Monthly Archives: May 2016

Requirements of screen surface of shaker screen

The basic requirements of the drilling process for the shale shaker is not only recover drilling fluid as much as possible, but also remove harmful solid phase as much as possible. This requires that: Firstly, in order to improve the throughput and recycle drilling fluid, solids on the surface of the screen should be drained away as soon as possible; Secondly, the solid particles in the sieve surface is best not to make sliding movement in order to reduce screen wear; Thirdly, the critical particles that stuck in the mesh hole should be easily through the sieve hole or jump off the screen surface.

shaker screen

In order to meet the above requirements, shale shaker should let the solid particles do throwing motion on  the sieve surface. But tangential acceleration along the screen surface of particles not need to be too big, because over large screen normal acceleration will accelerate the the impact to screen when particles falling down, so that part of the cuttings group was crushed, and increase the screening rate, it is not easy to recycle liquid phase.

So as long as the particles can overcome the adhesion force, firction and surface tension  between itself and the drilling fluid and to ensure drilling liquid go through the screen smoothly. At the same time, the shorter the time that the solids phase stay on the the screen is, and the less the beat frequency is, so the smaller of the probability of screening is.

Technology definition of centrifugal pump

There are many methods of terminology difinition retated to sand pump, roughly as follows:

Flow: the volume of liquid through a pipe at a given time. Most of the horizontal axis of pump curve represents the flow of pump, the unit is gal/min or m ³ /h.

Friction loss: when the liquid enters the pipe and get in touch with the internal diameter of pipe, valve, element, etc., the head loss caused by the force that block the fluid movement in the pipe or due to the turbulence or delay.

Pressure head: the distance of the water in a pipe with a bottom opening will be increase, and its value is measured at the bottom of the tube.


Hisilicon K3

Usable net suction head: pressure head value greater than absolute zero on the suction flange of sand pump. Friction loss, atmospheric pressure, fluid temperature/steam pressure, altitude and abnormal gravity will all affect the value. This value must be calculated.

The net positive suction head that requested: the inlet pressure head is greater than the absolute zero that required to make the centrifugal pump do normal work. This value varies with the size and flow of the pump, which is generally expressed in the pump curve.

TDH: when pressure head of pump entrance is excess, the pressure head value produced by sand pump. This value is found in the left axis of most pump curves.

The total lift: the summation of entrance pressure head and total dynamic head of centrifugal pump.

One set of Dachuan mud cleaner shipped to India

One set of linear motion shale shaker is  going to shipped to India from our company.

The mud cleaner is designed according to customer’s requirements, which is composed by two parts: desilter and shale shaker.

The mud cleaner is intended to be used as solids control equipment in oil well drilling operation for removal of fine solids or silts from the drilling mud. Mud cleaner shall use two stage mechanical processes for solid control. First stage shall remove fine solids through desilter(Hydro cyclones). In the second stage of desilter under flow will discharge on fine mesh screens of linear motion vibrating shale shaker.

delivery cleaner

The specifications of this mud cleaner as followings:

Desilter cones  100mm4″×16
Working pressure 0.25~0.45  Mpa
Handling capacity 160-240 m3/h
Separation point 20~44μm
Inlet pipe diameter 150mm
Discharge pipe diameter 200mm
Shale shaker model DCS630-3
Motor power 1.5kW×2
Suitable power supply 380V /50Hz
Vibration intensity 7.2g
Screen area  2.36m²
Screen dimension 1250×630mm, 3pieces150-250mesh
Outline dimension 25100×2000×2150mm
Total weight of equipment 2800kg

Knowledge of separation point of drilling fluid centrifuge

The drilling fluid centrifuge do the separation based on the size and density of the solid phase, and its processing and separation ability is not only determined by the characteristics of the device itself, and it also has a great relationship with the process operation.

The separation point is one of the important parameters of drilling fluid centrifuge, for example, the separation point of one drilling fluid centrifuge to barite is 2 ~ 4μm, it means that most solids phase particles in the overflow  is less than 2 ~ 4μm after input into the drilling fluid centrifuge, and solid particles in the underflow is much greater than 2 ~ 4μm. If centrifuge parameters adjusted to the appropriate level, the overflow will contain colloidasl solid and some superfine solids, and underflow containing ultrafine solid and almost all of the large solid particles.


