There is a new generation of in-well monitoring technologies that are being characterized under the Acoustic Energy sensing banner. Some are essentially disturbance or vibration event monitoring techniques but this paper describes a Distributed Acoustic Sensing (DAS) technology [1]. The subject sensing system uniquely allows the user to listen to the acoustic field at every point along many kilometers of fiber optic cable deployed in the well. With a spatial resolution of 1 meter, for example, there will be 10,000 synchronized sensors along a 10,000 meter fiber. The system uses a novel digital optical detection technique to precisely capture the true full acoustic field (amplitude, frequency and phase over a wide dynamic range) at every point simultaneously. A number of signal processing techniques have been developed to process a large array of acoustic signals to quantify the coherent temporal and spatial characteristics of the acoustic waves. Potential in-well monitoring applications have been identified, and significant benefits are predicted for optimizing and maximizing production in many types of oil and gas fields by facilitating informed decisions. The system can be retrofitted to existing installations of permanent in-well fiber optics based monitoring systems with the addition of surface instrumentation. New installations are also planned. The paper also describes the background technology with focus on full reconstruction of the acoustic signal along the well bore, sensing system capabilities and the results of field trial surveys, with first generation instrumentation in seven offshore Norwegian Continental Shelf wells. These seven offshore wells already contained in-well fiber optics sensing systems, and comprised of two water injectors, one gas injector, three producers with gas lift valves, and one high rate Gas Oil Ratio producer. Installed sensing included Bragg grating based Pressure and Temperature gauges and fiber based flow meters. DAS measurements were recorded on fibers with both types of sensors installed on the same fibers. An acoustic signal for flowing wells was obtained in all cases and for most of the wells it was possible to also extract qualitative information on the flow regime, speed of sound and an estimate for flow velocity in at least parts of the wells.

For any production optimisation system to function effectively it must reliably receive quality data on demand. Over the past decade the reservoir monitoring industry has been addressing the issue of reliability including implimentation of a step-change technology - Passive Optical Sensing Systems. Since the first installation of an in-well optical pressure gauge over 10 years ago, the industry has built a substantial track record with over 85 installations of P&T gauges and hundreds of DTS installations - acceptance is growing! Initially Optical Sensing systems were expensive, complicated to install, and could only support limited applications. Today, they are on a par with electronic gauges with respect to performance, cost and installation simplicity. The state- of-the-art in optical sensing technology includes Bragg-grating based Pressure and Temperature sensors, permanent Distributed Temperature Sensing (DTS), Single- and Multiphase Flowmeters, and Seismic sensors. This paper describes the operation of each of the sensing systems mentioned above, the data/information provided, together with details of application case histories. These range from simple single-gauge installations to complex wells with integrated pressure sensing, flow measurements and remotely activated zonal flow control - true Smart or Intelligent Wells. The future direction includes even more complex intelligent completions and subsea deployments. Also high accuracy distributed array temperature sensing, optical distributed pressure sensing, sand detection, and distributed strain (e.g. for riser monitoring), are just a few of the new generation of sensing systems that are described in the paper. As subsea continues to play an important role in our industry, the presentation (not included in this paper) will also include a synopsis from the SPE ATW "In-well Optical Sensing - Subsea Well Applications - Are We Ready"? held February 7th and 8th, 2006 in Galveston. Introduction To manage and optimize well production, operators need in-well monitoring systems that deliver high-performance measurements throughout the life of the well, and reliability without the need for routine maintenance or intervention. In the 1980's, the initial applications for optical sensing were focused on the military and areospace industries. The requirements that drove early development of optical sensing systems were not readily available in comparable electrical systems. These requirements included:Small physical size, allowing simple integration into small locations and embedding in composite structural systems.Multiple sensing point and measurement types on a single fiber, replacing multiple electrical sensors, instrument types and associated electrical wiring. This reduced system complexity and weight is critical in aerospace systems.Silica with high temperature fiber coatings, enabling the development of sensing systems for applications with operating temperatures in excess of 1,000°C.High reliability, maintained by having simple sensing elements at the measurement point and the sensor's instrument in a readily accessible location for servicing or repair.Immunity to interference from local radio or electrical transmission sources.No spark hazard, reducing the risk of fire. Also optical communication systems significantly improve signal performance, data density and transmission distance. These requirements also fit the needs of oil and gas in-well monitoring applications. Subsequently the first in-well optical Pressure and Temperature gauge was installed in a producing land well in the Netherlands in 1993. This initial system operated successfully for a period of more than 5 years. And so began the journey to broader acceptance of the technology in our industry. Through significant investment by service companies and operators in the development of sensor systems, a wider range of commercial optical sensing products and services has been brought to the oil and gas market.

