Paillet F L, Williams J H, Oki D S, Knutson K D
US Geological Survey, Denver, CO 80225, USA.
Ground Water. 2002 Nov-Dec;40(6):577-85. doi: 10.1111/j.1745-6584.2002.tb02544.x.
Deep observation boreholes in the vicinity of active production wells in Honolulu, Hawaii, exhibit the anomalous condition that fluid-column electrical conductivity logs and apparent profiles of pore-water electrical conductivity derived from induction conductivity logs are nearly identical if a formation factor of 12.5 is assumed. This condition is documented in three boreholes where fluid-column logs clearly indicate the presence of strong borehole flow induced by withdrawal from partially penetrating water-supply wells. This result appears to contradict the basic principles of conductivity-log interpretation. Flow conditions in one of these boreholes was investigated in detail by obtaining flow profiles under two water production conditions using the electromagnetic flowmeter. The flow-log interpretation demonstrates that the fluid-column log resembles the induction log because the amount of inflow to the borehole increases systematically upward through the transition zone between deeper salt water and shallower fresh water. This condition allows the properties of the fluid column to approximate the properties of water entering the borehole as soon as the upflow stream encounters that producing zone. Because this condition occurs in all three boreholes investigated, the similarity of induction and fluid-column logs is probably not a coincidence, and may relate to aquifer response under the influence of pumping from production wells.
如果假定地层因数为12.5，那么液柱电导率测井以及由感应电导率测井得出的孔隙水电导率视剖面几乎是相同的。这种情况在三个钻孔中得到了记录，在这些钻孔中，液柱测井清楚地表明存在由部分穿透的供水井抽水所引发的强烈钻孔流。这一结果似乎与电导率测井解释的基本原理相矛盾。通过使用电磁流量计在两种产水条件下获取流量剖面，对其中一个钻孔的流动状况进行了详细研究。流量测井解释表明，液柱测井与感应测井相似，这是因为通过深层盐水和浅层淡水之间的过渡带，流入钻孔的水量向上系统性增加。一旦上升水流遇到生产层，这种情况就使得液柱的性质能够近似进入钻孔的水的性质。由于在所研究的所有三个钻孔中都出现了这种情况，感应测井和液柱测井的相似性可能并非巧合，并且可能与生产井抽水影响下的含水层响应有关。
