冷东地区下干柴沟组上段沉积储层特征研究

Sedimentary facies and reservoir characteristics of upper reservoir of lower Gangchaigou formation in eastern Lenghu region

综合运用重矿物、岩心、测录井及物性资料,对冷东地区浅层下干柴沟组上段沉积储层特征进行了研究。结果表明该区沉积期离物源距离较近,发育辫状河三角洲平原沉积,砂岩类型以长石岩屑砂岩和岩屑长石砂岩为主,成分和结构成熟度较低。储层孔隙类型主要为残余原生粒间孔,碎屑的粒径大小与孔渗高低呈正相关性。根据储层分类标准,将研究区储层从优至劣分为三类,大部分为Ⅱ类和Ⅲ类储层,孔隙度和渗透率较低,属于中低孔—低渗储层,且非均质性较强。研究区储层物性与沉积时的水动力强度有关,优质储层主要分布于辫状河三角洲平原分流河道较厚的砂体中。

Based on the data of the heavy mineral, core, logging and physical, we studied the sedimentary microfacie reservoirs＇ characteristics of the upper reservoir of the lower Gangchaigou formation in eastern Lenghu region. The results show that during the deposition period, the area is close to the source, and the developed raided river delta plain, sandstone type is mainly composed of feldspar lithic sandstone and lithic feldspar sandstone, and its composition and structure maturity are low. The main pore types of the reservoir are the residual intergranular pores, and the grain size is positively correlated with the porosity and permeability. According to the reservoir classification standard, the reservoir area is divided into three types, most of which not only belong to reservoir Ⅱ and Ⅲ with low porosity and permeability, but also belong to medium and low porosity-low permeability reservoirs with strong heterogeneity. The physical properties of reservoirs in the study area are related to the hydrodynamic forces at the time of the sedimentation. The high quality reservoirs are mainly distributed in thick sand bodies with braided river delta distributions.