Patent news: Smart fiber optic technology in the oil and gas field

The justification for using cutting edge technology in the oil and gas field scarcely requires explanation. Drilling and pipeline infrastructure are extremely expensive undertakings. For their part, pipelines must withstand extreme weather conditions over hundreds and thousands of miles through myriad terrains. Similarly, drilling operations can now plunge well over thirty thousand feet into the earth, on land and off shore. Thus, investing in technology that can improve the chances for success or limit the possibility of disaster is well worth it. Smart fiber optic technology works well in these harsh conditions. Moreover, smart sensors can measure fluid flow, temperature, pressure, seismic activity, valve positions, chemical composition and biological contamination. The following patents detail some of the applications associated with placing sensors deep with in a well. World Patent 2006064181 is particularly timely as it offers a possible monitoring system that could be used on the Alaskan pipeline to monitor joint strain and corrosion.

U.S. Patent 7009707: Apparatus and method of sensing fluid flow using sensing means coupled to an axial coil spring: Extreme pressures and temperatures reaching 190 degrees Centigrade make convention sensors impractical or simply unusable. This patent, issued in March of 2006, describes how passive fiber optic technology can be used to measure fluid flow rates in production tubing, pipelines, open wells and tunnels.

Abstract: An apparatus and method of sensing fluid flow are provided to measure fluid flow rates in production tubing, pipelines, open wells and tunnels. The proposed invention takes advantage of a sensor with processing means to interpret the fluid flow rate, the sensor being responsive to the mechanical perturbations of the sensor itself arising from the impingement of turbulent fluid flow on the sensor. In operation, the sensor is mounted in the fluid flow such that the fluid flows through an aperture in the sensor and/or around the outside surface of the sensor. The sensor of the invention bears definite advantage over known sensors and it is particularly suited to down-hole oil and gas applications. Preferably, the invention employs fiber optic sensing techniques which are amenable to multiplexing a plurality of the sensors with long down leads. Such an arrangement is robust to withstand the high temperature and pressure environment. Advantageously, the invention allows non-intrusive measurement of fluid flow in production pipes and measurement of differential fluid flows along perforated casing or open well sections in the pay zone.

U.S. Application 2006072869/US-A1: Optical fiber position transducer for flow control valve in smart wells. The application, published in April, 2006, describes an improvement on smart technology. While fiber optic sensors have been used in some applications, this application offers an improvement in which flow information is better obtained using a Bragg Network in a Fiber Bragg Grating, thereby improving the functionality of the flow control valve in the well.

Abstract: A fiber optics position transducer is described for flow control valve in smart wells, which comprises at least two load cells instrumented with Bragg (FGB) network sensors and supported by rings The cell is formed by a quadrangular body , provided with a central hole and hole for inlet/outlet and passage of a fiber optic and pins. Said cell measures the displacement of a spring used in the sliding sleeve, rotating or choke type valve from the smart completion system, the displacement (opening or closing) of the valve being monitored from the restoration force in the spring measured by the instrumented load cell. The transducer is built with dimensions and geometry so as not to present edges and allow the insertion of the same in the annular space of a sliding sleeve, rotating or choke type valve of an oil production system. In addition, the transducer's construction is such that allows it to be multiplexed to other kinds of well sensors, through the same optical fiber.

U.S. Application 2006086508/US-A1: Placing fiber optic sensor line: Declining well production and reduction in reserves was seen as the impetus in this U.S. application, published April 2006, that focuses on improving information gathering coming from an oil well. In the past, information was obtained from the well hole only sporadically, at times when production was stopped. In the past, fiber optics allowed for the permanent placement in information systems, allowing production to be optimized. However, early methods of placing lines were not as cost-effective or reliable as needed. The method in this application describes an improvement in placing fiber optic lines.

