Adaptability of Coiled Tubing Technology Enables Complex Well Abandonment in Gulf of Mexico Inland Waters

Abstract

An operator drilled an inland waters well in the 1960’s in southern Louisiana. By the time the well was scheduled for plug and abandonment (P&A), the canal had been transformed into wetlands and significant silt had built up around the wellhead, thus increasing the complexity of the abandonment operations. The environmental impact to the wetlands would be minimized by laying mats around the well in preparation for coiled tubing (CT) operations. However, these mats laid out on the soft wetlands would not safely support the excessive weight of the CT unit and reel, so they were rigged up on a barge 125-ft away from the wellhead. A CT drilling tower was used to provide stability to the wellhead stack. The wellbore conditions (11,300 psi MASP and 313 deg F BHT) increased the complexity of this operation further, requiring a very thorough job planning process. A mock rig-up of equipment was performed before mobilizing equipment to location to ensure the stability of the wellhead stack. The CT operations were completed successfully which allowed the operator to complete the decommissioning of the well. This paper presents a case study that demonstrates the adaptability of CT technology to meet the special requirements of well abandonment in the inland waters environment of the Gulf of Mexico.