Published: 12/28/2015
Published: 12/28/2015
For performing pit cleaning onboard the Ocean Valiant semisubmersible rig in the UK sector of the North Sea, Premier Oil has historically used traditional tank-cleaning methods, including high-pressure washers and vacuum units to clean the rig tanks between changing drilling fluids. This process is not only time consuming but also heavily relies on personnel confined-space time and generates large volumes of waste washwater, which then have to be properly disposed of at a significant expense.
After consulting with Premier Oil about its objectives, M-I SWACO recommended using the ATC automatic tank-cleaning technology, which comprises a skid-mounted washwater recycling unit and programmable tank-cleaning machines (TCMs) that can be deployed on hard-to-reach areas. The technology requires only 7 m3 [44 bbl] of washwater, which is continuously cleaned and recycled throughout the cleaning process for reduced wastewater generation.
As a result, the technology delivers significant reductions in personnel confined-space time, overall pit-cleaning time, and the volume of wastewater and slop created compared with the traditional methods used in past pit-cleaning operations.
ATC technology was rigged up and cleaned six pits in 56 hours, representing a 90% reduction in cleaning time compared with previous operations using traditional tank-cleaning methods. Only one hour of confined-space time was necessary to place the TCMs in one of the tanks. A fixed volume of 7 m3 of washwater with 1% surfactant was used during the cleaning job. By deploying the ATC technology, Premier Oil achieved a 56% reduction in wastewater generation compared with the cleaning method previously used.
Challenge: Reduce personnel confined-space time, overall pit-cleaning time, and volume of wastewater created while cleaning the tanks of a semisubmersible rig in the UK sector of the North Sea
Solution: Deploy the ATC automatic tank-cleaning technology
Results:
