Wellhead Movement Analysis with a Finite-Element Model for Well Integrity Assessment of Complex Configurations
| Autor: | Albert R. McSpadden, Richard G. Cooper, Ruggero Trevisan |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
business.industry
Well integrity 02 engineering and technology Structural engineering 010502 geochemistry & geophysics 01 natural sciences Finite element method Movement analysis 020401 chemical engineering Wellhead 0204 chemical engineering business Geology 0105 earth and related environmental sciences |
| Zdroj: | Day 1 Tue, March 03, 2020. |
| DOI: | 10.2118/199606-ms |
| Popis: | Analysis of mechanical and thermal-induced wellhead growth and resultant loads is critical for tubular stress design and failure analysis of offshore platform wells. A particular need to address is the growing trend of field life extension projects for platform installations in which outer structural casings are retained. In most cases this involves installation of a new completion and often entails well conversion to new purposes different from the original design basis. Another key feature is the use of mudline suspension (MLS) systems for wells drilled in various water depths. For well integrity assessment of these and other complex configurations, wellhead movement analysis with a 1-D finite-element model (FEM) is described by which diverse configuration and analysis scenarios are accommodated in a comprehensive analysis. The wellhead movement analysis presented uses standard FEM techniques for structural analysis with 1-dimensional linear or non-linear bar members. This is based on the familiar structural stiffness matrix. Because the wellbore system may be discretized as needed, it is straight-forward to accommodate a wide variety of well configuration options and well integrity factors. Likewise the wellhead movement model need not be limited to a single degree of freedom (DOF) at the wellhead itself but rather can and should accommodate the full complexity of the real-world configuration. Hence multiple degrees of freedom involving multiple MLS hangers or failed components are included for explicit analysis. Due to the aging infrastructure of many mature offshore assets, the ability to economically and safely exploit remaining reserves may depend on the suitability of retained casings. Thus it is necessary to accommodate a variety of infrastructure integrity issues such as wall loss from corrosion, weakened connections, and damage to cement or grout. Another frequent design issue arises from the prevalence of MLS systems. These introduce an extra degree of freedom which makes wellhead movement analysis more complex, especially if problems arise during installation. Problems with tiebacks in a well featuring an MLS system do arise and a case study is given to demonstrate the level of flexibility required to correctly and safely assess operational parameters. Aside from the analysis model itself, the interaction of wellhead movement and well integrity degradation on ageing and re-purposed offshore platform wells is given detailed attention. Also potential complications involved in MLS configurations are demonstrated. Building on previous work, the analysis methodology and case studies discussed in this work provide an explicit and intuitive approach to wellhead movement and loads. Certain types of wellhead load events which are not accommodated using available commercial software are modeled and analyzed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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