The derivative plot is what made modern transient analysis possible. Pressure change alone is a smooth curve on which several very different reservoir behaviours look similar. The derivative of pressure with respect to superposition time amplifies the features that distinguish them: a flat derivative indicates radial flow, a half slope indicates linear flow, a quarter slope indicates bilinear flow, a unit slope at late time indicates a closed boundary, and a dip and recovery indicates dual porosity behaviour. Almost every misinterpretation in well testing comes from working without a derivative or from misreading one.

Non-uniqueness is the discipline's central difficulty. Several different reservoir models can reproduce the same pressure response within measurement error, and choosing between them requires information from outside the test: geological interpretation, offset well data, core and log measurements, and the physical plausibility of the resulting parameters. An interpretation presented without acknowledging the alternatives that also fit is incomplete, and interpretations that quote permeability to three significant figures usually indicate that this has not been considered.

Rate transient analysis has become the more common activity because shutting in a producing well is expensive. Analysing flowing rate and pressure data avoids that cost but introduces its own difficulties: rate histories are variable and imperfectly known, flowing pressures are often calculated from wellhead rather than measured downhole, and the data contains operational interruptions that are not reservoir signal. The interpretation methods are related to those of pressure transient analysis, but the data handling is substantially harder.

Finally, test design determines what a test can deliver. A buildup too short to develop radial flow cannot give permeability. A test in a well with high wellbore storage may be dominated by storage for its entire duration. An interference test between wells too far apart in low permeability rock will show no response within any practical time. Designing the test against the question it must answer, before it is run, is what makes the expenditure worthwhile.

By the end of this training, participants will be able to:

• Apply the diffusivity equation and its solutions to well and reservoir transient behaviour
• Handle variable rate histories using superposition and appropriate time functions
• Identify flow regimes from log-log diagnostic and derivative plots
• Apply specialised straight-line analysis to each flow regime to extract reservoir parameters
• Select and apply wellbore, near-wellbore and reservoir models to match observed responses
• Interpret dual porosity, layered, composite and fractured reservoir responses
• Detect and characterise boundaries and determine average reservoir pressure
• Apply rate transient analysis to production data including flowing material balance
• Assess non-uniqueness and constrain interpretations using independent information
• Design pressure and rate tests to answer specific reservoir questions

The training establishes the theory required and then moves quickly into interpretation, with participants working through an extensive set of real pressure and rate data sets covering the full range of reservoir and wellbore behaviours. Each interpretation is built in the same sequence: diagnostic plot, flow regime identification, specialised analysis, model selection, match verification and parameter assessment. Ambiguous data sets are used deliberately so that participants practise identifying alternative models that fit equally well. Test design exercises close the training, with participants specifying tests to resolve defined reservoir questions.

Organisations sending participants to this training will:

• Improve the quality of well test interpretation carried out in house
• Reduce expenditure on tests that cannot answer the question being asked
• Improve reservoir description through better use of transient data
• Strengthen review of interpretations produced by service providers
• Improve reserves and development decisions supported by transient results
• Extract more value from production data already being collected through rate transient methods

Participants will:

• Interpret pressure and rate transient data independently and confidently
• Identify flow regimes reliably and know what each yields
• Recognise and communicate non-uniqueness in an interpretation
• Apply rate transient methods to production data
• Design tests that deliver the information required
• Build a core reservoir engineering specialism that applies to every asset

• Reservoir engineers and well test analysts
• Production engineers analysing well performance
• Petroleum engineers working on well and reservoir surveillance
• Simulation engineers requiring parameter inputs and model constraints
• Reserves and evaluation engineers
• Well test operations and service company technical staff
• Geoscientists working on connectivity, compartmentalisation and boundaries

Upon successful completion of this training course, delegates will be awarded an official Certificate of Completion issued by the Petroleum Engineers Association (PEA), an ISO 9001:2015 certified training organization. The certificate carries 10 Credits and formally records the total learning hours completed.

Each certificate is signed by the Course Facilitator and the CEO of the Petroleum Engineers Association, and serves as verifiable proof of professional training that delegates can present to employers and professional bodies worldwide.