Effects of Drilling Mud Physicochemical Properties On Native Prairie Soil and Vegetation.

Exploratory and development drilling for oil and natural gas in native prairie is common in parts of North America. Drilling waste disposal in these sensitive ecosystems, however, often presents challenges to the petroleum industry. In western Canada, provincial regulations allow disposal (or landspraying while drilling, LWD) of spent water-based drilling muds (WBMs) on native prairie, in some situations, at low application rates. However, there is a lack of scientific information on the long-term effects of such a practice. The objective of this study was to explore the relationships between drilling mud physicochemical properties vs. soil and vegetation properties following spent WBM application on a semi-arid prairie in southern Alberta. This was part of a larger study that also examined the effects of differential WBM application rates, timing, and frequency on native prairie soil and vegetation properties. In this presentation, we focus on the use of partial least squares projection to latent structures to identify spent WBM properties that could be used to predict effects of LWD on soil and vegetation attributes.