When the centrifuge separation point is 10μm, if the diameter of solid phase in the drilling fluid that be input is greater than 20μm, then the overflow will be a pure liquid with no solid phase and underflow contains all of the solid phase. The separation point of the drilling fluid centrifuge is not fixed, it will change with the load and the adjustment of the equipment.

Processing the non weighted drilling fluid with mud cleaner

One purpose of mud cleaner is used to remove part of solid phase in the expensive non weighted drilling fluid, such as solid phase in KCl drilling fluid. In this case, the solids phase which size is bigger than sieve pore are removed through the underflow of desilter, and smaller solid and liquid is retained in the drilling fluid system through the shale shaker. This method is also effective for non – water – based drilling fluid and salt water – based drilling fluid.

In the non weighted drilling fluid system, underflow of desilter can reach the drilling fluid tank directly. The centrifuge can eliminate the larger solid phase while the smaller solid and most liquid remain in the drilling fluid system. If there is a centrifuge can be used in the well site, this method will be very convenient. The vast majority of the solids can be through the drilling fluid cleaner, but it is not easy for them to get through the centrifuge, the application of the two kinds of technology above are very extensive in field.


A good solid phase control process requires that the large drill cuttings generated during the drilling process can be separated after arrived on the ground, and it will not affect the performance of the drilling fluid. Usually, most of solid phase removed by mud cleaner is the barite powder. This indicates that the cuttings is mostly distributed to the drilling fluid.

When drilling smectite formation with clean water, most of the solids phase dispersed to drilling fluid are small particles which suggesting that the drilling fluid has good inhibition. Usually, the mud cleaner should be closed, to remove these small particles with the centrifuge. After the non weighted drilling fluid through the shale shaker, desander and desilter, the size of debris be removed will decrease in turn.

Due to the small size of some particles, which can not be separated by the cyclone yet, so it will still left over in the drilling fluid.

Adjustable pedestal type mud gas separator

Due to different floor height of drilling rig, so the height of solid control system matched to it is different, thus making the height from ground of liquid gas separator in well control and the connector of solid control system change. The height from ground of the past liquid gas separator and interface  of solid control system is the approximate height developed by oil field customers, and doing some changes to the ground where the liquid gas separator is located on if there is still disparity after delivery, pad it if lower and dig out the ground with equal size, which is not only a waste of time, delay the progress of the production, but also increased the intensity of labor.

Adjustable pedestal type liquid gas separator provides the pedestal that has a simple structure, reasonable design, easy to use and easy to adjust the height of the liquid gas separator.


In order to achieve the above purpose, the adjustable pedestal type liquid gas separator is realized by the following technical scheme:

  1. It includes the, a fixed tube and the bottom plate, four corners of the plate surface are all welded with fixed pipe, the lift pipe is inserted in each of the fixed pipe, a fixed tube is fixedly connected with lifting pipe through the fixed pin shaft and a pin.
  2. The lift pipe and the fixed pipe surface of adjustable pedestal type liquid gas separator of are equipped with a plurality of uniform arrangement of holes.

Compared with the existing technology, adjustable pedestal type liquid gas separator has the characteristics of low cost, simple structure, reasonable design, convenient use, practical, and effective realization of the easy adjustment of the height of the liquid gas separator, reduce the labor intensity, reduce the production cost and  improve the work efficiency.

Development trend of drilling mud waste management

Waste drilling fluid is one of the main pollutants in the oil industry. In recent years, with the increasing demand of energy in the world, the types of drilling fluids are increasing, and the harmful components and the additives are also increasing. According to the statistics, the waste drilling fluid produced annually in our country is about 2500-3200 million cubic meters, of which the 1/2 directly discharged into the surrounding environment, the ecological damage is increasingly serious, and the harmless treatment of waste drilling fluid is imminent.Mud-system (1)

With the increase of environmental protection requirements, the corresponding treatment has been carried out in various countries. According to the different treatments and discharges between domestic and foreign, waste mud management methods are also many and varied, and the effect of each are not identical, including curing treatment method, chemically enhanced solid-liquid separation technology, mechanical dehydration method, recovery circulation and usage method, safety landfill burial etc. Technology of harmless treatment by curing process is one of the methods to be used more, but it just do the conventional treatment of inhibition and conversion to the waste drilliing fluid, the pollution of the environment is still serious by this method. And then with it, the drilling fluid mud not landing treatment process opens up a new chapter of waste mud management.

