海拉尔盆地贝尔凹陷储层物性特征及控制因素

Physical Properties and Control Factors of Reservoir in Beier Depression,Halaer Basin

贝尔凹陷铜钵庙组一南屯组的储层类型为中一低孔低渗型，存在两个异常高孔隙发育带：第一异常高孔隙带为1300-1800m，第二异常高孔隙带为2400～2700m。异常高孔隙发育带的控制因素为：①火山碎屑物质对孔隙的保存及其溶解形成的次生孔隙；②碎屑颗粒包壳对原生孔隙的保存；③大气水淋滤形成的次生孔隙；④有机酸溶蚀形成的次生孔隙。其中大气水淋滤形成的次生孔隙对异常高孔隙的贡献较小。由于贝尔凹陷内有机质热解产生的有机酸主要溶蚀对象是火山碎屑岩，且火山碎屑岩溶蚀产生的各种阳离子是绿泥石和伊利石的主要组成元素，所以贝尔凹陷异常高孔隙发育的根本控制因素是储层岩石类型的特殊性。

The reservoir in Tongbomiao - Nantun Formation in Beier depression is characterized by low to medium porosity and low permeability. There are two anomalously high porosity zones in Beier depression; one is in the depth of 1 300 - 1 800 m, and the other is at 2 400 - 2 700 m. The controlling factors for these two zones are as follows：①pyroclastic materials can be dissolved and form secondary pores;②the coating of detrital grains is suitable for conservation of primary porosity;③leaching of meteoric water has led to the formation of secondary porosity;④corrosion of organic acid has resulted in the generation of secondary porosity. Among them, leaching of meteoric water has contributed less to the formation of anomalously high porosity zones compared to other factors. As pyroclastic rocks are the main objects dissolved by organic acid and the newly generated cations are the major components forming chlorite and illite, the major controlling factors for the formation of anomalously high porosity in Beier depression are the physical properties of those special reservoir rocks.