The Niger Delta Process Safety Dilemma: Restoring & Maintaining Well Integrity in the Face of Perennial Asset Vandalization

Abstract

Abstract Safely operating Oil and Gas wells in the Niger Delta region of Nigeria has become quite challenging to achieve owing to the prevalent vandalization of assets in the operating environment. The asset vandalization ranges from minor theft of Christmas tree accessories, flowlines vandalization, to major wellhead damages and in some cases, wells get blown up with explosives by criminal elements. The major dilemma for the operations teams in this environment lies around how to (not only) restore integrity on wells with a complex state of vandalism, but also how to produce these wells safely. Restoring integrity on vandalized wells depends on nature of damage. For subject wells, the complete wellhead systems were severed and carted away with only Down Hole Safety Valve and production packer preventing the release of hydrocarbon. Restoration included design of a false rotary, fishing of the severed tubing stumps on drill pipes, installation of plugs above the safety valve and chemical cut of the tubing above the plug. Casing plug was installed above cut tubing depth as second barrier. Casings were then cold cut below impacted depth and tied back to surface. NDT, heat treatment carried out on weld joints. In this paper, the unconventional well integrity challenges faced in the Niger Delta onshore wells (Ukp- wells 1, 2, 3 and 5) and the in-house capabilities (innovative and unconventional steps) developed to address these challenges are presented. The wells in this paper had all concentric tubulars severed from below the casing head housing and carted away by vandals. These wells had a very high potential of damage to the environment and reputational impact to the company due to the HSE exposure level, apart from not conforming to the Company's well integrity policy of a minimum of two (2) tested and independent barriers. The Well Integrity restoration team showcased various innovative ways which were applied in other to secure these wells safely, bearing in mind the non-existence of barriers for standard rig up of equipment for the securing operations. Integrity was successfully restored on the wells through the unconventional novel approach. The Heat treatment and NDT ensured integrity of the weld joints for safe rig up of the planned HWU for the abandonment. This innovative approach prevented the potential process safety incident which could have led to asset, environmental and reputational damage. This paper would detail the history of the wells, planning, design and execution of the innovative in-house integrity restoration operation. The operation led to a total cost saving of US$1.8mln versus plan for the four vandalized wells that were restored.