Category Archives: Drilling Mud Cleaning System

Solid control system optimization design is listed as one of the ten major subject of drilling equipment. According about 20 years development, domestic drilling rig technology has a great progress, solid control design and manufacture technology also have a gig improve, but because traditional view thinks the technology content of solid control system and equipment is low, appear a lot of design and manufacturers, and imitate each other, so creative technology is less, it can’t solve many practical problems.

The main existing problems in drilling fluid solid control system

The process of drilling fluid solid phase control is not perfect, the performance of solid control is singleness, the efficiency of solid control is low. Because rarely used desander, centrifuge and other equipment, the fine solid particles are difficult to remove, make drilling fluid solid phase content, viscosity is difficult to control, influence drilling speed, causing downhole complex, influenced drilling pump piston and lifetime of the cylinder sleeve. In order to keep drilling fluid performance, must add chemical agent, it increase drilling cost.

The cubage of drilling fluid store tank is small, it can’t meet the requirement of drilling work, the common cubage of store tank is 30m3, the volume of this kind of drilling fluid tank is small, if meet the complex well, it must use the reserve tank drilling fluid to compensate. Because the performance and quality of reserve drilling fluid, it often appear drilling fluid run way, cause pollute the environment and potential security liability. It is difficult to transport and install, drilling preparation for a long time.

The electric gas and circuit is the open line installation, the site layout is messy, it must be stringing and take out stitches every move home, so the workload is big and exist potemial safety hazard.

Now considering use the KCL- polymer and Gel- lignin sulfonate the two drilling fluid. The kcl is 528.34 yuan / m3, Gel- lignin sulfonate is 132.1yuan/m3, the drilling solid phase is 4% of kcl drilling fluid system, but the drilling solid phase is 5% of the Gel- lignin sulfonate.

 Different drilling fluid comparison

444.5(mm)well hole

KCL- polymer

Gel- lignin sulfonate

Solid control efficiency(Ef)



Average size of hole(mm)



311.2(mm) well hole



Solid control efficiency(Ef)



Solid control efficiency(Ef)



 Calculating the cost of every meters

The cost of every meters compared of different drilling fluid

Diameter of well hole

KCL- polymer

Gel- lignin sulfonate


186.27  yuan

52.01  yuan


61025   yuan

22.82  yuan

Generally speaking, the good KCL system, solid control efficiency is good and the well hole is regulation, although it has a big distinction in big diameter well hole, the cost of KCL system is all high, but in the system still has competitiveness in small diameter well hole.

In the surface well hole, usually use the cheap drilling fluid, maybe the drilling speed is more quickly, so this kind of drilling fluid has the higher solid phase compatibility limited; but in small well hole, using the polymer drilling fluid, the drilling speed maybe more quick, so polymer drilling fluid is good for solid phase control.

TangShan Dachuan Mechanical Equipment Co., Ltd. is a company focuses on the production, sales and after-sales maintenance service of solid control equipment of petroleum drilling (not excavation). The main products are mud vibrating screen, vacuum degasser, desander, disilter, mud cleaner, mud gas seperator, mud agitator, desander pump, shear pump, centrifugal, flare lgnition device, mix funnel, jet mud mixer, mud tank, water tank, diesel tank, etc.


We are concentrated on matching the requirements of our customers. Our management principle is to supply a high quality, rapid, honest, considerate service to our customers. Our aim is to supply the most advanced equipment and technology to our customers.

Company Structure:

Our company now has 85 staffs, including 15 senior engineer, 5 development persons and 15 senior artisans. We have the ability to develop and produce the equipments independently, and also cooperates with many professional institutes to guarantee the high precision of the exported equipment. Enough after-sales persons to supply the service and technology consulting.


Before service: According to client requirements, DC will provide optimal solutions at earliest time.  2. After service: All DC equipments will have one year guarantee after commissioning date except wearing parts and illegal operation.   3. Commissioning: As per user demand, DC can arrange engineer do 1st commissioning for free. We can also provide training courses to client staff.   4. Emergency solution: The time to client job site depend on visa issuance. Anyhow, we will do our best to solve emergency as soon as we can.   5. Spare parts supply: DC have considerable stock to stare various spare parts. This guarantee the spare parts can be sent to the clients in time.


