环江油田长2油层组低阻成因及识别新方法

Formation Causes and New Identifying Method of Low Resistance Oil Layer in Chang 2 Reservoir of Huanjiang Oilfield

鄂尔多斯盆地西南部的环江地区,延长组长2油层组的储层特征为中低孔、低渗型,具有比较低的含油饱和度,在测井响应中,油气产生的影响因子小,导致Rt/Ro<2.0,呈显典型得低阻油藏特征,这样就会造成通过电性资料来识别油气层的能力大大的降低了。研究认为,研究区油水重力分异作用、孔隙结构、岩石骨架粒度分布、黏土矿物含量较高导致的高束缚水饱和度是形成低阻油层的重要因素。通过对环江地区动、静态资料的分析,充分考虑该区低阻油层成因,提出适合该区的和测井新技术来识别低阻油层。

In Huanjiang area of Southwest Ordos basin, Chang 2 reservoir of Yanchang group is mainly low porosity and low permeability reservoir with low oil saturation, impact factor of oil and gas in the logging response is small, causing Rt/Ro〈 2.0, which is a typical low resistance characteristic, so the identification ability of oil and gas layer with the electrical data is greatly reduced. The research suggests that oil-water gravity differentiation, pore structure, rock skeleton particle size distribution, high irreducible water saturation caused by high content of clay minerals in the study area are important factors to form the low resistance oil layer. Through static and dynamic data analysis of Huanjiang area, fully considering the low resistance reservoir factors, new logging technology was put forward to identify the low resistivity layer in the area.