A centrifuge is a device that works on the concept of centrifugal force. The centrifuge makes an object rotate around its own fixed axis, making a circular motion at a very high speed. A decanter centrifuge does the work of separating the mixture of solid and liquid in industries.
In a decanter centrifuge , when the mixture if fed, the centrifuge is rotated at a very high speed. As the centrifuge spins in a circular motion, perpendicular force is exerted on the mixture. This causes the denser substance in the mixture to move out in a radial direction, that is, towards the surface of imaginary circle, while the substance that is less dense moves inside radially, that is at the center.
In drilling waste management in industries, this process helps in separating solids from liquids like oil, so that the oil can be recycled and reused, thus protecting our precious natural oils.
As a decanter centrifuge is used in many industries like Food Processing industries, oil industries, waste water treatment plants and chemical industries , it is very important to optimize its performance so that there is minimum wastage and maximum efficiency.
Criteria for improved performance of drilling waste decanter centrifuge:
Before feeding the mixture to the decanter centrifuges , the mixture should preferably fed to a shale shaker. This shale shaker will separate big solids from the mixture. Then the resulting mixture must be fed to the decanter for further filtration. This will reduce the wear and tear of the decanter.
Right amount of centrifugal force must be applied.
The Speed of the decanter must be optimal so that the solids in the mixture are safely transported out of the machine.
The decanter centrifuge is prone to abrasion as the solids in the mixture may rub against the walls of the device. So proper care must be taken by using abrasion resistant material especially at the input zone and at the solid output zone.
Drilling waste cuttings treatment of Pit Less Mud Systems are also known as closed loop systems. In this closed loop systems solid control equipment are used to minimize the wastage of natural oils used in drilling. The solid control equipment that are used in pit less mud system are:
1) Shale Shaker :
This is the first equipment in solid control equipment for drilling waste cutting. It consists of s screen that does the work of separating the solid and liquid from the mixture. The screen comprises of mesh clot that is attached to a frame using tension. This is usually used for separating very large solids from the liquid. The slurry that is obtained is stored into a tank and then again sent for further filtering to a mud cleaner.
2) Mud Cleaner :
A mud cleaner combines two processes of desanders and desilters. Here they use a device that separates sand and silt particles from the drilling fluid. As these sand particles are fine, they cannot be removed by a shale shaker. Desander is used for removing solids that are abrasive in nature and dedilters are used to remove silts. The resultant mixture is then sent to a Decanter centrifuge.
3) Decanter Centrifuge :
It is a fast rotating device that uses centrifugal force and sedimentation principle to remove the solid particles from the drilling fluid. Here the machine is rotated very fast so that the solid which is of high density is forced to go out and the liquid which is of less density is forced to go at the center.
After the mixture is separated, the drilling fluid that is obtained can be reused as a drilling fluid. This not only saves the cost but also helps to prevent the wastage of our limited natural resource.
Also the solid that are obtained are first dried before disposing them or resuing thwm for some special purposes.
Thus some part of the drilling waste cuttings is reused and some part of it properly disposed in an ecofriendly manner.
Drilling waste treatment approach by Kosun play a very important role in reducing waste generated during drilling activities to acceptable levels of the environment.
Oil and gas extraction has been a trillion dollar industry and will be for years to come. Thus the process and consequences of the extraction of these precious gifts from the earth also needs to be considered with some level of seriousness.
Due to the heavy demand of these commodities on a global scale, the activities that led to its production increases significantly over the years. This in turn, led to the generation of large quantities of unwanted waste, referred to as drilling waste.
So some suitable method for its disposal was requisite to the keep the problem under control. As a result of this, scientists and experts developed some effective techniques for effective and economical disposal of drilling waste and let’s take a look at some of the popular ones.
Drilling waste produced as a result of extraction of oil and gas are mainly categorized based on two different criterions. The first one, based on the nature of particles in the waste is divided into fluid wastes and solid wastes. The second classification based on how harmful the waste is towards environment categorizes it into acceptable and non acceptable waste disposal. Non acceptable are considered more dangerous and volatile to the environment and needs to be disposed off with greater care.
Today, with much importance given to ideas of sustainability and conservation, many companies in the extraction have taken it into making the process more environmental friendly. This can be done only through an effective waste disposal system.
There are truck services and transportation services available today that moves this waste from the extraction area for proper disposal. Later it is disposed off or converted into a useful form, agricultural fertilizers for instance. Salt water spills, fresh water drilling mud, crude oil spills etc are the byproducts of inefficient waste disposal. In cases of oil spillage, specialized services are available as well.
Drilling waste management is one of the most frequent duties that should be performed in any drilling area. A skilled management system must be developed for the drilling waste management.
If any drilling company fails to perform certain sustainable procedure while drilling waste, it is certain to face the eye of the storm for the lack of competency in managing drilling waste. So, in order to solve this problem, a very approach has been taken by the drillers all around the world.
They have developed a certain agenda of fundamental procedure for drilling and disposing the drilling waste in an environment friendly way. This is called the oil and gas handbook for drilling waste management. Now, here is a brief discussion about the handbook of drilling waste management is given below.
The handbook of drilling waste management: According to the handbook in order to manage shale shaker generated oil and gas drilling waste, the construction and functioning of any commercial offshore waste management site, an application should be placed in front of the Environmental Bureau and to the oil conservation division.
A drilling company must confirm a financial assurance before establishing any waste management and disposal site in the area. Surface waste management facilities must only handle the non – intoxicating waste so that it can’t cause any environmental degradation.
There should be different approaches for managing different kinds of waste depending on their contaminating and radio activity level. The professionals that are responsible for managing the drilling waste must be certified and well trained. Drilling sites must not expose any intoxicating waste to the environment in any circumstance. After gathering waste from shale shaker, shaker screen there should be a proper and an extensive procedure to decontaminate the drilling waste right before the disposal.
Finally, the handbook for waste management provides the necessary and valuable guideline to the drillers for a sustainable waste management.
Drilling waste management companies – Kosun offer Oil and Gas handbook for gives a set of rules that must be followed to manage Drilling waste. It is available on requesting Oil and Gas Commission (OGC).
Drilling waste management companies told you that, it is important to first separate the mixture of solid and the drilling fluids. The drilling fluid that is obtained can be reused. The solids that are obtained must be either disposed of in an eco-friendly manner or can be used in some particular places.
Some the standard rules that must be adopted to minimize waste are:
1] Drilling Waste Containment:
• The waste obtained from drilling must be properly contained either in a sump (earthen hole) or good quality tanks.
• There must be proper record of how the drilling waste is stored and how is it disposed.
• It must not be mixed with other wastes.
2] Suitable Disposal Sites:
• The site where the waste is doing to be disposed must suitable and must not cause pollution.
• The suitability of the sites is soil is assessed and its salinity is measured.
• Any toxic waste cannot be disposed. These types of wastes needs to be treated.
• There are many reasons that can make the waste toxic, like, corrosion inhibitors, emulsifiers, lubricants, de foaming agents and even some type of bacteria.
3] Disposal Methods:
• There are many ways of disposing the waste of different kind.
• For water based mud systems, there are disposal options such as on- site disposal options and off-site disposal options.
4] Wastes from pipelines:
• When drilling a pipeline for fresh water or drilling a freshwater well, the drilling waste that is obtained here can be managed in many ways like, storage pits where pits are formed in soils and other off-site disposal options such as land spraying and land spraying while drilling.
Every process that is initiated has its outcomes. Oil drilling basically involves boring into the ground and penetrating rock by use of specially designed tools. During drilling, the rotary drill bit grinds downwards penetrating layers of rock. In the process, large rocks cuttings that have been broken up result. These rock cuttings are called drill cuttings. The process of drilling, separating and directing drilling fluid to the down-hole creates drill cuttings which are drilling waste.
However, drilling waste are not limited to drill cuttings alone. They involve
• Muds that have been so degraded that they can no longer be rejuvenated by recycling, but need to be disposed of.
• Mud that is discarded or spilled.
• Solid laden wet mud and cuttings that have been separated from the drilling fluid without having been recycled and are not useful for recycling.
• Solids that are removed by centrifuges from the mud stream.
Synthetic Based Muds (SBM) drill cleaner holes with minimal sloughing and produce less drill cuttings thereby generating less waste unlike the Water Base Muds (WBM). Most of the Oil Based Muds (OBM) and SBM are recycled and therefore minimize drilling fluid which reduces waste.
Wastage is a normal consequence of the drilling process. Drilling involves extracting the desired end product from a mass of other unwanted products such as sand, silt, fibres, drill cuttings and mud. Because the process involves drilling fluid and mud, the mass of waste is usually a wet mixture. If these unwanted products mix with the drilling fluid they will contaminate it and bring the process to nothing at inception. The use of Solid Based Mud (SBM) and Oil Based Mud (OBM) is recommended because they are less pollutant than the Water Based Mud (WBM) which cannot be recycled. It is important that companies adhere to the regulations governing drilling waste management.