Successful Remediation of Sustained Casing Pressures in Gas Cap Injector Wells with the Use of Flexible and Self Healing System

Several injection wells in Prudhoe Bay, Alaska exhibit sustained casing pressure (SCP) between the production tubing and the inner casing. The diagnostics on these wells have shown communication due to issues with casing leaks. Conventional cement systems have historically been used in coiled-tubing-delivered squeeze jobs to repair the leaks. However, even when these squeeze jobs are executed successfully, there is no guarantee in the short or long term that the annular communication is repaired. Many of these injector wells develop SCP in the range of 300-400 psi post-repair. It has been observed that the SCP development can reoccur immediately after annulus communication repair, or months to years after an injector well is put back on injection. Once SCP is developed the well cannot be operated further. A new generation of cement system was used to overcome the remedial challenge presented in these injector wells. This document provides the successful application of a specialized adaptive cement system conveyed to the problematic zone with the advantage of using coiled tubing equipment for optimum delivery of the remedial treatment.

Quantifying the spatial and temporal influence of infrastructure on seasonal snow melt timing and its influence on vegetation productivity and early season surface water cover in the Prudhoe Bay Oilfields

<p>Increased industrial development in the Arctic has led to a rapid expansion of infrastructure in the region. Past research shows that infrastructure in the form of roads, pipelines and various building types impacts the surrounding landscape directly and indirectly by changing vegetation patterns, locally increasing ground temperatures, changing the local hydrology, introducing road dust into the natural environment, and affecting the distribution and timing of seasonal snow cover. Localized impacts of infrastructure on snow distribution and snow melt timing and duration feedbacks into the coupled Arctic system causing a series of cascading effects that remain poorly understood.  In this study, we quantify spatial and temporal patterns of snow-off dates in the Prudhoe Bay Oilfields (PBO), North Slope, Alaska using multispectral remote sensing data from the Sentinel-2 constellation. The Sentinel-2 satellite constellation provides good spatial and temporal coverage of Arctic regions with adequate spatial resolution to quantify and monitor infrastructure impacts on the natural environment in polar regions. We derive the Normalized Difference Snow Index (NDSI) to quantify the presences and absences of snow on a pixel-by-pixel basis between 2015 and 2020. Additional indices, like the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) were derived to understand linkages between patterns in vegetation and surface hydrology, respectively, to patterns in snow-off dates that are influenced by the presence and type of infrastructure on a regional basis at PBO. Newly available infrastructure data sets derived from Sentinel-1 and 2 data were employed to quantify differences in snow melt patterns in relation to distance to roads and other types of infrastructure. Near-surface ground temperature measurements from multiple transects oriented in a perpendicular direction from the road up to 100 m provided ground-truth observations for snow-off timing derived from the remote sensing analysis. Our results from the regional remote sensing analysis show a relationship between snow-off date and distance to different types of infrastructure that vary by their use and traffic load during the snowmelt period as well as their orientation relative to the prevailing wind direction. Results from field data observations indicate that the early onset of snowmelt near heavily traveled infrastructure corridors impacts near-surface soil freezing degree days, vegetation productivity, and waterbody surface cover.</p>

A lateral well in the Shublik Formation, Alaska North Slope, with implications for unconventional resource potential

Analyses of a horizontal well drilled in the Shublik Formation within the southern part of the Prudhoe Bay field provide the first glimpse of the unit’s potential as an unconventional resource. Drilled in 1996, the 1450 ft (442 m) long well, PBU X-19B L1, targeted the 17 ft (5 m) thick Shublik Zone B. More than 70% of the lateral well path sampled that target, a feat of precise geosteering years before the unconventional revolution. The well operator’s drilling plan focused on the middle subzone of Zone B. The well history ascribes the focus on the middle subzone to its high silt content, open fractures, and significant hydrocarbon shows. Contrary to the drilling narrative, cuttings from 41 intervals indicate that siltstone monotonically decreases in Shublik Zone B, on average, from 50% to 40% to 30% in the three subzones from top to base. The limestone concentration inversely varies with the siltstone concentration through Zone B, steadily increasing from top to base (40%, 50%, and 60%). Hydrocarbon shows in the upper and middle subzones of Zone B range from good to fair, whereas the shows in the lower Zone B are weaker. Unfortunately, scant geochemical analyses of oil produced from the Shublik flow test combined with engineering difficulties prevent a definitive conclusion as to the source of the oil — the fractured Shublik Formation or the underlying Ivishak Sandstone. However, on the basis of favorable lithology, hydrocarbon shows, and fracture density, the upper and middle subzones of Zone B should be targeted as a potential unconventional accumulation if and when a well is drilled in the pod of active source rock downdip.

Intertextual analysis of the BP Prudhoe Bay disaster: applying the 5 Bs of antenarrative

Purpose This paper aims to offer an analysis of the British Petroleum (BP) Prudhoe Bay environmental disaster. The primary purpose is to elucidate the fivefold of antenarrative in sensemaking environmental accidents. The analytic framework enables organization to envision futures where they want to be, and work to get there as more socially responsible companies. Design/methodology/approach The authors conducted an intertextual analysis of texts by ascribing voice and affiliation to each antenarrative. The multiple voices and antenarratives quoted within the texts were compared and coded and theme analysis was conducted over time to understand dynamics and see if organizational learning was occurring. Findings The antenarrative method generated several findings: BP is faulty beneath in how they conceive of safety, lacking foresight. BP executives leave out elements of safety, a fore having that does not include what needs to be prepared for. BP foretells that it is socially responsible, yet the reality of events seems contradictory. Within fore structure, some of BP’s leaders deny or ignore claims of critics through intertextual connections of events. By fore caring, BP mediates the problem in response to the disaster and critics. Their sensemaking in this case is more retrospective and reactive than prospective. Practical implications Organizations can avoid environmental disasters and negative backlash by adopting practices that provide more transparent discourse and greater accountability. The fivefold of antenarrative serves as a storytelling framework to promote care by using trial and error problem solving on future bets. Originality/value To date, few intertextual analyses have been performed to study organizations. By applying a fivefold antenarrative storytelling framework, which reflects new advances in storytelling theory, the authors offer an original perspective on environmental accident sensemaking.

Eliminating the Uncertainties in Hydraulic and Ice Loads on Berm Breakwaters

A model for the computation of failure probabilities for partly reshaping mass-armored berm breakwaters in the Arctic is presented. The model consists of a reliable tool for the design of port structures in the rapidly changing Arctic environment and considers the simultaneous effects of wave and ice forces. The applied probabilistic approach was based on Bayesian inference. Hydrodynamic and ice historical data from Prudhoe Bay, Alaska were collected and analyzed to supply the Bayesian network with a large pool of information for the analysis. The model performed real-time predictions based on historical data and the user’s prior knowledge and assigned relevant values to load and resistance parameters. The predictive skill of the Bayesian network was validated with log-likelihood tests. Furthermore, the main outputs were applied for a Level III (fully probabilistic) reliability assessment of the structure. The study shows that a well-formulated Bayesian network can be a powerful tool in the design process and for the purpose of reliability analysis of coastal structures in highly unpredictable environments, such as the Arctic. The model can represent the dependencies between wave and ice loads in relation to the characteristics of the breakwater, as well as, its response. The average deviation of computed probabilities of failure relative to the prior estimates was 58.7%.