Drilling mud Equipment

The drilling fluids is nowadays widely used in drilling projects and under the strict regulation on environment protection, how to minimize the discharge of environmental hazardous waste solids and maximum the drilling fluids recovery is the mainstream topic among the industry.
The using of mud tank to store the drilling fluids coming back from the drill well has been widely accepted and recognized by all the drilling contractors. Without digging a mud pit on the ground greatly reduce the pollution to the soil. Especially for some limited job area, the mud tank would be the preferred choice for drilling fluids. The using of the various kinds of the solids control equipment highly speeds up the separation of solids in drilling fluids.

The closed loop drilling mud solids control system, if complete configuration, will include 2 parts. Drilling mud solids control and waste drilling cuttings treatment. The purpose of this 2 parts is same for minimize the discharge of environmental hazardous waste solids and maximum the drilling fluids recovery.
For solids control, after treated by the shale shaker, desander, desilter, even the decanter centrifuge. The ultra fine solids particles would be removed out from the drilling mud, and then active mud could be re-used.
The waste cuttings treatment part is functioned to recovery as much as possible the drilling fluids and make the cuttings dry enough for easy transportation to further environmental friendly treatment process. The cuttings out from the solids control shale shaker and desander, desilter would be transferred to drying equipment first. The drying equipment would be different according to water base mud or oil base mud is used. A high G force drying shaker would be better for water base drilling mud cuttings. The Verti G cuttings dryer, e.g. GNCD930 cuttings dryer could be used for both the water base and oil base cuttings drying. The drilling fluids out from the drying equipment would be pump into high speed decanter centrifuge for ultra fine solids separation.
By doing so, the drilling fluids would be maximum recycled and no discharge to outside of the tank system. The discharge drilling cuttings is dry enough for further treatment. Greatly guarantees the environment protection and high working efficiency.

Oilfield operation need various electrical equipment like control panels, electrical motors and so on. All these electrical equipment performing well make sure the entire project job done well. But the most import is a safe working environment on the oilfield as there is the risk of explosion any time during oilfield operaton.

As per the define of the IEC (International Electrotechnical Commission), the explosion working environment is classified as gas explosive and dust explosive. When we talking about the explosion proof standard electrical equipment, we are talking about the equipment used in the various gas explosive working environment. And then according to the existence time of the gas explosive, the working environment is classified to 3 zones as below:
1. Zone 0 – Under normal operation condition, the gas explosive exists continuously. Always more than 1000 hours per year.
2. Zone 1 – Under normal operation condition, the gas explosive exists sometimes. More than 10 hours buy less than 1000 hours per year.
3. Zone 2 – Only under abnormal operation condition, the gas explosive exists. Always less than 10 hours per year.

The Zone 0 always represents some airtight space such the gas storage tank. On the oilfield, the Zone 1 represents the area around the drilling rig. And the area which includes the space for mud recycling system, mud pump, water tanks and other drilling field equipment. As per the minimum ignition power required, the gas explosive are classified as 4 degrades separately Ⅰ,ⅡA, ⅡB, ⅡC. This classification can also be treated as the equipment group. The equipment used in group Ⅰ is for mining industry. Group Ⅱ is for other industry working environment. The equipment used in group ⅡC can also be used in ⅡA, ⅡB which means the equipment in Group ⅡC has a higher explosion proof level.
GN could provide the solids control equipment with motor and control panel explosion proof certified. The explosion proof level is ExdⅡBT4 which could meet the demand of gas explosive Zone 2.

It is more often heard about dewatering unit in drilling industry but most of the persons in this industry are not very familiar with the dewatering unit. In this article, we may give a simple introduction on what is dewatering unit and the application.
Dewatering unit we can also call it ultra fine solids removing system. It always includes the polymer mixing system and fine solids separation system.

