Serva Auto Cement Mixing Skid - ACS-II-260

Recirculating Mixer System with Averaging Tank

High Energy Mixer "Patent 6,749,330" Automatic Density Control Key Job Parameter Recording Built-in Pre-job System Check Built-in Manual Simulator 20 BBL Averaging Tank W/Agitator Transfer centrifugal pump Closed loop hydrostatic transmissions power centrifugal pumps

The Serva Auto Cement Mixer Model ACS-II-260 system is the latest in mixing technology, density control and includes a 20 bbl averaging tank. This system can be used for all cement, flush and spacer mixing operations. The 20 bbl averaging tank with agitators allows the batch mixing of up to 25 bbl of cement for plug and squeeze cementing. In addition, the 20 bbl averaging tank further adds additional mixing energy, provides averaging of slurry density and additive concentration is further made uniform. The large averaging tank makes the operators job easier by making the process more forgiving to potential job problems such as poor bulk delivery. Thus the quality of the resulting slurry and versatility of the unit adds significant value to the service company and the operator company.

Major Specifications

Optional Equipment

A. SERVAacm microprocessor will record one pressure and one pump rates, which can be down loaded to a PC. (Include's computer software, cable's, reels, and one rate generator. This does not include the pressure transducer)
B. SERVAacm microprocessor will record one pressure and two pump rates, which can be down loaded to a PC. (Include's computer software, cables, reels, and two rate generator's. This does not include the pressure transducer)
C. SERVAacm microprocessor will record two pressures and two pump rates, which can be down loaded to a PC. (Include's computer software, cables, reels, and two rate generators. This does not include the two pressure transducers)

Description

The system is the latest in mixing technology, density control and includes a 20 bbl averaging tank. This system can be used for all cement, flush and spacer mixing operations. The 20 bbl averaging tank with agitators allows the batch mixing of up to 25 bbl of cement for plug and squeeze cementing. In addition, the 20 bbl averaging tank further adds additional mixing energy, provides averaging of slurry density and additive concentration is further made uniform. The large averaging tank makes the operators' job easier by making the process more forgiving to potential job problems such as poor bulk delivery. Thus the quality of the resulting slurry and versatility of the unit adds significant value to the service company and the operator company.

The system consists of two basic parts: 1) mixing system and 2) power supply unit.

1. MIXING SYSTEM SKID
(1) 7 bbl mixing tank
(1) 20 bbl averaging tank
(2) SERVApump 5x6 centrifugal pumps (cement mixing recirculation and transfer to triplex pumps)
(1) 3x4 centrifugal pump (mix water)
(1) Automatic Control Mixer (SERVAacm) for density

2. POWER SUPPLY UNIT
(1) Customer supplied, 260 HP Engine
(2) Closed loop hydrostatic transmissions
Seawater or air to liquid cooling of engines and hydraulics (customer must select)

SKID DIMENSIONS and WEIGHT (including engine power supply)

Recirculating Mixer System with Averaging Tank

General Specifications

• The Serva ACS-II-260 is a skid-mounted state of the art mixing system. The unit consists of a recirculating mixing system with averaging tank, all required controls and instrumentation and a hydraulic system to drive the mixing equipment.
• The fluid handling system consists of centrifugal pumps for recirculation, transfer and mix water. Manifold consists of necessary piping, valves and connections to perform cementing jobs.
• The mixing system consists of a high energy multi-jet recirculating type mixer, high rate recirculating pump and tub agitator. The diffuser aids in removing air entrainment from bulk cement. A densitometer is mounted in the recirculating line and the mix water is measured with a turbine flow meter. The one compartment 1 M3 (7bbl) mixing tank maintains the ability to mix cement on the fly with good density control and provides adequate residence time for good cement mixing. The 20 bbl averaging tank allows for greater residence time, more mixing and density averaging. The averaging tank along with the mixing tank allows the batch mixing of up to 25 bbl of slurry for plug jobs and other purposes that require 25 bbl or less. Tanks have full flow piping to rear of unit for ease of cleanup.
  The system is capable of mixing 2.3 m3/min (14.4bpm) and densities up to 2.7 g/cm3 (22 lb./gal).
  

The following are included as part of the equipment specification

• Dust Eliminator
• Third centrifugal pump for dedicated fluid transfer
• Control panel labeled in English only
• Control panel gauge units in English and Metric

Environment Parameters

Temperature

• Minimum operating 20° C (?4° F)
• Maximum Operating 50° C (122° F)
• Humidity Relative: 90%
• Vibration/Shock Maximum shock: 1g

Operational Performance

1. Job locations
The unit is designed for land and offshore operations
2 Component Size
· No component is greater than 2.44m (96in.) wide or greater than 2.77m (109in.) in transport height
· Total weight is approximately 15,909 kg (35,000 lb.)
· Length: 4.26 m (14ft.)
3. Flow Rate
Maximum flow rate is 3.0 m3/min (18.74BPM) for fluid transfer and triplex boost operations
4. Density Range of Slurry
Maximum slurry weight is 1.0 - 2.7 g/cm3 (8.33-22.6 lb/gal)
5. Slurry Mixing Capacity Range
Mixing range will be 0 2.3 m3/min (0 -14.4BPM) 14.4 bpm is for very high water requirement slurries only.
6. Automatic Control Density Tolerance
When mixing in automatic control mode the density ranges can be controlled to within +/- 0.01 to 0.02 g/cm3 (±. 083 to .167 lb./gal) of indicated densitometer reading during near steady state operations. This assumes reasonable steady output of bulk delivery system.
7. Continuous Working Time: 6 hours

