Monthly Archives: May 2014
ZJ70 Drilling Rig Solids Control System for Sale
ZJ70 drilling rig solids control circulating system is designed into the configuration of five stages purification equipments, including shale shaker, vacuum degasser, desander, desilter, medium speed centrifuge, shear pump, etc, it can meet the requirements of drilling fluid circulation, mud aggravation and shearing and other accident treatment under special circumstances.
This system is a newly designed product that based on the advantages of domestic and overseas drilling fluid circulation and purification systems and combined with the actual needs of drilling process, which uses a number of sophisticated new technologies, and at the same time taking full account of some details during the operation process, with the features of reasonable design and easy installation.
Drilling fluid purification system meets the SY / T 6276, ISO/CD14690 “oil and gas industry health, safety and environmental management system”, all AC motors and control circuits in this solids control system are comply with the requirements of explosion-proof. Technical process and devices all complies with API 13C and related standards and norms.
This system adopts integrated modulars, which is easy for assembly and disassembly, not only can satisfy the requirements of ocean and railway transportation, but also can meet the loading and unloading of crane and draging in the jobsite.
ZJ70 drilling rig solids control system produced by Dachuan solids control includes the following equipments:
1. Shale shaker 3sets;
2. Vacuum degasser 1set;
3. Desander 1set;
4. Desilter 1set;
5. Middle speed decanter centrifuge 1 set;
6. Centrifugal pump 8sets;
7. Shear pump 1set;
8. Mud agitator 20sets;
9. Mud gun 18sets;
10. Mixing hopper 4sets;
11. Screw pump 2sets;
12. Mud tank 6sets;
13. Diesel tank 1set.
If you want to get professional solution, fast response and best transportation cost, pls contact us.
Major factors that affect the performance of jet mud mixer
Jet Mud mixer is a single jet mud mixing device that typically consist of a sand pump and a jet mixing hopper, they are connected by manifold valve and installed on a base or double jet mud mixing device that composed of two pumps and two mud hoppers.
Major factors that affect the performance of jet mud mixer:
- In the mixed funnel water along the loss must be as far as possible to reduce the otherwise processing capacity can be greatly reduced.
- In the nozzle from the Venturi tube’s gap to fit the best efficiency when the distance in the 32 – 90 m m, the general situation is not to be more than 90 m m, or heavy crystal stone feeding speed can significantly reduce. Exergy
- In the outlet pipe back pressure to the back pressure will reduce the mixing funnel processing quantity, excessive moderate. For example, when the nozzle outlet diameter is 50 m m in the nozzle to the Venturi tube’s gap is 90 m m, mixing funnel work pressure head of 21 – 23 m in back pressure value is not reached before the inlet pressure of the mixing chamber has 50% a high degree of vacuum in the back pressure values near the inlet pressure of 50% vacuum almost zero drilling fluid began to leak back flow in the bucket.
- The larger the inlet pressure, the higher the treating capacity of the jet mud mixer.
- Mixing hopper mounted higher back pressure, the higher the mixing capacity will be reduced.
Please contact DACHUAN Solids Control if you are interested in our product.
Drilling mud gas separator design and operating
There are a number of design features which affect the volume of gas and fluid that the separator can safely handle. For production operations, gas oil separators can be sized and internally designed to efficiently separate gas from the fluid. This is possible because the fluid and gas characteristics are known and design flow rates can be readily established. It is apparent that ‘gas busters’ for drilling rigs cannot be designed on the same basis since the properties of circulated fluids from gas are unpredictable and a wide range of mixing conditions occur downhole.
In addition, mud rheological properties vary widely and have a strong effect on gas environment. For both practical and cost reasons, rig mud gas separators are not designed for maximum possible gas release rates which might be needed; however, they should not handle most kicks when recommended shut-in procedures and well control practises are followed. When gas low rates exceed the separator capacity, the flow must be bypassed around the separator directly to the flare line. This will prevent the hazardous situation of blowing the liquid from the bottom of the separator and discharging gas into the mud system.
The atmospheric type separator operates on the gravity or hydrostatic pressure principle. The essential design features are:
Height and diameter of separator.
Internal baffle arrangement to assist in additional gas break-out.
Diameter and length of gas outlet.
A target plate to minimise erosion where inlet mud gas mixture contacts the internal wall of the separator, which provides a method of inspecting plate wear.
A U-tube arrangement properly sized to maintain fluid head in the separator.
Since most drilling rigs have their own separator designs, the Drilling Supervisor must analyse and compare the contractor’s equipment with the recommended design to ensure the essential requirements are met.
NOV Mud Conditioner and DC Mud Cleaner
The combination of hydrocyclones and shale shaker is called mud cleaner in China solids control equipments manufacturing and Mi-Swaco, and in Nov, it is called mud conditioner.
A mud cleaner is a combination of desanders and/or desilters mounted over a shale shaker with a fine mesh screen. A mud is fed to the inlet of the hydrocyclone(desander and/or desilter) to separate particles and the underflow passes to the fine screen mesh where in particles larger than barite are discarded and thrown away. In most drilling operations, a mud cleaner is installed in its mud systems. It is usually located in a mud tank in the same location as with the desilters.
