In oil and gas industry, a specialized drilling fluid known as high-vis sweep is often used and its primary purpose is to optimize hole cleaning and remove cuttings from the wellbore. What distinguishes this fluid is its heightened viscosity, a quality achieved by incorporating polymers or other additives into the base drilling fluid. This augmented viscosity empowers the sweep fluid to transport cuttings up the annulus out of the well.
High-vis sweeps are particularly useful in directional and horizontal wells, where cuttings tend to settle at the low side of the wellbore due to gravity. The higher viscosity of the sweep fluid helps to resuspend these cuttings and prevent them from accumulating, which can lead to various drilling problems, such as stuck pipe and reduced drilling efficiency.
Here’s a concise overview of the principal characteristics and applications of high-vis sweeps in drilling operations:
High Vis Sweep Characteristics:
- High viscosity: Typically ranges between 100 to 200 seconds on a Marsh funnel.
- Increased shear rate: Facilitates the maintenance of viscosity even under high flow rates.
- Higher mud weight: May slightly exceed that of the base drilling fluid.
- Cleaning the wellbore: Effectively removes cuttings and debris from the annulus.
- Preventing stuck pipe: Averts the accumulation of cuttings, reducing friction.
- Enhancing drilling efficiency: Improves hole cleaning and reduces drilling time.
In addition to these primary functions, high-vis sweeps can also be harnessed to:
- Control fluid loss: The elevated viscosity aids in sealing micro-fractures in the wellbore.
- Improve wellbore stability: The increased mud weight offers enhanced support to the wellbore.
- Enhance mud properties: The additives augmenting viscosity can also positively impact other mud properties, such as gel strength and lubricity.
In the grand scheme of things, high-vis sweeps emerge as pivotal players in upholding efficient and successful drilling operations within the oil and gas industry. Their efficacy in thorough wellbore cleaning, stuck pipe prevention, and drilling efficiency enhancement positions them as invaluable tools for drilling professionals. The two images below show results before arrival of High-Vis Sweep and during High-Vis Sweep on a shale shaker. It can be seen that High-vis sweep bring a lot of cutting in comparison to the baseline performance.