Thermally Insulated Tubing Application to Prevent Annular Pressure Buildup in Brazil Offshore Fields

Abstract

AbtractHeat transfer issues in offshore wells construction and maintenance are increasing in last years. New production development scenarios are bringing challenges related to flow assurance, well construction and maintenance. Insulation projects are being considered to enable the oil and gas production. This paper presents the studies carried out in two projects of thermal insulation using VIT (Vacuum Insulated Tubing) technology and its structural and thermal evaluation using commercial software for numerical simulation.The present work aimed to evaluate VIT application in a production string to reduce APB (Annular Pressure Build-up) effects. This event happens when production flow is heating any well confined annulus causing its fluid expansion and increasing pressure inside it. In this way, annular pressure build up can lead casing collapse or burst even, in an exteme condition, production string damage. All these effects combined could lead to unacceptable well losses. VIT is uded to avoid APB effects.However, a VIT string isn't be able to provide a smiliar collapse and burst resistance than a usual same dimension tubing string. So VIT will dominate the string installation and production constraints due its back pressure lacking. In this way production string performance evaluation is a key issue on VIT design, length and technical specification.In order to evaluate the performance of the production string designed for two Petrobras projects, several numeric simulations were performed to evaluate loads and strains on intermediate casing and production string during its installation and well production, including the APB events.In addition, the length of pipes with insulation needed to mitigate the effect of AFE was defined and a sensitivity analysis performed to define the value of the minimum apparent thermal conductivity, which would allow operation without risk to well integrity.

A Review of Research Status and Prospect of Vacuum Insulated Tubing Insulation System

“…At present, the technology of high-efficiency heat preservation and insulation abroad is relatively mature, and the technology of vacuum heat insulation tubing is widely used in the world. The application of VIT in Troika Oilfield in Britain keeps the fluid in the wellbore at a higher temperature and reduces energy consumption; the high-efficiency heat insulation pipe used in Kern River Oilfield in the United States reduces the energy loss of the wellbore by about 5%; the heat insulation tubing has been applied in actual production in Gulf of Mexico [11] and offshore oil field in Brazil [12] .…”

A Review of Research Status and Prospect of Vacuum Insulated Tubing Insulation System

“…At present, the technology of high-efficiency heat preservation and insulation abroad is relatively mature, and the technology of vacuum heat insulation tubing is widely used in the world. The application of VIT in Troika Oilfield in Britain keeps the fluid in the wellbore at a higher temperature and reduces energy consumption; the high-efficiency heat insulation pipe used in Kern River Oilfield in the United States reduces the energy loss of the wellbore by about 5%; the heat insulation tubing has been applied in actual production in Gulf of Mexico [11] and offshore oil field in Brazil [12].The VIT produced by ConocoPhillips is successfully applied to in waxy crude oil extraction technology under arctic environment [6]. In the wellbore of deep water oil field in Gulf of Mexico, VIT has been successfully used for heat insulation, solving the problems of paraffin deposition and hydrate blockage, which hinder the flow of well fluid.…”

Heat Transfer Modeling of Wellbore with Vacuum-Insulated-Tubing (VIT)

“…However, in some conditions, the induced temperature redistribution can impact the wellbore integrity and/or its intended functions. Wellbore failure can occur as a result of annular pressure buildup (APB), caused by heated annuli fluid thermal expansion (Ferreira et al 2012;Vargo et al 2003;Azzola et al 2007), and the hydrate formation because of produced hydrocarbon temperature loss resulting in flow assurance issues (Feeney 1999;Lively 2002). In such cases, temperature management is required to control the temperature changes at an acceptable level to protect the fluid in the tubing or to protect its outside surrounding components.…”

“…Over the past three decades, VIT has proven to be an effective thermal isolation management tool in increasingly challenging environments, including deepwater challenges, steam challenges, and onshore challenges (Purdy and Cheyne 1991;Azzola et al 2007;Bradford et al 2004;Ellis et al 2004;Ellis et al 2004;Ferreira et al 2012;Li et al 2010;Singh et al 2007;Pattillo et al 2004;Lively 2002;Feeney 1999;Karra et al 2014;Kutzak and Gunn 1989;Nowinka et al 2005;Gonzales and Bajwa 2010).…”