REDWING/AICSM –UCEMM - UNIVERSITY OF ABERDEEN REPORT Small-Scale Airborne Platforms for Oil and Gas Pipeline Monitoring and Mapping AUTHORS: Cristina Gómez |David R. Green 1. INTRODUCTION ...................................................................................................................................... 1 1.1 Monitoring oil and gas pipelines ................................................................................................................... 1 1.2 UAV remote sensing ..................................................................................................................................... 1 1.3 The report ..................................................................................................................................................... 2 2. RATIONALE AND CONTEXT FOR OIL AND GAS PIPELINE MONITORING WITH SMALL-SCALE AIRBORNE PLATFORMS .................................................................................................................................................... 3 2.1 Context .......................................................................................................................................................... 3 2.2 Alternative methods for monitoring oil and pipelines .................................................................................. 4 3. UNMANNED AERIAL SYSTEMS (UAS) ...................................................................................................... 5 3.1 Flying platforms ............................................................................................................................................ 5 3.2 Sensors ........................................................................................................................................................ 10 3.3 Auxiliary equipment .................................................................................................................................... 19 3.4 Regulations ................................................................................................................................................. 22 4. USE OF UAVS FOR OIL AND GAS PIPELINE MONITORING ...................................................................... 26 4.1 Current use of UAVs for oil and gas pipeline monitoring ............................................................................ 26 4.2 Detection of hydrocarbon leaks from pipelines .......................................................................................... 28 4.3 Advantages and limitations of UAVs for monitoring pipelines ................................................................... 29 5. MISSION AND PLATFORM CONSIDERATIONS ........................................................................................ 30 5.1 Flying Time, Distance, and Area Coverage.................................................................................................. 30 5.2 Flying height and ground control ................................................................................................................ 31 5.3 UAV altitude control ................................................................................................................................... 31 5.4 Manual and automated launch / landing ................................................................................................... 32 5.5 System Failure and Retrieval ...................................................................................................................... 33 5.6 Flying Conditions ......................................................................................................................................... 33 5.7 Mission planning ......................................................................................................................................... 33 5.8 Operation and control ................................................................................................................................ 34 5.9 Digital image processing software ............................................................................................................. 34 6. DEVELOPMENTS IN UAV AND RELATED TECHNOLOGIES ....................................................................... 35 6.1 Hot Swappable Sensors............................................................................................................................... 35 6.2 Platform Development ................................................................................................................................ 36 6.3 Multi-UAV Configuration (Swarms) ............................................................................................................ 36 6.4 Cloud-Based Data Storage .......................................................................................................................... 36 6.5 Battery Technology and other UAV Fuel Sources........................................................................................ 37 6.6 3D Printing .................................................................................................................................................. 39 6.7 GIS ............................................................................................................................................................... 39 6.8 Costs............................................................................................................................................................ 