Vibration motor is from top MFG: 2. Standard steel is from Chinese top manufacturer: HBIS3. Paint oil is from famous Kansai & COSCO Paint Co. Ltd4. Electrical materials from SIMENSE or Schneider5. All motors and electric parts are explosion proof type 6. All outsourcing parts are from top manufacturers both domestic and overseas.7. All painting: a. Sand Blast Treatment before painting b. Two pack Epoxy zinc-rich primer painting c. Two Pack Epoxy hi-build containing anticorrosive pigments.  d. Surface pigmented with high quality light fast PU pigments


1 Our factory is more than 21000 square meters

3. ISO 9001:2008 certificate

4 Offer free guarantee and training courses

5 Have stock all the year to offer convenience to our customers

6Can be customized

7We attend solid control exhibitionr: Dongying 2012,

8 Main marketing: America, Europe, Africa, Mid East, Europe, Asia, Domestic Market ect.


According the function of each components of drilling fluid solid control system put forward the reasons why choose this equipments, discussing the general arrangement methods of drilling fluid solid control system.

The function of solid control equipment

Following the development of drilling well technology, the effect of drilling fluid solid control system to the drilling well working is more bigger, there are all kinds of solid control systems, no matter the type of solid control how to changes, its basic function can’t be changed, it rely on the mechanical clear device and drilling fluid storage tanks and other auxiliary equipment to work together to complete the basic effect.

In drilling well, drilling head, crushing, grinding the ground, make the rock breakages, formation the different size of drilling cuttings, the size is between 2 and 2×10³μm. The single clear equipment remove rang of the solid phase particles is small, so depending on a device can’t reach the purpose of maximum clear the solid phase.

The different equipment can remove the different size solid phase particles. To guarantee carrying the drilling cuttings to the ground, drilling fluid must has the enough up return speed. So must accord the size of the well and the drilling machine to decide the displacement of drilling pump.

Drilling fluid is made of dispersion medium, dispersion phase and additive.

Drilling fluid is mainly made of liquid phase, solid phase and chemical treating agent. Liquid phase can be water (fresh water, saline), oil (crude, diesel oil) or lactescence (mix oil emulsion and inverse emulsion). Solid phase is including useful solid phase (expansive soil, additivi material) and the useless solid phase( rock). Chemical treating agent is including inorganic, organic and polymer compound.

Water base drilling fluid is use the water as dispersion medium, it is a sol Suspension hybrid system. The major components are water, clay, additive and all kinds of chemical treating agent. There are five stages of the base water drilling fluid, the nature drilling fluid (1904-1921), fine dispersion drilling fluid (1921-1946), coarse dispersion drilling fluid (1946-1937), don’t spread low solid phase drilling fluid (1966 until now).

The base water drilling fluid is divided into;

a The fresh water drilling fluid. The content of sodium chloride is less than 10mg/cm&sup3, the content of calcium ion is less than 0.12mg/cm³。

b The saline drilling fluid ( seawater and salt water drilling fluid included). The content of sodium chloride is higher than 0.12mg/cm³.

c The saturated salt water drilling fluid. It is saturated solution with a kind or various soluble salt.

d The calcium treatment drilling fluid. The content of calcium ion is less than 0.12mg/cm³

e The hybrid emulsion drilling fluid, it has the water base drilling fluid with 3%-40% emulsified oil.

     f The don’t disperse and low solid phase polymer drilling fluid, the contend of solid phase is less than 4%, it has the moderate polymer

     g The potassium base drilling fluid, the content of the potassium chloride is higher than 3%, from 1978, it was used in our country oil field.

    h The polymer drilling fluid. The polymer as the main body, the ingredients is viscosity reducer, filtrate reducer, prevent collapse agent,

lubricant and all kinds of chemical treating agent. It is a new drilling fluid system developed in the 1980s.


