How can you clean drilling fluid in complex wells?

1 Choose the right mud system

The first step to clean drilling fluid in complex wells is to choose the right mud system for the well conditions and objectives. Different mud systems have different characteristics and advantages, such as water-based, oil-based, or synthetic-based muds. You should consider factors such as the formation type, the well geometry, the drilling parameters, and the environmental regulations when selecting the mud system. For example, oil-based muds can provide better lubricity and stability in complex wells, but they may also pose higher environmental and disposal risks.

2 Use adequate solids control equipment

The second step to clean drilling fluid in complex wells is to use adequate solids control equipment to remove the unwanted solids from the mud. Solids control equipment includes shakers, hydrocyclones, centrifuges, and filters that separate the solids from the liquid phase of the mud. You should use the appropriate size and configuration of the equipment to match the mud flow rate, the solids concentration, and the cut point. You should also monitor and adjust the equipment settings and performance regularly to optimize the solids removal efficiency and minimize the mud losses.

3 Apply proper mud treatment chemicals

The third step to clean drilling fluid in complex wells is to apply proper mud treatment chemicals to modify or enhance the mud properties and performance. Mud treatment chemicals include viscosifiers, thinners, weight agents, fluid loss additives, pH control agents, and scavengers that affect the rheology, density, filtration, and compatibility of the mud. You should use the recommended types and dosages of the chemicals to achieve the desired mud specifications and functions. You should also test and analyze the mud samples frequently to evaluate the chemical effectiveness and identify any potential issues.

4 Implement effective hole cleaning practices

The fourth step to clean drilling fluid in complex wells is to implement effective hole cleaning practices to prevent the accumulation of cuttings and other debris in the wellbore. Hole cleaning practices include selecting the optimal drill bit and nozzle design, maintaining the appropriate mud flow rate and velocity, applying sufficient pipe rotation and reciprocation, and conducting periodic sweeps and wiper trips. You should also use suitable hole cleaning tools and devices, such as stabilizers, reamers, scrapers, and submersible pumps, to assist the mud in transporting the cuttings to the surface.

5 Monitor and manage gas influxes

The fifth step to clean drilling fluid in complex wells is to monitor and manage gas influxes that can contaminate the mud and cause safety and operational hazards. Gas influxes can occur due to drilling into gas-bearing formations, encountering pressure transitions, or experiencing kicks or losses. You should use reliable gas detection and measurement devices, such as mud loggers, gas separators, and gas busters, to identify and quantify the gas in the mud. You should also follow the appropriate procedures and protocols, such as circulating out the gas, adjusting the mud weight, or activating the blowout preventer, to control and mitigate the gas influxes.

6 Optimize the mud disposal and recycling

The sixth step to clean drilling fluid in complex wells is to optimize the mud disposal and recycling to reduce the environmental impact and the cost of the drilling operation. You should follow the applicable regulations and standards for the mud disposal and recycling, such as the type, volume, and location of the waste. You should also use efficient and environmentally friendly methods and technologies, such as thermal treatment, biodegradation, or solidification, to process and treat the waste. You should also consider the potential reuse or recovery of the mud or its components, such as the base fluid or the weight agent, for future drilling operations.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?