A MOSDAX pressure probe is used for making pressure measurements. The probes record pressure, temperature and a number of performance diagnostic parameters.
A MOSDAX* pressure probe is used for making pressure measurements. The probes record pressure, temperature and a number of performance diagnostic parameters. The output from the sensors is digitized in the probe and sent to the surface in digital format. This permits the use of a rugged but light-weight, single-conductor armored cable. The probes communicate with a surface memory and control unit (an MPCI or a MAGI) which can be connected to a handheld controller or a notebook computer.
Strings of Probes
MOSDAX probes can be connected in series along a single cable to provide continuous multi-level pressure measurements. Up to 31 probes can be placed on a cable up to 1,200 m (4,000 ft) in length. The data is recorded on a MOSDAX data logger (MDL) or on a MAGI™ data logger.
The data can be recorded at pre-selected intervals or when the pressure exceeds settable windows. Alarms can be triggered and phoning sequences initiated.
Modems or RF communication units can be attached to the data loggers to send the data to remote offices. Probes can be instructed to undergo in-situ calibration checks for periodic assurance of sensor performance.
The strings of probes can be removed for recalibration, repair or replacement of individual probes. When a series of probes is used in an array of boreholes, real-time, 3-D fluid pressure data can be obtained. A row of boreholes equipped with strings of probes could be used to construct a pressure-sensing wall to automatically detect any significant variations in fluid pressure.
Since its introduction in 1978, Westbay System has been used for a variety of applications around the world, including:
Groundwater basin management
Using Westbay System to construct a three-dimensional network of monitoring zones provides the data necessary to observe groundwater behavior on a "macroscopic" scale. This detailed data allows basin managers to optimize the use of groundwater resources.
Environmental and geological repository site characterization studies
Westbay System has been used in the nuclear waste research programs in Canada, the United States, Japan, Spain, the United Kingdom, Switzerland, France, and South Korea.
Scientists involved in studying the possibility of burying nuclear waste deep underground agree that the most likely pathway for radionuclides to return to the biosphere is through groundwater.
As a result, careful evaluation of groundwater conditions is critical to determine the feasibility of an underground disposal site. The detailed, defensible data collected through Westbay System provides the key to a thorough understanding of groundwater conditions at a proposed repository site.
Deep contaminant monitoring projects
Information on the vertical distribution of fluid pressures and chemistry is the key to characterizing, managing and remediating contaminated groundwater sites. Westbay System enables you to collect the data you need to identify the problem—affordably.
Geotechnical studies for landslides, ground settlement, mines, tunnels, and dams
Engineers and geologists involved in the geotechnical sector have received vital pore pressure data and water chemistry information using Westbay System technology on large construction projects that involve slope stability, dewatering and settlement.
Because fluid pressures and displacements are two of the most important parameters in the study of slope stability, Westbay System has been used on some of the largest landslide and slope stability studies ever undertaken.
Draw on our knowledge and experience to help you select equipment and develop well designs to meet your technical objectives, borehole conditions and Westbay System capabilities.
We'll start by asking you about your project (objectives, depth, geology, drilling method, etc.) and help you select the best Westbay System components and type of borehole completion method for your particular situation. Our Westbay System casing can be installed in an open hole, through a temporary guide tube or in a cased well. The type of seals (e.g., packers) selected must match the drilling equipment and the expected borehole dimensions and stability conditions. Where packers are not used, monitoring zones can be sealed by backfill.
Field installation
Our on-site technician helps your installation proceed smoothly. We work with your field installation team according to a well-proven process:
Approve the monitoring well design.
Visually inspect and lay out the Westbay System casing components in sequence.
Record the serial numbers for each packer, measurement port, and pumping port.
Assemble each casing joint and test the hydraulic seals.
Lower the casing into the borehole.
Test the hydraulic integrity of the entire casing string.
Inflate the packers sequentially from bottom to top, recording the inflation pressure and volume of water used for each packer.
Measure fluid pressures at each measurement port to confirm proper operation and check the annular hydraulic seals between monitoring zones.
Then QA zones have been added between monitoring zones, pressure measurements in them help confirm packer seal quality.
Maintenance and repair
Westbay System monitoring well components require little maintenance. That said, we recommend that you invest in a comprehensive maintenance, service and QA program for the portable measurement and sampling equipmentfor good QA of monitoring data and to support their continued reliable operation. Our maintenance programs can include annual recalibration of sensors, parts replacement, and priority response when you require repairs.
Operator training
We'll train your field operators to meet our high standards and yours. We provide training in all aspects of operating Westbay wells, including:
Pressure profiling—with pressure probes or sampling probes.
Sample collection using a Westbay sampling probe and accessories.
Using pumping port open/close equipment and any pump supplied, if you plan to carry out purging.
Hydraulic testing using pumping ports.
Deployment, programming, downloading, and recovery of automated data acquisition equipment.
Operating procedures, QA checks, and routine equipment maintenance in the field.
Upon successful completion of the training, you'll receive a certificate as well as comprehensive equipment manuals to guide you along the way.
QA testing and review
Our technical services staff can also advise you on quality assurance testing and evaluation and, upon request, will review your data to verify that your equipment is operating properly.
Trust us to help you choose and implement the best combination of instrumentation and operations to meet your unique groundwater monitoring needs.
Westbay System casing is available in two sizes:
Westbay55 (55 mm ID):Install larger diameter casing deeper, providing you greater flexibility and upgrade potential.
Westbay38 (38 mm ID):Functions like Westbay 38 but with a smaller diameter.
Operational capability
Variation of system size and material of construction provides operational capability ranging to depths of greater than 1,200 m (4,000 ft) in boreholes or wells ranging in size from 76 mm (3 inches) to 160 mm (6-1/4 inches) and larger. Varying well completion methods are available to meet specific project requirements and/or hydrogeologic environments.
Operating specifications can vary considerably from project to project. We can help you to choose the system that best meets your requirements.
Schlumberger Water Services provides innovative groundwater monitoring and sampling instruments, field data acquisition accessories, and software for environmental data management, analysis, visualization, conceptual modeling and simulations, with a complete range of training and support services for environmental consultants, government agencies, industry, and educational/research institutions.
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