The Schoonebeek heavy-oil field was first developed by Nederlandse Aardolie Maatschappij B.V. (NAM) in the late 1940s. Because of economics, it was abandoned in 1996. In 2008, the Schoonebeek Redevelopment Project, using a gravity-assistedsteamflood (GASF) design concept, was initiated with 73 wells (44 producers, 25 injectors, and 4 observation wells). Steam injection and cool-down cycles subject a cement sheath to some of the most severe load conditions in the industry. Wellbore thermal modeling predicted that surface and production sections would experience temperatures in excess of 285°C (545°F) and considerable stress across weak formations. A key design requirement was long-term integrity of the cement sheath over an expected 25- to 30-year field life span. Complicating this requirement was the need for lightweight cementing systems, because lost-circulation issues were expected in both hole sections, particularly in the mechanically weak Bentheim sandstone. The long-term integrity challenge was divided into chemical and mechanical elements. Prior research on high-temperature cement performance by the operator provided necessary guidance for this project. Laboratory mechanical and analytical tests were conducted to confirm the high-temperature stability of the chosen design. In addition to using lightweight components, foaming the slurry allowed the density, mechanical, and economic targets to be met. A standardized logistical plan was put in place to allow use of the same base blend for the entire well, adjusted as needed, using liquid additives, and applying the foaming process when necessary. This single-blend approach greatly simplified bulk-handling logistics, allowing use of dedicated bulk-handling equipment. The first well was constructed in January 2009; all 73 wells have been successfully cemented to surface. The steaming process, initiated in May 2011, has progressed with no well integrity issues to date.
Seismic inversion requires two main operations relative to changes in the frequency spectrum. The first operation is deconvolution, used to increase the high frequency component of the observed seismic data and the second operation is integration of a reflectivity function to decrease the high frequencies and increase low frequencies of the seismic signal. The first operation is very unstable and non-unique for noisy seismic data. The second operation is very sable in high frequencies but has problems in low frequencies due to undefined low frequency data in seismic traces. By performing both of these operations simultaneously the operation will be stable in high frequency area and can be effectively stabilized in low frequency area based on an a priori acoustic impedance power spectrum and use Tikhonov and Arsenin‟s (1979) regularization technique. This approach can be applied to poststack and pre-stack seismic data.
The Intetech Well Integrity Toolkit (iWIT) is a web-based program which provides a comprehensive approach to well integrity management covering all potential integrity threats to the whole well. Using its own or existing client databases, this software carries out quantitative data analysis in real-time and provides feedback to the operator about the condition of individual wells and also overviews of the whole field integrity status to support timely, informed, decision-making.
Case histories are described of seven different operations introducing the software. The diverse reasons for introducing the software and the direct and indirect benefits ensuing are described. Each is a unique story, highlighting how flexible and comprehensive this successful software product has been. A common element is the management of data spread across multiple 3rd party datasystems which have been successfully integrated in each case, sometimes utilizing data entered in tablet PCs in the field directly linked to iWIT. More challenging is the vast range of data analysis and presentation which has been customized for each client to achieve their goal. This includes risk evaluation against complex criteria, determination of tubing condition based upon varying production conditions, calculating MAASP values per well per annulus, managing and generating well handover documentation from the software, tracking scaling issues, determining mean time to failure of equipment to establish risk-based inspection frequencies and many more detailed analyses.
The iWIT software has allowed these operators to prove their adherence to Well Integrity Management policies and provides numerous report formats including email alerts for engineers and managers. By ensuring well problems are proactively identified and responded to within guideline timeframes the software ensures that well integrity related shut-downs are reduced, thus providing improved productivity from the well stock and at the same time raising safety within the operations.
Key Benefits of the iWIT Software Identified from Case Histories
1) Reduction in number of wells shut in for well integrity reasons by about 80% over two years resulting in higher productivity and major cost saving.
2) Clear indication of wells' integrity status customised to meet company philosophy and local regulatory requirements.
