HPHT Well Engineering

HPHT (High Pressure - High Temperature) wells have a downhole environment of more than 10,000psi (690 bar) and/or 300 deg F(140 deg C).  These conditions are increasingly encountered in many basins worldwide, as exploration and production examine deeper and hotter objectives.

 

In attending this course,  participants will gain knowledge and develops skills relating to HPHT Well Engineering.  The course focuses on key characteristics and challenges of HPHT well design, planning and engineering . 

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It covers a range of topics including:

• Well Design  - Casing and drillstring design, well barriers, thermal effects,  drilling fluid and cement selection

• Operational Planning  - Rig selection, BOP equipment issues, Wellbore Breathing

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Competence Development

At the end of this course delegates should be able to:

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1. Understand the differences in well design between HPHT and conventional wells

2. Describe the effects of HPHT on casing and fluids design

3. Successfully pick casing seats to manage the transition from conventional to highly over-pressured formations

4. Understand the difference between working stress and probabilistic well design

5. Explain the impact of high temperature on casing performance properties

6. Quantify casing loads associated with HPHT wells

7. Perform biaxial collapse and triaxial burst casing design for HPHT wells

8. Identify rig equipment critical to HPHT well delivery and select rigs suitable for HPHT drilling operations

9. Explain and describe the challenges of well control in HPHT environments from pressure prediction, detection and well control procedures

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Course Content

The following subjects will be addressed during the course:

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Characteristics of HPHT wells –the industry definition of an HPHT well and examines the characteristics that make HPHT wells challenging.  A review of why HPHT wells fail is considered in order to focus attention on the key differences between HPHT and conventional wells.

 

Casing design in HPHT wells – a review of the principals of casing design with a focus on  the effects of temperature on casing design criteria, such as load and yield strength changes.  

 

The course will review uniaxial and triaxial pipe strength,  the implications of manufacturing standards and tolerances as per ISO 10400 and the impact of downhole environmental conditions. 

 

Participants will develop an understanding of the how connections are tested using ISO 13679 and how to select suitably pre-qualified connections for use in a well.

 

The importance of casing wear and it’s impact on casing design and well integrity are discussed.  Participants will master the process of detailed casing design, identifying relevant load conditions for the lifetime of the well and producing an optimised casing scheme that can withstand triaxial burst and biaxial collapse loading under downhole conditions.   HPHT Service Load design challenges such buckling and trapped annular pressures will be addressed as well as managing the impact of corrosion and casing wear

 

 

Drilling fluids and cement –  Temperature has a profound effect on drilling fluid rheology while the high gradients required to balance high bottom hole pressures create challenges to carrying capacity and barite sag.  High temperatures can also compromise drilling fluid additives.  This section addresses the selection and design of drilling fluids for HPHT wells including the choice between water based and oil based fluid systems.  Thermal impact on rheology and additive stability is discussed as is rig  fluid system design including shakers and mud coolers.  Thermal impact on cement slurries and cement placement practices are also addressed. 

 

Rig and equipment selection – A detailed review of the essential requirements of the rig and drilling equipment is provided which covers the rig, fluids control equipment and well control equipment, and instrumentation.  Particular attention will be given to qualification and testing of BOP equipment and the sizing and performance assessment of surface gas handling equipment.  

 

Managed Pressure Drilling (MPD) -  MPD offers solutions to a number of the challenges of HPHT well delivery, specifically the narrow margin between pore and fracture pressure through the transition zone.  Some Operators require all “dry BOP” HPHT wells to be drilled with MDP in place while recent riser developments are seeing subsea and deepwater HPHT wells using MPD equipment too.   This section addresses the benefits of MPD operations and examines the equipment and practises for its implementation in HPHT wells.

 

Well Control – Comprehensive knowledge and sound skills in the principals and practises of well control are critical to HPHT operations.   This section addresses pore pressure prediction and narrow margin environments and their profound impact on kick tolerance in the region of the transition zone.  The origin of abnormal pressure, and an explanation for narrow pressure margins between pore and fracture pressure is covered.  The causes of kicks and kick detection are addressed including early kick detection technology.  

 

HPHT Well Evaluation – This section reviews the temperature and pressure limitations of conventional logging tools and examines the equipment and operating practises now available to evaluate wells in hostile conditions.  Evolving technologies including ahead of the bit measurements and the use of real time petrophysical data to update pore pressure prediction models and optimise drilling fluid gradients will be discussed

 

HPHT Well Integrity and Failure Modes – This section will address well integrity problems associated with HPHT Well Delivery and Production.   A number of case studies will address problems encountered during the drilling phase, reservoir compaction during production as well as zonal isolation prior to and after well suspension and abandonment.