mud mixing

Mud system will not work if there are no mud tanks. In the mud recycling system, the tanks are used to store the drilling mud to be a base where the solids control equipment to be installed. Normally, more than one mud tanks
will be used in the oil drilling mud system. For different purpose, the design of the mud tank is different, especially the inner structure of the mud tanks.
There are mainly 3 types of mud tanks recycling tank, intermediate tank and premixing tank. Then what are the different among these 3 types of mud tank?
The recycling tank is where to install the primary shakers and degasser unit, and also the de-sanding and de-silting unit. Each of equipment needs a compartment in the mud tank. As the recycled drilling mud is treated by the solids control equipment one by one. After treatment by each of the equipment, the drilling fluids will be cleaner than before. Thus the drilling fluids cannot be mixed. The wall between two compartments always has an overflow port for balance of the drilling mud in the tank.

Mud-Tank-for-ZJ-50

Mud Tank System

For the tank to install the de-sander and de-silter unit, inner structure of the mud tank would be much complex as there are pipes for centrifugal pump to such the drilling fluids from inside of the tank and transfer to the cyclone for further treatment. Operator has to know which pipe is for de-sander and which pipe is the desilter.
On the mud tanks for installing the solids control equipment on, there always have the walkways and handrails. The walkways provide enough space for the operator to walk around the equipment for operation and maintenance. Intermediate tank is a type buffering tank, part of this tank is for mud recycling, and other parts are used for mud storage. Operators can easily tell how many compartment in this tank.
The premixing tank is used to mix drilling fluids. It always is connected with the jet mixer unit. The mixing pumps suck liquid from mud tank and send liquid back again with added mud materials from the hopper. Thus the pump should be able to suck the drilling mud from anywhere in the mud tank used for mixing and storage.
Therefore, in the mixing tank, there are two groups of pipelines, one for sucking, and the other one is for sending liquid back. Mug agitators and mud guns are always installed on the mixing tank.
Though, the inner structure of the above tanks is different, the outer dimension and design are always the same for purpose of easy transportation and assembling.

Normally, the drilling mud recycling system is consisting of mud recycling tank skid and mud mixing tank skid. On
the mud recycling tank skid, the solids control equipment like shakers, mud cleaner, and even decanter centrifuge unit will be installed for removing the cuttings and useless solid particles in the drilling fluids. After several times recycling, the useful mud materials will loss together with the cuttings, and then the mud engineer need add new mud materials into the drilling fluids to maintain the proper mud property for the drilling job. The mud mixing unit is the equipment used for adding the mud materials into the fluids.

gn-mud-mixer-unit-1

Mud Mixing Hopper

What is the Function and Principle of the Mud Mixing Unit
The mud mixing unit is always installed at end of the mixing tank. Before starting the drilling, the driller need have sufficient drilling mud to keep a continuous drilling. Thus at the first, the mud mixing unit is used to make the drilling mud by mixing clean water and mud materials. With the drilling going on, once the mud property is not proper for the drilling process, new mud materials like barite or other polymers need to be added into the drilling fluids. The mud mixing unit is sucking the drilling mud from the mixing tank, and then pump the mud together with materials back again into the mixing tank. Normally, the mud agitators would be equipped on the mixing tank for fully blending.

What Components are Included in the Mud Mixing Unit
1. Centrifugal Pump – the inlet of the pump is connected with the mixing tank for sucking the drilling mud from tank. And the outlet is connecting with pipe manifold that will transfer the mud to the hopper unit. As this pump is fixed with the mixing hopper, it is also called mixing pump. This pump is driven by an electric motor via direct shaft connection. By higher efficiency shearing purpose, GN will used belt driving for a shearing pump.

gn-mud-mixer-unit-2

Mixing Hopper Bag Breaker

2. Mud Hopper – GN’s mud hopper is Ventri type connected with the pipe manifold via a T pipe. The mud materials will be added into the hopper and then immediately sucked into the drilling fluids as there is a vacuum produced by the high speed flow. For the hopper, GN uses the material of stainless steel for better anti corrosion performance and long life time. Inside the hopper, there is a bad beaker for quickly adding of powders. On the pipe manifold, there is a pressure gauge for the operator to inspect the working pressure of the mixing pump.
3. Control Panel – GN’s mud mixing unit is equipped with explosion proof control panel for application in Zone 1. The operation of the control is easy for only three buttons on the panel. One on, one off and one for emergency stop, accordingly, the signal lights is installed to reflect the operation.

GN’s mud mixing unit could be installed both at the end of the mixing tank or separately mounted on a small skid. This mud mixing unit can also be designed as a dual hopper dual pump type for larger capacity or in case one of them is broken down.

Mud Agitator is one of the solids control equipment that is mainly used to mix the drilling fluids in the mud tanks to keep the solids inside the drilling fluids suspending other than sedimentation down to the tank bottom.
GN’s sales team ever received many inquiries on the mud agitators; unfortunately, most of the clients have no idea on how to choose the right model for their project and even don’t know how to use the equipment properly to ensure a longer life time.

