基于高压压汞和核磁共振的致密砂岩渗透率预测

Prediction of tight sandstone permeability based on high-pressure mercury intrusion(HPMI)and nuclear magnetic resonance(NMR)

分析影响致密砂岩渗透率的主控因素并准确预测致密砂岩渗透率对致密油气藏的开发具有重要意义。以鄂尔多斯盆地延长组致密砂岩为研究对象,基于高压压汞和核磁共振对致密砂岩渗透率主控因素进行了研究,分别评价并优选了更适用于致密砂岩的基于高压压汞和核磁共振的渗透率预测模型。结果表明:影响致密砂岩渗透率的主要因素是孔喉半径,其中中值孔喉半径与致密砂岩渗透率相关性最强;与核磁共振T2加权平均值相比,T2几何均值与致密砂岩渗透率的相关性更强;在3种不同的核磁共振渗透率预测模型中,SDR-REV模型的预测效果要优于SDR模型和KCT2w模型;在3种不同的高压压汞渗透率预测模型中,基于r40和r45的Winland模型渗透率预测精度较高。研究成果对鄂尔多斯盆地延长组致密砂岩的进一步有效开发具有指导意义。

It is of great significance for the development of tight oil and gas reservoir to analyze the main factors affecting the permeability of tight sandstone and accurately predict the permeability of tight sandstone.Taking the tight sandstone from Yanchang Formation in Ordos Basin as the research subject,the main controlling factors of tight sandstone permeability were studied based on high-pressure mercury intrusion(HPMI)and nuclear magnetic resonance(NMR).The permeability prediction models based on NMR and HPMI were evaluated and optimized respectively.The results show that pore-throat size is the main factor affecting tight sandstone permeability,and the median pore-throat radius size has strongest correlation with tight sandstone permeability.Compared with NMR weighted average T2,geometric mean T2 has stronger correlation with tight sandstone permeability.Among the three different NMR permeability prediction models,SDR-REV model has better permeability prediction results compared with SDR model and KCT2 w model.Among the three different HPMI permeability prediction models,the Winland model based on r40 and r45 has the highest permeability prediction results.The research results have guiding significance for the further effective development of tight sandstones of Yanchang Formation in Ordos Basin.