吴起地区谷104区长631油藏储层低产原因分析

Analysis of Cause of low-yielding of Chang631 reservoirs in Gu104 area of Wuqi region

针对吴起地区谷104区长631储层初期产能较低及目前见水规律复杂等特点，在对储层物性及沉积微相等地质因素分析的基础上．运用层次分析法定量计算了储层各项参数对油井产能的影响权重。结果表明：①沉积微相及储层物性是研究区储层低产低效的主要原因。沉积微相对研究区储层控制作用明显，水下分流河道为研究区主要的沉积微相；研究区由南到北、由东向西，储层物性逐渐变差，且储层渗透率、孔隙度与初期产能分布对应关系良好。②研究区储层非均质性整体较强，储层变异系数与现阶段单井含水有一定正相关关系，裂缝型、裂缝一孔隙型见水井基本都分布在变异系数大于0．6的北部区域。③层次分析法定量计算认为：储层渗透率、启动压力梯度以及孔隙度权重较高，表明其对油藏产能影响较大。渗透率和孔隙度越大．相应产能越大，两者成正相关关系；启动压力梯度越大，相应单井产能越小．两者呈负相关关系。

In the light of features such as low initial productivity of Chang631reservoir in Gu104 area of Wuqi region, and the complex law of injected water response at present, on the basis of analysis of geological factors of reservoir properties and sedimentary miemfaeies, the impact weights of reservoir parameters on the well productivity are quantitatively calculated by using analytic hierarchy process （AHP）. The results showed that： （1） sedimentary miernfaeies and reservoir properties are the main reasons for inefficient and low yield of the study area. The sedimentary mic, rnfaeies has an obvious control over the reservoirs of the study area. Underwater distribu- tary channel is the main microfaeies of the study area. From south to north and from east to west of the study area, the reservoir properties gradually deteriorate. Permeability and porosity of tile reservoirs have good correspondence with the distribution of initial produetion capacity; （2） reservoir heterogeneity in the study area as a whole is strong. The c, oeffieient of reservoir variation has a certain positive eorrelation with single-well＇s water cut at the current stage. Fissure and fissure-pore types of response wells are basically located in the northern region with variation coefficient of greater than 0.6; （3） quantitative calculation with AHP shows that： high weights of reservoir permeability, porosity, and starting pressure gradient indicate a great impact on reservoir production capacity. The greater the permeability and porosity, the larger the corresponding capacity, being a positive correlation. The greater the starting pres- sure gradient, the smaller the corresponding individual well productivity, being a negative correlation.