North Energy (Norway)

Clearance management is the airfield management’s daily work. In this paper, combined with the technology of GIS, established the 3D model of airfield clearance limit surfaces, evaluated and applied the method in airfield. It offers an effective management method to airfield.

Abstract By combining multibeam bathymetry and backscatter with accurately placed piston cores, and integrating these data with 2D multi-channel seismic and high-resolution sub-bottom profiling, we can gain a better understanding of the processes active in a marine basin. In addition on mass transport complexes, basin floor fans, slumps, and faults, we can identify and sample potential hydrocarbon seeps that provide direct samples of a petroleum system. This paper will examine features imaged during a large (400,000 sq. km.) survey carried out in Indonesia in 2006-2008. Using hull-mounted systems, an average 1000 sq. km. of high resolution (25m bathymetric bin, 5m backscatter pixel) data were acquired per day in water depths from 100 to 3500m. Piston cores accurately placed on seafloor targets using USBL navigation were described visually on the coring vessel, sub-sampled for geochemical analyses, with the remainder of the core preserved for later analysis. Approximately 35% of the cores have been CT scanned, highlighting density differences related to seepage (such as authigenic carbonate and shell fragments), or related to sedimentological features (where higher density sand grains can be distinguished from lower density mud). The cores, and the targets they analyzed, provide a catalog of anomalous backscatter features that have been ground-truthed to constrain the processes that created the features. Features such as basin floor fans, overbank deposits, upslope climbing mud-rich mega-dunes, sand-rich channel axes, drowned carbonate reefs, mud volcanoes, and chemosynthetic seeps have been sampled throughout the program. This catalog demonstrates that backscatter can be calibrated by cores to specific processes, and thus that multibeam backscatter is a robust tool for constraining geologic processes active in a basin including present-day sediment distribution on the seafloor. Piston cores accurately placed on zones of potential hydrocarbon seepage interpreted based on multibeam backscatter can significantly impact exploration. Specifically, the presence of oil and gas in a basin, and the composition of the hydrocarbons, can dramatically reduce the exploration risk by providing information on source, migration, and maturity. Introduction Human beings have been gathering information about the seafloor since they first took to boats. Until the development of acoustic techniques, soundings were taken by lowering a weight to the seafloor (lead line), and marking the length. Acoustic techniques involving a " ping?? of energy sent out, and then received, by a transducer, only became commonplace after World War II (for an excellent discussion on the evolution of seafloor mapping, see Mayer, 2006). The next big leap in seafloor mapping capabilities came in the 1960s.

Abstract Techniques for identifying deepwater chemosynthetic communities can be classified as indirect (inference from geophysical data), direct (bottom samples), and visual (ROV/submersible). Exhaustive visual inspection is the best, but most expensive, means of detecting chemosynthetic communities. Some less-common techniques employ both indirect (multibeam echosounder) and direct (cores) methods. These surveys have the specific purpose of locating sediments near potential seeps to assess reservoir potential in frontier basins and predict chemosynthetic distribution in deep basins. Other methods are routine, such as environmental baseline studies that establish a " snapshot?? of seabed conditions and geotechnical cores for mooring and pre-development site investigations. These are direct methods that are routinely collected for specific purposes, but not for the assessment of potential chemosynthetics. Direct sediment sampling is underutilized for assessing chemosynthetic potential. Sulfides and methane in sediments are nutrients for microfauna which then feed macrofauna, forming the chemosynthetic community. Deepwater operators desiring to minimize exploration/production impacts on the environment can analyze sediment during routine sampling programs, thereby assessing local chemosynthetic community potential by geochemical and biochemical analyses. Use of these analyses can target and minimize costly ROV usage. Because geochemical analyses quantify sulfide and methane fluxes, they can quantitatively assess the potential for chemosynthetic development. Biochemical analyses of stable biomarkers can assess whether chemosynthetic communities have been present over certain timescales. The presence of sulfides and methane flux is required to have a chemosynthetic community. The best method to identify chemosynthetics, ROV/submersible observation, is expensive. Improved utilization of chemical analyses of routine cores taken by industry can provide for robust assessments of chemosynthetic communities in deepwater development sites. Introduction The rapid expansion of exploration activities in deepwater worldwide, begun in the 1990s, has now led to the field development stage of the discovered hydrocarbon resources. The cumulative footprint of development on the deep seabed will continue to increase as will the requirement for far more detailed knowledge of the foundation zone conditions. In concert with expansion of designed facilities is a progression of survey efforts to characterize foundation zone conditions. For example, for the exploration well, tophole and foundation zone hazards will often be assessed with conventional exploration 3-D seismic data, or less often with traditional surface towed subbottom profiler and high resolution 2-D seismic (HR 2-D) lines. Development drilling will often continue with the foundation zone information inferred from the same data sets. However, the planning and design of subsurface facilities and production structures require far more foundation zone information than is typically assessed for development drilling. Foundation zone survey requirements for subsurface facilities and production structures typically involve deep-towed subbottom profiler data and geotechnical borings, at a minimum. Now more commonly, multibeam, sidescan sonar, and subbottom profiler data from an Autonomous Underwater Vehicle (AUV), an untethered high-resolution seafloor and foundation zone survey platform, are used.