What’s the main constitute part of shale shaker?

Shale shaker is the first stage purification solids control equipment in oil drilling. Its function is to remove large solids in drilling fluids. Under the action of the shale shaker, drilling operating keep maximum high porosity, high screening efficiency, large treatment capacity, easy to replace screen, reduce cost. Shale shaker with larger screen surface and treatment capacity can meet requirement of manufacturing at site.
Drilling mud shale shaker is mainly composed of the following components.
1.  Buffer slot
Drilling fluid returning to ground from the bottom of the well flow into buffer slot of shale shaker, decreasing drilling mud speed, and make the drilling liquid flow into the screen evenly and slowly.
2.  Screen box
It is used to tight shale shaker screen, support vibration exciter, and transfer continuous vibration from vibration exciter to screen, so as to achieve the purpose of screening
3.  Shale shaker screen
It used to remove solid, recover important part of the drilling fluid. Shale shaker removing solids size completely depend on screen hole mesh size.shale-shakers1
4.  Vibration exciter
It is the power source of the screen box vibration. Producing periodic exciting force make screen box continuous and periodic vibration.
5.  Damper spring
To support the screen box and a vibration exciter and ensure enough space with vibration sieve box. At the same time, as the auxiliary to meet screen box vibration requirements, and buffering and reducing dynamic load on base and a drilling fluid tank.
6.  Base
Support all the parts for convenient installation and transportation.

Some suggestions for sand pump operation

As a special type in solids control system, sand pump is power source for desander, desilter, swirl mixing device, etc, in drilling mud solids control equipment. Furthermore, it also can be used as grout pump and for assisting grouting, as a make-up pump for wellhead supply, as a delivery pump for drilling mud transport between mud tanks.

Since drilling mud is suspension with a large number of solid particles and various chemical additives, impeller and pump case of sand pump should be accordance with motion law of two-phase flow system so as to reduce wear and prevent corrosion. For sand pump works in dreadful environment for long time, the sealing of shaft end should be very reliable.

Moreover, drilling mud has a certain abrasive and corrosive, pump body often is destroyed, we must validly block the solid particles into the impeller front and rear guard. And another important question is that flow and head sand pump should be matched with desander, desilter and swirl mixing device, otherwise, hydraulic cyclone can not work normally.

We should notice the flowing points in the process of sand pump running.
1. Check once per hour. Increase the number of checks in key areas and weak links.
2. Pay attention to current instructions and pump operation, add oil timely.
3. Often pay attention to the surface of the pump. Pay attention to stabilizing head of sand pump. If the efficiency has declined should raise the head amount, if the amount is too large must take measures to adjust.

How to solve the commen failure of shear pump

  1. Packing seal problem of shear pump:

Fault: Serious leakage of sealing filler, and the packing is wore heavily, the surface of shaft sleeve is wore.

Solution: Remove the packing, move in the wall of the shaft sleeve with a fine wire which is bent 90 degrees. Replace the axle sleeve If a deep groove is checked out, packing gland pressure too tight lead to serious wear of packing.

  1. Polyurethane problem of shear pump:

Fault: The serious wear of oil seal causes serious leakage.

Solution: Replace the polyurethane oil seal. In general, the polyurethane oil seal and the sleeve at the place of shaft seal should be replaced after the pump running for 3-6 monthsshear pumps

  1. Shear pump packing is burnt:

The reason: Filler cap pressure too tight, causing overheating.

Solution: Replace the packing and the gland pressure can not be too tight.

  1. The rotation of impeller or vice impeller of shear pump is not normal:

Reason: The gap between the back of the impeller and the guard plate is small, or

the gap of the secondary impeller between the shield plate and the stuffing box is too small.

Solution: Use the bolt and nut to adjust the clearance. Twirl the shaft by hands after adjustment, there should be no resisitance card and friction sound in each part, and it should be rotating flexible.