Drilling ultra-extended-reach (ultra-ERD) wellbores has redefined industry standards. Operators and service companies must fully assess the accompanying risks to maximize the overall productivity of an asset. New drilling technologies, such as improved drilling fluid design and geomechanics analyses, allow wellbores to be drilled to the lateral displacement of greater than 13 km. This requires improved absolute wellbore positioning, in conjunction with reduced uncertainties. When developing these drilling technologies, the economics must be considered so as not to exponentially increase the cost per barrel of oil. The increase in infill drilling of nearby offset wellbores requires developing improved methods that reduce wellbore position uncertainty when placing the wellbore in the reservoir, in addition to avoiding collisions. The proposed geomagnetic referencing technique is suitable for the application to the Sakhalin-1 project in eastern Russia. Here there is a predominance of ultra-ERD wellbores coupled with considerable knowledge of the varying depth of the basement rock structure. This paper presents a process used for creating a geomagnetic crustal field model that can be updated to the actual survey location with the date and time for real-time application. This process can also be used in the reprocessing of legacy measurement-while-drilling (MWD) data. The application of this process significantly improves wellbore position accuracy. The ability to have a greater understanding of the overall geomagnetic field, along with enhanced techniques in multistation algorithm processing, removes the effects of drillstring and the cross-axial interference due to mud shielding effects. Additional benefits of this application include reduced wellbore tortuosity for planned wells, improved anticollision separation factors, and improved torque and drag profiles. This new geomagnetic model, updated to the actual survey location, date, and time and incorporating realistic uncertainty determinations based on basement rock depth analysis, has resulted in a 50% improvement in the overall ellipse of uncertainty (EOU) when compared with previous definitive surveys, in addition to an accurate bottomhole location. Incorporating these advanced techniques reduces position uncertainty that improves overall 3D wellbore positioning. Other studies, such as a disturbance field study, evaluate the effects of the magnetospheric ring current, auroral electrojets, and secondary induced fields, and was conducted by analyzing the magnetic observatory data from the same magnetic latitude to quantify the maximum and minimum declination variations during a magnetic storm.

The drilling records of Extreme Reservoir Contacts (ERC) like Extended Reached Drilling (ERD) and Multi-Lateral wells(ML) continue to be broken. From the initial limit of MD 10,000ft to now almost 50,000 ft with extended reach depths and from dual-lateral to quad-laterals’ with 40,000-50,000ft reservoir contact. Completions rule of engaging with this type of wells continues to play ‘catch-up'. As a result, getting the full potential out of these extreme wells with limited completions options had always been a challenge. Recent innovation in "wireless electric connect/disconnect" technology combined with all electric integrated intelligent completions architecture has addressed these challenges. The well completion design is an all electrical system that provides a multi trip connect/disconnect system enabling seamless communication between upper and lower completions enabling permanent downhole monitoring and control, at the sand face. The highlight of this digital edge solution and deployment architecture enables completions to deploy in ERC wells meeting targeted drilled depths and achieving reservoir goals. The digital enablement provides real time downhole data for permanent production logging and zonal well testing capability while producing. Production and reservoir management is at finger tips of the end user. A new innovative down hole electric telemetry enabled data transmission and power to be distributed across multiple sensors like pressure, temperature, water cut and electric flow control valve. Run on a single electrical cable, this digital completion technology with its induction coupling capability continue to complete record-drilling wells and makes today's completions limitations a history. It is now a reality for fully-digitalized Intelligent Completions solution, which can support any well type scenarios; multi-zones, horizontals, multi-laterals and extended reached drilling (ERD), including subsea completions. Each zone can be equipped with a permanent downhole infinite position valve-control, flowmeter, water-cut sensor and/or pressure/temperature gauges. This allows real-time reservoir measurement and supports ‘Dial A Rate’ flow control. Conventional flow control valves depend on hydraulic actuation system, although the technology has worked for decades, it has some inherent limitations such as need for multiple control lines limiting the number of zones, maximum depth of deployment as well the response time of hydraulic systems for very long completions. Electric valves are free from these limitations by design and provides lot more flexibility in the hands of the completion engineer. The multiple sensors measurement and data integration is achieved with a single surveillance, monitoring, diagnostics and valve-optimization production software to ensure real time data streaming, management and bringing insights to production and reservoir engineers for production optimization through remote valve control. This digital solution of Intelligent Completions technology can finally claim that completions is no longer the limiting factor, effective reservoir management with intelligent completions can follow wherever the drill bit can go. It has been deployed worldwide from the Middle East to the open Sea in Pacific to enable zonal production-control and reservoir management. Its borderless completions architectures and standardization of modular system is the answer for Digital Oilfield and Data driven continual production optimization and reservoir management without intervention. For the first time in Completions history, extended drilling records are matched with completing the entire well to Measured Depth (MD) with fully digitized solution of multi-zone measurements, infinite-control valves and real time data enabled production optimization system.

