准噶尔盆地陆西地区石南13井区侏罗系三工河组砂体结构及控藏作用

Sand-body structure and reservoir forming control of Jurassic Sangonghe Formation in Well Block Shinan 13,Luxi area,Junggar Basin

准噶尔盆地陆西地区侏罗系三工河组油气成藏条件优越,是非常有利的勘探区带。通过岩心观察、粒度分析和单井相分析等,明确了石南13井区三工河组二段二亚段一砂组(J1s22-1)为多期叠置的三角洲前缘水下分流河道砂体。J1s22-1砂组具有2类砂体结构单元,分别为水下分流主河道结构单元和水下分流河道侧翼结构单元,前者自底向顶砂岩粒度变粗、单期砂体厚度变大、物性越来越好,后者自底向顶砂岩粒度变细、单期砂体变薄、物性变差。精细油藏解剖和失利井分析表明,水下分流主河道结构单元顶部砂体的储集性能远远好于侧翼结构单元顶部砂体的储集性能,这一因素是控制石南13井区油气藏的关键。基于高精度三维地震资料,综合地震属性研究和单井相分析,刻画了水下分流主河道砂体的发育区,论证并部署了和8预探井。在和8井目的层的试油中获得了产量8.29t/d的工业油流。钻探结果与预测一致证实了地质认识的正确性,揭开了陆西地区三工河组油气勘探的新局面。

The Jurassic Sangonghe Formation in Luxi area of Junggar Basin has predominant hydrocarbon accumulation conditions as a favorable exploration area.Based on well core observation,grain-size analysis and single-well facies analysis,the J1 s22-1 of Sangognhe Formation in Well Block 13 is determined as underwater distributary channel sand body at the multiphase superimposed delta front.There are two kinds of sand-body structure units in this area.The first is underwater distributary main-channel structure,where the sand grain size becomes larger,single-phase sand body becomes thicker and physical properties become better from bottom to top.The second is underwater distributary channel flank structure,where the sand grain size becomes smaller,single-phase sand body becomes thinner and physical properties become worse from bottom to top.Through the fine analyses of reservoirs and failure wells,the first structure has better reserving property than the top sand body of the second one.This is the key of controlling the hydrocarbon reservoirs in Well Block Shinan13.Based on high-precision3 D seismic data,seismic attribution research and single-well facies analysis,this study presents the development area of underwater distributary main-channel sand body,and has validated and deployed the exploratory well He 8.The commercial oil flow of 8.29 t/d was obtained through the pilot oil production of target layer in Well He 8.This drilling result is consistent with the prediction,thus proving the correct geological knowledge and revealing new exploration prospects of Sangonghe Formation in Luxi area.