What is the composition of the dewatering unit

1. Automatic polymer mixing system.

GN dewatering unit automatic polymer mixing system is 2 tanks system. It is equipped with medical feeding system, water injection system, delivery system and mixing system, gauge system and electrical control system. This APM system has 2 screw conveyors, one is used to transfer the powder medicines to the hopper on the mixing tank, and the other screw conveyor is located under the hopper to deliver the powder into the pre-mixing tank. The pre-mixing tank would receive the powder from the screw conveyor and the water from the water injection pipe which could automatically inject the water as per the control of the control panel when the water flow gauge send the signal to the control panel. The mixing tank is divided into 2 parts and 2 compartments is same design and the function is also the same. According to the signal send to the control panel, one of the either compartments is mix the medicine while the other one is already full and to start the output of the flocculation.

2. Feeding System

GN’s dewatering system has 2 screw pumps used for transferring the flocculation and the slurry to the decanter centrifuge. The chemicals and the slurry meet at the feeding pipe of the decanter centrifuge and the flocs also produced here. Then the slurry with large size flocs gets into the centrifuge together and there for separation.

3. GNLW553-VFD dewatering centrifuge for separation

GN dewatering unit choose GNLW553 various frequency drive model as the separation centrifuge. The control panel is designed as four various frequency drive for the centrifuge main motor, back motor and two feeding pumps for slurry and medicals. After the separation of the centrifuge, the large size flocs would be removed out, then the ultra fine solids is separated out.
GN’s dewatering unit is also equipped with pre-separation system. The separation includes the shale shaker and mud cleaner which could remove the large size solids then make the drilling fluids could be fed into the centrifuge for dewatering process.

 

GN’s engineer just finished the commissioning in West Africa for 4 units GNLW363 centrifuge. Besides the centrifuge, this customer also ordered the screw pump and screw conveyor from GN Solids Control.
All most all the countries within the territory of West Africa or near the Gulf of Guinea have rich oil reserves. It is proven that the oil reserves at gulf of Guinea have more than 80 billion BBL, which accounts for about 10% of the world’s total reserves. In past several years, a large percent of the world’s oil production increase belongs to Africa.

GN solids control has established contact with many oil industry customers coming from the West Africa countries. Some of the customers already placed order to GN even repeated orders.

Applications of GN Decanter Centrifuge

GN’s decanter centrifuge could be used for various applications, from primary solids control system barite recovery to ultra fine solids separation to drilling waste cuttings management, then to dewatering unit system. Barite recover always need a centrifuge with RPM 1600 to 2000, GN has a model of GNLW452 is especially for solids control barite recovery. Some of the drilling contractors would also equip one unit high speed centrifuge after the GNLW452 for ultra fine solids control separation.

GN could provide centrifuge with both fixed speed control panel and VFD control panel. Just like this West Africa customer, they bought GNLW363G-VFD for their waste cuttings management. GN’s VFD control panel for centrifuge could be designed as 3 various frequencies for main and back drive on centrifuge, and the third VFD is for the feeding pump. With the VFD control panel, GN’s largest model of centrifuge GNLW553 would be used as dewatering centrifuge for waster base drilling fluids colloidal size particles separation. By using VFD panel, the user could adjust the feeding rate and RPM according to specified slurry material and working conditions. Comparing with the fixed speed model, the VFD model has a more wide application.

Drilling fluids is now widely used in oil, gas drilling and other drilling projects. By using the solids control equipment, the drilling fluids could be recycled many times for cost saving and environment protection. This article would give a simple introduction on the function of the drilling fluids.

What is the function of the drilling fluids

1. Flushing bottom of the well – the high pressure drilling fluids get out from the drill bit would flush the bottom of the well then make no obstacles for drilling process.
2. Carry cuttings – the drilling fluids would take the drilling cuttings out to the ground surface for mud cleaning process.
3. Balance formation pressure – due to very deep drilling, the drill bit may go through different formations such as rock formation and ground water formation. The drilling fluids here functioned to prevent the ground water getting into the drilling well. This would protect the geological structure.
Besides, the drilling fluids could also function to cool down and lubricate drill bit, protect borehole wall and provide downhole power.

