Materials in drilling muds are known to sometimes distort the geomagnetic field at the location of the Measurement While Drilling (MWD) tool magnetometers that are used to measure the azimuth of well path. This distortion or shielding effect can contribute to substantial errors in determination of azimuth while drilling deviated wells and with significant well displacements, these errors may result in missing the target of a long deviated section in the range of 1–200m; and thus impact on the overall productivity expectation of the well. The article describes significant shielding effects observed while drilling long wells. The criteria for acceptance of the surveys were not met and resultantly, an alternative survey source had to be obtained with resulted in increased cost and time to the client. A number of measures were implemented to eliminate this shielding effect. The effects of drilling fluid contamination by magnetic materials are calculated, and a method to evaluate the magnetic properties of the drilling fluid is proposed. The effect of taking measurements with the pumps on versus off is quantified.

The emergence of real-time enabled support centers has significantly improved the level of service delivery that is received by the operator companies that are drilling across the numerous oil fields in Russia. These support centers are multidisciplinary in approach and are focused on supporting measurement-while-drilling, logging-whiledrilling, and directional drilling services and executing work flows without incurrence of nonproductive time. Many challenges, ranging from ensuring connectivity in remote areas to client acceptance of the role of support centers in their internal decision-making processes, have been successfully overcome. Key to this success was the implementation of work flows that optimize drilling processes in the holistic well construction cycle with incorporation of geomechanics and that support the optimal geological well placement based upon petrophysical analysis and interpretation.These process work flows were synthesized to capitalize on the strong petrotechnical expertise and synergies existing within the collaborative environment of the support center. To further improve on the performance of such support centers, an engineering study was conducted in 2010 to assess further possibilities for improving service quality. Several areas of opportunity were identified, one of which included the incorporation of Lean and Six Sigma techniques to quantify the effect of modifications on these work processes. It was critical in this assessment to ensure that these process work flows seamlessly integrated into the work flows of the internal and external stakeholders that are beneficiaries of the support centers. This paper discusses the results from the initial generations of these process work flows and the way forward for the continued process work flow integration, using a support center that was developed in Russia as an example. The application of these work flows has brought demonstrable financial and service-quality benefits to both operators and service companies, and the broader applications in its consistent execution have presented a critical step change in Russian environment drilling performance.

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.

In difficult drilling environments, a critical aspect for success is BHA design optimization in the pre-job phase. In previous operations, modeling and run simulations have proven valuable at helping operators improve drilling efficiency (reduce NPT; increase footage/day), produce high-quality log data and properly position the wellbore to increase contact with the reservoir. To further improve modeling accuracy/reliability, a dynamic modeling system was used for BHA analysis. The FEA (finite element analysis)-based system enables engineers to leverage the team's combined expertise and full suite of drilling tools to optimize a BHA for a specific application.Four criteria are used to evaluate BHA performance during simulations: stability; robustness/reliability; measurement quality; steerability. Simulations are run to determine each configuration's potential for axial, lateral/torsional vibration and identify the root cause and dominant mode. To ensure maximum BHA robustness, the loading on BHA components is mapped/rated allowing refinements to increase BHA service life and reduce the potential for costly NPT. Simulations are run to observe the potential for MWD/LWD tool deformation and sag angle to determine the adverse effect sensor motion could have on measurement quality. To mitigate steerability issues, build/walk tendencies are simulated to determine how the BHA will respond to steering command from RSS/PDM.A wide-range of factors can be considered in this procedure. Various cutting structures and steering tools are analyzed and modified as required. The type and location of BHA components are also modeled and re-positioned for optimization purposes. Various drilling scenarios and operating parameters are fed into the system including RPM/WOB, sliding/rotating time, back-reaming and rotating off bottom. Formation characteristics including rock types, friction factor, heterogeneity/homogeneity, degree/amount of interbedding can all be varied to investigate the BHA's corresponding directional implications and vibrational response.All potential BHA designs are evaluated under a set of pre-defined drilling scenarios. A comparative analysis is performed to investigate BHA responses against each specific criterion to identify the optimum BHA configuration. Operating conditions are analyzed for each BHA and an optimal parameter window of minimized BHA shock and vibration is generated with a range of RPM/WOB recommendations. The authors will present several conclusive case studies that document the method's effectiveness and cost reducing capabilities.

Drilling in Russia's Far East has always been associated with industry-defining ultra-extended-reach drilling. With the emergence of more powerful drilling rigs and advances in measurement- and logging-while-drilling (MWD and LWD) tools, these wellbores can be designed to reach farther. Therefore, accurately penetrating and exploiting distant reservoirs have resulted in critical dependence on high-accuracy surveying techniques. Successful target penetration and meeting anticollision requirements without the need for shutting production in nearby wells are key proponents for a geomagnetic referencing service (GRS). Geomagnetic referencing is the technique to minimize the lateral position uncertainties when using MWD. This is particularly important for wellbores that extend the boundary of the drilling envelope with stepouts greater than 13 km. The wellbore azimuth accuracy is highly dependent on the quality of the magnetic data used to produce the geomagnetic reference model. This model characterizes the absolute magnitude and vector direction of the natural magnetic field for every point along the wellbore. Representation of the local crustal magnetic contribution is key to the process since it constitutes a significant error in the lateral wellbore position. Since 2011, a new, highly accurate geomagnetic referencing methodology has been used in Russia's Far East. Global contributions are accounted for by a high-definition geomagnetic model (HDGM). In addition, the local crustal magnetic anomaly is represented by 3D ellipsoidal harmonic functions tracking the shape and depth of the Earth, thereby providing seamless integration with HDGM and avoiding distortions faced by conventional plane-Earth approximations. A comparison with the previous industry standard shows improvements of 0.5° in azimuth determination. This high-degree geomagnetic technique will serve well for a number of upcoming developments in Russia's Far East, continuing to push the drilling envelope and providing essential, accurate wellbore positioning, while offering significant time and cost savings.