Abstract

A data base containing information on up to 70 physical and chemical parameters for 118 produced water samples collected from 47 sampling locations at 18 heavy oil recovery sites in Alberta and Saskatchewan was developed by Environment Canada's Wastewater Technology Centre. One use of the data is to determine treatment requirements for produced water recycle. It was found that treatment to reduce oil, total suspended materials, iron and hardness concentrations to make the produced water amenable to recycle would be necessary for all regions sampled. Treatment for silica and total dissolved materials removal would be required for produced waters from the North Cold Lake region and Cold Lake/Lloydminster regions respectively.

Introduction

Water produced during the in-situ recovery of heavy oil (termed "produced water") contains a variety of dissolved and suspended contaminants, both inorganic and organic. The identification and quantification of these contaminanls are essential in determining the requirements for the treatment of the produced water for disposal, or for recycle to oil field steam generators. Therefore, Environment Canada's Wastewater Technology Centre (WTC) inijiated a sampling program in 1984'. The objective of the sampling program was to develop a comprehensive data base on the characteristics of produced waters from in-situ heavy oil recovery operations in Alberta and Saskatchewan. This paper presents the data from the produced water characterization program, and summarizes the mean concentrations and distribution of selected parameters in the major heavy oil regions of Alberta and Saskatchewan. Particular emphasis is placed on the parameters which are most relevant to produced water recycle (i.e. oil, total suspended solids, total dissolved solids, iron, hardness and silica).

Experimental Details

Generally, the oil industry in Alberta and Saskatchewan recognizes live distinct heavy oil producing regions: Peace River, Alhabasca, Wabasca, Cold Lake and Lloydminster. For the purpose of this paper, the Cold Lake region has been further classified inlo North, Mid and South Cold Lake regions. Also, the Uoydminster region is considered to have an additional sub-group: Macklin. The produced water characterization program entailed collection of produced water samples from all these heavy oil producing regions followed by analyses in the field and in the WTC laboratory in Burlington. One hundred and eighteen samples of produced water were collected from 47 sampling locations at 18 heavy oil recovery plants in these heavy oil regions. Table 1 shows the number or sampling sites and the total number of samples collected in each of these regions. The 47 sampling locations included 13 skim tanks, 29 well head tanks, 4 lest separators and 1 slop tank. In the case of tanks and test separators, the produced water samples were obtained from the lower section of the vessel. Table 2 lists the heavy oil recovery sites included in the study, and also indicates the sampling locations at each site.

Equations (available in full paper)

The sarotpling under this study started in August 1984, and continued until January 1986. The skim tanks and wellheads were sampled approximately once per month for 6 to 14 months, depending on the site, while the test separators were sampled only once during the sampling program.

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