Description
Giovanni Da Pratt
Giovanni Da Pratt is a Ph.D. in Petroleum Engineering (1981) and MS in Geophysics (1977) from Stanford University, specialized in well test pressure transient tests analysis and reservoir evaluations; worked in technical and management positions in PDVA, Schlumberger, and Halliburton, and as consultant currently president of Daprat Well Testing, lectures on pressure transient analysis with Kappa engineering software, associated with MineaOil Limited and is the country manager for Leopardus Petroleum in Buenos Aires Argentina.
Has been main advisor testing exploration and appraisal wells in Venezuela, Colombia, Argentina, USA and Australia, in Plataforma Deltana, Camisea, Dragon and Patao, San Jorge and Neuquén, Perla gas carbonate, Santos basin, Alaska North slope, and the Orinoco heavy oil belt.
Has trained over a thousand engineers worldwide, as instructor for NExT, Schlumberger and for the IFP, in Buenos Aires, Argentina, Cape Town and Kuwait, for clients as Kuwait Petroleum Corporation, National Iranian Oil Company, PDVSA, Repsol, YPF, Halliburton, Schlumberger, Chevron. Tecpetrol, Pluspetrol, Wintershall and SPEI.
Was a SPE Distinguished Lecturer in 2003-2004 with the subject “Well Testing Management. Impact on Reservoir Evaluation and well productivity”. In 2016 was invited by the SPE Argentina to lecture on “Pressure Transient Analysis – a conventional look to non-conventional reservoirs”, has published over a hundred technical articles, presented at SPE conferences, author of the book “Well Test Analysis for Fractured Reservoir Evaluation”, Elsevier 1990,
The Reservoir flow capacity and well productivity index can be derived from pressure transient analysis using data acquired during well testing. In the case of exploratory wells, testing rates as well as bottom hole pressures are acquired under a temporary well completion that consists basically of a production tubing and a separator (no flow lines), which may not be the final production system layout for the well.
A simple production system layout consists of wells, flowlines, production manifold, separator, metering instruments just to mention a few and the study of the pressure-rate relationship throughout the system helps in defining the expected value for the well flow rate for a given values of production parameters. All pressure drops from the reservoir, completion, production manifold and flowlines to the final crude storage vessels need to be known at any production time. Flow rate sensibility to different controlling parameters like pipes ID, gas-oil ratio, wellhead, separator and flowline pressures, PVT fluid parameters, water cut should be carried out to understand the impact on final well production rate.
Although rate transient analysis and decline curve analysis according to the literature is treated almost independently of pressure transient analysis needless to say that well productivity and reservoir performance evaluation is enhanced by combining simultaneously both pressure and rate transient analysis.
- To provide a solid knowledge in pressure and rate transient analysis (RTA/ PTA) in conventional and non-conventional reservoirs. (INFLOW)
- Learn to analyze the production system performance, considering the impact of pressure drops taking place from the reservoir, through the completion, pipes, production lines, and other elements of the system, in the actual production rate either natural flow or assisted via a gas lift or ESP pump. (OUTFLOW)
- Carry out practical exercises using commercial specialized software that will be available throughout the duration of the course
- To provide participants with a sound understanding of both practical and advanced methods currently in use for pressure and rate transient analysis
- Understand why, when, and how to test a well and in the right way
- Understand the principles of fluid flow through porous media and through all the components of the production system configuration
- Learn how to interpret pressure and rate transient data acquired in non-conventional oil or gas reservoirs
- Learn how to determine the well production rate considering reservoir influx, and the total pressure drop from the completion to the final crude or gas storage destination
- Reservoir and petroleum engineers
- Production engineers
- Exploration and development geoscientists
- Well test engineers
Day 1
Pressure Transient Analysis (PTA)
- Brief introduction to well testing and well test analysis methodology
- Well testing objectives as well as type of tests. Reservoir and well information derived from pressure data analysis and the methodology currently used for pressure transient analysis.
- Fluid Flow through porous media Solutions
- Flow regimens and Interpretation models
- Pressure transient analysis methodology
- Practical and advanced methods(deconvolution)
- Minimum testing time to achieve objectives.
- Examples using software application.
Day 2
Rate transient analysis (RTA)
- Summary of traditional decline curve analysis methods.
- Introduction of material balance time and advanced decline methods of analysis applicable to conventional and non-conventional reservoirs are discussed.
- Reservoir flow capacity determination from transient rate analysis
Fetkovitch, Blasingame and Arps models - Decline Curve Analysis
- Models currently used, Arps, hyperbolic, exponential and Duong.
- Examples using software applications.
Day 3
Production System performance. Part 1
- The analysis of the production system, considering the impact of pressure drops taking place from the reservoir and through the completion, pipes and production lines, as well as other elements of the system is presented.
- Inflow Performance relationship and well productivity index
- Pressure drop calculation trough production and all components of the system considering multiphase flow
- Pressure drop trough the well completion and VLP (Demand)
- Transient and pseudo steady state IPR
- Examples using software application.
Day 4
Production system performance. Part 2
- The analysis considering the impact of artificial lift systems (mainly gas lift and ESP pump), as well as other elements of the well completion, in the value of actual production rate is presented. In addition, a brief summary is given to flow assurance concepts as well as the impact of sand and water production.
- Flow pattern and calculation of pressure transverse
- Gradient curves
- Artificial Lift Systems (gas lift and pump)
- Gravel pack
- Flow assurance
- Sand and water production
- Examples using software application.
Day 5
Non-Conventional Reservoirs
- Summary of the modelling fluid flow behaviour in non-conventional reservoirs.
- Methods for pressure and rate transient analysis applicable to horizontally fractured wells are presented.
- Decline curve analysis and the uncertainties in pore volume and reserves estimation.
- Basic reservoir description, reservoir and well model. Analytical and numerical solutions
- Well completion; multistage hydraulic fractures.
- Flow regimes and transient rate and pressure analysis
- SRV (stimulated reservoir volume)
- Geomechanics impact on well production
- Examples using software application.
End of the training
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