Equipment Introduction Cementing requires specially designed equipment. Equipment may be high-powered like the CPF-376 double-pump cement trailer or CPT-372 double-pump cement truck or highly versatile to accomplish numerous cementing operations each day, like the CemSTREAK cementing unit. Even more specialized equipment is required for use offshore, with the skids designed to deliver high power with high reliability. In many cases, offshore cementing is done using liquid additives and LAS* liquid additive systems are used for precise delivery of the additives to the mixing system. When subsea heads are used, the DeepSea EXPRESS plug launching system is used for reliable wiper plug launching. Monitoring and recording of the cementing operation is done using the CemCAT computer-aided treatment software and a portable computer. Innovative mixing control is accomplished using the SFM* Solids Fraction Monitor.
CemSTREAK land cementing unit The CemSTREAK land cementing unit is a lightweight, low-maintenance truck with four-wheel drive that can be used for almost any cementing application. Its rugged, compact design enables operation even in hard-to-reach locations. The simplicity of design and extensive test program provide a high level of reliability over rough terrain and in bad weather and allow quick rig-up, rig-down and cleanup. This unit enables as many as six jobs to be performed in one day.
The compact CemSTREAK unit can service wells in difficult-to-reach locations. Designed for fast rig-up and rig-down, the unit can perform multiple jobs in one day.
Cementing Services and Products
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The CemSTREAK unit is equipped with one triplex pump and two 1.1-m3 [6.9-bbl] displacement tanks, one of which doubles as the mix tank. The hydraulically driven triplex pump allows control of flow rates and pressures and delivers 127 kW [170 hhp] of power. Two centrifugal pumps enable high-energy mixing, pressurizing the triplex pump as well as bringing water onto the unit. The unit carries 38 m [125 ft] of treating hose, rated to 20.7-MPa [3,000-psi] working pressure, to serve as the high-pressure conduit to the well. The hose is stored on an automated reel for fast deployment and retrieval. A nonradioactive mass-flow meter provides accurate measurements of slurry density, flow rate and fluid volume even during U-tubing of fluids in the well. Cleaning of the unit starts with the displacement tanks, which minimizes wastewater and hence environmental impact.
Applications ■ ■ ■ ■
Cementing services Low- and intermediate-range pumping services Remedial cementing operations requiring very low pump rates Low-range pressure testing
Benefits ■ ■ ■ ■ ■ ■ ■
Ability to reach difficult locations Savings in rig time through rapid rig-up and rig-down Minimal environmental impact Weight compliant with various road ban rules Crew of only two operators for improved logistics, reduced risks and costs Downtime probability reduced or eliminated by reliability of equipment Ability to mix all slurry types
Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
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Four-wheel drive 127-kW [170-hhp] triplex pump Rating of 20.7-MPa [3,000-psi] working pressure 38 m [125 ft] of 50.8-mm [2-in.] hose rated to 20.7-MPa [3,000-psi] working pressure Powered reel for hose storage, deployment and retrieval 1.11-m3 /min [7-bbl/min] pump rate Nonradioactive densitometer SLURRY CHIEF Mark III cement mixer Oilfield or metric gauges Integrated data-acquisition system Two 1.1-m3 [6.9-bbl] displacement tanks CemCAT real-time monitoring Four separate systems for pressure relief Self-sufficient unit, including cement head and extra treating iron
Cementing Services and Products
CPF-376 double-pump cement trailer This cement trailer is a state-of-the-art mixing and pumping unit for land operations. The highpower unit allows mixing and pumping cement at rates to 2.7 m3 [17 bbl/min] and at pressures to 68.95 MPa [10,000 psi]. Pumps are available with rating to 137.9 MPa [20,000 psi]. The unit is fully redundant, allowing operations to continue in the event of failure of one of its components.
The CPF-376 double-pump cement truck delivers high reliability in high-pressure pumping operations.
A SLURRY CHIEF mixer with automated density control is used in conjunction with a 0.95-m3 [6-bbl] mixing tub and a 2.2-m3 [14-bbl] averaging tank. This arrangement produces superior density control and separates the critical mixing stage from downhole pumping. It also provides the ability to mix 3.2 m3 [20 bbl] of cement in batch mode for squeeze and plug operations.The CemCAT system is used to monitor and record treatment parameters and to provide a job report.
