Testing and interpretation in layered reservoirs
This paper summarizes recently developed techniques for testing layered reservoirs that field test have shown to be successful. The effects of layering on conventional pressure-transient tests have been studied by a number of investigators, starting with a model for the commingled reservoir system in 1961. In a multilayered reservoir, each layer may have distinct values for its thickness, porosity, permeability, and formation skin factor. In gas wells, each layer may be subject to an additional skin because of non-Darcy flow near the wellbore. Layers may communicate vertically in the reservoir by formation crossflow. For interpretive purposes, the reservoir system is organized into zones, which are groups of communicating layers. Between adjacent zones there are impermeable barriers. Interpretation procedures assume that each zone is either infinite-acting or confined by either a constant-pressure or no-flow outer boundary. Finally, single-phase flow is assumed in the formation. Each change in the surface rate causes downhole transients, which depend on the system properties. Under commingled flow, the bottomhole flowing pressure is affected by the total system. The fluid flow rate to or from each layer, however, is a function of the properties of the layer and the adjacent communicating layers. Often, there may be flow in the wellbore from one layer into another. Determination of the layer properties by these techniques is not prevented by the presence of wellbore crossflow and/or wellbore storage.
- Research Organization:
- Schlumberger Perforating/Testing
- OSTI ID:
- 5921086
- Journal Information:
- J. Pet. Technol.; (United States), Vol. 39:9
- Country of Publication:
- United States
- Language:
- English
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NATURAL GAS WELLS
LAYERS
TESTING
RESERVOIR ROCK
PERMEABILITY
FLUID FLOW
FORMATION DAMAGE
HYDROLOGY
POROSITY
RESERVOIR FLUIDS
RESERVOIR PRESSURE
STRATIFICATION
FLUIDS
WELLS
030300* - Natural Gas- Drilling
Production
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030200 - Natural Gas- Reserves
Geology
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