Assessment of HPHT Conditions: Survey of Industry Requirements
By D Smyth-Boyle
Within the Oil and Gas (O&G) industry, the term High-Pressure High-Temperature (HPHT or HP/HT) is often used to describe hydrocarbon production wells (i.e. oil and/or gas producing) that exhibit abnormal behaviour due to elevated downhole pressures and/or temperatures. The first reported HPHT reservoir was discovered by Shell in 1969, which led to the development and use of the first 20ksi wellhead system in 1972 and 30ksi system in 1974. The term HPHT as applied in the O&G industry denotes conditions beyond the prevailing norm and thus has evolved with time, but is often used to describe downhole pressures and temperatures at and beyond 10,000 psi (10ksi/ 69MPa/ 690bar) and 150°C (300°F). The term HPHT has only recently entered common usage, due in part to the comparatively small number of HPHT wells in operation.
In 2014, TWI proposed to develop an ambitious High Pressure High Temperature (HPHT) sour testing capability with public funding support under the Structural Integrity Research Foundation (SIRF) project, in response to expressions of interest from Industrial Members. However, the expressions of interest did not convert into actual testing requirements following the reduction in oil price.
The purpose of this report is to clarify the current and future O&G industry requirements in the area of materials testing, structural integrity and joining, and in support of HPHT technologies. The initial step involved identifying the key stakeholders with interests in HPHT, including national and independent oil and gas producers, supply chain manufacturers, regulatory agencies and engineering standards bodies. Topics of concern included design (verification and validation), material testing and selection, and manufacturing. Some of the important non-technical aspects used to assess the commercial viability of HPHT resources are also discussed. This information is used to assess current capability and facilities at TWI and make informed judgments on future resources, in order to ensure that TWI continues to provide an important service for Industrial Members.
- API TR 17TR8 provides the most up to date and comprehensive design approach for HPHT developments, based on use of laboratory measurements of material resistance to crack extension under fatigue and fracture as design inputs.
- Significant empirical work is required before API TR 17TR8 can be developed into an engineering standard, which TWI may be able to contribute to on behalf of its Industrial Members.
- TWI should continue to develop its sour fatigue and fracture capability, both with respect to testing and ECA, in response to evolving Industrial Member needs for elevated temperature and pressure and HPHT developments.
- TWI should watch developments in data treatment and artificial intelligence and seek to apply the latest technologies to extract the maximum benefit for Industrial Members from TWI’s historic data and future data capture processes.
- The market requirements for HPHT development are not compelling, as technically simpler, lower-cost and lower-risk options are always available to independent producers and national oil companies, so it is likely to remain a niche activity.
- The timing of the transition to ‘New Energy’ and large-scale electrification of transportation is uncertain but all oil and gas producers are likely to seek to adapt their current business models accordingly, which will impact HPHT developments.
Hierarchy of pressure and temperature tiers (namely HPHT, ultra-HPHT and extreme HPHT). (Adapted from Avant et al, 2012: ‘Testing the limits in extreme well conditions’, Oilfield Review, Vol 24, No 3, pp. 4-19).
Location of HPHT wells. (Adapted from Debruijn et al, 2008: ‘High-pressure, high-temperature technologies’, Oilfield Review, Vol 20, No 3, pp. 46-60).
Publications associated with HPHT in the O&G industry from 2000 to Q1 2019.