Abstract: The present invention generally relates to a method and an apparatus for placing fiber optic control line in a wellbore. In one aspect, a method for placing a line in a wellbore is provided. The method includes providing a tubular in the wellbore, the tubular having a first conduit operatively attached thereto, whereby the first conduit extends substantially the entire length of the tubular. The method further includes aligning the first conduit with a second conduit operatively attached to a downhole component and forming a hydraulic connection between the first conduit and the second conduit thereby completing a passageway therethrough. Additionally, the method includes urging the line through the passageway. In another aspect, a method for placing a control line in a wellbore is provided. In yet another aspect, an assembly for an intelligent well is provided.

U.S. Patent 7040390: Wellbores utilizing fiber optic-based sensors and operating devices: This patent, granted in May 2006, likewise describes a method for the permanent placement of sensor devices capable of operating in the harsh conditions at the bottom of a borehole. Obtaining the information is extremely important to maximizing production. Sensors in the wells are needed to obtain information concerning temperature, pressure, the presence of solids in the flow, corrosion, scale and paraffin build-up, vibration, velocity, radiation, pH values, humidity and many others. Additionally, this invention describes a method for transmitting motive optical energy down the borehole.

Abstract: This invention provides a method for controlling production operations using fiber optic devices. An optical fiber carrying fiber-optic sensors is deployed downhole to provide information about downhole conditions. Parameters related to the chemicals being used for surface treatments are measured in real time and on-line, and these measured parameters are used to control the dosage of chemicals into the surface treatment system. The information is also used to control downhole devices that may be a packer, choke, sliding sleeve, perforating device, flow control valve, completion device, an anchor or any other device. Provision is also made for control of secondary recovery operations online using the downhole sensors to monitor the reservoir conditions. The present invention also provides a method of generating motive power in a wellbore utilizing optical energy. This can be done directly or indirectly, e.g., by first producing electrical energy that is then converted to another form of energy.

WO-2006064181-A1, EP-01672344-A1: Structural joint strain monitoring apparatus and system: Published in June, 2006, this application addresses the use of smart fiber optics in monitoring oil pipelines. The invention offers an improvement on the current method of monitoring pipeline integrity. The possibility of corrosion, the inherent vibrations in the flow of oil or gas and the need for high loads make all too real the possibility of pipeline failure. The current method of inspection is based on the intermittent use of remotely operated vehicles or "intelligent pigs," machines that travel from location to location in the pipeline to perform inspections. An improvement would involve real time measurements made continuously. This application describes a fiber optic "jacket" that can be installed at joints in the pipeline which can constantly measure strain. This invention also uses a Fiber Bragg Grating (or a Fiber Bragg Grating Fabry-Perot Etalon).

Abstract: Structural joint strain monitoring apparatus comprises jacket means in the form of first and second jacket elements, each having a primary jacket part and substantially perpendicular secondary jacket part. The jacket elements together define a compartment for receiving a joint, between two pipes, to be monitored. The jacket means additionally comprises two primary web elements provided between the primary and secondary jacket parts. Three fibre Bragg grating (FBG) strain sensors and an FBG temperature sensor are provided within an optical fibre, bonded to the primary web elements and each end of the second jacket element respectively, for measuring strain or temperature at their respective locations. The FBG sensors are optically coupled, via optical fibre, to optical fibre sensor interrogation apparatus, operable to interrogate each FBG sensor.

PDF of international application | PDF of European application

U.S. Patent 7104324: Intelligent well system and method: Complex well designs require complex monitoring systems. This patent, granted in September, 2006, provides a system and method of placing smart fiber optic sensors in a multilateral oil well.

Abstract and Exemplary Claim: An intelligent well system and method has a sand face completion and a monitoring system to monitor application of a well operation. Various equipment and services may be used. In another aspect, the invention provides a monitoring system for determining placement of a well treatment. Yet another aspect of the invention is an instrumented sand screen. Another aspect is a connector for routing control lines.

- A method of completing a well, comprising: placing a plurality of completions in a plurality of lateral branches of a multilateral well bore; deploying a screen with an intelligent completion device in each of the plurality of lateral branches; and completing the plurality of lateral branches with a gravel pack operation.