,使断裂上盘高部位更倾向于富油气,并发现断裂对储层改造强烈,特别是走滑断裂作为油气运移通道对油气分布具有重要的控制作用,决定了不同区域的古油藏在晚喜山期遭受气侵的强度,控制了不同相态油气藏的分布;奥陶系鹰山组上部发育的致密段对古油藏的保存具有积极的作用。该认识对相似地区碳酸盐岩油气富集规律研究及勘探开发具重要的参考价值。

In the northern slope of Tazhong in Tarim Basin,Ordovician is the main hydrocarbon exploration target,and many hydrocarbon reservoirs have been discovered in this horizon.There are multiple reservoir types in this area,with complicated oil/gas/water distribution and various oil/gas characteristics.By analyzing mass wells＇production performances as well as testing data and discussing the distribution of fluids,faults,reservoir and high capacity or water wells,the oil/gas distribution regularity and its main controlling factors were revealed.The weathered crust unconformity developed in the top of O1 ycontrolled the reservoir depth and reservoir thickness vertically;the horizontal inhomogeneity of the reservoir was the important reason for the oil/gas differential distribution. Height difference caused by fault had apparent impact on fluid accumulation,and structural high in the upside was more apt to oil/gas accumulation;the faults have seriously reformed the reservoirs,and the strike-slip faults as the migration pathway had obvious control action on oil/gas distribution especially,which decided the gas cutting intensity of different fossil reservoirs in the late Himalayan and the different phase reservoirs＇distribution.The tight-layer located in the upper part of O1 y was significant for the fossil reservoirs＇preservation.This study will serve as an important reference to the hydrocarbon accumulation regularity research and exploratory development in the similar carbonate region.