华庆油田长6致密油藏油水分布特征与成因分析

Characteristics of oil-water distribution in tight Chang6 oil reservoir of Huaqing oilfield and cause of formation analysis

鄂尔多斯盆地华庆地区长6主要发育大型岩性油藏，在分析油藏特征的基础上．评价了产水井分布和地层水化学特征等因素，探讨了致密储层产水成因。华庆油田生储配置组合条件优越，油层纵向厚度大，横向连续性好．储层物性致密，平均孔隙度分布在8％～14％，平均渗透率为0．1～0．5mD，属中低孔特低渗储层，具有较强的非均质性。长6油藏范围内砂岩储层分布稳定，试油以产纯油为主，少数井试油产水，产水层为局部孤立团块状分布，地层水的水型为氯化钙型原生滞留弱酸性水，钠氯系数主要分布在0．49～0．58，地下水处于相对封闭的还原环境，油藏整体保存奈件有利。从储层非均质性、成藏致密史、产水类型和构造条件等方面分析了产水的成因，非均质性影响了储层含油及含水性，微细喉道和隔夹层越发育，储层渗透率越低．可能残存原生地层水越多；储层致密演化和充注成藏同时进行又相互影响，增强了油水赋存关系的复杂性：岩性油藏经历了差异聚集的成藏过程，储层产水主要有透镜状致密储层含水、油层与水层叠合分布、充注不饱满3种类型；构造变化对油水分布影响较小。

Ordos Basin Huaqing Chang 6 layer mainly developed large reservoir lithology, reservoir characteristics on the basis of the analysis on the evaluation of the distribution and chemical characteristics of formation water production wells, and other factors discussed tight reservoir water pro- duction reasons. Huaqing oil-reservoir configuration combinations favorable conditions, a large oil portrait thickness, lateral continuity is good, tight reservoir properties, with an average porosity distribution of 8 to 14 percent, with an average penetration rate 0.1 - 0.5roD, belong to the low porosity and low permeability reservoir characteristics layer, with a strong heterogeneity. Long range within 6 reservoir sandstone reservoir distribution stability test oil to produce pure oil, but a few test oil wells producing water, the water layer is locally produced isolated lumpy distribution of formation water is calcium chloride type water-native slightly acidic water retention, sodium chlorine coefficient mainly in the 0.49 to 0.58, the reduction of gruund- water in a relatively closed environment, favorable overall reservoir storage conditions. From the reservoir heterogeneity, dense accumulation history, aspects of water production conditions, the type and structure analysis of the causes of water production. Reservoir heterogeneity affect oil and mois- ture resistance. Fine throat and interlayers more development, the lower reservoir permeability, possibly remnants of native formation water more; dense reservoir evolution and reservoir filling and mutual influence simultaneously enhances the complexity of the relationship between the occurrence of oil and water; lithology Reservoir experienced a difference accumulation process aggregation. There are lenticular reservoirs produced water tight reservoir water, oil and water distribution stacked together, not full filling throe types; structural changes in the distribution of water less affected.