Continuing advances in onshore drilling fluid technology are driving the need for improved biological and chemical testing techniques focused on the terrestrial environment. Efforts have been undertaken to re-incorporate ASTM E1676 “Standard Guide for Conducting Soil Toxicity Test with Lumbricid Earthworm Eisenia foetida” to the testing of drilling fluid components. This technique uses a soil matrix and allows for identification of toxicity values and characteristics for the base fluids, the salt, and the weighting agent as individual components or within a whole drilling fluid.

The soil provides a matrix in which testing can occur, however, it is possible to elevate the ecological relevance with the use of simulated drill cuttings spiked with whole drilling fluid. This allows for the determination of relative toxicity between various substances as reported by the worms and test matrix. Such spiking techniques also address the key targets of repeatability and practicality.

Toxicity information based on ASTM E1676 with the worms is a biological evaluation tool for soil health, but a full understanding of impacts should also be determined in conjunction with additional biological and chemical analysis. These are based on soil health and leachate (including chlorides, electrical conductivity, and heavy metals). The use of whole drilling fluid and simulated drill cuttings provides a matrix in which these can be performed for a supplemental testing suite in addition to the efforts on worm toxicity.

Primary Author / Conference Presenter:
Patrick Tyczynski
M-I SWACO, a Schlumberger Company
Houston, Texas, USA

Kristina Daeffler, M-I SWACO, a Schlumberger company
John Candler, M-I SWACO, a Schlumberger company