ABSTRACT

Within the Oil&Gas activities, the Produced Water (PW) management is a key aspect to deal with.

This study aims at identifying and testing a sequential methodology applicable to different offshore environments for the assessment of environmental effects associated to potential PW management solutions, such as injection, discharge into the sea, etc.

For the quantification and comparison of the environmental pressures associated to the involved processes (drilling of injection wells, pumping, water treatment, discharge), a standard Life Cycle Assessment approach, in line with the ISO 14044, is implemented.

Then an integrated approach is adopted to screen for the presence of biodiversity and ecosystem services (biodiversity screening), combining global and local datasets and scientific bibliography, in order to identify the significant receptors potentially occurring within the project area.

In order to evaluate with a quali-quantitative approach the significance of the effects on receptors, a matrix approach is proposed, combining:

  • the sensitivity of species and habitats to project pressures;

  • the magnitude of the local pressures.

Lastly, considering the potentially high significance of some effect, a further detailed modelling of a specific impact can be carried out.

The result of the process shall be a complete and quantitative assessment of the best option for PW management, both from a global prospective (LCA considering processes and project peculiarities) and from a local prospective (focus on receptors through biodiversity impact assessment and dispersion modelling).

INTRODUCTION

This study aims at identifying and testing a Methodology for the assessment and comparison of the environmental effects associated to different solutions for the management of produced water (PW).

The study is focused on a Gas Field project located offshore (about 200 km from coasts, see next figure), used as Pilot test for the application of the Methodology. Reinjection and discharge into the sea are the 2 options considered for PW management in such project.

The present paper describes both:

  • the methodology, applicable also to other environments and to other PW management options, such as transfer to an authorized site, reuse, etc.;

  • the assumptions, inputs and results for the Pilot test project.

Keywords:
project area, scenario, information, assessment, upstream oil & gas, impact category, hydrocarbon, produced water discharge, receptor, water management
Subjects:
Environment, Water use, produced water discharge and disposal
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2019. Offshore Mediterranean Conference
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