渤海Q29-2油田沙河街组复杂岩性储层有效性评价及物性下限值确定

Effectiveness evaluation and physical property lower limit values determination of complex lithology reservoirs of Shahejie Formation in Bohai Q29-2 oilfield

渤海Q29-2油田古近系沙河街组发育厚层碳酸盐岩和砂砾岩混合沉积的低孔渗复杂岩性储层,储层岩性及物性变化快,非均质性强,储层有效性评价和物性下限值确定是测井评价的重点及难点。利用Pe曲线指示法和孔隙频谱分析法定性评价了该油田沙河街组复杂岩性储层有效性,丰富了低孔低渗复杂岩性储层的有效性评价方法。利用毛管压力法和核磁共振实验法综合确定了该油田沙河街组复杂岩性储层物性下限值,其中孔隙度下限为9%,渗透率下限为0.4 mD。本文成果突破了渤海油田古近系沙河街组储层物性下限的传统认识,可以解放该地区大量油层,为Q29-2油田储量评价提供了关键技术支撑。

Thick bedded complex lithology reservoirs with mixed deposition of carbonatite and glutenite develop in Paleogene Shahejie Formation of Bohai Q29-2 oilfield, which is low porosity and low permeability reservoir with characteristics of strong heterogeneity, fast change of lithology and physical properties. Effectiveness e-valuation and physical property lower limit values determination of the complex lithology reservoirs are the key and difficult points for logging evaluation. Pe curve indicating method and electric imaging pore spectrum anal-ysis are used to qualitatively evaluate the effectiveness of Shahejie Formation, enriching the evaluation methods of the low porosity and low permeability complex lithologic reservoirs. Capillary pressure method and nuclear magnetic resonance experiment method are used to determine the physical property lower limit values for Sha-hejie Formation in the oilfield, in which the porosity lower limit value is 9% , and the permeability lower limit is 0. 4 mD. The research results break through the traditional opinion on physical property lower limit values of Shahejie Formation of the Bohai sea, releasing a large amount of oil reservoirs in this area. The study pro-vides key technology support for reserves evaluation of Q29-2 oilfield.