Best Practice in Pore Fluid Pressure and Fracture Pressure Prediction
|Prof. Dr Richard Swarbrick (Swarbrick GeoPressure Consultancy, Durham, United Kingdom)|
|Geology – Geological Modeling|
|10 CPD points|
CARBONATES DRILLING INTERPRETATION OFFSHORE PORE PRESSURE SEDIMENT SEDIMENTOLOGY SHALE TECTONICS WELLS
All wells drilled require a pre-drill prediction of pore fluid and fracture pressures that defines the ‘drilling window’. This course explains the objectives, methods and uncertainties of prediction, based on extensive global experience. The necessary understanding of the geological/geophysical context of abnormal pressures leading to standard algorithms will be provided. Part of the challenge is terminology and contrasting display methods of geoscience and operations/drilling groups. Both approaches are necessary and investigated in interactive exercises, which will form an essential component of the course.
Upon completion of the course the participants will be able:
- To know the elements involved in well planning that relate to pore fluid and fracture pressures;
- To understand the causes and to recognize the occurrence of abnormal pressures in the subsurface;
- To know how to collect appropriate data to solve standard equations for pressure prediction;
- To comprehend the uncertainties in predictions from data selection as well as the variation in prediction methods and approaches;
- To understand how to communicate between geoscience and operations/drilling personnel in relation to pressure prediction.
Session 1: Introductions; Objectives; Terminology; What is “Best Practice”?
Session 2: Data types and displays as pressure-depth and equivalent mud weight-depth plots. Defining the "drilling window" and input to well planning. Importance of context: prediction of lithology and its influence on pressure profiles.
Exercise One: Context for frontier well proposal – EAGE-1;
Exercise Two: Lithological prognosis for EAGE-1.
Session 3: Pore fluid pressure prediction: methodology around vertical effective stress estimation. Estimating shale pressure gradient using the “Swarbrick Method”.
Exercise Three: Determining the Fluid Retention Depth.
Pore pressure prediction using shales; determining the overburden pressure; selecting a Normal Compaction Trend (NCT); Equivalent Depth (Effective Stress) and Eaton models; pore pressure from seismic velocities.
Exercise Four: Developing a Bowers Transform for solving velocity to vertical effective stress. Solving Terzaghi equation for pore pressure from vertical effective stress.
Exercise Five: Pore pressure prediction from seismic interval velocities for EAGE-1.
Session 4: Recap of Day One. Using velocity-density cross-plots to identify overpressure generating mechanisms; lateral drainage and lateral transfer. Limitations of existing methods. Pore pressure prediction in carbonates. Revision of pore fluid pressure prediction.
Best practice in pore pressure prediction – a review.
Session 5: Fracture pressure prediction: Determination from local-derived LOT data, where available. Using published algorithms related to overburden;
Exercise Six: Estimate of fracture pressures from standard Leak-Off test (LOT).
Session 6: Understanding how fracture pressure is coupled to pore fluid pressure; Lahann & Swarbrick fracture gradient model, compared to Matthews & Kelly method. Group exercise using LOT data from four wells to develop solution for EAGE-1.
Best practice in fracture pressure prediction – a review.
Session 7: Pore fluid pressure – fracture pressure (PP-FG) and the requirements for well planning. Determining Min-Expected-Max ranges. Generating and communicating using an Equivalent Mud Weight (EMW) vs Depth plot. Common pitfalls.
Session 8: Conclusions. Best practice in conventional hydrocarbon plays; Best practice in “unconventional” plays. Confidence matrix for pore fluid pressure.
Note: Sessions may be adapted to include material relevant to the local area.
The course is designed for geoscientists (geophysics, petrophysics, geomechanics), engineers (operations, reservoir and drilling) and managers.
Participants should have a working knowledge of oilfield operations, including the data types that are used in defining the geology of the subsurface as well as the components of drilling wells.
About the instructor
Professor Richard Swarbrick is currently an independent consultant for the oil and gas industry specialising in sub-surface pressures, whilst retaining research and teaching interests at Durham University. After completing a BSc in Geology from Durham and PhD in sedimentology/tectonics at Cambridge University Richard worked as a petroleum geologist and exploration supervisor for Mobil for ten years from 1979. During that time he worked on both exploration and production assignments in UK and Alaska Division, USA.
