松辽盆地中央古隆起带南部酸性侵入岩储层特征与主控因素

Reservoir characteristics and main controlling factors of acid intrusive rocks in southern part of central paleo-uplift belt,Songliao Basin

通过岩芯观察、薄片鉴定、孔渗分析和测井解释等方法,对松辽盆地中央古隆起带南部基底酸性侵入岩类储层特征及优质储层主控因素进行研究。结果表明,松辽盆地中央古隆起带南部基底酸性侵入岩主要为花岗闪长岩(富铝)与二长花岗岩,储集空间以裂缝和溶蚀孔为主,平均孔隙度为3.46%,平均渗透率为0.52×10^(-3)μm^(2)。优质储层主控因素包括岩性、矿物组合与风化壳结构发育特征,基底岩性及矿物组成是松辽盆地基岩优质储层发育的内在因素,风化淋滤作用对基岩储层的改造是外在因素。基底储层的风化壳结构分为3层,风化淋滤带为最有利的储集部位,裂缝发育带储层非均质性较强,风化堆积层与内幕段没有储集能力。

Based on the observation of cores and thin sections indentification,porosity and permeability analysis,and logging interpretation,the authors studied the reservoir characteristics and main controlling factors of high-quality reservoirs of basement acid intrusive rocks in the southern part of the central paleo-uplift of the Songliao Basin.The results show that the basement acid intrusive rocks in the Songliao Basin are mainly granodiorite(aluminum-rich)and monzongranite.The reservoir space is dominated by fractures and dissolved pores,with an average porosity of 3.46%and an average permeability of 0.52×10^(-3)μm^(2).The main controlling factors of high-quality reservoirs of basement acid intrusive rocks include the lithology,mineral assemblage and development characteristics of weathering crust structure.The basement lithology and mineral composition are the internal factors for the development of high-quality reservoirs of basement in the Songliao Basin,while the transformation of basement reservoirs by weathering and leaching is the external factor.The weathering crust structure of the basement reservoirs can be divided into three parts.The weathered leaching zone is the most favorable reservoir location,the fracture zone is relatively heterogeneous,and the weathered accumulation layer and insider segment have no storage capacity.