贝尔凹陷苏德尔特构造带南屯组火山碎屑沉积岩储层特征及成岩作用研究

Characteristics and diagenesis of the volcaniclastic rock reservoirs from the Nantun Formation within the Sudert structural zone in the Buir depression

关键词:  火山碎屑沉积岩  苏德尔特构造带  南屯组一段  储层特征  成岩作用

Key words:  volcaniclastic rock  Sudert structural belt  first member of the Nantun Formation  hydrocarbon reservoirs  diagenesis

摘要:

贝尔凹陷苏德尔特构造带南屯组一段Ⅰ-Ⅳ油组为火山碎屑沉积岩储层,岩性为凝灰质砂砾岩、凝灰质砂岩、含凝灰泥岩和沉凝灰岩。该含油层段的储层物性与埋深没有直接关系。凝灰质颗粒大小对储层物性影响很大。I油组凝灰质砂砾岩以中-高孔、低渗-特低渗为主;Ⅱ、Ⅲ油组凝灰质砂岩以中-低孔、特低渗-超低渗为主;Ⅳ油组含凝灰泥岩以低孔隙度、特低渗-超低渗为主。凝灰质砂砾岩、凝灰质砂岩、含凝灰泥岩的主要成岩作用为压实作用、胶结作用和重结晶作用。压实作用和胶结作用是使储层孔隙变小、物性变差的因素;矿物的多形转变作用产生脱玻化孔,有助于微小喉道的发育。

Abstract:

The oil measures I to IV in the first member of the Nantun Formation in the Sudert structural belt, Buir depression are made up of the volcaniclastic rock reservoirs including tuffaceous sandstone and conglomerate, tuffaceous sandstone, tuffaceous mudstone and sedimentary tuff. The contents and grain sizes of tuff have consequences for the porosity and permeability of the hydrocarbon reservoirs. The tuffaceous sandstone and conglomerate from the oil measures I have moderate to high porosity and low to extra-low permeability. The tuffaceous sandstones from the oil measures II and III have moderate to low porosity and extra-low to ultra-low permeability. The tuffaceous mudstones from the oil measures IV have low porosity and extra-low to ultra-low permeability. The diagenesis of the above-mentioned tuffaceous sandstone and conglomerate, tuffaceous sandstone and tuffaceous mudstone include compaction, cementation and recrystallizaion, of which the former two act as the key factors resulting in the production of poor porosity and permeability. The devitrification pores caused by the polymorphic phase transition of minerals may facilitate to the development of the micropore throats.