The industry has seen the gradual implementation of step-change optical sensing technology as one way to address the issue of reliable permanent downhole gauges. This paper will include case histories that indicate an ever-broadening acceptance of this technology with application scenarios ranging from simple single-gauge installations to multi-zone intelligent wells with integrated sensing and remotely activated in-well zonal flow control -true Smart or Intelligent Wells, with now over 600 installations worldwide.Present measurement capabilities include Pressure and Temperature, Distributed Temperature Sensing (DTS), Single-and Multiphase Flowmeters, Seismic Accelerometers and hydrophones, and the paper will also detail additional downhole and subsea optical sensing systems currently under development.As subsea continues to play a vital role in our industry, it has been recognized that there are a number of challenges to be addressed before optical sensing systems will be widely adopted subsea.These challenges are being addressed in part by a new thirty member company industry group, SEAFOM (Subsea Fiber-Optic Monitoring) -this group's activities will be described.In addition, a number of operating and service companies have on-going related initiatives. For example, StatoilHydro has an Integrated Operations (IO) initiative aimed at significantly increasing overall recovery rates of subsea production assets. As part of that initiative, StatoilHydro and Weatherford signed a three year Technical Development Cooperation Agreement in June 2006. This project will make real-time reservoir monitoring and downhole data available everywhere on a StatoilHydro network infrastructure. This paper includes the rationale for selecting fiber optics as the baseline technology and also describes the technical solution for an open, high speed communication infrastructure. The project is also developing interfaces towards existing subsea systems with only electrical, low bandwidth communication systems. Solutions are being developed for both Green and retrofit Brown field applications.

This paper describes:The technical solution and infra-structureThe work processPlans and visions for the future This project will contribute towards the Statoil Increased Oil Recovery (IOR) strategy as it will make real-time reservoir monitoring and downhole data available everywhere on a Statoil network infrastructure. It will be a frontrunner in the development and implementation of downhole fiber optic sensors and infrastructure as a basis for online reservoir management. The goal is to resolve any hurdles for implementing fiber optic monitoring and data transmission from subsea developments where this technology can give Statoil an improved business value. Focus is on detailed seabead system solutions to create an open, and high speed communication infrastructure which the fiber optics technology opens up. The project shall also develop interfaces towards existing subsea systems with only electrical, low bandwidth communication systems. Background On June 20th 2005, Statoil requested technical and commercial proposals relating to the development of:Integrated Fibre Optical Systems - an integrated subsea fiber optics communications systemReliable Downhole Sensors - of which some eight were identified This was part of the much larger Statoil Integrated Operations initiative aimed at increasing overall recovery rates of subsea and Tail End production assets. Weatherford subsequently formed agreements with FMC Technologies and Nexans Norway to jointly develop the proposal submitted, with Weatherford as the lead contractor, and on June 29th, 2006, Statoil and Weatherford signed a 3 year Technical Development Cooperation Agreement. The resultant program is a 50/50 jointly funded R&D program with resources (personnel and test facilities etc.) being supplied from all four participating companies to work on each subproject of the overall project. Weatherford concurrently signed back-to-back sub-contractor agreements with FMC Technologies and Nexans Norway. Subsequent to contract award, a three year Technical Cooperation Agreement was set up and funded to address the scope of work. The scope of the project (figure 1) can be summarized as follows: "Qualification of fiber optic sensing systems for subsea well applications and integrated subsea solutions for transmitting sensor signals to onshore through optical fibers." Figure 1 - The complete integrated system (available in full paper) There are two key project areas: Downhole Sensors (DHS) - the following three having been agreed upon from the initial listing of eight: Sand monitoring - identification and quantification Multiphase flow meter - for intelligent well applications Distributed pressure and temperature measurements Integrated Fiber Optic Subsea System (IFOSS) Subsea well sensor interrogation solutions Subsea control system Subsea telecommunication and transmission system Integrated fiber optic system Solutions are to be developed for both Green and retrofit Brown field applications. The current status of the project is that detailed Project Plans were completed on October 23rd and the project officially kicked-off October 25th. This paper describes in detail the planned project activities and the anticipated system outcome.

Operators have always sought the capability to monitor pressure, temperature, and flow across the sandface in gravel and frack-pack (and stand-alone screen) completions in real time in order to optimize production, and gain advanced notice of remedial needs.In most sandface completions, the lower completion contains the screens, and the completion is performed in two stages: the service tool string is run first to perform pack operations, and the second stage "mates" the upper completion string to the lower completion.The unique capabilities of fiber optics sensing techniques such as Distributed Temperature Sensing, Point Pressure and Temperature, Array Temperature Sensing, and Distributed Acoustic Sensing can provide the desired production and reservoir information across the sandface. However, accomplishing this requires a fiber optics wet-mate connector system to link the fibers in the lower and upper completions.Weatherford had run a fiber optics wet-mate connector system in Oman in April 2005, and a key driver for the new connector system was to use a lower profile connector to maximize the production flow area with Halliburton's gravel and frac-pack completion technology.The design essentials for the 9 5/8-in. x 4 ½-in. to 5-in. system, and required field operations for successful deployment are described in the paper along with the development and qualification process performed in laboratory, and test well conditions completed in May 2013. These were to ensure that the two key challenges of alignment and debris management had been successfully resolved. The final System Integration Test (SIT) for qualification was run at approximately 3,000 ft, and witnessed by a major operator. Subsequently, a demonstration SIT in the same well was witnessed by multiple operators in November 2013. The mechanical and optical measurements taken during the qualification process will be presented to demonstrate that the desired production/reservoir information can be provided.