What is free water level?
What is free water level?
The free water level is the highest elevation at which the pressure of the hydrocarbon phase is the same as that of water. The hydrocarbon-water (oil-water or gas-water) contact is the lowest elevation at which mobile hydrocarbons occur.
How is capillary pressure calculated?
Capillary pressure is defined as Pc=Pnw−Pw and for water saturation decreasing, Pnw outside the pore throat is greater than Pw inside the pore throat, resulting in a positive pressure.
What is the pressure in the capillaries?
Capillary pressure physiology Normal capillary pressure, measured at the apex of the capillary loop with the capillary at heart level, ranges from 10.5 to 22.5 mmHg (Figure 4).
What is the difference between FWL and OWC?
The difference between the OWC and the FWL is greater in tight reservoirs, and may be up to 100m difference. A difference between GOC and free oil level exists for the same reasons, but is much smaller, and is often neglected.
What is free water in reservoir?
When processing reservoir fluids, the water that separates easily under gravity separation is known as free water.
What is free water in cementing?
Free water is defined as water not required for cement hydration. When the cement slurry flow stops, free water separates on the top of the cement column. A cement slurry is basically made up of dry cement mixed with water in a correct ratio.
Is capillary pressure positive?
Capillary force equilibrium at an interface between two immiscible fluids. By definition, the capillary pressure is always a positive (or zero) quantity. The capillary pressure is often expressed as an equivalent water height, denoted hc and called capillary‐pressure head.
What causes capillary pressure?
Vasoconstriction of pulmonary vessels causes an increase in both alveolar capillary pressure and vascular fluid shear stress. Flooding of pulmonary capillaries and increased capillary permeability occur. Fluid and inflammatory cells leak into the air sacs that are normally dry.
Do capillaries have high or low pressure?
Structure of blood vessels
| Artery | Capillary | |
|---|---|---|
| Direction | Away from the heart | From arteries to veins |
| Pressure | High | Low |
| Size of hole (lumen) | Small | Very small |
| Wall thickness | Thick | One cell thick |
Why is free water level important?
The free water level is located at the base of a hydrocarbon column and the transition zone. Above this level, the reservoir produces water alone, hydrocarbon and water, or hydrocarbon alone on a production test. Below this level lies the aquifer of a water drive reservoir system. It produces water only.
What is capillary pressure?
Capillary pressure is the pressure difference across the curved interface formed by two immiscible fluids in a small capillary tube. The pressure difference is Equilibrium between fluid phases in a capillary tube is satisfied by the relationship force up = force down.
What is the free water surface of a capillary curve?
The free water surface is the highest elevation with the same oil and water pressure (zero capillary pressure). The oil-water contact corresponds to the displacement pressure (DPdrill pipe) on the capillary pressure curve. The transition zone is the interval with co-production of water and hydrocarbons.
How much does capillary pressure affect water saturation?
Figure 5 Effect of capillary pressure (left) on water saturation (right). At any given height above the free water level, water saturations vary widely among rock types (A-E) due to diffferences in capillarity. For example, at 50 ft above free water level, water saturations vary from 18% (rock type A) to 95% (rock type E).
How can I convert capillary pressure data into reservoir conditions?
Laboratory capillary pressure data can be converted into reservoir conditions. Thus, from a small core, the saturation distribution of a reservoir can be constructed if the core represents a pore system that is representative for the investigated reservoir section (homogeneity). This process covers two steps: