Offshore oil and gas extraction carried out on large drilling platforms faces many technical challenges and risks. Offshore drilling requires specially formulated drilling fluid, also known as mud. The mud is used to lubricate drilling equipment and to prevent potentially catastrophic blowouts.
A blowout is the uncontrolled release of hydrocarbons under extremely high pressure that can erupt from the sub-sea well hole. Very specific measures are deployed to prevent and contain these blowouts.
barite And Blowouts
The natural mineral barite is often added to mud as a “weighting agent” to provide density to the fluid in order to equalize the pressures encountered in the drilling process. This prevents damage to the surface that could restrict oil or gas production.
Barite is both heavy and non-magnetic, which is essential to safe and effective sea-based drilling. The weight allows the fluid to create a heavier-than-water blanket on top of pressurized pockets during drilling. The non-magnetic properties of barite also ensure there is no interference with sensitive drilling instrumentation. The deeper the hole, the higher percentage barite is needed.
Barite must be ground to a small, uniform size before added to mud. The required properties are specified by the American Petroleum Institute or other international agencies. Precise mixing of the mud is carried out by drilling fluid companies, with engineers mixing and controlling the fluid before pumping it down the hole.
Offshore drilling requires large quantities of blended mud that require specialized logistics and turnkey bulk systems to transport, mix and dispense. These systems must include barite, as well as bentonite clay to maintain fluid viscosity, plus other additives like sodium bicarbonate, soda ash, oils and other specialty products.
These bulk systems are delivered from suppliers in Scandinavia to platform construction facilities, mainly located in Singapore, Malaysia, Korea, Brazil or China. The packages include one or more bulk solid holding tanks containing drilling cement used for stabilizing the drill-hole with casings.
The number of bulk system units on a drilling platform or ship depends on the size of the rig. Normally, it is four, but can range from two to 12. As soon as the rig platform or ship has arrived at its drilling location, it needs to fill bulk solids tanks with barite, bentonite and drilling cement. Supply vessels carry these materials from a base situated onshore near the rig, and the dry powders are blown from the supply vessel into the bulk tanks on the platform.
OFFSHORE Sampling SOLutions
During this filling process, samples of the solids need to be obtained. This process could happen once a week or every two weeks, depending on the activity on the rig and the need for material.
Properties that need to be sampled are specifically weight, size fraction and humidity. These properties undergo rigid quality control and documentation due to the extreme costs involved if a catastrophic event (like a blowout) should occur. Additionally, these rigs need to have appropriate sampling equipment to have a drilling license.
Therefore, a reliable bulk solids sampling solution is key for any offshore drilling operation. This system should be able to:
- Handle nearly any bulk solids and powder sampling application
- Offer trouble-free operation in harsh conditions
- Assess exact operational requirements
- Be configured by size, flow, materials required, accessories and more
As a critical yet relatively inexpensive part of each complete bulk system and drilling platform, samplers are considered critical to providing a safe and efficient operating environment in some of the harshest conditions on earth.