安塞油田长6油层酸敏性研究

A LABORATORY STUDY ON ACID SENSITIVITY OF RESERVOIR CHANG-6 IN ANSAI OIL FIELD, CHANGQING

研究了安塞油田长6油层对盐酸、磷酸、乙酸的敏感性。通过油层天然岩芯室内试验,得出了油层对不同酸液的敏感性,分析了产生不同敏感结果的机理。本文还采用了对比压汞曲线的方法来了解酸敏结果。

The sensitivity of the reservoir Chang-6 in Ansai Oil Field, Changqing, to 15% hydrochloric, 5% phosphoric and 5% acetic acid solutions Is studied in laboratory flow tests through natural cores of the reservoir. Flooding cores by 0.5, 1, and 5PV of HC1 and by 5PV of H3PO4 leads to decreasing oi core permeabilities to formation water (in opposite direction), while flooding cores by 10PV of H3PO4 and 1 and 5PV of CH_3COOH—to increasing of these values. The reactions between acids and cores are discussed. On the basis of coresponding core mercury curves it is believed that the big pores in the cores are enlarged in seize but the small ones are plugged after the cores having been acetic acid flooded; all the pores in the cores are subjected to plugging in some extent alter the cores having been flooded by HCland by H_3PO_4(5PV), and the less the poresize the more seriously the pore is plugged.