Drilling Waste Management

ViST is Vacuum Shaker Screen Technology which is developed and designed by GN Solids Control. The shaker screen vacuum unit is to work with shale shaker to reduce drilling waste and recycle drilling fluids. At some jobsites, clients use screen vacuum unit to replace drilling waste high G drying shaker.

There are insert type screen vacuum unit and external mounting type screen vacuum unit. For GN own design shale shaker and some other shaker model which use frame screens, if there is space to insert the catch pan (tray) under the outside discharge end shaker screen, we call it insert type screen vacuum unit. It is relative small modification on job site shale shaker. If for GN brand shale shaker, all shaker models reserve the design to add screen vacuum unit directly.

For insert type vacuum screen unit, the catch pan is fixed directly under the discharge side shaker screen. The screen API size depends on the shale shaker API screen, or the high G drying shaker API screen.

But for the external type screen vacuum unit, the client will use a small screen after the shale shaker or high G drying shaker.
Some clients want to use very fine screens, like API-230,270 and 325 while they add the external screen vacuum units to the shale shakers on offshore drilling rig mud system.

GN Solids Control does not recommend clients to choose such fine screens for external screen vacuum unit after solids control shale shaker. As solids control shale shaker does not use very fine screens. The high G drying shale shaker may use fine screens. But API 230, API 270 and API 325 are not used by solids control shale shaker. The small screen API size should be similar to the shale shaker screen. It cannot be too fine. Otherwise, it may cause block.

In other job site while clients use the screen vacuum unit for GN shale shakers, the max. shaker screen API size they use is API 120 and API 140. Hardly over API 140.

A drilling waste dewatering unit and a solidification unit is finished the installation at job site in Africa. The client start to use the dewatering unit and the drilling cuttings solidification unit to treat the waste slurry.

It is a 20ft containerized dewatering unit used at this job site. There is a 3-tank automatic polymer dosing system and a single tank PE tank for liquid chemical. The single PE tank is for manual operation. Client can choose to use both dosing system or either of them.

A 14 inch decanter centrifuge is used together with the chemical dosing system for dewatering treatment. Normally, there will be a shale shaker or high G drying shaker used before decanter centrifuge for reducing the solids content and remove the big size solids. But at this job site, there is no big size particles, and the solids content is small. The client does not need to use shale shaker separater, but use dewatering centrifuge separation directly.

After decanter centrifuge dewatering treatment, the client will use the solidification unit to make the solids waste dry. GN Solids make automatic drill cuttings solidification unit, all auger inside the solidification unit are equipped with VFD control panel. The operators can set up feeding speed before start the solidification unit.

Besides the containerized dewatering dosing system, GN Solids Control offers different sizes of 3-tank automatic polymer dosing system and single tank liquid chemical dosing unit. Clients can choose different models and modular to use it separately, or use more sets for bigger capacity.

GN Solids Control makes various sizes dewatering centrifuge, the bowl size is varying from 9 inch, 14 inch, 18 inch, 22 inch and up to max. 30 inch. And GN Solids Control offers fixed speed control, VFD control and FHD control to various size centrifuges to meet clients’ demands.

GN Solids Control also makes screw conveyor, sludge and solids vacuum pump, vertical cuttings dryer, oil sludge separation unit and waste oil/water treatment unit to meet different applications.

In April, a full set of drilling cuttings washing system is ready for commissioning for a China client at client’s job site. The drilling cuttings washing system is used to wash and separate oil base drilling cuttings and oil sludge generated from oil and gas drilling, and refinery.

There are 7 treatment modular in this drill cuttings treatment washing system:
1.Pre-treatment: A set of coarse shale shaker is used in this modular for crushing the big rocks and for pre-seperation. It is the pre-treatment before all separation steps.
2.Screening separation modular. There is a high G drying shale shaker used in this step to remove the big size particles.
3.Washing modular with static mixing for mixing and preparing solids and liquid mixture. After that, the liquid mixture can be separated by next step separation equipment.
4.Liquid and Solids separation modular with decanter centrifuge for 2-phase separation. It is the 1st time liquid and solids separation.
5.The 2nd time washing modular with dewatering treatment to remove the fine solids in the liquid.
6.The 2nd time 2-phase decanter centrifuge separation unit for ultra fine solids separation.
7.The liquid recovery modular.

It is a a full function oil based drilling cuttings washing and separation system with a full set of separation and treatment equipment. Below list is the major treatment equipment used in this oil based drill cuttings washing system:
1.A Drum shale shaker is used in the pre-treatment unit to crush the big rocks and remove it.
2.A high G drying shale shaker is used in the screening separation modular to remove the big size particles. It is the most hot sale shaker model GNZS594F which is widely used in oil and gas drilling solids control systems.
3.2 sets of static mixing unit are used in the 2 stage washing modular.
4.A inclined plate clarify is used for soil settle down in the oily liquid, which is discharged from decanter centrifuges.
5.Screw conveyor and belt drive conveyor are used in the system to feed for shaker and for solids discharge from decanter centrifuges and shale shakers.

High G drying shaker and vertical cuttings dryer are the major products for drilling cuttings treatment. This week, some sets of high G drying shaker are vertical cuttings dryer are packed for shipping to an offshore drilling company. The high G drying shaker are installed on a small holding tank. There is a centrifugal pump used as transfer pump to transfer mud out from the small holding tank.

The different is that, high G drying shaker is mainly used to separate water base mud and water base cuttings. While vertical cuttings dryer are used to treat oil base mud and oil base cuttings. In some cases, vertical cuttings dryer can be used to treat water base cuttings. But it is easier to be blocked than high G drying shaker.

High G drying shale shaker utilize API RP13C complied shaker screen. Operators can choose suitable API screen to reach the expected cut point. But vertical cuttings dryer use screen basket. Most supplier can only offer 2 sizes of bigger opening screen baskets. GN Solids Control offers 3 options of screen basket: 0.25mm, 0.35mm and 0.5mm. Operators can choose the suitable size per his job site situation and their performance demands. Generally speaking, the fine opening can get more clean liquid, and it may cause more block than big size screen opening. And the more the feeding flow rate, the wetter in the solids discharge.

Vertical cuttings dryer itself cost higher than high G drying shaker. And its motor power is much higher than high G drying shale shaker. But while be used to treat oil base mud, Vertical cuttings dryer can reduce the oil on the cuttings to 3% ~ 5%. But the high G drying shaker can only reduce oil on cuttings to 10% ~ 15%. There is a much difference.

Normally, water base mud is used at the the early drilling sections, and oil based mud is used at deeper drilling. In this case, some clients will choose both high G drying shaker and vertical cuttings dryer to treat WBM and OBM separately. Clients can also choose neither high G drying shaker or vertical cuttings dryer per their job site situation.

As the oil sludge treatment is a new trend. It means a new business scope for many companies. Many clients do not have much experience before they run GN waste management plant.

In order to ensure they have enough knowledge to operate the unit and reach good performance, GN Solids Control will send engineer to job site to help for the first time commissioning. GN engineer will support to test the treatment unit with real oil sludge and to train their stuff about how to adjust the system based on the material situation in order to reach a good performance. And GN engineer will give training about normal maintenance and trouble shooting if requested by clients.

Recently, GN Solids Control engineers just finished the commissioning job of an oil sludge treatment plant. The treatment plant is for a China domestic client which is used in China. It is a middle size oil sludge treatment system with 14inch centrifuges to treat oil contaminated wastes. And it is also the most popular size oil sludge treatment plant.

It is a complete oil sludge treatment plant for 2-phase and 3-phase separation. Below is the major separation plant of the oil sludge treatment plant for this project:

1) The 1st modular of the oil sludge treatment plant is premixing and heating tank package. The solids and liquid inside the raw oil sludge is not equal. Or some time, the solids control is too much high. The first stage is to prepare the sludge and make it suitable for separation. The processes which maybe be used in this stage are: mixing, dilution, heating, chemical dosing. Clients and chose 1 or more process based on the material situation.

2) The 2nd modular is drying shaker tank unit for coarse separation. The drying shaker is customized with rubber sealing cover and steam nozzle pipelines for heating. Clients choose the right API shaker screen to remove particles above a certain sizes.

3) The 3rd modular is decanter centrifuge C/W a holding tank for 2-phase separation.

4) The 4th modular is 3-phase centrifuge C/W holding tanks

5) The 5th modular is containerized dosing system to supply chemicals for the whole treatment process.

Vertical cuttings dryer (vertical centrifuge) and decanter centrifuge are major separation equipment for drilling mud and drilling cuttings treatment. A set of vertical cuttings dryer can decanter centrifuge are ready for shipment in GN Solids Control factory. They will be shipped to an international drilling company for waste management.

Vertical cuttings dryer in this project is GN latest model GNCD930E-VFD with advanced design. Mostly, fixed speed control is used for vertical cuttings dryer. For this project, client choose VFD control panel for the vertical cuttings dryer to control the rotation speed and G force.

Vertical cuttings dryer is also called as vortex centrifuge or vertical centrifuge. It is the major separation equipment to treat oil base mud and oil base cuttings. It can used to treat drilling cuttings discharged from shale shaker, desander and desilter. But it cannot treat drilling cuttings from decanter centrifuge. As decanter centrifuge is used for fine solids separation. GN Solids Control offers 3 options for screen basket opening of vertical cuttings dryer: 0.25mm, 0.35mm and 0.5mm. The soil cake from decanter centrifuge is too fine. They will all go through the screen basket. No solids can be removed while treat decanter centrifuge solids.

As the screen opening of vertical cuttings dryer is big opening. The solids control and mud weight will be high for the mud recovered from vertical cuttings dryer. In order to reduce the mud weight for reuse, decanter centrifuge will be used after decanter centrifuge for fine solids separation. Cut point of high speed decanter centrifuge is 2~5 microns. After centrifuge separation, the mud can be qualified for reuse.

Decanter centrifuge used in this project for the international drilling company is a big bowl model GNLW553C-VFD. It is a big bowl big volume centrifuge with VFD control panel for variable speed control. The big bowl centrifuge is usually used for waste management.

GN Solids Control applied the technology of heating washing and chemical enhancing to treat oil sludge, oil slurry, waste oil and water.

Heating system of GN oil sludge separation system

GN Solids Control equips heating pipes inside mud tanks of the oil sludge separation system, and heating pipes and nozzles on coarse separation shale shaker. Clients can choose electrical oil heating system or electrical steam heating system for the application.

As the normal temperature is high enough. The function of heating is to reduce the viscosity of the oil sludge. Another reason of heating is to maximize the performance of chemical agents. The most suitable temperature for chemicals is around 70C degree. In some countries of Middle east, heating system is not necessary.

Chemical agents used for oil sludge and dewatering treatment

There are normally 3 types of chemicals will be used for oil sludge treatment. Clients can choose to use 1 or 2 or 3 types of chemicals based on the sludge situation and separation demands.
1) Sludge separating agent or surfactant: If the oil sludge viscosity is till high and difficult to separate after heating, sludge separating agent can be dosed before separation. The function is to improve the separation performance of the oil sludge.

2) Demulsifier: After sludge separation agent, demulsifier can be added to make the oil sludge emuisified, to remove the oil and water in the emulsified oil-water mixture.

3) Flocculant (PAM) or coagulant (PAC) : for ultra fine solids separation before enter into decanter centrifuge and disc centrifuge. If you already dosed demulsifier, you should consider and calculate carefully to see you add PAM / PAC or not. As demulsifier is to make oil, water and solids separated. But PAM / PAC is for flocculation. PAM / PAC will reduce the demuisifier performance and to make the oil, water and soil mixture again.

In some projects, acid or alkali will be dosed before separation to balance the PH. If you need to add acid or alkali, it is normally added before other chemical agents. The suitable PH can improve separation performance in some degree, but not much.

Oil and gas drilling, refinery, and crude oil production will all generate a large number of oil sludge waste.The oil sludge waste generated from drilling, refinery and crude oil production have complex composition, which may cause serious pollution to the surrounding environment and wasted resources. As this reasons, it is essential and necessary to treat the oil sludge waste, to reduce and minimize the waste in order to protect our environment.

GN Solids Control utilizes heating washing technology with chemical enhancing system to treat the oil sludge from oil and gas drilling and refineries. 2-phase / 3-phase decanter centrifuge and 2-phase / 3-phase disc centrifuge are used in GN oil sludge treatment system.  The major function of GN oil sludge treatment system is to reduce the solids and liquid waste volume before enter into superior processing equipment.

The water recovered from GN oil sludge system can be reused in the separation system, or use the water for injection. But the water cannot be discharged into environment. They need further slurry separation treatment before discharge. The recovered oil can be sold to refinery companies. The solids can be used as construction field material, like to to make bricks for road construction.

With suitable chemical dosing, below is the major parameters of soil, oil and water after separation from GN oil sludge separation system:

The Oil on Solids Discharged from Decanter Centrifuge is around 1-3%. The solids waste volume is greatly reduced, clients can send the solids waste to TDU company to treat. The cost will be much lower than you buy a TDU. As the cost of TDU and its operation cost is greatly high. Besides TUD, the clients can also use Biodegradation technology to further reduce OOC to 0.5% or less.

Recovery Oil from 3 phase centrifuge BS&W is around 2-3%. Clients can sell it to refinery company.

Oil Content in recovery water from 3 phase centrifuge is 1000-3000PPM. The recovered water can be reused for premixing tank inside the treatment system.
You can add a Water Treatment system to reach 50-100PPM (Oil Content, Water after treatment unit). Or you send the water to slurry treatment company to treat for you.

GN Solids Control makes various sizes and types of decanter centrifuge for various applications. GN Solids Control various types of decanter centrifuge is designed for the drilling mud solids control and oilfield waste management. GN Solids Control VFD drive decanter centrifuge with variable speed allows drilling contractor or mud service companies to do the barite recovery, fine fine and ultra fine solids separation, dewatering centrifuge.

GN Solids Control makes the decanter centrifuge from 9 inch bowl to 22 inch bowl available for different applications. GN Solids Control decanter centrifuge bowl length and diameter ration is over 3, this gives the best result for the drilling fluids cleaning.

The smallest decanter centrifuge made by GN Solids Control is 9 inch. GN Solids Control makes 2 sizes of 9 inch bowl mini centrifuge. Besides GNLW224EP-VFD decanter centrifuge, GN Solids Control has another fixed speed decanter centrifuge with a shorter bowl length. The model type is GNLW223D.

The decanter centrifuge mostly supplied for the dewatering treatment process is GNLW224EP-VFD. The bowl of the centrifuge is 9 inch (220mm). As the compact design, GN Solids Control 9 inch decanter centrifuge is popular for client to use it in small capacity or limited space application for solids and liquid separation.

GN Solids Control 9 inch decanter centrifuge is also considered to be the ideal choice for experiment testing with decanter centrifuge. GN Solids Control 9 inch decanter centrifuge is optional in three types includes: fixed gear box drive, fully hydraulic drive, and variable frequency drive. GN Solids Control 9 inch decanter centrifuge is widely used for Industry Waste Water Treatment and for Diamond Core Drilling Fluids Treatment.

The centrifuge type is with 220mm diameter x 924 mm long Duplex Bowl. The duplex scroll with hardfacing and unique feed zone. Clients can also choose tungsten carbon tiles for more durable and for longer service time. The GNLW224EP-VFD decanter centrifuge is designed for 5000 RPM maximum speed, resulting in 3077 G force. While working with the VFD control panel, the type speed is ranging from 0 to 4500 RPM, and to generate maximum 2492 G force. All wetted area of GN decanter centrifuges are either Duplex or SS materials, all wear area’s are protected with replaceable Tungsten inserts.

Recently 2 sets of drilling waste management equipment are ready for shipment. They are customized for an Africa project. The drilling waste management equipment will be used to treat oil base mud and oil base drilling cuttings which generated from oil and gas drilling field. All equipment inside the waste management system are customized with client appointed color.

The 2 sets of drilling waste management equipment including following items:
1) Vertical cuttings dryer. Quantity: 2 sets. Model: GNCD930.
Vertical cuttings dryer is also called as vertical centrifuge. It is the major processing equipment to treat oil base mud and oil base cuttings. Vertical cuttings dryer can separate oil on the cuttings to 3% ~ 5%. Before vertical cuttings dryer treatment, the oil on the cuttings is around 10% ~ 20%. It means the vertical cuttings can recover more usable drilling mud with oil, which is valuable. More recovered oil means save more cost for clients. And further more, more recovered fluids means less wastes generated from the process. It can also save the cost of hazardous material shipment.

2) High speed decanter centrifuge. Quantity: 2 sets. Model: GNLW363C-VFD
GNLW363C-VFD is a 14inch high speed decanter centrifuge. It is the most popular size decanter centrifuge used for drilling mud solids control system and drilling waste management system. The typical speed of GNLW363 is 3200RPM. In some projects, clients want high speed decanter centrifuge over 3200RPM, GN Solids Control can also offer. The max. Typical speed of GNLW363 can up to 3600RPM. GN Solids Control can offer fixed speed control for 14inch decanter centrifuge for easy operation. GN Solids Control can also offer VFD control and FHD control for the 14 inch decanter centrifuge.

3) Screw conveyor. 4 sets. Each vertical cuttings dryer will use 2 screw conveyors. One screw conveyor is used to feed cuttings to vertical cuttings dryer. Another screw conveyor is used to transfer the discharged solids from vertical cuttings dryer.