40 6.9 Security systems .......................................................................................................................................... 40 7. PROPOSED UAV SYSTEM FOR MONITORING OIL AND GAS PIPELINES ................................................... 40 7.1 Considerations for specifications of a UAV system for monitoring oil and gas pipelines ........................... 41 7.2 Monitoring scenarios .................................................................................................................................. 42 8. SUMMARY AND CONCLUSIONS ............................................................................................................ 44 9. REFERENCES .......................................................................................................................................... 45 10. APPENDICES .......................................................................................................................................... 48 i | Page 1. INTRODUCTION 1.1 Monitoring oil and gas pipelines Oil and gas transmission pipelines comprise a network of more than three million km globally (CIA, 2013) that is in continuous expansion (Smith, 2013). Pipeline networks are made up of legs of different lengths, up to thousands of kilometres, and can have above- or below-ground configurations. The safety and security of all pipelines, regardless of their size, placement, or location, is of paramount importance to stakeholders and to the public. Proper maintenance of pipeline networks is also important for environmental protection. Equipment failure such as breakage or leaks can occur for many reasons, including overage of structures and material failure, natural ground movement, accidental hot-tap, and third-party interference. Large amounts of oil and gas can be lost following a pipe failure, and more importantly, hydrocarbon leaks can damage the environment through contamination and pollution, seriously affecting ecological health and human security. Developing and implementing monitoring systems that can continuously assess the state and condition of oil and gas pipelines is essential. Furthermore, monitoring pipeline networks also involves acquiring knowledge of the impact pipelines have on the environment over time, and how they affect vegetation and wildlife. Traditionally, monitoring pipeline networks has often been restricted to visual inspections or volume and mass balance measurements. Currently, most of the monitoring is still performed using conventional methods, mainly through periodic inspections by foot patrols and aerial surveillance using light aircraft or helicopters. Although ensuring a high level of security, the cost of monitoring methods where there is intensive human involvement in the measurements is also very high. Furthermore, the main disadvantage of the methods used for monitoring and inspection is the potential for late detection of failures, when the output (oil or gas) has been reduced, or the environment has already been affected and damaged. Some alternative approaches to monitoring pipelines that do not rely on human intervention utilise real-time monitoring systems based on small sensors. These sensors are connected to the pipeline network and can send (via wire or wireless) data to a control centre. However, even wired sensors are vulnerable to damage at any point along the network and wireless sensors’ networks can produce ambiguous data, and be unreliable, providing incomplete or inaccurate information (Wan et al. 2012). 1.2 UAV remote sensing With the advent and progress of remote sensing technology – including sensors and platforms - together with image processing software, new opportunities have emerged for the development of monitoring systems with the possibility for high frequency data collection, that provide a comparatively inexpensive and spatially precise means to identify hydrocarbon leaks. Amongst the most promising techniques, unmanned airborne or aerial vehicles (UAV) provide an important option with a number of advantages over the other more traditional aerial platforms such as light aircraft and helicopters. Such advantages include improved mission safety, flight repeatability, the potential for reduction in operational costs, and fewer weather-related flying limitations (e.g. a UAV 1 | Page can fly below the clouds). These advantages are, however, dependent upon the type and size of airborne platform, sensor type, mission objectives, and the regulatory requirements imposed. Small-scale airborne platforms, i.e. aircraft with fixed wing and helicopters with rotary wings, are increasingly being considered as reliable platforms for capturing remotely sensed images for environmental applications, and a low-cost alternative to larger-scale platforms (e.g. ARC, 2003). With recent technological developments (e.g. sensor miniaturization, stabilization and navigation systems) such small-scale platforms provide a powerful basis to gather data and produce information that can be tied to in-situ ground data collection and to large scale satellite imagery, providing a link between multiple spatial scales. Small-scale airborne platforms can therefore provide a very flexible means to acquire unique data and information. Currently there is a wide range of commercial small-scale airborne platforms available to anyone for the acquisition of low-cost aerial remotely sensed data. These platforms include kites, model aircraft, balloons or blimps, helicopters, Unmanned Aerial Vehicles (UAVs), Unmanned Aerial Systems (UASs), and Drones. Only