在用碱的化学驱油中硅铝垢的生成Ⅱ碱与岩芯组分的成垢机理和性能

ALUMOSILICATE SCALE FORMATION PRECIPITATES OWING TO ALKALIS IN CHEMICAL FLOODING SOLUTIONS Ⅱ PRECIPITATION OF ALUMOSILICATES IN ALKALI/CORE SYSTEMS AND MECHNIZMS INVOLVED

分别用X光衍射法和原子发射光谱法考察了固相与碱作用过程中固相中垢的生成和液相中硅、铝离子浓度的变化。研究结果指出，碱使固相中的硅、铝转入液相中，在温度、压力和组成合适的条件下生成铝硅酸盐结晶，晶粒逐渐长大而析出成垢。固相组成不同，生成的垢不同。蒙脱土，辽河和胜利岩芯与NaOH生成高硅垢。Na2CO3与辽河和胜利岩芯的成垢趋势很弱。在化学驱油中选用Na2CO3为碱剂是合适的。

The alumosilicates precipitated on minerals or reservoir cores from aqueous alkali solutions are detected and identified by X-ray diffraction and the concentrations of Si and Al ions in solutions are determined parallelly by inductive coupled plasma atom emmission spectroscopy.In reactions with 5% NaOH at 80℃ on kaolinite in 20 hrs low Si/Al ratios alumosilicates (LS4, LS2, LS1 ) are precipitated, on montmorillonite in 5 days - high Si/Al ratio alumosilicate (HS1) is formed, on reservoir cores from Liaohe and Shengli Oil Fields in 30 days - only trace or a small amount of high Si /Al ratio alumosilicates(HS1. HS2) are formed. The suggested mechanizm of alumosilicate precipitation is dissolving out of Si and Al ions from rock into liquid phase and recombination into compounds.The scaling tendency of the cores/Na_2CO_3 systems is very weak and Na_2CO_3 is a suitable Choice as alkali component in chemical flooding solutions.