基于电缆地层测试取样的水分析技术及泵抽时间优化

Technology of Water Analysis Based on Wireline Formation Test and Optimization of Pump Time

电缆地层测试作业因钻井液侵入、储层渗透性、泵抽效率等因素影响,经常不能取到较纯净的原状地层流体样品,导致储层流体性质判断困难。在传统的现场快速水分析技术基础上,此文提出利用甲酸根作为特征离子来计算样品的纯度,判别取样样品的流体性质。与此同时,提出采用电阻率计算方法,求取样品纯度与电阻率变化率的关系,进而提出电缆地层测试取样的最佳时间节点。海上数十口井实际应用表明,该技术不仅可为现场作业决策提供重要的依据,也可大大节约勘探成本,降低作业风险。

Due to the factors such as drilling fluid invasion,reservoir permeability,pump efficiency and other factors,pure undisturbed formation fluid samplescannot be obtained during the test operation of the cable formation,which leads to great difficulty in judge of reservoir fluid properties.Based on the traditional fast water analysis technology,in this paper,it is proposedthat formic acid can be used as the characteristic ionto calculate the purity of the sample,and to determine the fluid properties of the sample.At the same time,it is proposed the relationship between sample purity and resistivity change rate can be obtained by using the resistivity calculation method,and then the optimal time node for the cable formation testing is proposed.The practical application of dozens of wells at sea shows that the technology can not only provide an important basis for the field operation decision,but also greatly reduce the cost of exploration and reduce the risk of operation.