Abstract

Insulation is a critical aspect of offshore production systems, particularly in deeper waters where low ambient temperatures must be addressed and accommodated. The problems are normally associated with the effects on the flow stream when heat is lost to the surrounding environment. However, there are some situations where it is not the effects on the production stream from heat loss that is the problem, but the effects on the surrounding environment that creates the problem. This paper primarily focuses on the situation where reservoir heat in a production stream creates a technical problem in the area surrounding a well bore. The paper then presents a new insulation technology that was evaluated as part of the solution and discusses the successful outcome. The results are then used to address the potential utilization of this new technology for other flow assurance related heat control applications where the retention of heat in the production stream is desired, such as the need for insulating subsea flow lines, jumpers, manifolds, xmas trees, production risers and other associated production equipment.

Introduction

As the petroleum industry expands into new geographical areas for the exploration and production of hydrocarbons, new technical challenges arise. These new challenges sometimes require entirely new technical solutions in order to provide the step-change necessary for technical as well as economic success.

One aspect of this expansion is the increasing need to control the inherent heat in flow streams produced from hydrocarbon reservoirs and how this heat passes to and from the production stream during production. This has become a major part of the industry issue now known as "Flow Assurance". In some situations, retaining the reservoir heat in the production stream prevents problems associated with the production stream itself. In other situations, retaining the reservoir heat in the production stream prevents problems associated with the surrounding environment when excessive heat is transferred to it.

In many cases, it is not possible to control the reservoir heat by conventional flow assurance strategies. However, it is fundamentally desirable to avoid adding additional strategies to keep heat losses to a minimum, as each one generally results in the requirement for additional capital expenditures and/or additional operating costs. Therefore, the efficient control of reservoir heat can result in a sometimes-significant impact on life of field economics and ultimately the field's overall economic viability.

A heat control problem that is common in cold environment wells was encountered in a deepwater Gulf of Mexico (GOM) well. The problem was casing overpressure and is discussed in more detail below. To resolve the problem an insulation system utilizing a newly developed thin-film, multi-layer insulation material in conjunction with Vacuum Insulated Tubing (VIT) was selected for the well completion program. The well was brought on stream, and data of the well's thermal profile was collected and compared to the initial model developed to predict thermal performance of the insulation system.

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