Application of a mathematical model to determine the source of produced water in an oil field
Abstract
The XY, an oil field in Southern off shore Vietnam, has produced oil from a basement reservoir since 2003. In order to maintain reservoir pressure, water injection has been started from Dec 2004. Water was first appeared in produced fluid from the well X-1 in May 2004. Water encountered in other wells started to increase in late 2005. Hundreds of water samples were taken and analyzed. Analytical results indicated that the chemical compositions of produced waters vary from well to well and even from time to time in some wells. For monitoring and optimizing production performance, determining the source of the produced water was required, and this was set as the main objective of this study.
A mathematical model, the so-called the Linear Mixing Model was developed, mainly based on the statistical assessment of variation of conservative chemical species in available produced water analytical results, to identify all possible sources and the contribution of each source to the produced water. The results of the model indicate that the produced water is a mixture of three sources: formation water, injected water and drilling fluid. Among these sources, formation water is the dominant component in almost produced water samples.
This paper presents the mathematical model which was successfully applied to determine the source of
produced water in the XY oil field.
References
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