12. Bulk Cement Storage and Handling

Section 12

Bulk Cement Storage and Handling Table of Contents Introduction..............................................................................................................................................12-3 Topic Areas ..........................................................................................................................................12-3 Learning Objectives .............................................................................................................................12-3 Unit A: Bulk Material Plants ...................................................................................................................12-4 Pneumatic Plants ..................................................................................................................................12-4 Unit A Quiz ..........................................................................................................................................12-6 Unit B: Sampling of Field Blend .............................................................................................................12-7 Manual Blend Sampling.......................................................................................................................12-7 Automatic Blend Sampling ..................................................................................................................12-7 Unit B Quiz ..........................................................................................................................................12-8 Unit C: Bulk Transportation Equipment..................................................................................................12-9 400-ft3 Pneumatic Truck ......................................................................................................................12-9 Model 660 Pneumatic Cementing Trailer ..........................................................................................12-11 1410 ft3 Pneumatic Field Storage Trailer ...........................................................................................12-11 Offshore Operations ...........................................................................................................................12-12 General Safety Guidelines..................................................................................................................12-12 General Operator Maintenance ..........................................................................................................12-13 Unit C Quiz ........................................................................................................................................12-15 Answers to Unit Quizzes .......................................................................................................................12-16

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Use for Section Notes…

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Introduction •

Bulk cement handling systems are used for most modern oilwell cementing. With these systems, you can formulate compositions to suit any well condition. At bulk blending stations, cement is handled by pneumatic systems operated under 30 to 40 psi air pressure. This cement is then transported to the job site in weather-tight bins or tanks.

Before beginning any cement job, consider all aspects of the job you are about to do. Considerations range from a careful review of the call sheet to ensure the correct equipment and bulk materials have been ordered to getting needed equipment and bulk materials ready for transport to location.

For a specific cementing job, the dry ingredients are blended and loaded into bulk transport units that can carry about 300 to 600 ft3 of Portland cement.

The bulk plant operation, bulk materials sampling, and bulk truck operation procedures are the topics presented in this section to provide you with a basic understanding of the bulk materials operation.

For high-volume jobs, you may need several field storage bins. These bins may be located at the well and filled before the cement job. Offshore, supplies and pumping equipment must always be on hand for instant use in case of emergency. Supply-service vessels using a pneumatic system deliver bulk materials to containers located on the rig.

Topic Areas Included in this section are the following units: A. Bulk Material Plants

Bulk material handling involves the handling of large unpackaged quantities of cements or other dry materials. This eliminates the storage of dry materials in sacks or other containers making the cements easier and faster to use and transport. The handling of material in bulk form offers the following advantages: •

Cement is protected against weather while being stored, transported, or unloaded.

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Additives can be more uniformly blended at bulk cement plants.

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Cement mixing rates are faster and more uniform.

Large cement jobs are more practical.

B. Sampling of Field Blends C. Bulk Transportation Equipment

Learning Objectives Upon completion of this section, you should be familiar with

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The equipment designed to handle bulk materials

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The sampling procedures for evaluating the blend of bulk materials

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Unit A: Bulk Material Plants Bulk material plants are found in nearly all Halliburton locations. Although numerous types of bulk cement plants exist, the pneumatic type bulk plant is likely to be the most common bulk plant in use today.

Pneumatic Plants The following figures illustrate two types of pneumatic bulk plants: the permanent type pneumatic bulk plant (Figure 12.1) and the portable pneumatic plant (Figure 12.2). The portable plant can be dismantled and moved from one location to another and rebuilt quickly. Both systems operate in a similar manner.

Figure 12.1 – Permanent Pneumatic Type Bulk Cement Storage Plant

The handling of bulk cements through a pneumatic process involves the mixing of dry materials by moving them from tank to tank. The mixed dry material is then moved to the next tank or truck by discharging it into a high velocity air stream. Advantages of this type of system are •

uniform feeding of fresh aerated (fluidized), uncaked, and lump-free cement into the mixing system

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mixing of cement batches pneumatically by movement between tanks at 30 to 40 psi air pressure and into mixing or transfer tanks for continued aeration and a more complete mix of materials.