To fully obtain the drilling fluids advantages, there are several requirements on the drilling fluids.

1. The drilling fluids should meet demand for drilling mud recycling
Drilling cycle request the drilling fluids low pump pressure (low fluid viscosity), excellent ability to carry cuttings (dynamic force is high), low starting pump pressure (low static shear force), good lubrication performance, low friction (less solids particles)
2. Maintain the stability of borehole
It is requested to use drilling fluids column to balance the formation pressure. And when drill oil and gas layer, the drilling fluids is also needed to balance the pressure of the oil and gas. That would request a stable density of the drilling mud.
3. Oil and gas protection
After drilling oil and gas layer, drilling fluid contacts with oil and gas. To prevent drilling fluid damaging the oil and gas layer, the drilling fluids should be small filtration, thin mud cake, low solid content and low filtrate of hydration etc.
4. Protect the nature environment
Drilling fluid often contains oil and crude oil, diesel oil and a large number of chemical agents. In order to prevent the possible impact on nature environment, non-toxic, harmless drilling fluids should be used.

It is known that the solids control system is part of the complete drilling rig system. So, always we see the drilling mud solids control equipment is equipped for the drill rig at wild field where the working condition would be various. Some places the weather is four-spring like, while some other places very cold. When finished the drilling job at one well, all the equipment would be disassembled and transported to next well. It always takes few months to move all parts of the drilling rig system. Solids control system is only small part of the drill rig system. However, if the solids control equipment could be moved easily, that would be also benefit for the whole transportation of the drill rig.

With the rich experience on solids control management and job working, some customers came to GN Solids Control and talked about their idea to build a drilling mud system which could be easily transported and all equipment could be operated and repaired indoor. What they preferred are two options: Containerized and Frame Supported.

For the containerized design, all the equipment would be located inside a container or a same size mud tank, which is completely closed and with doors for operator in and out. The advantages of this design the all operation would be completed indoor, especially for some area with bad climate condition. With air conditioner installed inside the container, winter to prevent cold and summer avoid hot sun. On the other hand, this containerized design may not have sufficient space left for the operator to move do maintenance job freely. For the big size equipment, it is also difficult to be put into the container. Once GN provided Russia customer 2 units containerized drilling waste cuttings management system. To lift out the huge cuttings dryer out from the container, the container was opened a door on top and use a crane to get the rotation part of the dryer out.

For the frame supported idea, the solids control equipment like shale shaker and decanter centrifuge would be installed in a strong steel frame, the frame size is same with standard container. When assemble the system, the equipment could be easily positioned. For the operation and maintenance, there is enough space as there will be walkways surrounded the frame. The operator could make a thick canvas cover to cover the whole system to make it a closed unit.

Both the containerized and frame supported system are easy for transportation as no equipment need to be disassembled before moving. The frame is design same fixing point with the container that makes the system trailer available.
Welcome contact with GN Solids Control to get a solution for drilling mud recycling.

Verti G cuttings dryer is specially used in drilling fluids solids control system to recover the waste cuttings out from the primary shale shaker and mud cleaner. At present, the company CSI is the world accepted most famous manufacturer for the Verti G cuttings dryer unit. No matter on quality and production series, CSI is the No. 1.

GN Solids Control has been dedicated to design and manufacture the Verti G cuttings dryer in the past three years, and now GN 2nd generation cuttings dryer have been tested successfully and already applied on site. GN’s verti G unit is workable for both the water based drilling mud and oil based mud which makes GN Solids Control occupy the first seed in China solids control market. To ensure the smooth performance of the verti G dryer, GN equipped on the unit with flushing and blowing system.

