西峰油田庄36井区长81储层特征及评价

针对西峰油田庄36井区面临单井产量下降和含水上升较快的问题,应用测井资料、岩石薄片、扫描电镜、X衍射、粒度分析、压汞测定等资料,对长81储层的岩石学特征、物性特征和孔喉特征等进行了深入分析。结果表明:庄36井区长81储层属低孔—特低孔、特低渗—超低渗储层,岩性主要为细粒岩屑长石砂岩,发育粒间孔和溶蚀孔,孔喉结构类型属小孔隙、微细喉道型,其储层物性主要受沉积作用和成岩作用的共同影响,造成水下分流河道和河口砂坝物性明显好于河道侧翼。根据储层物性和孔隙结构参数,将研究区储层分为4类,即Ⅰ类储层为好储层、Ⅱ类储层为较好储层、Ⅲ类储层为较差储层、Ⅳ类储层为差储层。研究区含水上升井主要分布在Ⅲ类和Ⅳ类储层中,Ⅰ类储层的单井产量高且稳产,分类结果符合实际。

Characteristics and evaluation of Chang 81 reservoir of Zhuang 36 well area in Xifeng Oilfield

In view of the problems of the oil yield decline and the rapid water saturation in single well of Zhuang 36 well area in Xifeng Oilfield, Ordos Basin, the logging data, rock section, scanning electronic microscope, X diffraction, grain size analysis and mercury penetration were used to analyze the lithology characteristics, physical properties, pore throat of Chang 81 reservoir. The result shows that Chang 81 reservoir belongs to low-ultra low porosity and low-ultra low permeability reservoir; the main sandstone is fine-grained lithic arkose; the reservoir mainly developed intergranular pore and dissolved pores; the pore throat structure is the type of small pore and micro throat. Sedimentation and diagenesis have impacted on the reservoir properties together, which leads that the physical properties of subsea distributary channel and mouth bar were better than that of channel frank. According to the physical properties and pore strueture paramelers, the reservoir in the study area can be divided into four types. The type Ⅰ belongs to the best reservoirs, The type Ⅱ belongs to the good, lhe type Ⅲ belongs to the bad and the lype Ⅳ belongs to the worsl. The water produciug wells mainly distributed in lhe reservoirs of the type Ⅳ and type Ⅲ, and the oil yield in the wells of the Iype l is good and stable.