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minimal contamination from previous cement batches.

Figure 12.2 – Portable pneumatic Bulk Cement Storage Plant Figure 12.3 illustrates a typical permanent pneumatic bulk cement plant system consisting of a series of separate tanks for storage, weighing, and blending. A description of the tanks and their functions appear below.

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Figure 12.3 – Pneumatic Bulk Storage Plant •

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wasted material until proper disposal is possible.

Storage tanks - cone-shaped or square vertical bin providing storage and unloading capability for cements and additives commonly used in that geographical location. Most portable or offshore bulk systems use pressurized storage tanks that allow them to be placed anywhere, whereas permanent storage tanks operate on a gravity feed principle.

At least four complete pneumatic transfers are required to properly blend material. These transfers are 1. Cement is blown from scale tank to blending tank (all material in the scale tank must be transferred) 2. Cement is blown or vacuumed from blending tank back to scale tank.

Scale Tank - cone-shaped pressurized tank into which bulk cement materials are blown or vacuumed pneumatically and weighed. Overhead Receiver/Blending Tank - most bulk plants are equipped with either a nonpressurized gravity feed overhead receiver tank or a pressurized blending tank. These tanks further mix the dry materials as well as temporarily hold the cement and additive materials prior to being discharged to the bulk truck for transport. Waste Tank - a storage-type tank with a dust collector into which other storage tanks and trucks being pneumatically filled may be vented. It may also store field returns and

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3. Cement is blown or vacuumed from scale tank back to cementing tank. 4. Cement is blown from scale tank to blending tank (or from the scale tank directly to the bulk truck). Additives that are not held in bulk form in the plant’s storage tanks must be added to the cement through the admix hopper. These additives must be carefully weighed prior to being poured into the admix hopper. Proper weighing will ensure that the right percentage of additive will be added to the bulk cement. When only part of a sack is required, the additive should be weighed on a set of scales accurate

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enough to read to the closest 0.5 lb, yet be capable of weighing as much as 50 lb.

plant is similar. The size and location of the field service center determines to a large degree the size and type of bulk plant in operation at that center.

Although many types of pneumatic bulk plants are in use today, the basic operation of each

Unit A Quiz Fill in the blanks with one or more words to check your progress in Unit A. 1. The handling of large quantities of cements and other dry materials in ___________________ form has greatly increased the ease with which cements can be handled. 2. The permanent and the portable ___________________ bulk materials plants are most commonly used by Halliburton. 3. In the pneumatic bulk process, cements are mixed by transferring ________________ from tank to tank. 4. The scale tank is a ____________________ tank to which the bulk cement materials are blown or vacuumed pneumatically and _____________________. 5. Blended dry materials are usually blown to the bulk truck for transport to the location from the _____________________ or _________________ tank. 6. After the cement is transferred from the storage tank to the scale tank, ___________ pneumatic transfers are required to ensure proper mixing. 7. The admix hopper is used for adding the chemical additives that are not stored in the plant in ___________________ form. 8. To ensure that the right percentage of additive will be added to the bulk cement, proper __________________ is required. This involves the use of a scale capable of accuracy to ________________ pound.

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Unit B: Sampling of Field Blend After the third blending transfer is completed, it is important that a sample of the blend be taken to ensure the desired blend was obtained. For proper analysis, take a sample large enough to fill a one-gallon container. Two methods of sampling the blended cement are discussed in this unit: •

Manual Blend Sampling

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Automatic Blend Sampling

Storage

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Manual Blend Sampling

Figure 12.4 – Manual Sampling Valve

Manual sampling usually occurs after the third blending transfer at any point in the bulk loading process.

Automatic Blend Sampling

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Truck sample - using a “grain thief”, a sample is taken from the loaded storage tanks on the truck.

