Approach Allows Safe, Environmentally Sound Well Abandonment in Urban Setting
Authors: C. Carpenter
Year: 2023


 
 This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31394, “An Electrifying Integrated Solution Toward a Safe and Environmentally Sound Well Abandonment in an Urban Setting,” by Syah I. Mohamad and Lambertus C. Joppe, SPE, Baker Hughes. The paper has not been peer reviewed. Copyright 2022 Offshore Technology Conference. Reproduced by permission.
 
 
 
 In the Netherlands, many onshore wells are near urban areas or close to forests where emissions and noise reduction are important to consider. A depth of collaboration is required to ensure minimal impact upon the local community and the environment. The operator, together with Baker Hughes as the project management lead, formulated a low-impact solution with fully electrified equipment that mostly uses grid power.
 
 
 
 The project consists of plugging and abandoning (P&A) onshore oil and gas wells in 23 locations across the Netherlands. The main objective is to abandon all planned wells without any remaining liabilities; reduce cost burdens upon taxpayers; and minimize the impact on people, environments, and assets (PEA).
 Before the execution phase, the wells are categorized as simple or complex. The work may consist of a range of services such as slickline, electric line, cementing, pressure pumping, and downhole fishing and can include cutting, pulling, and milling. These services are provided as an integrated well-abandonment campaign with a single point of contact—the project manager.
 A typical well consists of a single 3½-in. or 4½-in. production tubing, 7-in. or 7⅝-in. production 9⅝-in. intermediate casing, and 13⅜-in. surface casings. Wells are approximately 3000 m deep, with some having well-integrity issues requiring annular remediation. Because these wells are more than 50 years old, the wellheads generally have a distinct set of challenges before well entry.
 A typical well P&A sequence would require installing a mechanical plug by slickline and setting a cement plug to provide the primary barrier. A second phase of well P&A may consist of cutting and retrieving tubings and casings. In some wells, cement remediation is required before retrieving the conductors to restore well integrity and establish a competent barrier envelope during P&A. The latest annular remediation methods were applied to this project, such as perforate, wash, and cement; and perforate, circulate, and cement and section milling.
 This subsurface work is not possible without the use of a hydraulic workover unit (HWU). The HWU capabilities for this project must meet the criteria of well P&A activities to be conducted while several optimizations are considered at the same time, such as footprint reduction; quick, efficient site-to-site and well-to-well moves; and minimal tripping time.
 
 
 
 A well P&A design often involves contingency measures to minimize any chance of failure within the primary design. For example, a secondary well-barrier envelope is prescribed in addition to the primary envelope in the unlikely event that the primary envelope is compromised at any point after execution.