HPHT Experience

High pressure high temperature environments typically present unique set of challenges for the entire well life cycle i.e., design, planning, construction, completion, production, and abandonment phases. The challenge gets amplified by the presence of gases like CO2 and H2S and other harmful elements such as lead, mercury and or elemental sulphur. The mixture of highly corrosive environment assisted cracking (EAC) risks with high temperature and pressure is what makes the HPHT environment challenging for the entire well life cycle.

WellPerform follows IADC Lexicon, NORSOK D10 and Oil and Gas UK HPHT guideline to define HPHT environments i.e., surface pressure equal to 10,000 psi (690 bar) or higher, bottom hole static temperature equal to 150 deg. C (300 deg. F) or higher and/or reservoir overpressure gradient of 0.8 psi/ft. Also refer to below infographic.

WellPerform is actively involved in supporting operators i.e., not only in the North Sea (offshore) but across other geographical locations worldwide in providing niche engineering, planning, and operational support including HPHT well management services.  

An overview of WellPerform recent HPHT wells experience is presented in the info graphics below.

One of the recently completed HPHT projects is summarized here.

WellPerform was engaged in 2023 for a 10-day HPHT review workshop by a large national oil company in North Africa. The purpose of this workshop was to review the existing HPHT well design, planning, and operational approach and to identify gaps specifically in context of HPHT gas field located in the Sahara Desert. The context wells are deep (TVD ca 5500.0m) and potential frac. candidates.

Expected bottom hole static temperature was ca 175deg. C (350 deg. F) and post frac. high gas production rates are expected to result in high production temperatures at the surface.

The workshop was attended by senior engineers from the drilling and production department. Key focus areas identified were:

• HPHT Design standard and HPHT operations procedure/guideline – A MUST.
• API/NORSOK/NACE/ISO standards required for HPHT Well Application.
• Technical workshops, risk assessments and HSE for HPHT Operations (DWOP, TWOP, CWOP, HAZID, HAZOP).
• 15K Compact WHS w/Mandrel Hangers, lock rings,Metallic Seals etc.
• All casings with premium connections CAL IVqualification a requirement for primary flow-wet and secondary non-flow-wet barriers.
• Flow-wet OCTG material – Group 1 or Group 2 CRA(Super 13 Chrome 110 ksi or higher). Refer to API 5CRA for more information ongroup 1 and 2 CRA.
• Group 1 or Group 2 CRA material for other well consumables – Well head, tubing hanger, Flow-wet liner hanger systems (LHS),Tubing retrievable sub surface safety valve (TRSSSV) etc.
• Hydraulic set LHS with bi-directional slips – Expandables not an option.
• Special focus on the cement/Mud/Frac. design for high temperature compatibility and stability.
• MPD – detailed evaluation required. Elevated Well Control preparedness.
• Drilling/Logging tools survival assessment underhigh temperature exposure.
• BOP selection and qualification for the high temperature sections, Mud cooler deployment for 12 ¼” section and 8 ½”reservoir section drilling.
• Well fixity considerations including N2 cushion deployment and annulus pressure management implementation.
• Engineering Software’s for well engineering (design and planning) and for material selection etc.

Connected capabilities include:

Design Standard: Authored framework for HPHT design work for several operators in the North Sea, Europe, and South Asia.

Material selection: Follow the link to read WellPerform’ s recommended step wise approach on “Metallurgy Selection for a HPHT well”.