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Manual sampling valve - after the third blending transfer, a sample of the mixed cement and additives is taken during a pneumatic transfer by placing a plastic or brown paper sack under the sampling valve. The ball valve is opened and closed slightly to allow cement to be discharged into the sample bag (Figure 12.4). For proper analysis, collect enough cement to fill a one gallon container.

The automatic sampler is a device installed in the loading line between the blending plant and the truck. This device is controlled by an inside and outside timer and can be set up to take a sample of the bulk cement blend as frequently as once every second. During the loading cycle, the sampler inserts a probe into the stream of cement materials as they are being blown to the truck and takes a small sample. Then the probe withdraws from the line and the cement with additives discharges from the probe into a bag that is attached to the bottom of the discharge opening. As mentioned earlier, allow the bag to fill until a sample large enough to fill a onegallon container is obtained. The automatic system has proven to be a reliable method for ensuring both a proper blend and a successful cementing job.

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Unit B Quiz Fill in the blanks with one or more words to check your progress in Unit B. 1. Two methods are available for taking a sample of the blended cement mixture. Both the __________________ and ___________________ blend sampling methods require at least ________________________ of sample to be taken for proper analysis. 2. Sampling of the blend in a manual fashion can occur __________________ in the bulk loading process. 3. The automatic sampling method uses a probe for taking blend samples at regular intervals. This device is installed in the _________________ ______________ between the blending plant and the truck.

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Unit C: Bulk Transportation Equipment valves for the fill, vent, aeration, discharge, and control functions, the truck has three major components:

400-ft3 Pneumatic Truck The 400 ft3 Pneumatic Truck with Drum blower (Fig. 12.5) is used for transporting bulk materials (cement blends and fracturing sand) from service centers to job locations. This selfcontained truck can either pneumatically discharge to bulk storage units or discharge directly to pumping equipment during a job. In addition to interconnecting piping, fittings, and

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two ASME-coded 200 ft3 pneumatic storage tanks

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one ASME-coded 21 ft3 Steady Flow® separator assembly with dust collector

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one power-takeoff (PTO) driven air blower assembly rated at 270 scf/min at 29 psig

Figure 12.5- 400 ft3 Pneumatic Truck with Drum Blower

Pneumatic Storage Tanks

Gross Aeration System

The two 8 ft diameter, 200 ft3 pneumatic storage tanks are ASME-coded pressure vessels with 36 psig maximum allowable working pressure (MAWP). This MAWP allows operators to use a higher-pressure compressor from another unit, even though the maximum pressure of the truckmounted blower is 29 psig.

Each storage tank is equipped with a gross aeration system for unloading stored materials. This system consists of two aeration cartridges in the bottom of each tank. The air inlet nozzle of each aeration cartridge extends through the tank cone. These cartridges can be lifted out through the 20 in. manway after the hose adapter and jam nut are removed from the nozzle.

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The gross aeration system in each tank conditions materials with air so that a fluid mixture or solution of air and dry materials will result. When the discharge valves of the tank are opened, the pressure in the tank forces the aerated materials to flow steadily through the discharge line until the tank is emptied.

Top Air Connection Air is also fed into the top of each tank through a 1.5 in. coupling. The top air connection allows a higher flow rate into the tank. A vertical checkvalve in the top air line automatically provides a calibrated restriction to force air through the aeration pads in the bottom. A pressure-gauge line runs from each tank to a 0 to 60 psi pressure gauge, which allows the operator to monitor the pressure in each tank continuously.

Figure 12.6 – 20 in. Manway

Tank Openings The following openings are in the top head of each tank: •

two 4 in. victaulic nipples for pneumatic filling and venting

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one 1.5 in. air-inlet coupling

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one 1.5 in. vent coupling

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one 20 in. manway

Figure 12.7 – Drum Model XHPD450 Blower Assembly

The 20 in. manway (Fig. 12.6) is secured by six cams, and it can be used for overhead bulk material loading as well as inspection and maintenance.

