Specific implementation of Well Testing interpretation workflow of pressure transitions in terms of well properties and formation properties of connected subsurface reservoirs.
Despite the explicit name It does not necessarily refer to analysis of a stand-alone pressure transient and also cover the complex pressure histories with numerous pressure transitions.
Both downhole and surface pressure records can be a source of information recoverable through PTA.
The quantitative interpretation of pressure transitions is based on pressure diffusion model.
Below are the major types of PTA:
Objectives
| Primary deliverables | Math Symbol | Conditional Deliverables | Math Symbol |
|---|---|---|---|
Current formation pressure | p_e | Initial formation pressure assuming no or little historical interference with offset wells | p_i |
Skin-factor | S | Formation damage as permeability deterioration assuming damage penetration is known Formation damage penetration assuming damage value is known Fracture-network development around the well | |
Formation transmissibility | \sigma | Permeability assuming flowing thickness h is known Flowing thickness assuming permeability k is known Water-oil column assuming permeability k and flowing thickness h are both known | k h h_{OWC} |
Minimum drainable volume around the well | V_\phi | Minimum hydrocarbon reserves around the well Drainage area around the well assuming flowing thickness h is known Flowing thickness assuming the drainage area A around the well is known Boundary proximity assuming the circular boundary | V_{hc} A_e h r_e |
| Minimum drainable area around the well | A_e | Half-size of drainage area r_e providing the shape of the drainable area is known | |
Boundary type | PSS, \, SS, \, BAFFLE | ||
Fracture presence and its size | X_f | ||
Dynamic fracture opening threshold | \delta P_{X_f} | ||
Proximity r_{ext} of the remote reservoir composition Transmissibility \sigma_{ext} of the remote reservoir composition | W_{ch}, \, D_{ch} R_{owf} R_{ogf} | Channel width and proximity to its nearest boundary Proximity to oil-water front Proximity to oil-gas front | |
| Scanning area around the well | A_{\rm scan} | Scanning radius of the area r_{\rm scan} around the well assuming radial isobaric propagation |
Interpretation
Samples
|
|
| Fig. 1. Transient responses in vertical producer | Fig. 2. Transient responses in horizontal producer |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Well Testing / Pressure Testing
[ Well & Reservoir Surveillance ]