The NOV COBRA Mud Conditioner utilizes a combination of hydrocyclones and a COBRA shale shaker to separate solids from liquid. The combination of hydrocyclone cones utilized is dependent upon the specific application of duty. Cone combinations typically consist of a desander cones (10-inch or 12-inch) and desilter cones (4-inch) which are properly sized to handle over 125% of the flow rate.
These cones are mounted above the screen deck of the shale shaker. The drilling fluid (mud) is fed first through the hydrocyclones, where the discharge cascades down over the shale shaker screens. This helps to reduce the amount of mud attached to the discharged cuttings. The screens used on the shale shaker determine the cutpoint for the mud cleaner unit. When weighted muds are used, screens are selected in a manner that ensures that the majority of the weight material is returned to the mud system. Typically, API 170 screens (>82.5 to 98.0 microns) are utilized to reduce the amount of weight material discarded by the screens.
DC mud cleaner is very popular all over the world, and especially suit for the Chinese ZJ series drilling rig equipments, or alike rigs. Customized design are also available.
Waste Sludge Processing of Decanter Centrifuge
One of the largest applications for the decanter centrifuge, certainly in terms of machines sold, is the dewatering of waste slurries arising from industrial processing, from raw water treatment, and from the treatment of municipal sewage. Almost all industrial manufacturing processes generate liquid wastes containing suspended solids; even an industry as apparently unconnected with liquid processes in its operations as machinery manufacture. Machining uses complex liquids for cooling and lubricating machine tools, which then become contaminated with dirt and metal scrap.
Machine tool fluids are usually valuable enough to need recycling, and so they must be cleaned before re-use. This is also true of many industrial wastes, that the liquid, once cleaned, or the separated solids, once dewatered (and, perhaps, washed) can be recycled profitably. However, the main bulk of waste slurries have to be dewatered in order that the suspending liquid can be discharged to a river or lake without polluting it, and the solids can be sent for final disposal in as small a bulk and as safe a condition as possible.
Waste sludges, once adequately dewatered, can be sent to landfill, or for soil improvement or fertiliser use, or to incineration. For most of these final destinations, a high degree of water removal is beneficial, and the decanter’s ability to achieve high drynesses has led to its wide acceptance in the treatment of waste slurries.
The whole process of drilling fluid circulating system
Drilling the drilling process, a large volume of cuttings are generated and carried out of the well by the drilling fluid. These cuttings must be separated from the mud liquid so the liquid can be reinjected into the drill string to remove more cuttings. The effectiveness of separating cuttings can be enhanced if the cuttings size is kept as large as possible.
The first stage of separation is to remove large cuttings from the mud with a shale shaker. Shale shakers are vibrating screens over which the mud passes. The liquid and small cuttings pass through the screens, while the large cuttings remain on the screen. If the mud contains gas, the shale shaker will aslo separate much of it from the mud. The mud and small cuttings that pass through the screens are returned to the mud pit, where additional separation of cuttings and gases occurs from gravitational settling. The effectiveness of vibrating screens depends on the vibrator placement, vibration frequency, vibration amplitude, speed of solids as they pass across the screen, and screen opening size.
Chemicals can be added to the mud that cause the small clay particles to coagulate or flocculate into large groups of particles. The larger flocculates then settle more rapidly in the mud pits. This process involves the neutralization of the surface charge on suspended particles and allow aggregates to form.
If a drilling mud contains gas that is not removed by the solids separation equipment, a vacuum chamber can be added to the mud system. This lowers the mud pressure in the chamber and expands the size of the gas bubbles, allowing them to be separated from the liquid bu gravity more rapidly. In these system, the mud is typically passed over inclined planes in thin layers to enhance separation.
Operations of Vacuum Degassers
The effective throughput of a degasser depends on a number of variables:
- The vacuum level is limited in part by how high the drilling fluid has to be lifted to enter the vacuum chamber. Lifts of more than 10 feet (3 m) are probably counterproductive.
- The denser the drilling fluid, the more the displacement force of the bubble upward, but this is not generally as important as the
properties of the fluid fraction of the drilling fluid. A higher drag coefficient reduces the ability of the bubble to rise. This is related to
viscosity effects and initial gel strength and is generally greater in higher-density drilling fluids.
3. Polymers and fine solids in the drilling fluid tend to build a tougher film around the bubble.
4. The more fluid is pumped or ejected, the less the residence time in the vacuum; or contrary-wise, with more gas, there will be less fluid throughput. With any particular drilling fluid, volume of entrained gas, and height of the degasser suction, there is a limit to the ability of the degasser to remove all the gas from the drilling fluid. Since it is not possible to predict all the drilling fluid/gas conditions, degasser planning is based on experience in the area. Some manufacturers have test curves that will show the real output of the degasser under fixed conditions.
Why Drill Wells That Are Non-Vertical?
