Evolving in the Cooper Basin
The Cooper basin of South Australia is home to some of the nation’s most significant on-shore oil and gas resources. This sedimentary basin possesses thick accumulations of coal and shale mature source rocks that contain multiple unconventional deposits; including tight gas, tight oil, shale gas and coal seam gas.
A major Australian oil and gas company recently discovered how Newpark’s high-performance water-based EVOLUTION® drilling fluid technology, could be used in the Cooper basin to boost the rate of penetration (ROP). This translated to roughly 50 percent fewer projected days in the lateral section of the wells being drilled, cutting as much as 7 days of drilling time and resulting in significant AFE cost savings.
Torque Trouble Solved
From October 2013 to December 2013, the company drilled its first horizontal shale well in the Cooper basin with the help of Newpark Drilling Fluids. The operator’s drilling plan for the well initially included only conventional water-based drilling fluid. The conventional water-based fluid was used in the 17 ½” vertical section and continued into the 12 ¼” build section. But once the 12 ¼” section reached a measured depth of 8644’, severe erratic torque was experienced as the well was drilling at a 50.6° angle through the Toolache formation (comprised of interbedded sandstone, siltstone, mudstone and shale).
Newpark recommended that EvoLube DPE be incorporated into the drilling fluid system to solve the problem and a sweep of 20 barrels containing EvoLube was run. There was an immediate reduction in torque. Additional concentrations of EvoLube DPE were added to the active system as operations progressed. Drilling continued, reaching an angle of 70°, where the 12¼” hole was cased and cemented without any further delays.
Due to the success seen in the well’s 12 ¼” section, it was decided that the 8 ½” production interval of the well would maintain the EvoLube DPE concentrations. Again, this section was drilled, cased and cemented without any difficulties.
On to the Next
Following the substantial benefits seen while drilling its first well, the operator once again turned to Newpark while drilling a second horizontal shale well in the Cooper basin. This time the company resorted to using EvoLube DPE at the outset to prevent any torque issues. The well progressed smoothly to a 9,579’ measured depth, 7 days ahead of the previous well for the same depth.
A geological side track was then drilled in just 8 days and the well was cased for the 12 ¼” build section without running into any of the torque problems encountered when using conventional water-based fluid. The 8 ½” lateral section was subsequently drilled in 8 days with no issues (totaling 3,585’). When comparing the progress made with the similar sections of the first well, the second well was drilled 10 days faster—despite being 1,121’ longer.
EVOLUTION at the Ready
The EvoLube fluid additive allows rigs with power/weight limitations to drill longer laterals than would otherwise be possible with a traditional fluid. Case in point, this major Australian oil and gas company decided to try it when faced with such a challenge.
Ultimately, by partnering with Newpark to explore use of the EVOLUTION suite of technologies, the operator alleviated the torque problems it encountered and was even able to finish the wells ahead of the projected time due to a drastic increase in ROP. Based on these successes, the company has continued to partner with Newpark to implement fluid solutions on 3 other rigs.