considering electric UAVs, the total market value is expected to reach over one thousand million dollars by 2023 (IDTechEx, 2014). Many of these small airborne platforms can be equipped with traditional but lightweight versions of single-lens reflex (SLR) or digital cameras, as well as video cameras, for the collection of panchromatic, true colour, and colour infrared photography, as well as digital video footage. The use of camera filters e.g. infra-blue can also enable useful information as the basis for deriving vegetation indices (e.g. Normalised Difference Vegetation Index—NDVI) images for assessment of vegetation condition. Additionally, multi-spectral imagery can also be captured through repeated overflights with the aid of filters—or more recently through the use of on-board multi- or hyper-spectral sensor systems—as well as thermal infrared (TIR), Radar, and LiDAR data. Some of these platforms are also large enough to carry multiple payloads and can use wireless transmissions and video downlinks for real-time data capture, image viewing, and use of the Cloud for data storage. The rapid development of microelectronics and microprocessors, battery technology, GPS and navigation systems, together with reduced costs over the last five years have all helped in triggering an unprecedented demand for, and growth in, the use of UAV platforms for many civilian applications (Watts et al., 2012; Colomina and Molina, 2014). Furthermore, sensor miniaturization has facilitated the collection of a range of spectral and other sensory measurements from small aerial platforms that were not previously possible. 1.3 The report This report explores the current scientific and non-scientific literature on the use of UAV platforms and sensors that have been used to date for monitoring oil and gas pipelines, with a specific focus on the detection of leaks in oil and gas from onshore pipelines and their effects on the area surrounding the pipeline, such as soil pollution and vegetation stress. The report will include sections covering the following: 1) a general overview of the characteristics of UAVs; 2) the use of small airborne platforms for oil and gas pipeline monitoring to date with particular attention being paid to the strengths, successes and opportunities, as well as the weaknesses and reasons for the failure of different UAV systems; 3) considerations and developments in the technology of small-scale aerial platforms and sensors specifically tailored to oil 2 | Page and gas pipeline monitoring applications, including battery, sensor, navigation, software, and platform; 4) the legal framework concerning the uses of UAVs as this will have a significant part to play in the future type, scale and use of UAVs; and 5) future prospects for UAV development and application. 2. RATIONALE AND CONTEXT FOR OIL AND GAS PIPELINE MONITORING WITH SMALL- SCALE AIRBORNE PLATFORMS 2.1 Context Currently there are more than three million kilometres of transmission pipelines carrying hydrocarbons around the world (CIA, 2013). In the USA there are 2.2 million km, 287000 km in Europe (EC, 2011), and 115000 km in Canada (CEPA, 2014). As of 2014, the global network of pipelines is valued at more than 8680 million dollars (MarketsandMarkets, 2014). The volume of hydrocarbons transported daily by pipeline is ever increasing (PGJ, 2011) as they provide the safest means of transport. Pipelines, including pipes, compressors and pumps, are frequently located in environments which are difficult to monitor and secure (e.g. offshore, remote areas). Attacks or damage to such installations can lead to enormous ecological impact and loss of revenue, potentially leading to international oil market disruptions. Improving oil and gas installation security is a matter of global importance, and the main rationale for the monitoring of oil and gas pipelines is for safety reasons. Catastrophic events have occurred historically in many countries: a number of accidents happened during the 2000s in Nigeria, where pipelines were frequently vandalised and exploded or leaked causing thousands of fatalities. In 2004, a major natural gas pipeline exploded in Ghislenghien (Belgium), killing 24 people and leaving 122 wounded. In January 2014, one of the TransCanada Corporation gas transmission pipelines exploded and burned, causing a natural gas shortage in Manitoba (Canada) and parts of the USA. In 2010, a large pipeline (> 1m diameter) failed through corrosion and fatigue cracks spilling more than 3000 cubic meters of heavy crude into the Kalmazoo River (Michigan, USA). Hundreds of Michigan residents suffered health effects relating to toxic exposure from the oil, and clean up costs were estimated at 800 million dollars, making this accident the most expensive on-shore spill in U.S. history. With age, oil and gas pipelines become more prone to corrosion and failure (Figure 1). Furthermore, minor incidents and failures, much more frequent than catastrophic accidents, can cause important environmental damage and economic losses. According to the Energy Resources Conservation Board (ERCB) the number of pipeline breaks per 1000 km in Alberta (Canada) was 1.5 in 2011 and 2012 (ERCB, 2012). In Russia, this rate is estimated to be 110 to 140 per 1000 km per year. In Alberta during 2010 there were 20 crude oil pipeline failures and 241 multi-phase (pipeline carries crude oil and gas) pipeline failures. As the overall infrastructure gets older it requires more frequent revision to prevent incidents that could have a huge impact on the environment, people and economies. Monitoring systems that regularly provide parameters for characterization of the structural and functional conditions of the pipelines, can help to prevent failures, detect problems over time, and undertake maintenance and repair activities. 