海拉尔盆地贝尔凹陷轻质油层录井综合识别与评价

海拉尔盆地贝尔凹陷的油层主要为轻质原油(轻油)层。含轻油砂岩岩心颜色浅，具较浓油气味，普照浅黄色，二次观察含油颜色不明显，油气味变淡或消失，二次荧光普照无荧光颜色。轻油密度范围为0.79～0.82 g/cm³，粘度为1.60～5.40 mPa·s。轻油全烃最大值一般大于0.50%，比值大于3.0。热解分析总烃含量值大于2.00 mg/g，原油轻重指数为2～6。轻油气相色谱分析反映碳数分布范围为nC₈-nC₂₅、主峰碳数为nC₁₈-nC₂₀，进行二次气相色谱分析，色谱呈直线形态。利用单位重量储层的含油量与有效孔隙度交汇图版可识别出油层、油水同层、水层；将原油轻重组分指数与原油的密度、粘度进行回归分析，建立原油类型判别标准及图版，实现轻油层及稠油层的判别。根据静态产能指数和动态产能指数识别高产、工业、低产和偏干4类油层，预测符合率大于90%。

In-situ Recognition and Evaluation of Mud Log for Light Oil Bed,A Successful Case in Beier Depression of Hailaer Basin

Most of the oil found up to now belong to light oil bed in Beier depression of Hailaer Basin. The fresh light oil-bearing core sections of sandstones show light colour, strong odour, yellowish fluorescence. But the colour, odour and fluorescence will lost after exposed sometimes. The density range of light oil is 0.79-0.82 g/cm³. The range of viscosity is 1.60-5.40 mPa·s. Max value of total hydrocarbon is more than 0.50%, and the ratio is more than 3.0. Total pyrolysis hydrocarbon is more than 2.00 mg/g. The ratio of lighter hydrocarbon to heavier hydrocarbon is from 2 to 6. Gas chromatography of light oil shows the range of carbon number is from nC₈ to nC₂₅ and the main peak carbon is nC₁₈-nC₂₀. The chromatography changes into line after oil exposed sometimes. Oil bed, oil-water bed and water bed were identified by using crossplot of specific oil content versus effective porosity. Standard and crossplot of oil type differentiation were formed base on regression analysis among index of PS, density and viscosity. The light oil bed and heavy oil bed were differentiated according to this standard. High productivity oil bed, industry oil bed, low production oil bed and dry bed were identified according to static productivity index and dynamic productivity index. The prediction accuracy was more than 90% with this method.