Extreme HPHT Projects - Tailoring a VAM® Connection to the Application

04/01/2017 - Oil&Gas

OCTG supplier perspective: Lessons Learned from supply to Extreme HPHT Projects
HPHT wells are critical and demand a high degree of coordination from the initial design phase to the running of the tubulars. Vallourec has been actively involved in HPHT projects globally over the last 30 years. The Group has developed extensive knowledge and capabilities through its interaction with operators on their projects worldwide. This has generated numerous lessons learned including mitigation of issues, improved efficiency, increased analysis and enhanced performance.

In this series we will share HPHT Case Studies highlighting aspects of three projects and the Lessons Learned.

Case study 1 – A VAM® Connection Tailored to Application

An HPHT well in Asia downhole conditions were at around 19000psi, 350degF, along with mild H2S exposure. The requirement was for the 125ksi production casing to withstand loads and be suitable in terms of weight requirements. The existing solution of 10 ¾" 110.2# VAM® HP SC 80 exceeded the performance requirements. The test data was already available per connection envelope and well loads. However, it was not suitable for the application due to dimensional constraints, and therefore a new OD and design were required.

Working with the customer, Vallourec identified the new required design through an iterative process on development of a new pipe and connection. This lead to the development of the 10 ½" 96# VAM® HP connection for the project. Through collaboration an agreement was reached on the extrapolation philosophy, the connection testing protocol was modified, a new pipe dimension was developed, and material was rolled for connection testing.

Lessons Learned:

Success requires active involvement from all partners at the initial stages. This process allows definitions of requirements to be clearly communicated, and highlights all aspects (testing, timing, contingency) along with 'risk' effect.

The aim was to utilize connections from existing portfolio where possible. However if not possible, the customer and supplier need to look at iteration and extrapolation from existing connections to reduce testing time and costs. A new connection development can take up to 1.5 years from development to completion of testing. In either case, Vallourec provided substantial FEA analysis and strict testing protocols ensuring the quality and performance of the connection to be used in the well.

For the project to be successful, the end user and Vallourec agreed on philosophies. Thus all parties shared the same understanding, definitions and responsibilities. This allowed the project to move faster and be more cost effective. It also resulted in risk reduction in testing. The defined connection testing parameters (used 140ksi) were more extreme than downhole conditions, and provided support for future developments.