赵凹油田泌304区块低阻油层成因分析及识别研究

Study on genesis and identification of low-resistance oil layer at B304 block in Zhaoao oilfield

赵凹油田泌304块位于泌阳凹陷陡坡带中段,北部紧邻深凹生油区,储层主要为凹陷南部扇三角洲沉积,岩性复杂。同时由于构造幅度较小,油水过渡带较宽,造成近1/3油层出现电阻率低于或相当于水层电阻率的特点,从而给测井解释上识别油层造成困难。从构造、储层物性、流体性质等方面分析了形成这种特征的本质原因,综合研究该区块储层"四性"特征,建立了低阻油层测井识别标准,大大提高了低阻油层的测井符合率。

B304 block of Zhaoao oilfield,located in the middle slope of Biyang depression,is adjacent to the deep depression where source rocks are abundant.The reservoir is the deposit of fan delta from the south depression with a complex lithology.The minute structure extent and the wide oil-water transitional zone bring about 1/3 oil layers low resistance or the resistance equal to that of water layer,thus generating difficulty to identify oil layer.The reasons are analyzed from the structure,the physical properties of reservoir.By synthetically analyzing the four features as lithology,electric property,physical property and oil-bearing character,the standard to identify the low-resistance oil layer is established, thus highly enhancing the coincidence ratio of lowresistance oil layer by logging interpretation.