松辽盆地长岭断陷东部营城组火山岩储层特征

摘要

Explorations of volcanic reservoir have achieved great success in the east of the Changling Fault Depression of the Songliao Basin in the past few years. Gas is found in the Yingcheng Formation in many wells. Volcanic reservoir is the key for natural gas accumulation. Based on core, logging and testing data, volcanic reservoir was analyzed from origin and evaluated. Due to low porosity and permeability, pores and fractures are well connected in volcanic rock, providing relatively good condition for accumulation. Especially in rhyolite and tuff, there exist multiple types of pores and fractures, including both primary ones generated during diagenetic stage and secondary ones transformed by later slacking.Reservoir parameters are closely related to rock density, rather than burial depth. Different volcanic facies have different reservoir condition due to different composition. The overflow and outbreak phases are favorable for reservoir formation. Besides, weather-worn may influence reservoir formation. Unconformities are also beneficial for reservoir formation.%近年来,长岭断陷东部进行火山岩领域油气勘探取得了重大成果,多口井钻遇营城组气层,研究发现火山岩有利储层是天然气成藏的主控因素.通过取心、测井、测试等资料对火山岩储层进行成因分析和综合评价,认为火山岩为低孔低渗储层,孔与缝连通性好,具有一定的储集条件.其中,流纹岩和凝灰岩广泛发育多种孔隙和裂缝,既有喷发阶段形成的原生孔隙,也有后期风化改造的次生孔隙;储层物性不随埋藏深度的增加而变小,而与岩石密度密切相关,不同的火山岩相,成分不同,储集空间存在较大差异,溢流相、爆发相火山岩是形成有利储层的重要部位.另外,风化剥蚀对储集条件影响较大,不整合面分布区也是有利储集区.