3 | Page Figure 1. Examples of transportation pipelines failures. (a) Internal corrosion has produced oil leak; (b) Pipeline damaged by external physical aggression; (c) Ruptured pipeline spilling oil that is burnt under control in Cohasset, Minnesota (July 2002) (Photo: US National Transportation Safety Board); (d) A 40-year-old underground 1 m diameter pipeline is fractured producing oil leakage. 2.2 Alternative methods for monitoring oil and pipelines Currently, the most widely used monitoring methods for oil and gas transmission pipelines are foot patrols along the pipeline route and aerial surveillance using light aircraft or helicopters. Patrols help to prevent placing pipelines, the surroundings, and the security of supplies at risk. However, they have to be carried out at regular intervals throughout the year, and regardless of weather conditions. The economic cost associated with these approaches is therefore also very high. Progress in high-resolution remote sensing and image processing technology has provided the basis for designing pipeline monitoring systems using remote sensors and context-oriented image processing software (Hausamann et al., nd). Traditional airborne solutions - although beneficial in some ways - bring their own difficulties, in terms of safety and operation: manned aircraft using pilot and/or operator for detection and identification are forced to fly very close to the terrain; frequently can only detect visible effects (i.e. not gas leak detection for instance); and require expensive manned aircraft limiting the frequency and duration of flight. As an alternative, Europe has invested in numerous projects using satellite based remote sensing (e.g. PRESENSE, PIPEMOD and GMOSS) to reach the demands of pipeline monitoring required by pipeline operators. To date, the only conclusion from these projects is that more work is necessary to reach the demands of the pipeline operators. 4 | Page The use of unmanned aerial vehicles (UAVs), to complement conventional approaches to pipeline supervision, is a new way to efficiently ensure continuity in production. The key to taking advantage of the proliferation of UAV technological innovations lies in determining what business value can be derived from automated data gathering and which tasks can be both electronically and mechanically automated in a workflow. It is also equally important to identify the type of insights that can be obtained from the new data gathered from these environments. These insights can then be used to drive operational decisions or to improve business processes, such as shortening the lead time to problem detection or to ensure productive maintenance of pipelines. Internationally there is increasing legislation and regulatory pressure to improve the safety and integrity of pipelines carrying hydrocarbons. Oil and gas pipeline monitoring is a specific environmental application of UAV technology, and UAVs are now evolving as highly effective tools for tackling the requirements of pipeline monitoring. 3. UNMANNED AERIAL SYSTEMS (UAS) Unmanned systems are associated with a host of terms: Unmanned Aerial Systems (UAS), Drones, Remotely Piloted Aircraft (RPA), Unmanned Vehicle Systems (UVS), and Unmanned Airborne or Aerial Vehicles (UAV) reflecting the variety of system configurations and fields of application. Different sources use UAV or UAS as the preferred term. UAV is the term adopted by the UK Civil Aviation Authority (CAA), whilst others suggest that UAS is more correct. An unmanned aerial vehicle (UAV) is flown without a pilot onboard and is either remotely and fully controlled from another place (e.g. ground, another aircraft, space) or programmed and fully autonomous (ICAO, 2011). An unmanned aerial vehicle or system comprises the flying platform—an aircraft designed to operate without human pilot onboard—, the elements necessary to enable and control navigation, including taxiing, take-off and launch, flight and recovery/landing, and the elements to accomplish the mission objectives: sensors and equipment for data acquisition and transfer of data—including devices for precise location when necessary. Aerial and remotely controlled systems for surveillance and the acquisition of Earth surface data have a relatively long history, typically associated with military activities. Photogrammetry and remote sensing technologies identified the potential of UAV/UAS sourced imagery, acquired at low altitudes with high spatial resolution, more than thirty years ago (Colomina and Molina, 2014). However, civilian research on UAVs only began in the 1990s (Skrypietz, 2012). Currently, a profuse emergence of UAV in civilian applications’ domains (e.g. agriculture, forestry, mining, marketing, patrolling) has raised awareness of the potential of these aerial systems. A brief description of each of the main elements (platforms, sensors, and auxiliary equipment) now follows: 3.1 Flying platforms Remotely piloted aircraft or automatic flying platforms can be classified under different schemes, using criteria such as flying height and range, size, and weight (frequently referred to as maximum take-off-weight - MTOW). A strict categorization of UAVs is not however possible because certain characteristics in the various classes overlap (Skrzypietz, 2012). Table 1 provides an overview of the 5 | Page flying platform