Applications ■ ■ ■
Cementing services High-power pumping services Remedial cementing operations
Benefits ■ ■ ■
Equipment
Full redundancy ensures ability to complete job Downtime reduced or eliminated by reliability of equipment Ability to mix all slurry types
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Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
194-kW [260-hhp] power per triplex pump, for a total of 388 kW [520 hhp] 2.7-m3 /min [17-bbl/min] pump rate Working pressure rating to 137.9 MPa [20,000 psi] Fully redundant for high reliability SLURRY CHIEF Mark III cement mixer Automatic density control system Two nonradioactive densitometers Oilfield or metric gauges Underdrive for pumping at low rates Direct drive centrifugal pumps for reliability Integrated data-acquisition system CemCAT real-time monitoring Self-sufficient unit, including treating iron
CPT-372 double-pump cement truck The CPT-372 truck is a high-power cement mixing and pumping unit that allows mixing and pumping at rates to 2.7 m3 [17 bbl/min] and at pressures to 68.95 MPa [10,000 psi]. The unit is fully redundant, allowing operations to continue even if one component fails.
The CPT-372 double-pump cement truck delivers high reliability in high-pressure pumping operations.
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Cementing Services and Products
A SLURRY CHIEF mixer is used in conjunction with a 0.95-m3 [6-bbl] mixing tub. This arrangement produces superior density control and separates the critical mixing stage from downhole pumping. It also provides ability to mix a maximum of 3.2 m3 [20 bbl] of cement in batch mode for squeeze and plug operations. The CemCAT system is used to monitor and record treatment parameters and to provide a job report.
Applications ■ ■ ■
Cementing services High-power pumping services Remedial cementing operations
Benefits ■ ■ ■
Full redundancy ensures ability to complete job Downtime reduced or eliminated by reliability of equipment Ability to mix all slurry types
Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
Power to 388 kW [520 hhp] Pump rate to 2.7 m3 /min [14 bbl/min] Working pressure rating of 68.95 MPa [10,000 psi] Fully redundant for high reliability SLURRY CHIEF Mark III cement mixer Nonradioactive densitometer Oilfield or metric gauges Integrated data-acquisition system CemCAT real-time monitoring Self-sufficient unit, including treating iron
Offshore cementing skids Schlumberger provides a versatile line of CPS* cement pumping skids specially designed to meet all offshore cement mixing and pumping requirements. These skids can produce up to 1,490 kW [2,000 hhp] for high-pressure pumping. Two triplex pumps equip the unit for simultaneous high-energy mixing and downhole pumping or for parallel downhole pumping. Two engines (diesel or electric) power the unit. The design focuses on reliability, redundancy and noise reduction. The units are typically controlled from a local console but optional remote control packages are available. Optional marine cooling kits and a helicopter lift unit are available. Cement slurries are mixed using the SLURRY CHIEF recirculating mixer fitted with an SFM quality control monitor or an SFM-C* process control unit for automatic density control. The SLURRY CHIEF unit mixes consistent slurries at rates to 1.75 m3 /min [11 bbl/min]. Equalizing tubs provide excellent slurry uniformity (3 m3 [19 bbl]).
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CPS cement pumping skids are available in a number of configurations to fit any requirement.
Offshore cementing skids are fitted with all sensors necessary for direct connection to the CemCAT data-acquisition and monitoring system. The CemCAT system monitors and records the critical job parameters including rate, pressure and slurry density. Batch mixers, such as the CBS-961 twin 50-bbl mixer, are available for mixing of cement slurries or other fluids. The CBS-961 unit features two centrifugal pumps for picking up fluids from remote tanks, recirculating for mixing and for delivering fluid to high-pressure pumps.
Standard equipment ■ ■ ■ ■ ■ ■ ■ ■
SLURRY CHIEF cement mixer Nonradioactive densitometer Two triplex pumps Stainless-steel displacement tanks Slurry pump Recirculation pump Two mixing water pumps Full selection of fluid ends
Optional equipment ■ ■ ■ ■ ■ ■ ■ ■ ■
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SFM package Automatic density control Zone II-certified engine package Remote control package Split skid with bulkhead Optional loose equipment skid Marine cool kit Liquid additive metering system Soundproof enclosure (for CPS-601 and CPS-665 units)
Cementing Services and Products
Applications ■ ■ ■ ■ ■ ■
All cementing jobs High-pressure pumping services Fluid pickup from remote sources Metering of mixing fluids Metering and pumping of displacement fluids Downhole pumping using one or both triplex pumps
Table 6-1. Dimensions of Offshore Cementing Units CPS 361
CPS 601
CPS 665
CPS 763AC
CPS 763DC
Length (mm [in.])
