Mathematical models use volumetrics. Darcy relationships, and conservation of mass to describe the reservoir.

数学模型利用体积法、达西关系式和质量守恒原理来描述油藏。

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The staples of the Volumetrics plan -- water-rich foods like brothy soups, fruits and vegetables, whole grains, low-fat dairy, lean meat, and fish -- not only help control hunger by filling you up, but they also do it on fewer calories.

CNN: Eat more and weigh less with Volumetrics