Operation Procedures For specific operation and maintenance instructions, refer to the manual titled 400 ft3 Pneumatic Truck with Blower, SAP 100078427. The manual can also be downloaded from the following HalWorld site:

Air Blower The Drum Model XHPD450 blower assembly (Fig. 12.7) is driven through a power takeoff (PTO) from the truck transmission. This blower is rated at 275 scf/min at 29 psig and 1,600 rev/min. A relief valve on the blower assembly prevents blower overpressure

http://halworld.halnet.com/hes/hesPS/hespszi/he spszipm/hespszipm_Manl/hespszipm_Manl_935 49191/hespszipm_Manl_93549191.asp

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to 12 in. (30.48 cm) ahead of the bogie centerline.

Model 660 Pneumatic Cementing Trailer The Model 660 pneumatic cementing trailer has three versions: • short-wheelbase trailer • long-wheelbase trailer

Figure 12.8 – Model 660 pneumatic cementing trailer.

• desert service trailer

Features The Model 660 pneumatic cementing trailer includes the following features: •

Chassis- 22,000 lb (9977 kg) axles with 44,000 lb (19 960 kg) spring, 11 R 22.5 tires, SAE standard 2.0 in. kingpin; or desert service 30,000 lb (13 605 kg) axles with 50,000 lb (22 260 kg) springs

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Pneumatic tanks- Two 330 ft3 (9.35 m3), 36 psi (248 kPa) working pressure

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Discharge manifolding- A 5 in. (127 mm) separator-to-RCM, 5 in. tank-to-separator and tank-to-storage; 5 in. nominal drain and cleanout

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Model 660- Approximate Discharge Rates

Fill manifolding- A 4 in.(102 mm) fill manifold with 4 in.vent for loading tanks pneumatically (includes bulk-plant dust collector)

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Mileage totalizer- Engler Hubodometer

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Optional separator and dust collectorConstant-pressure 21 ft3 (0.59 m3) separator

Figure 12.9 – Model 660 with long wheel base.

Sand to Mountain Mover

20 sk/min

Cement to field storage bin

35 sk/min

Sand to hopper

25 sk/min

Cement to hopper

80 sk/min

Cement to RCM

50 sk/min

1410 ft3 Pneumatic Field Storage Trailer

Benefits The Model 660 pneumatic cementing trailer can provide the following benefits:

Features

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The 1410 ft3 Pneumatic Field Storage Trailer includes the following features:

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The Model 660 desert service trailer can be used with tractors having sand tires and fifth wheels located up to 10 in. (35.24 cm) ahead of the bogie centerline. The Model 660 short-wheelbase trailer can be used with tractors having fifth wheels up

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Chassis- 22,000 lb (9977 kg) axle with 20,000 lb (9070 kg) spring, 11 R 22.5 tires, kingpin SAE standard 2.0 in.

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Pneumatic tanks- 380, 425 and 435 ft3 (10.76, 12.03 and 12.31 m3) capacity all ASME-coded to 39.5 psi (272.3 kPa) working pressure

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Separator and dust collector- Constantpressure 170 ft3 (4.81 m3) separator with Cyclone dust collector

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Discharge manifolding-

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5 in. (127 mm) nominal to separator

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5 in. nominal separator bypass

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4 in. (102 mm) drain and cleanout

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5 in. nominal blow-through front and rear discharge extension

Figure 12.11 - Water-borne service vessel.

General Safety Guidelines By following these guidelines, operators can help ensure that Halliburton bulk trucks work properly and safely.

Fill and vent manifolding- 5 in. nominal to tanks

Optional compressor system and mileage totalizer.

Weight Limitations The maximum allowable tandem axle weight for trucks in most areas of the United States is 34,000 lb. The maximum front axle weight is 18,000 lb. Therefore, when loading the tanks, operators should consider the axle weights of the vehicle as well as the volume of material in the tanks. When loaded, the overall weight of the vehicle should never exceed 52,000 lb.