6,511 [256]
7,710 [304]
7,863 [310]
8,180 [322]
7,823 [308]
7,164 [282]
Width (mm [in.])
2,578 [102]
3,011 [119]
2,898 [114]
3,007 [118]
3,150 [124]
3,841 [151]
Height (mm [in.])
3,043 [120]
3,467 [136]
3,333 [131]
3,339 [132]
3,323 [131]
3,267 [129]
32,180 [70,960]
33,840 [74,600]
37,360 [82,380]
38,010 [83,810]
46,795 [103,180]
Operating weight (kg [lbm]) 20,658 [45,550]
CPS 2000
Table 6-2. Performance of Offshore Cementing Units CPS 361
CPS 601
CPS 665
CPS 763AC
CPS 763DC
CPS 2000
Power (kW [hhp])
410 [550]
626 [840]
1,044 [1400]
1,194 [1600]
1,194 [1600]
1,490 [2000]
Max. rate at 41.4 MPa [6,000 psi] (m3 /min [bbl/min])
1.6 [10]
3.1 [19.7] at 46.9 MPa [6,800 psi]
2.9 [18.3]
2.9 [18.3]
2.9 [18.3]
3.8 [24.0]
LAS liquid additive system Modular systems, such as the CMP-351 unit, deliver metered amounts of liquid additives to the cement slurry as it is mixed. Metering of liquid additives adds versatility to the mixing process, enabling the mixing of various slurry systems from bulk storage of neat cement. Metering can be manual, or automatic when the CMP-751 LAS metering unit is used. With the CMP-751 unit, electromagnetic flow meters control the additive metered into the displacement tanks.
Applications ■ ■
Offshore cementing operations Operations in remote areas
Benefits ■ ■ ■ ■ ■ ■
Equipment
Allows use of neat (unblended) cement for all operations Provides high versatility in slurry designs Simplifies logistics Enables last-minute design without regard to time of transport from base Eliminates waste of unused blended cement Enables decisions on treatment volumes at time of job
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Features ■ ■ ■ ■ ■
Meters up to four different additives into mixer Stainless-steel construction for durability Remote control of additive addition Certified for Zone II operations Electromagnetic flow meters
CemCAT cementing computer-aided treatment software The CemCAT system is a quality control (QC) and data-acquisition software for acquiring, recording, displaying, and reporting cementing and related pumping treatment data in real time. CemCAT system real-time displays and plots present detailed job information to decision-makers. User friendly and quickly accessible, the CemCAT system provides enough defaults for the system to be used quickly with a minimum of user input, or it can be completely customized. By acquiring data from existing hardware on cementing units, the CemCAT system provides efficient data transfer between the Wellsite Reporting System and Schlumberger CemCADE cementing design software. Integration of up-to-the-minute data with design and evaluation soft ware results in precise treatment design and execution. During the job, the CemCAT system tracks the design and displays actual job parameters compared with planned values. With the CemCAT system, quality assurance (QA)/QC plots can be generated at the end of each treatment to determine if a job was pumped within the designed density range. Internet connectivity allows the transmission of data from a remote wellsite to anywhere in the world for real-time analysis. The CemCAT system also provides the means to easily archive job data for future use.
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Primary and remedial cementing operations Miscellaneous high-pressure pumping services for testing blowout preventers or for leakoff or formation integrity tests Matrix acidizing and coiled tubing services
Benefits ■ ■ ■ ■
Superior QC during all treatment phases Precise treatments that follow job design Immediate data for job-critical decisions, thus reducing risk Exceptional flexibility, performance and reliability
Features ■ ■ ■ ■ ■
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Complete integration with CemCADE design and evaluation software Clear, customizable digital displays and plots of job data Real-time data transmission from wellsite to any location worldwide Detailed postjob plots including QA and QC plots and reports Archive of job data for future use
Cementing Services and Products
SFM-C process control An important element of successful low-density slurry placement and ideal set-cement properties is QC. A key measure of quality in cement slurries is the solids fraction, which is the percent of dry components in the slurry. In a conventional cementing operation, densitometers measure slurry density, and the solids fraction can be calculated from the density measurements. Variation in the solids fraction of the slurry affects all the cement properties. Too many solids and the slurry will be too viscous and set early. Too few solids and free fluid will be high and the compressive strength will be low and develop late. For certain slurries, such as very low density slurries, slurry quality cannot be determined using density measurements. In ultralightweight slurries, the densities of the dry blend and the mix water can be nearly the same, so density measurements cannot discriminate between water and solids. The density would be the same, even if the slurry consisted entirely of water. For example, a slurry designed at 1020 kg/m3 [8.5 lbm/gal] with 57% solids content and monitored using only a densitometer with a variation of ± 12 kg/m3 [0.1 lbm/gal] in density will have a solids content ranging from 24% to 84%. The SFM-C process control system provides a new method for real-time slurry QC that accurately determines and controls solid/liquid ratios without making density measurements. The system measures the rate of mix water and slurry flows and calculates the solids fraction from those measurements. From this determination, the fluid density is easily computed. The solids fraction is automatically maintained by process control of the water and cement flow into the mixer.
