scholarly journals A Bioeconomic Analysis of the Impact of Decommissioning Programs: Application to a Limited-Entry French Scallop Fishery

2004 ◽  
Vol 19 (2) ◽  
pp. 225-242 ◽  
Author(s):  
OLIVIER GUYADER ◽  
FABIENNE DAURES ◽  
SPYROS FIFAS
Keyword(s):  
Limited Entry ◽  
The Impact

Can We Engineer Better Multistage Horizontal Completions? Evidence of the Importance of Near-wellbore Fracture Geometry from Theory, Lab and Field Experiments

2015 ◽  
Author(s):  
B.. Lecampion ◽  
J.. Desroches ◽  
X.. Weng ◽  
J.. Burghardt ◽  
J.E.. E. Brown
Keyword(s):  
Pressure Drop ◽  
Field Experiments ◽  
Horizontal Wells ◽  
Fracture Plane ◽  
Hydraulic Fractures ◽  
Multiple Fractures ◽  
Fracture Geometry ◽  
Complex Fracture ◽  
Limited Entry ◽  
The Impact

Abstract There is accepted evidence that multistage fracturing of horizontal wells in shale reservoirs results in significant production variation from perforation cluster to perforation cluster. Typically, between 30 and 40% of the clusters do not significantly contribute to production while the majority of the production comes from only 20 to 30% of the clusters. Based on numerical modeling, laboratory and field experiments, we investigate the process of simultaneously initiating and propagating several hydraulic fractures. In particular, we clarify the interplay between the impact of perforation friction and stress shadow on the stability of the propagation of multiple fractures. We show that a sufficiently large perforation pressure drop (limited entry) can counteract the stress interference between different growing fractures. We also discuss the robustness of the current design practices (cluster location, limited entry) in the presence of characterized stress heterogeneities. Laboratory experiments highlight the complexity of the fracture geometry in the near-wellbore region. Such complex fracture path results from local stress perturbations around the well and the perforations, as well as the rock fabric. The fracture complexity (i.e., the merging of multiple fractures and the reorientation towards the preferred far-field fracture plane) induces a strong nonlinear pressure drop on a scale of a few meters. Single entry field experiments in horizontal wells show that this near-wellbore effect is larger in magnitude than perforation friction and is highly variable between clusters, without being predictable. Through a combination of field measurements and modeling, we show that such variability results in a very heterogeneous slurry rate distribution; and therefore, proppant intake between clusters during a stage, even in the presence of limited entry techniques. We also note that the estimated distribution of proppant intake between clusters appears similar to published production log data. We conclude that understanding and accounting for the complex fracture geometry in the near-wellbore is an important missing link to better engineer horizontal well multistage completions.

Frac Charge Performance at Downhole Conditions: Assessments and Implications

2021 ◽  
Author(s):  
Brenden Grove ◽  
Jacob McGregor ◽  
Rory DeHart ◽  
Ron Dusterhoft ◽  
Neil Stegent ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Fracture Initiation ◽  
Fracture Network ◽  
Hole Size ◽  
Eagle Ford Shale ◽  
Technical Performance ◽  
Limited Entry ◽  
Surface Test ◽  
The Impact ◽  
Surface Testing

Abstract Hydraulically fractured completions dominate industry perforating activity, particularly in North American land basins. This has led to the development of fracture-optimized perforating systems in recent years. Aside from overarching safety, reliability, and efficiency priorities, the main technical performance attribute of these systems is consistent hole size in the casing, driven by limited entry fracture design considerations. While the industry continues to seek further improvements in hole size consistency, attention is also being directed to the perforations more holistically, from a perspective of maximizing the effectiveness of subsequent hydraulic fracturing and ultimately production operations. To this end, this paper presents two related activities addressing the development, qualification, and optimization of perf-for-frac systems. The first is a surface testing protocol used to characterize perforating system performance, in particular casing hole size and consistency. The second is a laboratory program, recently conducted to investigate perforating stressed Eagle Ford shale samples at downhole conditions. This program explored the influences of charge size, formation lamination direction, pore fluid, and dynamic underbalance on perforation characteristics. Casing hole size was also assessed. For the first activity (surface testing), we find that using cement-backed casing can be an important feature to ensure more downhole-realistic results. For the second activity (laboratory program), perforation casing hole sizes for the charges tested were in line with expectations based on existing surface test data, exhibiting negligible pressure dependency. Corresponding penetration depths into the stressed shale samples generally ranged from 3.5-in to 5-in, which is much shallower than might be expected based on surface concrete performance. Dynamic underbalance was found to exhibit some slight effect on the tunnel fill characteristics, while pore system fluid was found to have minimal influence on the results. An interesting feature of the perforated samples was the complex fracture network at the perforation tips, which appeared "propped" to some extent with charge liner debris. Some of these fractures were formation beds which had delaminated during the shot, a phenomenon observed for perforations both parallel and perpendicular to the laminations. The implications of these results to the downhole environment continues to be assessed. Of particular interest is the impact these phenomena might have on fracture initiation, formation breakdown, and treatment stages which accompany subsequent hydraulic fracturing pumping operations.