Drilling fluid solid phase control is mainly remove the harmful solid phase and save the useful solid phase, also can control the gross of solid phase in drilling and the grain size distribution in the reasonable ranges, the drilling technology can meet the requirements of the performance of drilling fluid. Usually drilling fluid solid phase control is short for solid control and mud purification system.

The classify and size distribution of solid phase

According the difference characteristics, there are different classification methods.

1 According the different effects of solid phase in drilling fluid: useful solid phase and harmful solid phase.

2 According the density of solid phase: the high density solid phase and the low density solid phase. The high density solid phase is according the requirements of drilling fluid technology add the aggravate materials to improve the density of drilling fluid, the low density solid phase include the bentonite and treating agent of the need of configuration drilling fluid and rock debris.

3 According the reaction of the solid phase and liquid phase: activity solid phase and inertia solid phase. The solid phase and liquid phase is react is called activity solid phase, solid phase and liquid phase don’t react is called inertia solid phase. The activity solid phase is bentonite, shale, clay and ect. The liquid phase are limestone, granite and barite ect.

In the drilling, because the type and drilling parametric of lithology drill head is different, so the content of solid phase and the grain size distribution is different.

The common solid control method are

Irrigation method, replace method, natural sedimentation, chemical sedimentation and mechanical  eliminate.

1 Solid phase total

Solid phase refers to the solventless solid in drilling fluid. Usually the solventless solid in drilling fluid use percent by volume to express. The high density drilling fluid solid phase content consist of low density solid phase and high density solid phase, but the common drilling fluid solid phase content is all the low density solid phase.

2 Liquid phase

In drilling fluid, use liquid as dispersion solid phase continuity, it is called liquid phase. Usually, water, oil, soluble salt, thinner and other produce included.

3 Low density solid phase

The low density solid phase is including commercial clay and drilling cuttings. Usually, in the solid control work, assume that the density is 2.6/cm3 or 2.65g/cm3, the actual value in the 2.0-3.0cm3 fluctuation.

4 High density solid phase

The high density solid phase improves the density of the drilling fluid, make the annulus fluid column pressure is greater than the formation pressure. The barites is a kind of high density solid phase, the barites density is recommended by American petroleum institute is bigger than 4.2/cm3.

5 Aggravate drilling fluid

The commonly known as aggravate mud, the common aggravate materials is barites, according to requirements also can use other aggravate materials, in order to keep the minimum density.

6 Drilling cuttings

Drilling cutting belongs to solid phase, it is the main pollution source of drilling fluid. It is greatly affected the performance of drilling fluid, so must make the content is stably, so have the important issues, in the process of drilling should do regular treatment to keep the content is stably of drilling cuttings.

7 The clay

The clay is mainly made of clay minerals, the form is the super fine particles, most diameters is less than 2um, it has dispersibility in water, charged sexual, ion exchange, these performance is important to drilling fluid.

8 Colloid particles

The clay diameter of solid particles is less than 2um is called particles, the material of clay particles have a big surface area. Sodium montmorillonite can shape clay suspension in water, the dispersibility of the sodium montmorillonite is good, it can improve the viscosity of drilling fluid.

9 Oil base and water base drilling fluid

The oil base drilling fluid base on oil as continuous phase, the insoluble solid phase particles is scattered to the continuity liquid phase; Water base drilling fluid base on water as continuous phase.

10 saturated brine

saturated brine is allocated by sodium chloride, the density is 1.20/cm3



Solid control system is mainly made of a group of store drilling fluid solid control tank and a group of equipment which rid of the solid phase in drilling fluid, solid control tanks which store drilling fluid are divided into circulating tanks and store tanks. Circulating tanks as a part of the ground cycle, there are shale shaker, vacuum degasser, deserter, desande and centrifugal on the surface of tank. The store tank is according to the need of drilling condition to allocated the different performance drilling fluid, or store drilling fluid which used for different drilling condition.

