Researchers from CSIRO, in conjunction with US firm Halliburton Energy Services’ Baroid Drilling Fluids, have developed a low-cost, environmental product to help alleviate this industry headache: ‘green muds’.
“Our aim is to reduce drilling costs, improve performance and operate within increasingly strict environmental limits – and the new ‘green muds’ have the ability to do just that,” says team leader Dr Chee Tan.
The ‘green muds’, were created by CSIRO and Baroid to perform as well as traditional oil- and synthetic-based fluids when drilling difficult oil wells.
A world patent has been filed for the formulations, which are being comercialised by Baroid as the BarOmegaÔ (Osmotic Membrane Efficiency Generating Aqueous) drilling fluid system. The new muds are now entering field trials in the Gulf of Mexico and the North Sea.
“The ‘green muds’ can also be more cost-effective than oil- and synthetic-based fluids which are normally used to maintain shale stability in the drilling of long-reach wells.
“One clear advantage of this is that if operators can drill successfully and economically out to 10 kilometres or beyond, fewer platforms are needed to exploit the field.”
The key to drilling these long wells in shale is to maintain the precarious balance between drilling fluid pressure and rock stresses over extended periods of time.
Although they go by the unromantic name of ‘muds’, drilling fluids are in fact delicate works of art, combining:
· weight to prevent hole collapse and to withstand formation pressure
· lubricity
· thermal stability
· high drilling penetration rate
· ability to prevent stuck pipe
· good ability to transport cuttings smoothly
· resistance to contamination
· efficiency of the membrane with which they ‘coat’ the surface of the wellbore.
To this exacting list of qualities has now been added one other vital requirement: because the fluids are usually disposed of at sea, the oil industry is under growing pressure to reduce the environmental impact of drilling.
“For this reason we have to design fluids with the entire life-cycle in mind, right through to final disposal,” Dr Tan explains. “We can foresee a time, not far away, when the marine disposal of oil- and synthetic-based fluids may be banned in most parts of the world.”
The new ‘green muds’ contain special polymers which ‘coat’ the surface of hole and prevent, or at least minimize, fluid from the drilling mud from seeping in and destabilising the wellbore.
Dr Tan and his team of scientists from CSIRO Petroleum are now working at ARRC (the Australian Resources Research Centre), the South-East Asian Region’s new centre of expertise for Petroleum, Mining and Minerals research.
ARRC is located in Perth’s Technology Park and also houses CSIRO’s Exploration and Mining Division and Curtin University of Technology’s Department of Exploration Geophysics, Centre of Excellence in Petroleum Geology and Department of Petroleum Engineering.
More information:
Dr Chee Tan, CSIRO Petroleum
61 (0)8 6436 8769
Email: Chee.Tan@csiro.au
0413 457 195
Deanne Paisley, CSIRO Petroleum
61 (0)8 6436 8707
Email: Deanne.Paisley@csiro.au
0408 947 030