SFM-C system instantly displays critical data in convenient, readable formats.
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Slurry density Slurry rate
Solid frac tion
(%)
Solid frac tion
100 90 80 70 60 50 40 30 20 10 0 0
5
10
15
20
25
30
35
40
10 9 8 7 6 5 4 3 2 1 0
Slurry density
(lbm/gal) Slurry rate
(bbl/min)
45
Time (min)
Volume (%)
100 90 80 70 60 50
88% of volume ± 2% of the solid-frac tion target 99% of volume ± 0.2 lbm/gal
40 30 20 10 0 0
10
20
30
40
50
60
70
80
90
100
Solid frac tion (%)
The SFM-C system controls the solids fraction, which in turn controls the density.
The SFM-C system is a complementary technology, designed to provide QC for very low density LiteCRETE slurry systems. Although SFM-C technology was developed specifically for light weight-cement operations, it is effective for slurries of any density. This new SFM-C technology allows cementing crews to maintain slurry properties while continuously mixing and pumping large slurry volumes. The system requires a slurry flow meter, such as the nonradioactive densitometer already available on cementing units, a residence tank sensor, a water flow meter and process-controlled valves. These retrofits can be added easily to land or offshore mixing equipment. User-friendly software helps cementing crews monitor and easily switch between automatic and manual control.
Applications ■ ■
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All cementing operations Slurries with very low densities (less than 1,320 kg/m3 [11 lbm/gal])
Cementing Services and Products
Benefit ■
Excellent QC
Features ■ ■ ■ ■ ■ ■ ■
Continuous-mixing control of all slurries, even at densities equal to or lower than that of water More sensitive method for controlling cement mixing than by density measurement Independent of specific gravity of components Automatic control of slurry quality Real-time monitoring Complete compatibility with all data-acquisition systems Easy installation on conventional mixing equipment
Nonradioactive densitometer Density measurement and control in the oil industry have traditionally been accomplished by using radioactive densitometers, mainly because they are nonintrusive, durable and easy to use. Unfortunately, the radioactive technique has several major drawbacks; the radioactive source presents safety and environmental concerns, and the required accuracy (12 kg/m3 [0.1 lbm/gal]) is difficult to attain. Because of the deficiencies of radioactive densitometers, Schlumberger uses a nonradioactive densitometer that employs a proven method; poses no health, safety, or environmental hazard; and provides direct density measurements with an accuracy of better than 12 kg/m3 [0.1 lbm/gal]. The nonradioactive densitometer is extremely reliable, easy to use and requires no on-site calibration. Additionally, it measures flow rate with an accuracy of ±0.5% of reading and can be used as a flow-measurement instrument for acidizing service. The vibrating tube principle governs the density measurement in the nonradioactive densitometer.
The nonradioactive densitometer is a rugged, field-proven instrument with excellent reliability.
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Applications ■ ■ ■ ■
Cementing operations with slurry density over 1,200 kg/m3 [10 lbm/gal] Land and offshore (including Zone II) Process controlled operations Can be used for acidizing service
Benefits ■ ■ ■
Accurate density measurement Reliability, requires no on-site calibration Minimal environmental and safety concerns
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No radioactive source Superior accuracy and field-proven reliability for measuring density and flow rate Accuracy greater than 12.0 kg/m3 [0.1 lbm/gal] Virtually maintenance-free Easy configuration; easily drained and cleaned in place Output (density, rate) independent of changes in temperature, pressure, flow profile or viscosity Fast response time
Cementing Services and Products
