Since the purpose is to minimize alteration, a fresh core has often been drilled with a bland mud, either water - or oil-base, but with a minimum of chemical additives and weighting material.

其目的是为了将岩心的变化降到最低，通常用泥浆或水基、油基泥浆钻取岩心，但是使用少量的化学添加剂和加重物质。

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A core taken so as to preserve the in-situ water saturation of the rock. A native-state core is usually drilled with oil-base mud or crude oil from the same reservoir.

使用油基泥浆或原油钻取的岩心，以保证岩心的含水饱和度与岩石在储集层状态的含水饱和度相同。

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