Abstract Underbalanced drilling is one of today's fastest evolving technologies in the oil and gas industry. Gasified drilling fluid is most commonly used in underbalanced drilling of pressure-depleted reservoirs. Nitrogen gas, which is inert and not flammable, has been the predominant choice in underbalanced drilling operations, with relatively few operations using natural gas or compressed air. Nitrogen consumption incurs a significant (20% to 30%) portion of the overall underbalanced drilling operation cost. One option to reduce nitrogen consumption would be to recycle it. This operation involves the recovery of the return gas from the separation unit for re-compression and re-injection into the well. In most cases, the return gas is still predominantly nitrogen unless the well is a prolific gas producer. For successful implementation of gas recycling, it is essential to maintain consistent quality and rate of the return gas. The feed gas for the compressors must be sufficiently dry to ensure that any water or hydrocarbon vapors do not condense out during the compression cycle. Secondly, the return gas rate must be stable so that the gas can be re-compressed and re-injected into the well at a specified injection rate and pressure. Northland Energy Corporation with Porta-test International Inc., designed and fabricated a system to recover and re-circulate the return gas for underbalanced drilling. A comprehensive yard test was designed and implemented to test the prototype system. Initial results indicate this system is ideal for field applications, though some refinement will be necessary to realize the full benefit of such a system. Introduction One of today's fastest evolving technologies in the oil and gas industry is underbalanced drilling (UBD). Preventing drilling damage is seen to be a major contributor to well performance, especially when dealing with high cost horizontal wells. Long "pay zones" will naturally require longer drilling time, thereby extending exposure to damaging conditions. When properly designed, underbalanced drilling programs allow the circulation pressures to be within a specified range, normally just below the formation pressure. Reduced differential pressures can prevent fluid loss and reduce fines migration, thus reducing the damage to the producing formation. Furthermore, underbalanced drilling can allow drilling in highly fractured formations or pressure depleted formations which may otherwise experience fluid loss and numerous other drilling problems (i.e., stuck pipe). In most of the applications for underbalanced drilling in Canada, low formation pressures have not allowed the use of single phase liquid systems as the hydrostatic pressure would have been above the reservoir pressure. Consequently, to achieve lower pressures requires that the drilling fluid be lightened by entraining a gas in the drilling fluid. The gas is injected into the circulating drilling fluid and then recovered from the well into a closed separator where solids, liquids and gases are separated and metered. To date, the majority of Canadian underbalanced drilling operations have been undertaken using cryogenic nitrogen with liquid nitrogen supplied from air separation plants. Unfortunately many of the prime underbalanced drilling targets are located far from a source of liquid nitrogen. This results in significant costs for the transport of liquid nitrogen.