Abstract
As the number of mature wells that are no longer economically viable increases, so does the need for effective well abandonment processes that meet stringent environmental and regulatory conditions. Because of varying well configurations and types, a unique or more tailored engineering approach is required to meet plug and abandonment governmental requirements, as well as operator-specific objectives for varying well designs. Through proper planning and design, this method also decreases operational and health, safety, and environmental (HSE) risks for a variety of challenging scenarios. This paper presents case histories of the successful use of a single-trip abandonment approach that saves time for the producers by addressing specific well types by simplifying the abandonment process in an economical and flexible manner through engineering planning and shaped-charge performance design.
The single-trip abandonment approach can drastically reduce associated costs common in well abandonment campaigns, including rig time and support services that are involved in making multiple trips in and out of the well. With an average rig rate of USD 500,000 per day for floaters, USD 100,000 per day for jackups, and USD 60,000 per day for barges (Rigzone 2015), any reduction in rig time exposure can be beneficial to the producer. By providing a method of successfully abandoning a well in one trip, as opposed to separate trips involving the cutting and removal of casing strings, the single-trip well abandonment approach allows producers to successfully plug and then spot cement in a combined action, permitting an expedited well abandonment process.
Through extensive testing and development of both tool technology and shaped-charge design, the single-trip well abandonment approach has proven to be a versatile and an effective system for a variety of well abandonment scenarios. Providing flexibility in operational capabilities for abandoning a well, squeezing off zones, providing limited casing entry, and allowing annular cement squeezing for remedial work, the single-trip abandonment approach has proven to be reliable and efficient, particularly in operations in the AsiaPac region. Using the engineering aspects of advanced tubing-conveyed perforating (TCP) design and capabilities as a building block in the single-trip system allowed for the successful implementation of required abandonment procedures while also providing the capability to be deployed in a variety of casing sizes, weights, and wellbore conditions.
This paper provides an in-depth study of the technical design, advanced modeling, multiconditional testing, and shaped-charge optimization of the systems for the single-trip abandonment approach. Additionally, the paper provides beneficial information that could be applied to well abandonment projects around the world.
