Optical SenSors

Optical systems can provide data for more efficient development and operation of simple and complex reservoirs. They offer clear advantages for certain well types and applications in terms of performance, reliability, cost and ease of installation. In fact, for multi-zone and other challenging well environments, optical systems deliver capabilities that no alternative technology can match.

The sensors themselves are all glass to withstand high temperatures, pressures and vibration. The glass is also immune to interference from local radio or electrical transmission sources. From a simple P/T optical gauge above-the-packer to horizontal, multizone sand screen completions, Weatherford provides an integrated optical architecture for virtually all life-of-asset measurements that you may need.

Typical Applications for Optical Systems

High Temperature/High Pressure

Optical sensing systems can withstand temperatures to 347°F (175°C). All the electronics are located at the surface and are more easily accessible for upgrades and maintenance; high-reliability, passive components remain downhole.

Pressure/Temperature Applications

In horizontal completions, P/T gauges are useful for defining drainhole production efficiency. When coupled with flow-control valves or inflow control devices, these gauges can ensure uniform production across a long horizontal section.

Production and Injection Profiling

Optical distributed temperature sensing (DTS) and array temperature sensing (ATS) systems may allow determination of production and injection profiles across the reservoir sections of horizontal, multilateral and multizone wells.

Well Startup Monitoring

Optical P/T sensors can be used effectively during well startups, not only to measure real-time reservoir pressure, but to manage initial drawdown. Our proprietary EPS Products software, such as the PanSystem and PanMesh programs, are used to create inference tests and pressure transient analysis to provide reservoir boundary information.

Downhole Flow Measurement

Real-time downhole flow measurement is critical for optimizing production from many of today’s complex well designs, including intelligent, multi-zone and multilateral completions. Data from a downhole flowmeter can be used to reduce or eliminate the need for surface well testing and the resulting operational, safety and environmental effects.

Optical flowmeters have no borehole restrictions or intrusions into the flow path. They are bidirectional, scalable to any pipe size and feature a control-line bypass for use in intelligent well systems. These flowmeters can be configured for single-, two- or three-phase flow and are applicable to production and injection wells.

Distributed Temperature Sensing

DTS allows monitoring of the thermal profile of the entire well, giving an indication of the production or injection profile across the reservoir sections and helping to identify flow anomalies, such as tubing or casing leaks, thief zones and flow obstructions. DTS has also been useful in determining completion effectiveness and the performance of gas lift valves.

Array/Multipoint Temperature Sensing

ATS is temperature profiling with multiple, discreet temperature sensors spaced apart along an area of interest in the wellbore. Multiple sensors are combined on a single fiber using optical multiplexing technology. The optical temperature sensors provide reliable, accurate and stable point temperature data, useful in measuring small production-induced thermal changes and/or can provide accurate reference points for DTS measurements.

Sand Control

Optical systems are adept for monitoring across perforated intervals and open-hole sections, deployed inside or outside the sand screen.

Water and Steam Breakthrough

Temperature profiling with DTS and/or ATS can help detect the intrusion of water, gas or steam in wellbores.

Multizone Completions

In multilateral completions and wells with commingled production from stacked reservoirs, optical flowmeter data can help resolve production allocations issues and determine productivity index for individual zones or the entire well.

Seismic Imaging and Monitoring

Permanent in-well seismic monitoring performs time-lapse vertical seismic profiling (VSP), cross-well seismic imaging and surface seismic calibration. In addition, seismic monitoring has been used to map fracture propagation during well stimulation. Recently, geoscientists have been listening to microseismic activity that is associated with injection, production, or subsidence–adding a new dimension to dynamic reservoir characterization. The seismic stations can be installed in a production well or injector or a nearby observation well.

Instrumentation, Data Interface and Communications

Weatherford offers a full line of reservoir monitoring systems (RMS) to fit the scale and complexity of your completion projects. There is an RMS surface system for interior or non air-conditioned, even harsh environments. These systems provide web-enabled accessibility for reading on demand.

Our basic RMS provides integrated information to operators from multiple optical tools. It can operate as a stand-alone data-acquisition, management, display and communication system or it can seamlessly interface with legacy SCADA, secure intranets, Internet or communication systems. With considerable local storage available, the RMS can hold an extensive amount of high frequency data. The system features a single shared network for Modbus, TCP/IP and OPC.

The system supports a simple P/T application to multiple P/T and DTS tools. The RMS, RMS-WH (wellhead), and RMS-WH-Q (quartz) can monitor up to six optical or electronic tools.