基于微元法建模预测地层水化合物浓度*

Concentration Measurement of Compound in Formation Water Based on Infinitesimal Element Method

陈怡羽 郭建春 郭子熙 赵运祥 余莉珠

CHEN Yiyu GUO Jianchun GUO Zixi ZHAO Yunxiang YU Lizhu

为有效降低压裂液对煤层的伤害，可用离子色谱仪测定现场地层水样的组成成分，确定地层水的矿化程 度，用复配地层水作为压裂液进行水力压裂施工。为了节省时间与成本，基于微元分析法的基本思想建立了可 以实时动态地预测地层水化合物浓度的模型。根据现场生产井的排采情况，假设任意时间段内生产排采出的地 层水与远井地带注入地层水的体积相同，并且在微小时间段内，排采出的地层水中化合物浓度保持不变。结果 表明，由该模型计算新疆某区块煤层气A井不同生产时间下地层水中KCl和NaCl的浓度，其与离子色谱仪测得 的浓度值的平均误差分别为4.01%~12.10%、6.06%~10.46%，验证了该模型的正确性。图2表1参15

In order to effectively reduce the damage of fracturing fluid to coal seam，it is necessary to measure the composition of formation water by ion chromatograph，determine the degree of mineralization of stratigraphic water，and use compound formation water as fracturing fluid for hydraulic fracturing construction. In order to save time and cost，based on the basic idea of microelement analysis，a real-time and dynamic model for predicting the concentration of compound in formation water was established. According to the drainage situation of the field production wells，it was assumed that the volume of formation water produced in any time period was the same as that injected into the far well zone，and the concentration of compound in the discharged formation water remained unchanged in the small time period. The results showed that the average error between the concentration of KCl and NaCl in formation water of coal-bed gas well in a block of Xinjiang calculated by the model and that measured by the ion chromatograph was 4.01%—12.10% and 6.06%—10.46% under different production time respectively，which verified the correctness of the model.

10.19346/j.cnki.1000-4092.2020.02.031