含有机酸的油田水中碳酸盐含量的确定

QUANTITATIVE ANALYSIS OF CARBONATES IN RESERVOIR FORMATATION WATERS CONTAINING ORGANIC ACIDS

大多油田水中的可溶性有机酸，对测定水中碳酸盐含量有很大的影响，试验结果表明，当水中同时存在有机酸时，如用强酸滴定碳酸盐，用甲基红指示终点，则得到的碳酸氢含量将会高于实际值。在这种情况下，碳酸盐和有机酸含量可由滴定终点的ｐＨ值，水样的初始ｐＨ值和总碱度，以及离子强度计算出来。本文给出一确定水中是否存在有机酸。

Organic acids are present in many reservoir formation waters in significant concentrations which can affect the analysis of carbonate in the water. Unfortunately, not too much attention has been paid to this fact. By carrying out many titrations we have quantified the effects. An automatic titrator has been used. Our study shows that, if a strong acid is used to titrate carbonate and methyl orange is used to indicate the end point for bicarbonate, the measured concentration of bicarbonate will be higher than the real value. At this situation, we can obtain both the bicarbonate and organic acid anion concentrations from the total alkalinity, titration end point pH and ionic strength by estimation using equations developed in this work. A simple method is given in this paper to determine if there are organic acids present in a water and their concentrations.