Directional and horizontal drilling have been used to reach targets beneath adjacent lands, reduce the footprint of gas field development, increase the length of the “pay zone” in a well, deliberately intersect fractures, construct relief wells and install utility service beneath lands where excavation is impossible or extremely expensive.
Below is a list of six reasons for drilling non-vertical wells. They are graphically illustrated by the six drawings in the right column of this page.
A) Hit targets that can not be reached by vertical drilling.
Sometimes a reservoir is located under a city or a park where drilling is impossible or forbidden. This reservoir might still be tapped if the drilling pad is located on the edge of the city or park and the well is drilled at an angle that will intersect the reservoir.
B) Drain a broad area from a single drilling pad.
This method has been used to reduce the surface footprint of a drilling operation. In 2010, the University of Texas at Arlington was featured in the news for drilling 22 wells on a single drill pad that will drain natural gas from 1100 acres beneath the campus. Over a 25 year life-time the wells are expected to produce a total of 110 billion cubic feet of gas. This method significantly reduced the footprint of natural gas development within the campus area.
C) Increase the length of the “pay zone” within the target rock unit.
If a rock unit is fifty feet thick, a vertical well drilled through it would have a pay zone that is fifty feet in length. However if the well is turned and drilled horizontally through the rock unit for five thousand feet then that single well will have a pay zone that is five thousand feet long – this will usually result in a significant productivity increase for the well. When combined with hydraulic fracturing, horizontal drilling can convert unproductive shales into fantastic reservoir rocks.
D) Improve the productivity of wells in a fractured reservoir.
This is done by drilling in a direction that intersects a maximum number of fractures. The drilling direction will normally be at right angles to the dominant fracture direction. Geothermal fields in granite bedrock usually get nearly all of their water exchange from fractures. Drilling at right angles to the dominant fracture direction will drive the well through a maximum number of fractures.
E) Seal or relieve pressure in an “out-of-control” well.
If a well is out-of-control a “relief well” can be drilled to intersect it. The intersecting well can be used to seal the original well or to relieve pressure in the out-of-control well.
F) Install underground utilities where excavation is not possible.
Horizontal drilling has been used to install gas and electric lines that must cross a river, cross a road, or travel under a city.
The Importance of Proper Operation of a Shale Shaker
The purpose of a shale shaker is to remove large drilled solids from the drilling fluid. The shale shaker is the first piece of solids-control equipment to treat or condition the drilling fluid. Good shaker performance is necessary if the entire system is to function at or near design efficiency or capability.
Shakers now come in a dazzling assortment of sizes, shapes, and motions. Their performance is controlled by the size(s) and shape(s) of the openings in the screen(s), the drilling-fluid properties, the amount and type of cuttings arriving at the shaker, and the general mechanical condition of the equipment. The shaker selected for your rig may or may not be the best for the drilling at hand.Unfortunately, if it is not, it must still be kept operational, and with intelligent, conscientious work perhaps can be made to do the job. All commercial shale shakers, however, remove cuttings—and they remove cuttings better when properly maintained and operated.
Obviously cuttings cannot be removed until the drilling fluid first brings them to the surface. Solids coming off the end of shaker screens should have sharp edges. Cuttings that ‘‘roll around’’ in the borehole on the way to the surface have rounded edges. Rounded edges, or round cuttings, indicate that the cuttings are not being transported directly to the surface as fast, or directly, as they should be. The driller and/or mud engineer should be advised as to the shape of the cuttings coming over the shaker in regard to round edges. Rounded-edge cuttings indicate that there are many drilled cuttings stored in the annulus. This increases the mud weight in the annulus and the pressure at the bottom of the hole. The excess pressure significantly decreases the drilling rate and cuttings removal from beneath the drill bit.
Mud gas separator of solid control equipment
Mud gas separator is tied in downstream if the choke manifold. The major components are the inlet line. vessel, and vent line. This equipment separates gas from circulated drilling mud and minimizes mud loss during well control operations.
Separator sizing:
Separator vessel diameter is based on the gas flow rate seen at surface. The mud gas separator is a gravity settling device; gas flows up the vessel and liquid droplets dall. Liquid droplet terminal velocity, gas viscosity, and gas and liquid densities.
Vent line sizing:
The vent line configuration assumed for calculation purposes. Vent line equivalent length is greater than the 183ft. Indicated due to additional pressure losses at three elbows and the restricted entrance to the vent line.
Vessel internals:
A multitude of internal designs can be incorporated. An inlet impingement plate to prevent erosion of the vessel wall and to enhance fluid turbulence is recommended. Baffles above the inlet to provide maximum surface area for liquid drop coalescing, and baffles below the inlet to maximize surface area for gas break out and to maximize retention time are also recommended.
Materials and fabracation
Due to the varied operating conditions to which drilling equipment is subjected, it is recommended that mud gas separators and associated equipment be designed foe sour service. Additionally, abrasive fluids, severe temperature variations and mechanical vibrations due to liquid surges shoud be considered in material selection equipment fabrication.