Figure 12.10 - 1410 ft3 Pneumatic Field Storage Trailer.

Avoid overloading any vehicle for the following reasons: •

High tank levels increase the center of gravity and increase the likelihood of the truck overturning on slopes, irregular surfaces, or turns.

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Completely filling the tanks with some materials, such as cement or sand, will result in an overweight vehicle. Driving an overweight vehicle on the road could result in a personal traffic ticket, preventing the material from reaching the job.

Offshore Operations Waterborne service vessels using pneumatic pressure systems are usually equipped with their own weighing and blending plants. If they are not, you can obtain weighed and blended materials from a support vessel or shore station within the operating area (Fig. 12.11). Also, offshore, supplies and pumping equipment must always be on hand for instant use in case of emergency. Supply-service vessels using a pneumatic system deliver bulk materials to containers located on the rig.

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Pressurized Tank Safety When you are working with any tank or vessel that operates under pressure, be sure to follow these safety procedures:

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Before removing caps, hose connections, or opening valves to atmosphere, always completely vent possible trapped pressure in the discharge and vent lines. Caps and hoses removed under pressure could become dangerous projectiles, resulting in serious injury or damage.

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Prevent accidental discharge of air or material in the direction of yourself or others. Dry, abrasive material could be forcefully blown into the face or eyes.

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Never work under the vehicle when the engine is running. The vehicle could suddenly move or fingers, hair, or clothing could become caught in rotating shafts, pulleys, and belts, resulting in serious injury.

General Operator Maintenance Pre-Operation Checks

Never pressurize tanks above maximum allowable working pressure (MAWP). Pressurizing above the MAWP could result in violent tank rupture or a pressure explosion. If the safety relief valves allow overpressure, replace them before any additional operation.

Before leaving the field camp, inspect the following: 1. Check all belts for fraying and excessive looseness.

Frequently monitor the tank pressure gauges to prevent accidental overpressure. If the MAWP is reached, close the tank air-supply valve. Vent the tank if an extended delay is expected.

2. Check the blower assembly for loose or missing parts. Tighten or replace parts as necessary. 3. Check the following pneumatic equipment: a) Check the air and discharge manifold to ensure that the unit is ready for operation.

Do not operate the blower at maximum pressure with its relief valve venting for an extended period. The blower and air piping will become extremely hot, possibly resulting in personal injury and possible damage to the blower and relief valve. In addition, unnecessary energy is used because no aeration will occur at maximum pressure.

b) If they are not closed already, close the pneumatic tank air-supply valves and the separator air-supply valve to prevent air from being supplied to the tanks prematurely.

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Do not touch the blower case or nearby piping during or soon after operation. These items can become hot enough to cause serious skin burns.

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Always wear ear protection when working near the blower. Prolonged exposure to blower noise could result in hearing damage.

4. If the hatch will be opened, or if cam adjustments are necessary, open the air-vent valve to relieve any pressure in the tank, regardless of the reading on the tank pressure gauge.

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c) Check the top of the pneumatic tanks to be sure that the manway hatches are closed and latched.

Never lubricate or work on the blower with the engine running, even if the PTO is disengaged. Someone might engage the PTO or the PTO could accidentally engage and catch fingers, hair, or clothing, resulting in serious injury.

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Caution—Loosen but do not swing the hatch cams off until you verify that pressure is not trapped in the tank. If internal pressure exists in the tank, these cams will prevent the cover from being blown off. Warning—If air begins to escape from the hatch while you are loosening the hatch cams, stop loosening the cams and immediately relieve all pressure through the vent valves or pressure-

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relief valve on top of the tank. Excess pressure could result in equipment damage or personal injury.

Pneumatic Tanks and Manifolding- Before each trip, inspect the structural supports for the tanks, separator, dust collector, ladder, platform, manifolding, and fenders.

Routine Operator Maintenance

The tanks should always be cleaned before different materials are transported.

