24-09-2014, 02:47 PM
ABSTRACT Gypsum is a technologically driven private limited EPC company. Their core competency lies in providing trenchless services. Gypsum is a pioneer in this field having vast experience in executing Micro tunneling, Horizontal Directional Drilling (HDD), Pipe Bursting and Rehabilitation by GRP / CIPP lining projects. Today, Gypsum is one of the few companies in their field featuring a complete range of trenchless services. This has put Gypsum at the forefront of utility companies, municipalities and hydrocarbon companies in the underground pipeline business in India. Horizontal directional drilling or HDD, is a steerable trenchless method of installing underground pipes, conduits and cables in a shallow arc along a prescribed bore path by using a surface-launched drilling rig, with minimal impact on the surrounding area. Directional boring is used when trenching or excavating is not practical. It is suitable for a variety of soil conditions and jobs including road, landscape and river crossings. Directional boring is used for installing infrastructure such as telecommunicati
PROJECT REPORT
TO IMPROVE EFFICIENCY OF HDD BY USING MUD RECYCLING UNIT
ABSTRACT
Horizontaldirectional drillingor HDD, is a steerabletrenchlessmethod of installing underground pipes, conduits and cables in a shallow arc along a prescribed bore path by using a surface-launched drilling rig, with minimal impact on the surrounding area. Directional boring is used when trenching or excavating is not practical. It is suitable for a variety of soil conditions and jobs including road, landscape and river crossings.
Horizontal directional drilling is done with the help of aviscousfluid known as drilling fluid. It is a mixture of water and, usually,bentoniteorpolymer continuously pumped to the cutting head or drill bit to facilitate the removal of cuttings, stabilize the bore hole, cool the cutting head, and lubricate the passage of the product pipe. The drilling fluid is sent into a machine called a reclaimer which removes the drill cuttings and maintains the proper viscosity of the fluid. Drilling fluids hold the cuttings in suspension to prevent them from clogging the bore.
Due to this, drilling fluids are required in huge amount and also due to its cost they need to be utilized properly. Drilling fluids disposal also is one of the challenging tasks. In order to remove these problems mud recycling unit is used to cope up with these problems.
IMPORTANCE OF MUD RECYCLING UNITS IN HORIZONTAL DIRECTIONAL DRILLING OPERATION The advancement of the trenchless construction industry has given rise to many more challenging and demanding projects. Drilling rigs and tunnel boring machines have evolved to meet the demands of these projects and are working in exceedingly difficult soil conditions, from high density and abrasive rock to soft, sticky clay. Furthermore, increased environmental regulations and costs for drilling mud disposal make older methods of solids control such as dump-and-dilute and gravity-settling less practical and/or uneconomic. All these variables mean it’s now an absolute necessity to have an efficient and properly sized mud recycling plant for a successful project. Drilled solids present in the drilling fluid adversely affect rates of penetration, increase wear on downstream equipment, raise drilling mud, chemical and water usage, and can escalate disposal costs.
Efficient solids control can eliminate all of these issues, which can help to lower total operating costs and increase rates of penetration.
So this project shows how mud recycling unit improves the efficiency of an HDD project and reduces the cost of operation.
INTRODUCTION TO MUD RECYCLING SYSTEM
A drilling fluid/mud recycling system removes solids from fluids that have been pumped through the bore hole, allowing recirculated fluid to be reused. Most recycling systems also mix fluid additives and deliver fluid to the drill rig\'s mud pump or to a separate downhole pumping system.
Components of a recycler consist of: a holding tank, separated into compartments; one or moreshakerunits to separate larger solids from fluid; desanding and desilting hydrocyclones; and a pumping system. An efficient recycling system must mix, clean, recirculate and pump fluids to the drill rig- all at the same time.
Most of the recycling systems contain the above mentioned parts depending upon the requirement and type of job. But the basic parts of fluid recycling system have been discussed below.