3) Maximising value of all data about the well by making it available to all users in the company.
4) Integration of data from multiple sources by interfacing to existing 3rd party databases.
5) Real-time evaluation of environmental conditions which could result in failure of tubing in wells with variable production conditions.
6) Common system suitable for managing both brand-new field and mature field with aging wells.
7) Continuously updated risk status of all wells as data updates are made in real time.
8) Comprehensive scope capable of handling every type of data relevant to well integrity status; one-system covers all.
9) Common standards systematically applied throughout the company raising confidence in decision-making.
10) Reduction in data-gathering effort and report preparation by engineers, freeing them to carry out more detailed evaluation of workover options to resolve well issues; better utilization of skilled personnel.
While jar technology has been used in the oil industry for the better part of the last century, the basic function and capability has not taken many leaps forward. Increasingly complex well geometry and deeper target depths continue to push drillers into tighter, higher risk well conditions that raise the probability of stuck pipe events. As demand for hydrocarbons has forced our drilling capabilities to evolve, the increased risk associated with these wells has forced the evolution of jarring technology to drastically evolve.
By assessing the critical needs of the industry, a jar has been designed to operate in the harshest environments, with superior reliability, and the highest firing loads available to increase the levels of success in freeing a drill string during a stuck pipe event. Every pound of impact force delivered is critical to improve the chances of retrieving the drill string safely to surface and this new technology has raised the standard force by as much as 20%.
While the operation of this innovative technology remains consistent with industry standards, the performance in regards to torsional strength, damage resistance, and impact capabilities far exceed that of previously existing jar technology.
An optional performance component offers operators a safeguard against pulling the jar beyond its mechanical and hydraulic limits which can render it useless down hole. In addition to safeguarding the tool from damage, this module also allows the tool to be pulled to its maximum rating, every time, insuring the hardest possible impact every pull.
This paper will detail how the use of this innovative tool has provided flawless performance in the North Sea and offers a true step change in jar technology to the drilling industry. Case studies and field data provided will support and demonstrate increased performance unmatched in the industry today.
Norway is fast becoming one of the world's most technologically advanced areas for drilling and its culture has a reputation for early adoption of cutting edge technologies. Following the Ekofisk discovery on 1969, Norway's oil industry has continued to utilize the most advanced tools available to maximize returns while mitigating risks in their local drilling operations.
Today's drilling climate and market demand for increased return on assets (ROA) require operating companies and service companies alike to carefully safeguard against any potential risks associated with down time due to complications in drilling the well. Every year hundreds of millions of dollars in down time, BHA components lost in hole, and side tracking operations erode profitability and compromise the viability of drilling some high priced wells, despite the great lengths taken to minimize the risk of stuck pipe events. Year after year, well depths and extended reach horizontals continue to grow across the industry, and with them the risk of costly stuck pipe events. Unfortunately the primary tools used to free a stuck drill string have gone without significant improvement for many years. This critical component is often provides the last chance to retrieve expensive BHA equipment like rotary steerable systems (RSS), monitoring while drilling equipment (MWD), and other high cost bottom hole assembly equipment.
To-date, more than 450 heavy oil fields and deposits have been identified in the Republic of Tatarstan with oil-in-places ranging between 1.4 and 7.0 billion tons, according to different estimates. Thermal recovery has proved itself as a reliable method and seemed a logical solution however it did not work properly in vertical wells. Building on the experience of development of the Yaregskoye field (the Komi Republic, Russia) and oilsands in the Canadian province of Alberta, the focus was shifted on working out of recovery methods involving horizontal wells. Engineering solutions accounting for concrete geologic environment and the steam assisted gravity drainage method used for production of heavy oil aim at high-quality casing, leak control in the interstring space, sand control, etc. In shallow heavy oil reservoirs with variable oil saturation of utmost importance are production control practices to ensure profitable oil production, to maintain optimal steam-oil ratio and safe operating pressure to ensure cap rock integrity.