GN Verti G dryer flushing system

The flushing system on GN second generation verti G cuttings dryer is consisting of a screw pump and relative hoses. Usually the material getting into the Cuttings dryer would be high viscosity and dry. With the rotating of the dryer bowl, the fine solids and liquid would be sprayed on to the inner surrounded wall of the bowl and stick on it. To clean the inside of the cuttings dryer, the screw pump would feed clean water into the bowl. Under the high pressure of the flushing water, the fine solids and dirty liquid would be flushed down from the wall and get out from the dryer vessel.

GN Verti G Air Knife System

One of GN first generation Verti G cuttings dryer defects is that the discharged solids out from dryer unit is not dry enough for easy transportation. The air knife design could solve the problem of the block on the rotating screen opening. GN’s vertical cuttings dryer has 3 types screen for option, the opening is 250 microns, 350 microns and 500 microns. Under high pressure of the blowing air, the blocked opening of the screen would open and the solids would be blow to much dryer. This greatly enhances the working efficiency and makes the transportation of the discharged solid very easy.
Besides the verti G dryer, there would be another important equipment called decanter centrifuge which would remove the much fine solid particles in the drilling mud.

Decanter Centrifuge is one of the most common and well known equipment in drilling mud solids control project. It is often used as the fourth stage solids control equipment to remove the ultimate fine solids. To some extent, the performance of the centrifuge determines the success of the project.

How to define the capacity of the horizontal sedimentation decanter centrifug

Most of the oilfield application decanter centrifuge manufacturers worldwide claim the capacity which is tested by using the water. Take the GNLW363BG small bowl centrifuge as an example, the nominal capacity is 132GPM, this capacity is for water and the actual treating capacity would be various according to the drilling mud condition or other factors. That is why when customer asks how is the capacity of the centrifuge, GN always asks the user to provide as much information of the drilling mud as possible. Usually, the solid content percentage and distribution, the mud density and viscosity is necessary required.

How to select the suitable decanter centrifuge according the purpose

The decanter centrifuge is classified as middle speed and high speed, GN team recommended to select the decanter centrifuge rotation speed according the project purpose.
a. For barite recycling, the G force 700-1000, RPM around 2000
b. For High gravity solid separation, the G force 1000-2000, RPM 2500
c. For low gravity solids separation, the G force 1800-2300, RPM 3200

How to adjust the centrifuge technical parameters for proper operation

There are some parameters of the centrifuge during operation need to be given more attention for smoothly working and specified performance result. The parameters here involved would be the bowl speed, the differential speed, the feeding flow rate and liquid discharge port plate adjustment.

• If you want a large treating capacity, then you need raise the differential speed by raising the bowl speed.
• If you want the liquid as clean as enough, you need raise the bowl speed, reduce the differential speed, and raise the liquid discharge plate to a high position, thus the mud would stay in the bowl for longer time, and the liquid pool would be deep. More solids would be sediment towards the bowl wall. Then liquid discharged out would have less solid particle.
• If you want to the discharged solid material much dryer, you can raise the bowl speed, reduce the differential speed, and lower the liquid discharge part plate position. Then the liquid would be discharged quickly, and the solid may have a long distance for dewatering when getting out through the cone slope at the small end of the bowl.
• A proper feeding flow rate is also important for well performance of the centrifuge. Always, the operator would try several times with different flow rate to choose a best one. This can be implemented only by the variable speed control pump.

GN Solids Control could provide decanter centrifuge for both fixed speed and Variable speed. For more information, please feel free to contact with us.

At the end of the Past August, GN Solids Control attended the Shanghai CIPPPE 2014 and shown there 1 unit GNLW363BG-VFD decanter Centrifuge. The visitors from oil industry paid much interest on this unit and awarded the unique design of the structure.
The model GNLW363BG is the second generation of GN decanter centrifuge. This unit is with the main drive motor and back drive motor located on the same side. Thus more space is saved to locate the fixed speed control box and for operator standing. The main motor is connected with rotation bowl directly, and the screw propeller inside the bowl is driven by the back motor through belt pulley. Comparing with GN first generation centrifuge, 1 set belt is saved.