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Drilling Mud Agitator

GN’s sales are good at understanding clients’ specific request by asking few simple questions. With the answer from the clients, GN always could give the best proposal for clients. Now let’s see what these questions are and what information GN need to give a proposal.
a. What is the inside dimension of the mud tank or pit. From this question, GN will know the inside length, width and depth of the mud tank, and then GN will know how long the agitator shaft should be suggested for clients and how big impeller should be used. For the deep mud tank or pit, the stabilizer will be provided to hold the agitator shaft for stable performance.
b. What is the shape of the mud tank, cylinder or rectangular? Then GN will know how to design the agitator.
c. What is the electric specification, mainly GN would like to know the jobsite electric voltage and frequency. Different countries may have different frequency, the 50 Hz motor cannot be used under 60 Hz, and safety is ever the first think we should keep in mind.
d. What is the S.G. of the liquid? For very thick liquid, GN will propose bigger horse power motor to drive the agitator.
Mud agitator is always installed in mixing tank with jet mixing unit, active mud reserve tank and trip tank. For some clients who get the mud agitators from GN and make the mud tank by themselves, GN always recommends them to make the mud tank with same dimension, thus they can get the agitator all same model, which would be much better for clients’ future maintenance. GN suggest the RPM setting of the mud agitator between 40-96, too high will disturb the solids suspending, while too low will lead to solids sedimentation.

Last week, GN’s manufacturing department finished the fabrication of a mud mixing tank with double hoppers. Mud mixing tank is widely used in the drilling mud recycling system for mixing and re-configuration the drilling fluids. Also sometimes it will be used for storage the active drilling fluids.

mud-mixing-tank-with-double-hopper

mud mixing tank system

A mud mixing system is always consisting of mixing tank, agitators, mud guns, mixing pump and mud hoppers. Generally, the mixing pump and the mud hopper will be located at one end of the mud tank to make the mixing tank system a compact and single unit, while in some projects, the mixing pump and hopper are installed on a separate skid so that the mixing tank and the jet mud mixer could be used much freely. The picture in this article shows that the jet mud mixer skid was located at one side of the mixing tank. There are one mixing pump and 2 mud
hoppers on the skid. The mixing pump is connected with both hoppers, one of the hoppers is used for mixing barite to make weighted drilling fluids, and the other one is used for adding bentonite into the drilling fluids.
There is a steel frame around second hopper with steel bars over the hopper. This horizontal steel bar is used to hang the bentonite bag which will be hooked at 4 corners of the steel frame to make it easier for adding the bentonite powder into the hopper. It is worthy to mention that the steel bar is with forklift lifting slot so that the bar with bentonite bags could be lift and put on the frame by a forklift to save human power.
This mud mixing system is with a control panel to control mixing pump which could transfer mud to both hoppers. On the mixing tank, there is another charge pump which is used to transfer the active mud back to the rig for reuse.

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.

GN Drilling Mud Gun

GN Mud Gun with 3 Nozzles

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.

A complete drilling mud recycling system always includes 2 parts, the mud recovery and cleaning system part, the other part is mud mixing system. Just as the name implies, the mud mixing system is functioned to mix the chemicals with the mud base and make it usable for the rig drilling.

GN Mud Mixing Unit

GN Mud Mixing Unit

How many pipeline channels needed for mud mixing

As we know, the processing of mud mixing is consisting of mud suction from every mud tank compartment in the system and again pumping the mud back. There we will know we need design 1 mud suction line and 1 mud mixing line. Both of these 2 pipelines would be laid to each compartment for mud storage. Under the centrifugal force of the mixing pump, the mud would be sucked to the mud mixer unit; here the mud chemicals would be added into the mud and get to the mud tank for fully mixing with the flow of mud through the mud mixing pipeline. In order to produce the sufficient pressure for driving the mud, the inlet of the pump is larger than outlet. Accordingly, the mud suction line diameter is bigger than the mixing pipeline.

What is the location of the mud mixing pipeline inside the tank

Due to different functions of the mud suction line and mixing line, the location of the 2 pipelines are different either. For the suction line, to make sure it would be maximally suck the mud inside the tank, it always is designed to locate at the bottom of the mud tank. Thus, even very low liquid level; the pump could suck the mud for mixing. The mud mixing pipeline is connecting with the centrifugal pump outlet with extended steel pipeline which would be located on upper part of inside tank. The mud gets out from the mixing pipeline with high pressure and when dropping down, it would also stirs the existing mud for mixing, here the mud agitator would definitely is the main equipment for mud agitating.

As per the request capacity of the mud storage, the quantities of the mud tank would be different; we need design the connection parts among these tanks for the mud suction and mixing line to make all the tanks a communicating vessels so that the pump could suck from and delivery to each mud tank.