In 1989 he moved back to academia, and began teaching petroleum geology, basin studies and related courses at Durham. Developing a research interest in subsurface pressures, from 1994 to 2001 Richard was the principal investigator of GeoPOP (GEOsciences Project into OverPressure), a multi-disciplinary research group funded by 17 oil/gas companies. The research led to many publications related to overpressure mechanisms, pore pressure prediction methods, modeling pressure through time in basins, and the influence of overpressure on the petroleum system. He was involved in GeoPOP3 at Durham University from 2011-2015.
In 1997 Richard had founded the university spin-out company, GeoPressure Technology, producing niche software, later expanded into training, consultancy and multi-client pressure studies. From a back office in the Geological Sciences department the company grew to employ more than 20 geoscientists, and is now part of the Ikon Science Group. Richard left the company in 2013, but continues to teach pressure courses in many oil centres around the world, either as open courses or in-house training companies. He consults widely and continues to present conference papers and publish articles relating to sub-surface pressures.
Richard is a Fellow of Geological Society of London since 1982, and member of EAGE, AAPG and PESGB.
- Osborne, M.J. & Swarbrick, R.E., 1997. Mechanisms for generating overpressure in sedimentary basins: A re-evalution.AAPG Bulletin, v. 81, p. 1023-1041.
- Bell, D.W., 2002. Velocity estimation for pore-pressure prediction. In: Pressure regimes in sedimentary basins and their predictions. (Ed. Huffman, A.R. & Bowers, G.L.)AAPG Memoir, p. 217-233.
- Swarbrick, R.E., 2012. Review of pore pressure prediction challenges in high-temperature areas. The Leading Edge. v. 31, p. 1288-1294.
- Swarbrick, R.E. & Lahann, R.W., 2016. Estimating pore fluid pressure - stress coupling.Journal of Marine & Petroleum Geology, v. 78, p. 562-574.
Explore other courses under this discipline:
Instructor: Dr Dave L. Cantrell (Cantrell GeoLogic and Stanford University, USA)
Reservoir quality prediction has long been the ultimate goal of industry geologists, yet few have achieved this in a truly quantitative fashion. This workshop presents a new approach to reservoir quality prediction that involves the integration of a variety of modeling techniques to understand, quantify and predict the geological processes that control reservoir quality. Since initial reservoir quality is established at the time of deposition, numerical process models are used to predict initial reservoir quality; diagenetic process models are then used to modify these initial results and ultimately produce a quantitative and geologically-based prediction of present-day subsurface reservoir quality.
Instructors: Prof. Dr Stephen Tyson and Dr Ing Sebastian Hörning (Universiti Teknologi Brunei and The University of Queensland)
The course will show the attendees how to test for linear spatial dependence and introduce the concepts of non-linear geostatistics. Attendees will develop an excel spreadsheet and a python notebook which can be used for spatial data analysis and non-linear stochastic simulation. Existing geostatistics algorithms based on the kriging matrix can be shown to underestimate the connectivity of extreme values because they assume a linear spatial dependence model. Moreover, the estimation of uncertainty based on these techniques uses the kriging variance, which is not dependent on the values of the spatially distributed variable. It can also be shown that these uncertainty estimate are often implausible. This course will explain the reasons why most spatial variables in geoscience do not have a linear spatial dependence, even after monotonic transformations, and what the impact of this in the estimation of petrophysical properties. The course will show the attendees how to test for linear spatial dependence and introduce the concepts of non-linear geostatistics. Attendees will develop an Excel spreadsheet and a python notebook which can be used for spatial data analysis and non-linear stochastic simulation.
Instructor: Mr Jean-Jacques Biteau (retired from Total E&P, France)
This course on 'Petroleum Exploration Strategy' focuses on aspects like the evaluation of exploration projects (working sequence, costs, economic criteria etc), partnerships, contracts and mining acreage, but also on the missions and role of a geoscience/exploration manager.
Case studies from various regions are an important part of this course.
Instructor: Prof. Dr Alexei Milkov (Colorado School of Mines, USA)
The course enables participants to transform qualitative geological descriptions of plays and prospects into technically robust quantitative success-case and risked volumetric models. Obtained learnings will help participants evaluate probabilities of success (PoS) for exploration plays, segments, prospects, wells and portfolios and to assess the range of petroleum volumes in exploration projects. Examples and case studies come from both conventional and unconventional plays, prospects and wells around the world. The learning objectives are achieved through well-illustrated lectures, numerous hands-on exercises and active class discussions. We will cover:
- Play-based exploration;
- Assessment of success-case volumes;
- Assessment of exploration risks/PoS;
- Post-mortem analysis.