First Multilateral Well in the Most Congested Field in Abu Dhabi, Case of Study

2021 ◽  
Author(s):  
Felix Leonardo Castillo ◽  
Mohamed Sarhan ◽  
Abd El Fattah El Saify ◽  
Victor Jose Aguilar ◽  
Roswall Enrique Bethancourt ◽  
...  
Keyword(s):  
Lessons Learned ◽  
Drilling Fluids ◽  
Screening Criteria ◽  
Technology Application ◽  
Initial Stage ◽  
Limited Entry ◽  
Study Team ◽  
Multiple Reservoir ◽  
The Cost ◽  
The Impact

Abstract This paper will highlight the first level 2 Multi-lateral well in BAB Field with permanent limited entry liner completion in the lower borehole to enhance accessibility and production. The well presents a technical milestone to the company in the development of multiple reservoir by combining two (2) wells from different reservoir and produce from both by using same surface well construction. At initial stage, the economics related to the implementation of the multilateral approach were analysed. Calculation was done by comparing the cost related to the technology application against the cost to prepare one (1) location plus completing a well up to the 7″ liner and mobilizing the rig twice. Then, it was necessary to select the candidate wells to be drilled from the same slot where synergy between Study team and drilling team was in place in order to ensure proper target alignment to make feasible the drilling and completion operations at the same time that the production targets were fulfilled. This project confirmed the feasibility of multilateral well application in a very congested field in terms of wells construction and surface facilities. In order to achieve such goal full synergy must be in place to select proper wells candidates and align targets. Cost reduction is massive considering the elimination of three (3) well phases plus avoidance of one (1) location construction and also the elimination of 1 rig move represents a big impact in terms of economics. Furthermore, the impact in terms of the risk reduction must be considered By combining two (2) wells in one (1) and eliminating three (3) phases in the standard well construction the harmful impact of location preparation, drilling fluids and cuttings on the environment is reduced by 45%, especially with oil base mud system. Geological problems can be observed during drilling each phase of a new well. However, drilling multilateral wells will reduce this occurrence. Well was completed with 7″× 4-1/2″ top packer, 4-1/2″ Slotted tubing and seven (7) swellable packers in lower borehole as well as Dual upper completion with 7″ single retrievable and 9-5/8″ dual retrievable packer and 2-7/8″ and 3-1/2″ tubing combination in both short and long string. This paper presents ADNOC Onshore first and successful experience in the deployment of new acquired technology for the Drilling multi-lateral / dual completion systems in BAB Field. The screening criteria for selecting the system as well as the benefits realized and lessons learned from this experience are also discussed together with the design simulations required to ensure the success of the well construction.

Delay-difference model to estimate the catch of different categories of the western rock lobster (Panulirus cygnus) for the two stages of the annual fishing season

1997 ◽  
Vol 48 (8) ◽  
pp. 949 ◽  
Author(s):  
Norman G. Hall
Keyword(s):  
Management Strategies ◽  
Fishing Effort ◽  
Rock Lobster ◽  
Fishing Season ◽  
Limited Entry ◽  
Harvest Strategy ◽  
Panulirus Cygnus ◽  
Two Stages ◽  
The Impact ◽  
Delay Difference

The annual exploitation rate of the limited-entry rock lobster fishery of Western Australia is controlled by constraining the total allowable effort. An important aspect of the harvest strategy introduced in 1993 was the use of annual levels of allowed fishing effort that could be varied in accordance with predicted levels of recruitment to the fishery in order to increase the abundance of spawning females and to reduce the variability in the level of annual catch. A model was needed that could examine the impact of alternative management strategies on the catches both within and between fishing seasons. The model that has been developed uses a delay-difference structure in which the fishing season is divided into two periods. Growth between the periods, and over the closed fishing season, is determined from tagging data. Recruitment is estimated from the observed levels of puerulus settlement. The model has been fitted to the observed effort within the southern sector of the fishery. This model allows the evaluation of alternative levels of fishing effort within the management zone, providing managers and industry with a tool to explore alternative harvest strategies.

