Qualification of Well Barrier Elements - Test Medium, Test Temperatures and Long-Term Integrity

Abstract

This paper presents the challenges related to qualification and testing of well barrier elements related to the long-term integrity test, the exposed medium, the temperature, and how the testing and qualification are performed. The paper shows that the International organization for standardization (ISO)/ American Petroleum Institute (API) standards for well barrier elements such as drill pipe, BOP, packers and bridge plugs, subsurface safety valves, casing and tubing connections, gas lift equipment, and cement can be improved in relation to long-term integrity testing, the test temperature and the test medium.NORSOK D-010 is a well integrity standard developed by the Norwegian petroleum industry and available at www.standardnorge.no. The standard defines the well barriers as an envelope of one or several barrier elements preventing fluids or gasses from flowing unintentionally from the formation, into another formation or to surface. The standard states that the permanent well barrier should have long-term integrity properties. The long-term integrity test of well barrier elements is not described in NORSOK D-010 or in any other relevant ISO/API standard. The industry does not perform long-term integrity tests and this paper discusses the factors that need to be considered.The paper illustrates that the industry needs to further concentrate on qualification of the well barrier elements. The well barrier elements will impact well integrity and the possible degradation of the construction of the wells. The control of the well barrier status and quality is an important HSE factor in order to avoid incidents and major accidents caused by unintentional leaks and well control situations. Knowledge of well integrity status at all times enables the companies to take the right action in a proactive manner and thereby prevent incidents from occurring.

Types of Permanent Plugging Materials

“…4.13. The particles are kept packed by the electrostatic forces (Zeta potential 2 ) between the solid particles and the conducting fluid [37]. Figure 4.14 shows a commercialized unconsolidated sand slurry which has been used for both temporary abandonment and permanent abandonment operations.…”

“…As permanent plugging materials are intended to withstand downhole conditions with an eternal perspective, their long-term durability should be examined. The durability should normally be tested in accordance with recognized standards, however, there is no such standard for alternative materials to cement [37]. As unconsolidated sand slurries consist of quartz sand, silica fume, and crushed rocks, their interactions with downhole chemicals seems to be less probable.…”