01
Problem classification
Determine the engineering problem being investigated, the relevant discipline and the decision context in which the method will be applied.
Outputs
- —Problem type
- —Engineering domain
- —Decision context
- —Applicable workflow
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PEI Methods
Engineering methods applied with discipline.
Engineering methods provide the quantitative foundation for analysing petroleum systems. PEI organises methods around their physical purpose, required inputs, assumptions, validity conditions and appropriate interpretation.
Method discipline
An equation is only one part of an engineering method.
A technically correct equation can still produce a poor engineering result when it is applied to the wrong physical problem, with unsuitable inputs or outside its intended validity range.
Method selection therefore considers the physical problem, available evidence, input quality, assumptions, applicability and the way the resulting calculation will be interpreted.
Method sequence
01Engineering problem
02Governing principle
03Method selection
04Required inputs
05Validity & assumptions
06Calculation
07Independent check
08Interpretation
Analytical workflow
From method selection to engineering interpretation.
A disciplined method does more than generate a numerical result. It establishes why the method was selected, what information it requires, where it is valid and how the result should be assessed.
02
Principle selection
Identify the physical laws, engineering principles and governing relationships relevant to the problem.
Outputs
- —Governing physics
- —Engineering principles
- —Relevant relationships
- —Method candidates
03
Input definition
Determine the measurements, parameters and field data required by the selected method and assess whether the available inputs are suitable.
Outputs
- —Required inputs
- —Available data
- —Data quality
- —Missing information
04
Assumption & validity check
Establish the assumptions behind the selected method and determine whether the problem conditions fall within its appropriate application range.
Outputs
- —Method assumptions
- —Validity conditions
- —Applicability
- —Known limitations
05
Engineering calculation
Execute the appropriate equations, analytical procedures, models or numerical calculations using the defined inputs.
Outputs
- —Calculated parameters
- —Engineering results
- —Intermediate results
- —Calculation record
06
Independent verification
Where practical, compare the result using an independent calculation, alternative method, limiting case, historical data or another relevant engineering check.
Outputs
- —Independent calculation
- —Alternative method
- —Consistency check
- —Result comparison
07
Sensitivity & uncertainty
Evaluate how changes in important inputs and assumptions affect the result and identify parameters that materially influence the engineering conclusion.
Outputs
- —Sensitivity analysis
- —Uncertainty range
- —Critical parameters
- —Data priorities
08
Engineering interpretation
Translate the calculated result into an engineering interpretation that explains the physical behaviour, limitations and implications for the field problem.
Outputs
- —Technical interpretation
- —Problem diagnosis
- —Engineering implications
- —Decision evidence
Method families
Methods organised around engineering problems.
Petroleum engineering uses a wide range of analytical methods, correlations, models and numerical techniques. They are most useful when organised according to the engineering problems they help solve rather than as an indiscriminate collection of equations.
Flow & pressure
- —Darcy's Law
- —Radial flow relationships
- —Pressure distribution
- —Pressure transient analysis
- —Productivity relationships
Reservoir analysis
- —Material balance
- —Volumetric analysis
- —Reservoir simulation
- —History matching
- —Reservoir performance analysis
Well performance
- —Inflow Performance Relationship
- —Nodal analysis
- —Vertical lift analysis
- —Well deliverability
- —Artificial lift analysis
Formation evaluation
- —Log interpretation
- —Porosity evaluation
- —Water saturation
- —Net pay evaluation
- —Core and formation data integration
Well testing
- —Pressure build-up analysis
- —Pressure drawdown analysis
- —Pressure derivatives
- —Wellbore storage analysis
- —Boundary and interference analysis
Recovery evaluation
- —Recovery factor analysis
- —Waterflood evaluation
- —Injection analysis
- —EOR screening
- —Pilot evaluation
Calculation discipline
Precision begins before the calculation.
Engineering calculations can appear precise while still being technically weak if the inputs, assumptions or method are inappropriate. Calculation discipline therefore forms part of the engineering method itself.
- ✓Use the appropriate equation or method for the physical problem.
- ✓Preserve units and dimensional consistency throughout calculations.
- ✓Record the input values used rather than silently substituting missing data.
- ✓Distinguish measured values, assumed values and calculated values.
- ✓Respect the assumptions and validity range of each method.
- ✓Check calculations independently wherever practical.
- ✓Expose sensitivity to material parameters.
- ✓Do not convert an uncertain calculation into a falsely precise conclusion.
Engineering example
Darcy's Law as a connected engineering method.
Darcy's Law provides a foundation for understanding flow through porous media. In practice, its engineering significance extends into reservoir behaviour, well performance and production analysis.
Darcy's Law→
Reservoir flow→
Pressure behaviour→
Well testing→
Permeability→
Productivity Index→
IPR→
Artificial lift→
Production optimisation
The important engineering question is not simply whether an equation can be evaluated. It is whether the underlying physical relationship is applicable, whether the required inputs are defensible and what the resulting behaviour means for the actual well or reservoir.
Future capability
A structured foundation for repeatable engineering analysis.
As PEI develops, this method structure can support increasingly repeatable engineering workflows. The objective is to make established engineering methods easier to apply consistently while retaining professional engineering review and judgement.
Controlled calculations
Where an engineering relationship can be calculated directly, the calculation should be controlled and reproducible rather than dependent on generated prose.
Traceable inputs
Engineering inputs should retain their units, status, assumptions and supporting information so the analysis can be understood and reproduced.
Engineering review
Results should remain subject to method validity checks, independent verification and qualified engineering judgement.