砂岩黏土矿物相对含量分析中存在的问题

中华人民共和国石油天然气行业标准 SY/T 5163—1995《沉积岩黏土矿物的相对含量 X射线衍射分析方法》存在着一个明显的缺陷：当砂岩分离黏土时，粉碎样品、浸泡至小于2 μm粒径的那些以伊利石、伊蒙混层、绿泥石和绿蒙混层组成的塑性岩屑，不可避免地会被分散进入黏土组分中。塑性岩屑中的黏土矿物成分便和砂岩填隙物中的黏土矿物混在一起，直接影响储集层填隙物黏土矿物的组成分析，使储集层填隙物中的各类黏土矿物相对含量失真。为此，提出一种求准碎屑岩填隙物中黏土矿物相对含量的新方法，此方法避免了无法将储集层中塑性岩屑分离出来，造成填隙物中黏土矿物相对含量失真的现象。

The Problems Existing in Relative Content Analysis of Sandstone Clay Minerals

The current domestic analysis method for relative content of sedimentary clay minerals is based on the PRC Oil and Gas Industry Standards SY/T5163-1995 "The X?ray Diffraction (XRD) Analysis Method for Relative Content of Sedimentary Clay Minerals".The disadvantage of this analysis method is that when the separation of clay in sandstone, by crushing the samples, soaking to less than 2 μm in diameter, the plastic debris composed of illite and illite/montmorillonite mixing layer, chlorite and chlorite/smectite mixed layer will inevitably be dispersed into the clay composition which may mixed with clay minerals in sand interstitial materials and directly influence the composition analysis of the clay minerals in sand interstitial materials in the reservoir, resulting in lacking fidelity of relative content of various clay minerals and affecting precise evaluation of the reservoir sensitivity. This paper proposes a new method for such a relative content analysis of interstitial clay minerals, by which the plastic debris can be separated from the interstitial materials, thus avoiding the lacking fidelity phenomenon