PARTS OF MUD RECYCLING SYSTEM
Shale Shaker:
Shale shakersare components ofdrillingequipment used in many industries, such ascoalcleaning,mining, oil and gas drilling. They are considered to be the first phase of asolids controlsystem on adrilling rig, they are used to remove large solids also calledcuttingsfrom the drilling fluid, more commonly called "Mud" due to its similar appearance.
Shale shakers are the primary solids separation tool on a rig. After returning to the surface of the well the used drilling fluid flows directly to the shale shakers where it begins to be processed. Once processed by the shale shakers the drilling fluid is deposited into the mud tanks where other solid control equipment begins to remove the finer solids from it. Shale shaker consists of following parts namely, hopper, feeder, shaker screen, screen basket and vibrator etc.
Desander And Desilters
Desandersanddesiltersare solid control equipment with a set ofhydrocyclonesthat separate sand and silt from the drilling fluidsindrilling rigs. Desanders are installed on top of the mud tank following theshale shakerand thedegasser, but before the desilter. Desander removes the abrasive solids from thedrilling fluidswhich cannot be removed by shakers. Normally the solids diameter for desander to be separated would be 45~74μm, and 15~44μm for desilter.
Acentrifugal pumpis used to pump thedrilling fluidsfrom mud tank into the set ofhydrocyclones.
Ahydrocycloneis a device to classify, separate or sort particles in a liquid suspension based on the ratio of theircentripetal forcetofluid resistance. This ratio is high for dense (where separation by density is required) and coarse (where separation by size is required) particles, and low for light and fine particles. Hydrocyclones also find application in the separation of liquids of different densities.
A hydrocyclone will normally have a cylindrical section at the top where liquid is being fedtangentially, and aconicalbase. The angle, and hence length of the conical section, plays a role in determining operating characteristics.
Mud Tank
Amud tankis an open-top container, typically made of square steel tube and steel plate, to storedrilling fluidon a drilling rig. They are also calledmud pits, because they used to be nothing more than pits dug out of the earth.
Mud tanks play an important role insolids control system. It is the base of solids control equipments, and also the carrier ofdrilling fluids. Solids control equipments that are all mounted on the top of mud tanks include the followings:
shale shaker vacuum degasser desander desilter centrifuge mud agitator
Drilling fluids flow into the shale shaker directly after it returns to the surface of the well, and the solids that are removed by the screen would be discharged out of the tank, and the drilling fluids with smaller solids would flow through the screen into mud tank for further purification. Acentrifugal pumpwould suck the shaker-treated fluids up to the desilter or mud cleaner for further purification. And vertical slurry pump is used to pump the drilling fluids up to the centrifuge, and mud pump would pump the drilling fluids from mud tank into the borehole after it is treated by centrifuge. And the circulation system would continue.
The number of the mud tanks that are needed on the drilling rig depends on the depth of the well, and also the mud demands of drilling. Normally the shale shaker and vacuum degasser and desander are mounted together on the same mud tank as the first tank at the oilfield, while desilter and centrifuge on the second tank. And also the drilling rig would have other different tank as reserve tank, emergency tank, etc.
Advantages Of Mud Recycling System
Advantages of fluid recycling systems include reduced water requirements, savings in additive costs and disposal fees, extended life of pumps and downhole cutting tools, and increased productivity. They also often help drillers to cope up with environmental restrictions.
Investing in recycling equipment is an additional equipment expense, but study say the cost is recovered in savings resulting from reduced costs for fluid additives, labor to transport the water and fluid clean-up and disposal. Also, recycled fluid reduces wear of pumps and downhole tools, and is a factor in increased productivity. The use of a recycler eliminates the spread of fluids to surface areas of environmentally-sensitive job sites.
Advantages of mud recycling are:
Reduced disposal costs Lower landfill costs Lower transportation costs Reduced environmental impact Less pollution from reduced vehicle journeys Less material to landfill Solids not classified as hazardous waste Solids can be reused onsite or taken to conventional landfill sites for disposal Drill fluids are cleaned and can be reused again and again throughout the drilling process