The best way to avoid costly breakdowns and time-consuming troubleshooting is to keep the truck in good repair. This section discusses routine maintenance for the following major components:

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If the tanks will be loaded with a similar material, operators should blow the tanks out with air and inspect them before loading them again.

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If the tanks will be loaded with a different material (for example, tanks previously carrying cement will be loaded with frac sand), remove and clean the air pads and wash out the tanks.

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air-supply system

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relief valves

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pneumatic tanks and manifolding

Air-Supply System- Frequently check the drains on the underside of the air supply manifold for condensation. If drain valves will not pass air while the manifold is under pressure, clean or replace the valves. Routinely pressurize the air-supply system and operate all valves to be sure they are working properly. Repair or replace any valves that are leaking. Look for signs of cement backing up into the system. If check valves are not holding, cement may have been forced into the air lines. Relief Valves- Examine the relief valves for clogged or plugged discharge openings and cement buildup around the valve seat or valve spring. Verify that no parts are broken or missing. Test the safety valves at least once each month. Pressurize the system to the low-pressure safety valves set pressure and allow each valve to open and reset as it would during a normal job. Watch the system pressure carefully. Caution—Do not exceed the safe maximum pressure. If the safety valves are not operating properly the blower could be damaged or the tank could rupture, resulting in potentially severe or fatal injury.

Caution—Do not “blow down” the tanks and manifold without connecting the discharge manifold to a plant waste tank. Excessive and potentially harmful dust emissions would result. Important—Immediately report pressure vessel defects to a maintenance or safety supervisor. Never attempt unauthorized repair or alteration of ASME-coded pressure vessels. Coded vessels must adhere to strict qualification, procedural, and reporting requirements. Repairs may only be made by an ASME-authorized repair shop. If repairs or modifications are necessary, contact the Duncan manufacturing organization for assistance. Check all valves and manifolds on the tanks to make certain they are holding pressure. Cycle the valves to make sure they are opening completely. Repair or replace any worn valves, linkages, or handles. Inspect manifolds for loose or damaged parts, and check hoses for wear or leaks. Caution—Replace worn flexible hose immediately. A blown hose can ruin a job and possibly cause personal injury. On trucks with combination dust collectors (cyclone-plus- dustbag), remove and empty the bottom dust pan after each job. To increase bag life and improve operation, periodically brush materials from the inside of the bag.

Caution— Do not use safety valves for routine venting. Use them only often enough to be sure they are working properly. The more the valves are opened, the more likely they are to leak.

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collection chamber. Cement tends to build up in the throat and close off the flow area.

Trucks with cyclone dust-collectors should be serviced after each job. Open the dump valve and empty the dust chamber. If necessary, “rod out” the throat of the cyclone. The throat is the small end of the top where dust enters the

Unit C Quiz Fill in the blanks with one or more words to check your progress in Unit C. 1. The 400 ft3 pneumatic truck can either _________________ discharge to bulk storage units or discharge ____________ to pumping equipment during a job. 2. MAWP stands for _______________ __________________ ________________ ______________. 3. How fast can the Model 660 pneumatic cementing trailer deliver cement to a field storage bin? _______________ 4. What is the maximum allowable tandem axle weight for trucks in most areas of the United States? _______________ 5. Pressurizing a tank above the MAWP could result in ______________________________________. 6. If you find a pressure vessel defect, what should you do?___________________________________ ______________________________________________________________________

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Answers to Unit Quizzes Items from Unit A Quiz

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1. bulk

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2. pneumatic

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3. dry materials

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4. cone-shaped, weighed

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5. overhead receiver, blending

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6. complete

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7. bulk

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8. weighing, 0.5 lb

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Items from Unit B Quiz

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1. manual, automatic, one gallon

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2. at any point

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3. loading line

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Items from Unit C Quiz

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1. pneumatically, directly

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2. maximum allowable working pressure

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3. 35 sacks per minute

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4. 34,000 lb

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5. violent tank rupture or a pressure explosion

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6. Immediately report it to a maintenance or safety supervisor

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