The purification process

1 level1 purification

The mud disposed in shale shaker. The allocation drilling fluid enter into the bottom well under the foundation of the drilling pump and carry drilling cuttings return the ground, through the elevated tubes enter into the shale shaker, the larger rock debris in drilling fluid are screened

2 level 2purification

When drilling fluid have gas cutting, we can use vacuum degasser remove the gas which in the drilling fluid and can recovery the density of drilling fluid, steady the drilling fluid viscosity.

3 level 3purification

The drilling fluid is disposed by the 2level purification enter into the desander through the desander feed liquid pump, the harmful sold phase which the diameter is above 40-60um is separated in desander.

4 level 4purification

The drilling fluid is disposed by the 3level purification enter into the desilter through the desilter feed liquid pump, the harmful sold phase which the diameter is above 15-40um is separated in desilter.

5level 5purification

The drilling is disposed by the 4level purification enter into the centrifugal through the centrifugal feed liquid pump, the small harmful sold phase particles are separated in centrifugal.

Usually, the 5purification is working at the same time. If it works one equipment or several equipments, the parameters of the drilling fluid can meet the work requirements, it can work one equipment or several equipments. After the purification, drilling fluid can enter into the next common drilling cycle.

When drilling the air layer, because the rocks are destroyed, the gap of the rock have a large of gas to immersion the drilling fluid reach the big crack or cave gas reservoir. It is maybe appear the large of gas of replacement immerse the drilling fluid.

1 Characteristics

(1)The density of the different of depth of the gas invasion is different .

(2)The density of the gas invasion drilling fluid will be very small when it is close to the ground, even if the drilling fluid gas invasion of the ground is very serious, the density is reduced, but the decrease of the pressure of the drilling fluid column is not very big, this time we can’t use the density of the ground gas invasion multiplied by the depth of the well to calculation the liquid column pressure.

(3)Because of long time to stop cycle (change the rig head, maintain the pump or electrical logging and so on), there is a large of gas column which is formed by nature gas under the well, when it rise to expansion, maybe led to the drilling fluid overflow.\

(4)After the drilling fluid gas invasion and closed, because the density difference, the nature gas will slip up, finally accumulate on the well month.

(5)In the case of the gas rise but it is not expansion , the pressure of the ground unequal to the pressure of the well month plus to the pressure of drilling fluid column, so we can’t use this pressure to calculate the required drilling fluid density.

2The damage of the gas invasion

(1)Reduce the density of the drilling fluid, after the drilling fluid density reduced, if the liquid column pressure is inferior to the ground pressure, it is maybe led to the well kick or blowout

(2)Make the absorption of the desander pump, priming pump and the drilling pump is bad, even can’t work normally, cause the device vibrate.

(3)Part of the toxic gas overflow from the drilling fluid, the operating personnel maybe poisoning.

(4)It can lead to fire.

(5)After the gas invasion, drilling fluid density will be increased, make the mechanical drilling rate decreased.

So how do we processing the gas invasion ?

The common methods of disposed the gas invasion

1 Circulation drilling fluid degassing method

It use the mechanical equipment continuously circulation drilling fluid on the ground, make the bubbles emersion the liquid level and overflow, the method only rid of the bid bubbles. The bubbles of diameter of less than 1mm, especially the bubbles of high viscosity, the foundation of cycle degassing is small. When use the methods to degassing, in order to reach the degassing effect, required long times, the drilling industrial is not allowed.

2 Chemical degassing method

Adding chemical gas degassing to the drilling fluid gas invasion, the method adopt to rid of the own bubbles. Use the chemical degassing method, need to mix and the time of reaction, so need long time, the high cost. The foundation is small to the gas of external invasion.

3mechanical degassing metood

Using all kinds of mechanical equipment, according the degasser clear the gas which immersing the drilling fluid. The methods apply to all kinds of the drilling fluid degassing. The mechanical degassing divided into ordinary pressure, vacuum type and the centrifugal.