Instructor: Dr Bjorn Wygrala (Schlumberger)
The term “Petroleum Systems” and the technology “Basin and Petroleum Systems Modelling” will be introduced by showing applications in areas with critical exploration challenges, including salt basins and thrustbelts. Technical breakthroughs in the last 10-15 years have been the extension of the technology from 2D to 3D, and the ability to perform multi-phase petroleum migration modelling using different methods in high resolution geological models. This enables temperature, pressure and petroleum property predictions to be made with higher levels of accuracy and in the most complex geological environments such as in the sub-salt or in thrustbelts. Case studies will be used with live software presentations to illustrate key points. Applications of the technology will range from frontier exploration in which large areas with only sparse data are screened, to detailed assessments of exploration risks in structurally complex areas, to petroleum resource assessments of yet-to-find oil and gas.
Instructor: Prof. Dr Michael Poppelreiter (University Technology Petronas)
The most universal, comprehensive and concise descriptive documents on oil and gas wells are well logs. They impact the work of almost every oil field group from geologists to roustabouts to bankers. Familiarity with the applications of well logs is therefore essential for people forging their careers in the oil business. The instructor uses a core-based approach to help participants develop a good grounding in understanding and applying well logging techniques. General principles of physics are presented to explain the functioning of modern logging tools. Wherever possible, the physics of logging measurements is related to everyday tools and applications. Cross-plotting and reconnaissance techniques quickly and efficiently discriminate between water, oil and gas. Error minimization techniques, applicable only to computerized log analysis, produce optimal results. Participants benefit from realistic experience by working in teams on a comprehensive log interpretation exercise.
Instructor: Prof. Dr Richard Swarbrick (Swarbrick GeoPressure Consultancy)
All wells drilled require a pre-drill prediction of pore fluid and fracture pressures which defines the drilling window. This course explains the objectives, methods and uncertainties of prediction, based on extensive global experience. The necessary understanding of the geological/geophysical context of abnormal pressures leading to standard algorithms will be provided. Part of the challenge is terminology and contrasting display methods of geoscience and operations/drilling groups. Both approaches are necessary and investigated in the interactive exercises which will form an essential component of the course.
Instructor: Dr Dirk Nieuwland (NewTec International)
Unconventional hydrocarbon systems require unconventional approaches to decide on drilling locations and development techniques. The information contained in natural fracture systems can be used to support the drilling and well stimulation technique for the development of unconventional hydrocarbon systems such as shale gas. This short course is based on geomechanics as a technique that can be used to understand and to develop unconventional hydrocarbon systems such as shale gas systems, and fractured crystalline basement, where conventional logging and seismic systems are inadequate.
Instructor: Dr Tim Wynn (AGR TRACS International Ltd)
Reservoir modelling for field development planning is a well-accepted process but its application to fractured reservoirs requires specific considerations which are less commonly known. This course describes a practical methodology for building 3D static (“geocellular”) reservoir models for naturally fractured reservoirs using standard modelling software, covering such considerations. The issues addressed include the integration of log, core and seismic data, the sourcing and application of in situ stress data, the process of defining and building the static reservoir model itself, and the creation of output in a form appropriate for dynamic modelling using dual porosity reservoir simulators where appropriate. More complex workflows using discrete fracture networks will also be summarised, as will general issues of fracture description, uncertainty-handling and volumetrics.
Instructor: Prof. Dorrik Stow (Heriot-Watt University)
Sandstones deposited in deep marine environments form important hydrocarbon reservoirs in many basins around the world. Interbedded mudstones can be important as source rocks, as well as acting as barriers, baffles and seals. Deepwater reservoirs are currently the principal target for oil and gas exploration, with over 1600 existing turbidite fields and plays.
Instructors: Dr Mark Bentley (AGR TRACS International) and Prof. Philip Ringrose (Equinor)
This short course will provide an introduction to reservoir model design, covering the following main design elements:
- Model purpose;
- The rock model;
- The property model;
- Model scaling;
- Handling uncertainty.