This paper describes a study conducted to develop new capabilities for offshore geomagnetic surveying. To conduct the research we equipped two (2) new generation autonomous marine vehicles (AMVs) with towed marine magnetometers. This paper describes the validation study of the measurement system offshore between 2013 and 2015 that compares a regular pattern with main, tie and perimeter lines. It was investigated whether the new AMV was suitable for use as a "base station" to monitor time variations of the disturbance field. The geomagnetic data measured by the vehicles from May 11 - 14, 2015 was analyzed and compared against data obtained from the USGS Honolulu Geomagnetic Observatory (HON). Highly sensitive sensors were used to establish the minimum required separation between the AMV and the magnetic sensor payload. Directional drilling requires accurate knowledge of the geomagnetic field direction and strength in the wellbore. To compute wellbore azimuth, the measurement while drilling (MWD) tool takes a measurement of the magnetic field and then the directional driller compares it with the geomagnetic field reference in order to position the wellbore in real-time while drilling. By utilizing the AMV we were able to accurately map the crustal field direction and strength in the area of interest where the drilling activity for oil and gas will take place. This study shows that the AMV is ideally suited to carry out geomagnetic surveys in offshore remote locations. Correction for the disturbance field is essential for crustal field mapping that requires a base station recording the variations of the disturbance field. A second AMV circulating at a fixed location provides a more accurate base station than a land-based station. This is due to two factors: The land- based station is further away from the measurement site and the disturbance fields are different on land than in the ocean, due to the different electrical conductivity of the subsurface. The new generation AMV offers distinct advantages for data collection in offshore environments. Their low cost compared to seaborne or airborne vehicle allow them to be deployed in tandem and collect data repeatedly over predefined areas yielding accurate measurements to determine the disturbance and crustal fields. It solves the problem of accurately mapping the geomagnetic reference field in offshore locations that previously unknown of.

This paper describes a study using an autonomous marine vehicle with satellite communications, to accurately collect and deliver in real-time magnetic measurements, to calculate Total Magnetic Intensity in marine environments in the absence of Earth magnetic observatories. New capabilities in the monitoring of auroral electrojet disturbances allow improved well placement for increased oil and gas recovery in the Arctic, and provide operators accurate geomagnetic reference values, enabling tighter quality control of MWD equipment, enhancing safety and reducing nonproductive time. In the Arctic, Measurement while drilling (MWD) processing must include corrections for rapid changes in the geomagnetic field caused by auroral electrojet currents. The auroral zone is a region where the electric field of the magnetosphere precipitates along magnetic field lines into the ionosphere. Converting the magnetic azimuth to a true azimuth requires accurate knowledge of the geomagnetic field at the point of measurement downhole at the drill bit. Equipped with this information lateral uncertainties can be reduced by 50%. At higher latitudes, the strength of the horizontal component of the geomagnetic field shrinks, which exacerbates any error sources that accumulate while surveying. This has an enormously negative effect on surveying accuracy at high latitudes. Data from Earth magnetic observatories and variometer stations can be analyzed to characterize the auroral electrojets and compensate for the disturbance. Knowledge of the spatial structure of the electrojets’ magnetic signature is essential for deploying a ground network of monitoring stations in the Arctic. This network provides the real-time geomagnetic infrastructure essential to support MWD operations, making it the most cost-effective technology available to achieve accurate wellbore placement in horizontal, relief well, and extended reach drilling. However the number of Earth magnetic observatories is limited in the Arctic. Autonomous marine vehicles can now be deployed for geomagnetic surveying. In recent testing, two autonomous marine vehicles were equipped with towed magnetometers. To investigate the accuracy of the measurements, the two vehicles surveyed exact-repeat profiles. The measurements of the two vehicles agreed to within 2nT, exceeding even the stringent 5nT standard for geomagnetic observatories. This test demonstrates the utility of autonomous marine vehicles to carry out crustal magnetic surveys and monitor disturbance fields in support of offshore directional drilling operations. Note: This paper is a consolidation of 2 papers, Poedjono et al, OTC-25228 and OTC 1726418