Skid specifications

1. Diesel Power System
Provide by customer but requires the following:
260 hp minimum. Before order, must provide engine operating speed for matching gearbox ratio for hydraulic system.
Air compressor for operating air control valves and packing lube system.
Alternator for supplying 24 vdc power for control system.
Battery will be supplied and interfacing diagrams for wiring alternator

2 Plunger Packing Lubrication System
The plunger lubrication system is provided by a pressurized oil supply system. The packing lubrication system contains:
Lube oil reservoir
Distribution manifold
Required plumbing and hoses
pressure gauge
pressure regulator
Flow control valves for each plunger with setting locks

Fluid Handling System

Low pressure piping
· The suction manifold has a working pressure rating of 1.2 MPa (175 psi). The manifold includes various butterfly valves, which are convenient to operate, and various flanges, couplings, union connections, pipe and fittings that are easy to connect.
· Fluid from the mixing tank connects to both the recirculating & boost pumps. Fluid from the recirculating pump can be pumped into mixing tank via the densitometer and slurry mixer and into the discharge manifold for triplex pumps.
· Remote valves that are required for normal operation are air actuated.
· The suction manifold for the transfer pump is supplied from either the averaging tank or the mixing tank. The discharge manifold for triplex pumps is supplied by either the transfer pump or the recirculation pump.

Cement Mixing System
The mixing system is a high energy recirculating slurry mixer type. It consists of a high energy eductor mixer, diffuser, mixing tank, agitator and recirculating and mix water pumps. The mixer design maximizes wetting of all cement by forcing the dry bulk cement into and between the fresh water and the recirculating slurry. The mix water centrifugal pump and the recirculating centrifugal pump provide most of the high energy. The diffuser aids in removing air entrainment from the bulk cement and eliminates dust in the mix tank. The 1.27 m (7bbl) mixing tank allows adequate residence time for good mixing and averaging of density with varying bulk cement delivery. The deep tank design provides good pump head and minimizes vortexing and cavitating. A hydraulic driven paddle agitator provides improved mixing and a more homogenous slurry. The mixing capacity range is 0/2.3 m3/min (14.4bpm) with mixing density range of 1.0/2.7 g/cm3 (8.33/22 lb./gal). The mix tub piping delivers fluid to the suction manifold of the recirculating centrifugal pump via 152.4 mm (6 in) piping.

Mixing Centrifugal Pump
The 4x3 mixing centrifugal pump will meet the following specification.
Suction: 101.6 mm (4 in) pipe size
Discharge: 76.2 mm (3 in) pipe size
Flow rate at 110 psi: 1.65 m3/min (10.4 bpm)
Maximum closed-in pressure: 1.17 MPa (170 psi)
The mixing centrifugal pump takes on fluid from external sources
through a manifold with 101.6 mm (4 in) union connections.
The pump can discharge fluid into the mix tub only.

Recirculating Centrifugal Pump
The dedicated SERVApump 6X5 recirculating centrifugal pump has the following specifications.
Suction: 152 mm (6 in) pipe size
Discharge: 127 mm (5 in) pipe size
Max. flow rate at 64 psi: 3.7 m3/min (23 bpm)
Maximum closed-in pressure: 0.49 MPa (70 psi)
The recirculating centrifugal pump is capable of receiving fluid from the mix tub and from the displacement tank via the mix tank.
The recirculating pump can discharge fluid into the mix tub for recirculating or into the suction manifold for triplex pumps.

Boost Centrifugal Pump
The dedicated SERVApump 6x5 boost centrifugal pump has the following specifications.
Suction: 152 mm (6 in) pipe size
Discharge: 127 mm (5 in) pipe size
Flow rate at 64 psi: 3.7 m3/min (23 bpm)
Maximum closed-in pressure: 0.49 MPa (70 psi)
The boost centrifugal pump is capable of receiving fluid from the mixing tank, averaging tank and from outside sources.
The boost pump can discharge fluid into the mix tub for recirculating or into the suction manifold for triplex pumps.
Note: The recirculation and boost pumps are dedicated pumps for their respective functions but in case there was a problem with either pump, the other pump can take the place of the inoperative pump or can take both functions at the same time at a reduced rate.

Hydraulic System
The hydraulic system consists of closed hydraulic pumps and open loop systems. The closed loop systems are for driving the centrifugal pumps and the open loop systems is for the agitators and control functions. The system contains its own 160 liter (42 gal) stainless steel reservoir with sight gauge, filtration system, and heat exchanger. The following components are driven by the system:
Recirculating pump
Boost centrifugal pump
Mixing water centrifugal pump.
Mix tub agitator
Averaging tank agitator
Automatic Control Mixer (SERVAacm) power for Metering Valve actuator

Operation and Display System

Operator Console
The Operator console is a custom built steel cabinet with a protective stainless steel cover. The instrument panel is stainless steel with permanently engraved labeling in English. The location of the console allows the operator a full view of the various instruments and gauges of the console.

Instrumentation
· The hydraulic system has pressure gauges for each pump circuit and an oil temperature gauge mounted in the console.
· Console mounted pressure gauges are liquid filled with dual scale face reading in standard U. S. units and metric units.
· Most gauges and instruments read in both standard U. S. units and metric units.
· Mixing pump is equipped with a flow meter and pressure gauge.
· The recirculating/boost pump is equipped with a pressure gauge.

Density Control
The cement mixing system can be operated in a manual or automatic mode. In manual mode the operator uses a manually operated hydraulic control valve to control the cement metering valve. In the automatic mode, an electro-hydraulic control system operates the cement metering valve. The electro-hydraulic system is controlled by an industrial process controller/computer. The slurry density can be quickly reduced by the use of a bypass line (connected to the recirculation pump suction).