types as considered by UVS International, a non-profit association dedicated to promote unmanned aerial systems (both manufacturers and operators). Table 1. Characteristics of non-military Remotely Piloted Aircraft Systems (RPAS) Name Acronym Mass (kg) Range (km) Altitude (m) Endurance (h) Micro MAV < 5 < 10 250 1 Mini Mini < 20-150* < 10 150 * < 2 Close Range CR 25-150 10-30 3000 2-4 Short Range SR 50-250 30-70 3000 3-6 Medium Range MR 150-500 70-200 5000 6-10 MR Endurance MRE 500-1500 > 500 8000 10-18 Low Alt. Deep Penetration LADP 250-2500 >250 50-9000 0.5-1 Low Alt. Long Endurance LALE 15-25 >500 3000 >24 Medium Alt. Long Endurance MALE 1000-1500 >500 5/8000 24-48 High Alt. Long Endurance HALE 2500-5000 >2000 20000 24-48 Stratospheric Strato >2500 >2000 >20000 >48 Exo-stratospheric EXO TBD TBD >30500 TBD Source: Adapted from UVS international (2008) Note: *according to national legal restrictions Note: MAV Micro Air Vehicles; VTOL Vertical Take-Off and Landing; LASE Low Altitude, Short-Endurance; LALE Low Altitude, Long Endurance; MALE Medium Altitude, Long Endurance; HALE High Altitude, Long Endurance The very small platforms, micro and mini aerial vehicles (Table 1) can fly for less than one hour at an altitude below 250 m. Micro platforms are considerably smaller than mini platforms (i.e. < 5 kg versus 20-150 kg) but both have a similar flying range. An example of micro UAV is the Phantom 1 or 2 (Figure 2), with MTOV below 1.3 kg and a very light payload capacity; Aibot-X6 is another micro UAV with 3.4 kg MTOV and maximum payload of 2 kg. Mini is the most abundant type of platform produced for civilian applications, doubling the number of micro and medium range UAV platforms (UVS, 2014). An example of mini UAV is the Camcopter, with an MTOV of 68 kg and maximum payload capacity of 25 kg (Figure 2). On the other side of the scale, MALE platforms (e.g. Talarion, Predator) and HALE platforms (e.g. Global Hawk, Euro Hawk) have a flying endurance of several days at an altitude of 20000 m. The latter aerial platforms are comparable in size to manned aircraft. 6 | Page Figure 2. UAV platforms of various types and sizes. Phantom 2 and Aibot-x6 are micro UAV; Camcopter is a mini UAV; Talarion and Predator are MALE UAVs; Global Hawk is a HALE UAV. Developments of the technology are now providing so-called nanodrones, miniature UAVs able to carry small still and video cameras. These UAVs can fly in all directions and perform manoeuvres and mid-air stunts. For example, the palm-size Micro Drone 2 (Figure 3, a) weights 0.034 kg and has a flying range of 120 m and endurance of 6-8 minutes. Other small drones are now flown as tethered aerial vehicles to circumvent the risks associated with flying. The Pocket Flyer by CyPhy Works (Figure 3, c) is a 0.080 kg tethered platform that can fly continuously for two hours or more, sending back high quality HD video the entire time. With improved tether technology, all data, control and endurance can be built into the tether, providing long endurance. Furthermore, ZANO (Figure 3, b) operates on a virtual tether connected to a smart device, allowing simple gestures to control it. Figure 3. Nano drones in developing phase. (a) Micro Drone 2 quadrotor by Microdrone; (b): Pocket Flyer by CyPhy Works 7 | Page In the UK, UAVs are usually classified by their size and weight, from small and lightweight (less than 2.7 kg) with a relatively short distance range, up to systems with more than 20000 km range and weight of approximately 12000 kg. To date, only small platforms (< 20 kg) can be used for civilian applications in the UK. Leaving aside powered blimps and parafoils, as well as non-powered balloon and tethered kites, all small powered UAV platforms based on airframes can be grouped into two main categories: rotary wing UAVs and fixed-wing UAVs. The capacity for Vertical Take-Off and Landing (VTOL) as opposed to Horizontal Take-Off and Landing (HTOL) was a valid criterion for categorizing these two types of UAVs, until some fixed-wing airframes also acquired VTOL capacity. 3.1.1 Fixed-wing UAVs Fixed-wing UAVs are characterized by a relatively simple structure, making them reasonably stable platforms that are relatively easy to control during autonomous flights. Their efficient aerodynamics enables longer flight duration and higher speeds. This makes fixed-wing UAVs ideal for applications such as aerial survey which require the capture of georeferenced imagery over large areas. On the down side, fixed-wing UAVs need to fly forward continuously and need space to both turn and land. These platforms are also dependent on a launcher (person or mechanical) or a runway to facilitate takeoff and landing, which can have implications on the type of payloads they carry. Typical lightweight fixed-wing UAVs currently in the commercial arena have a flying wing design (Figure 4) with wings spanning between 0.8 and 1.2 m, and a very small fin at both ends of the wing. In-house vehicles tend to have slightly longer wings to enable carrying the required heavier sensors (Petrie, 2013). A second type of design is the conventional fuselage. The dimensions are around 1.2 to 1.4 m length for the fuselage and 1.6 to 2.8 m wing length. In the UK there are around 20 companies operating commercial airborne imaging services using fixed-wing UAVs (Petrie, 2013). Figure 4. Examples of lightweight fix-wing commercial UAVs. Top row are flying-wing design: (a) Trimble Gatewing X100; (b) swinglet CAM; (c) smartone. Bottom row are conventional fuselage design: (d) MAVinci Sirius; (e) Composites Pteryx; (f) CropCam. 8 | Page