Abstract In measurement while drilling (MWD), wellbore azimuth is determined relative to the direction of the geomagnetic field. Converting this magnetic azimuth to a true azimuth requires accurate knowledge of the direction of the geomagnetic field at the point of measurement downhole. In the Arctic, MWD processing must include corrections for rapid changes in the geomagnetic field caused by auroral electrojet currents.?The auroral zone, those latitudes at which the aurora borealis (or the northern lights) occurs, is a region where the electric field of the magnetosphere precipitates along magnetic field lines into the ionosphere. At 100 km above the surface, this electric field drives auroral electrojet currents in the east/west direction, generating the strongest magnetic field disturbances on the planet. The direction of the geomagnetic field in the auroral zone can change by several degrees in less than an hour. Data from geomagnetic observatory and variometer stations can be analyzed to characterize the auroral electrojets and compensate for the disturbance. Knowledge of the spatial structure of the electrojets' magnetic signature is essential for deploying a ground network of monitoring stations in the Arctic. This network provides the real-time geomagnetic infrastructure essential to support MWD operations, making it the most cost-effective technology available to achieve accurate wellbore placement in horizontal, relief well, and extended reach drilling, as well as in collision-avoidance applications. In one case study using historical data from two nearby observatories from 1995 to the present, the disturbance field was characterized and a time series of maximum disturbances was derived and extrapolated to the year 2020. Maximum disturbance in the magnetic field was found to lag the maximum of solar activity by approximately two years, predicting the next maximum in 2015-2019.

Abstract This paper assesses the current state of the art in horizontal directional drilling (HDD) for pipeline installation, reviews analytical methods associated with HDD pipeline design and installation, and presents concepts useful in the application of HDD techniques to pipeline construction in the arctic. The current state of the art is defined by a review of recent commercial applications of HDD to pipeline construction. Details on completed projects defining feasibility limits with respect to length and pipe diameter are presented. Restrictions with respect to subsurface conditions are examined. Theoretical limits on HDD pipeline installation are explored including a discussion of analytical methods available to calculate pulling loads associated with very long HDD Installations. The paper concludes with conceptual design examples of how HDD installation might be applied to obstacles presented by the arctic environment. Current State of the Art in Pipeline Installation by Horizontal Directional Drilling Three primary characteristics govern the feasibility of an HDD installation: subsurface conditions, pipe diameter, and drilled length. These three characteristics work in combination to limit what can be accomplished using existing HDD tools and techniques. Individual limits for each of these characteristics are discussed in the following paragraphs. It should be noted that, consistent with the objectives of this paper, this discussion is founded on commercial experience within the HDD Industry. The limits of directional drilling technology applied to drilling oil wells are not considered. While such tools and techniques may be applied to pipeline installation in the future, this paper discusses what is being utilized in the Pipeline Industry today. Subsurface Conditions The nature of the subsurface material through which the drilled path must pass is critical in determining the technical feasibility of an HDD pipeline installation. For a pipeline to be installed by HDD, either an open hole must be cut into the subsurface material so that installation of a pipeline by the pullback method is possible, or the properties of the subsurface material must be modified so that the soil behaves in a fluid manner allowing a pipeline to pass through it. In the open hole condition a cylindrical hole is drilled through the subsurface. Drilling fluid flows to the surface in the annulus between the pipe and the wall of the hole. Drilled spoil is transported in the drilling fluid to the surface. This is generally applicable to rock and cohesive soils. It may also apply to some sandy or silty soils depending on the density of the material, the specific makeup of the coarse fraction, and the binding or structural capacity of the fine fraction.