• Graham, Gordon M.
• Collins, Ian R.

Abstract

<jats:title>Abstract</jats:title><jats:p>The current practice of overboard discharge of produced water from offshore facilities is becoming increasingly less attractive owing to environmental concerns and the impact of more stringent regulations. An alternative to overboard discharge is produced water re-injection (PWRI) into depleted reservoirs or into non-communicating aquifers. However, as offshore developments become more complex, with new fields producing through existing facilities, PWRI must face the problems involved in combining and re-injecting incompatible fluids and/or production chemicals. In this paper we describe a laboratory testing programme which was devised to aid in the development of a PWRI scheme for a North Sea facility. In the proposed re-injection scheme, produced waters from five fields are combined at a central facility prior to re-injection. Initial brine/production chemical compatibility tests identified potentially problematic incompatibilities. A series of formation damage core floods were performed to investigate the effect of these incompatibilities on injectivity into reconditioned reservoir core material from the proposed re-injection well. These tests were followed by further core flooding work in which alternative solvent-based strategies for the amelioration of incompatibility issues were investigated. From this sequence of tests emerged a PWRI protocol suitable for advancement towards field trials.</jats:p><jats:p>This paper describes typical problems encountered in the development of multi-well produced water re-injection projects using commingled waters produced from different fields containing potential incompatibilities both from the co-mingled brines themselves and also as a result of the diverse range of treatment chemicals present in the individual production streams. The strategies employed to overcome these problems in this field case are discussed.</jats:p>

Topics

• impedance spectroscopy
• laser emission spectroscopy