Abstract As ADCO's oil fields mature, produced water increases. ADCO forecasts that the produced water may increase in the next 25 years as much as 10 fold (in excess of 600,000 BWPD by 2020 and more than 1,000,000 BWPD by 2027). On the other hand, in order to support the reservoir pressure, ADCO is sourcing brackish water from deep aquifers (D, S and U). The produced water is then disposed back into aquifer S. This practice has high financial and environmental costs:
In order to strategically manage increasing volumes of produced water as the main oil producing reservoirs reach maturity, ADCO started pilots to re-inject untreated produced water in three fields in early 2000: Field 1 in 2002, Field 2 in 2010 and Field 2 in 2003.
Positive pilot results in Field 1 led to field wide expansion of the Produced Water Re-Injection (PWRI) into one the oil bearing reservoirs and it was included in the Full Field Development Plan (FFDP).
A pilot for re-injecting untreated PWRI is currently running in Field 2 for the past 16 months at a rate of more than 20,000 bwpd. Positive outcome so far led to raising funds to extend PWRI network to achieve re-injection rates of 50,000 BWPD into one of the oil bearing reservoirs in this field.
The pilot for Field 3 was plagued with interruptions since the start caused by PWRI system material integrity issues which did not allow concluding so far whether untreated PWRI re-injection into one of the oil bearing formations is achievable. In order to address this situation, corrosion mitigation measures both for relevant surface facilities and downhole completions are being implemented and in parallel, an integrated coreflood testing/geomechanical properties study is on-going to assess the degree of treatment required to allow re-injecting produced water cost effectively in the most permeable oil bearing reservoir in this field.
ADCO's approach to managing increased produced water rates through pilots and learning from rock matrices testing/studies shows that managing field wide PWRI systems in a cost effective and environment friendly manner is achievable if planned sufficiently in advance and executed properly.