GNLW363BG centrifuge has 2 models of fixed speed and variable frequency drive. For the common drilling fluids solids control, GN always propose to use the fixed speed model for barite recovery. The normal fixed speed of GNLW363BG is 3200 RPM, and it could be adjusted to 2600RPM by changing the belt pulley. GN could provide the belt pulley for both speeds. To change the belt pulley may take some time, and then a better way is to use the VFD model.

The GNLW363VFD is equipped with 1 unit positive pressurized design PLC control panel, which make the speed is ranging from zero to 3200RPM, the operator could adjust the speed as per the actual working and mud condition. The rotation bowl assembling unit is seen as the key part for the decanter centrifuge. Beside the material of SS2205 of the main body of the bowl, the screw is protected by bolting the tungsten carbide tiles. And to avoid the solid accumulation at the solid discharge port, the GNLW363 has the design of solids plow at the discharge port, which could effectively reduce the settlement of the solids. And at the big end of the bowl where the liquid is discharged out, the liquid discharging plates are adjustable to adjust the humidity of the discharging solid cuttings. The operator could also reduce the solids accumulation by increasing the humidity.

Now, the GN third generation decanter centrifuge is under fabrication processing, this generation would much better solve the problem for solids accumulation and extent the critical part life time. GN sincerely appreciate the support and trust coming from the customers.

In last article, we gave a brief introduction on how GN layouts the mud suction and mixing pipeline in the mud circulation system. On the mud tank, there are also other functional pipelines that would be designed and laid properly for complete the mud circulation system utility and enhance the working efficiency. Today we would like to gave a explanation on how GN engineer team design the mud gun pipeline and cleaner water line.

What are the Functions of the mud gun line and clean water line

It is well known that in the mud tank, the mud agitator would be installed to agitating the drilling mud to prevent the solids particle sedimentation down to bottom of the mud tank, thus the drilling mud would be transferred or flow to next stage process as the suspension form. That would be benefit for subsequent equipment to work on the drilling mud. Mud agitator is high efficiency device. However, the mud agitator still can not get to the dead corner of the tank inner. For the issue, the solids control engineer always use the mud gun to solve the problem, the mud gun would be injected with drilling mud, high pressure mud out from the mud gun nipple would be jetted to the mud tank corner, by adjusting the angle of the mud gun, almost all the corner would be reached. During the mud recycling operation, the spraying mud would defile the equipment and lead to low efficiency. Moreover, the drilling mud would loss when separating. The mud engineer would have to add water into the mud tank to mix new drilling mud. The laying of the clean water pipeline would be necessary for these purpose, it should be very easy for the engineer to get the water.

How GN design the mud gun line and clean water line

GN’s mud tank are always rectangular, the top of the tank structure is applying the 4” tube steel. GN’s engineer would used this tube steel as the channel of the drilling mud and clean water. Only the seamless steel tube would be chosen in case of leakage of the liquid under high pressure. The mud gun line would be laid on every mud tank in the mud system so that the mud could be transferred to every mud tank compartment. Always, the mud gun line would occupy 1 length and 1 width of the tank top structure steel tube, between different tanks, the mud gun line would be connected by hose. To avoid confusion, the mud gun line would be laid at same side of the mud tank, while the clean water line is chosen as the counter sides.
The mud gun is installed inside the mud tank, thus the opening of the mud gun line would be inner the tank for easy connecting with mud gun terminals. While, the clean water line has several opening on mud tank top surface, the mud engineer would connect the water line by using a tap and control by a valve.

Regarding the power, the mud gun line is connecting with the mixing pump or high pressure mud tank. The clean water would be pumped into the water line with sufficient power. GN’s design on the mud gun line and clean water save cost on additional pipeline and effectively use the mud tank existing structure.