Limited Entry Policy and the Bristol Bay, Alaska Salmon Fishermen

1982 ◽  
Vol 39 (3) ◽  
pp. 415-425 ◽  
Author(s):  
J. Anthony Koslow
Keyword(s):  
Fishery Management ◽  
Local Population ◽  
Significant Proportion ◽  
Local Economy ◽  
Fishing Communities ◽  
Present System ◽  
Bristol Bay ◽  
Limited Entry ◽  
Salmon Fishery ◽  
The Impact

The impact of limited entry was examined upon the diverse groups engaged in the Bristol Bay, Alaska salmon fishery. Whereas limited entry was intended to enhance the state's rural fishing economies, the system has in fact significantly diminished access of the local population to the fishery, the region's primary economic activity. A significant proportion of local fishermen were intially denied entry permits due to entry criteria in which the implicit definition of a legitimate fisherman was based largely upon a nonrural model, development of an application poorly designed for use by the rural Alaskan population, and administration of the program by a bureaucracy that appears insensitive to the needs of the rural communities. The salability of the permits, combined with the poorer fishing earnings of local fishermen and the generally impoverished local economy, led to a further drain of permits from local areas. Unless the system is substantially altered, local fishing communities can be expected to suffer significant further impoverishment because the fishery is now effectively closed to their burgeoning youthful population. However, the present system substantially benefits urban Alaskan fishermen (as well as non-Alaskan fishermen), who are more effective politically than their rural counterparts, so no substantial change in the present system can be expected. Limited entry programs clearly must be based upon a better understanding of the socioeconomic and cultural characteristics of targeted fishing communities if such highly inappropriate consequences are to be avoided.Key words: limited entry, Bristol Bay, salmon fishery, socioeconomic, Oncorhynchus nerka, fishery management

Geomechanically Driven Casing Deformation During Multistage Perf and Plug Fracturing Operations: Investigation and Mitigation

2021 ◽  
Author(s):  
Arjang Gandomkar ◽  
David Katz ◽  
Ricardo Gomez ◽  
Anders Gundersen
Keyword(s):  
Active Tectonics ◽  
Oil Fields ◽  
Hydraulic Stimulation ◽  
Limited Entry ◽  
Stress States ◽  
Failure Conditions ◽  
Casing Deformation ◽  
The Impact

Abstract Casing Deformation has presented itself in numerous unconventional basins. Severe deformation interferes with multistage fracturing, in particular with plug-and-perforation (also known as plug-and-perf) operations, the most common stage isolation method in unconventional development. Casing Deformation can greatly impact 20-30% of field productivity of horizontal wells in certain US shale and tight oil fields (Jacobs, 2020). Reservoir accessibility and well integrity are the two separate issues when considering casing deformation. In this paper, the impact of geomechanically driven casing deformation on reservoir accessibility that in turn affects production and economics, will be discussed. Origin of casing deformation within a target zone lies in natural fractures placed in highly anisotropic stress regimes. When these fractures are perturbed by hydraulic stimulation, slow slip or dynamic failure of the rock may occur. This phenomenon is intensified by active tectonics, high anisotropic in-situ stresses, and poor completion practices, i.e., poor cement. This paper evaluates these processes by demonstrating failure conditions of wellbores in different stress states and well orientations representative of unconventional basins. It reviews how these conditions can be evaluated in the reservoir, so risk can be estimated. The mitigation procedures to reduce casing deformation impact to operations through either well planning or completions design are discussed. Finally, this paper will also review an alternative completion method to plug-and-perf that allows limited entry completion technique in restricted ID casing due to casing deformation with a field case study.

Natural Fracture Dominated Distribution of Slurry During a Multi-Cluster Hydraulic Fracturing Stage: A Marcellus DAS/DTS Case Study

2021 ◽  
Author(s):  
Eric Romberg ◽  
Andrew Adams ◽  
Jason Edwards ◽  
Taylor Levon
Keyword(s):  
Fractured Rock ◽  
Marcellus Shale ◽  
Natural Fracture ◽  
Drill Bit ◽  
Natural Fractures ◽  
Working Hypothesis ◽  
Naturally Fractured ◽  
Limited Entry ◽  
Environmental Laboratory ◽  
The Impact

Abstract In this paper, the authors examine the impacts of natural fractures on the distribution of slurry in a well with a permanent fiber installation and drill bit geomechanics data. Additionally, they propose a framework for further investigation of natural fractures on slurry distribution. As part of the Marcellus Shale Energy and Environmental Laboratory (MSEEL), the operator monitored the drilling of a horizontal Marcellus Formation well with drill bit geomechanics, and subsequent stimulation phase with a DAS/DTS permanent fiber installation. Prior to the completion, the authors used an analytical model to examine the theoretical distribution of slurry between perforation clusters from a geomechanics framework. A perforation placement scheme was then developed to minimize the stress difference between clusters and to segment stages by the intensity of natural fractures while conforming to standard operating procedures for the operator's other completions. The operator initially began completing the well with the geomechanics-informed perforation placement plan while monitoring the treatment distribution with DAS/DTS in real time. The operator observed several anomalous stages with treating pressures high enough to cause operational concerns. The operator, fiber provider, and drill bit geomechanics provider reviewed the anomalous stages’ treatment data, DAS/DTS data, and geomechanics data and developed a working hypothesis. They believed that perforation clusters placed in naturally fractured rock were preferentially taking the treatment slurry. This phenomenon appeared to cause other clusters within the stage to sand-off or become dormant prematurely, resulting in elevated friction pressure. This working hypothesis was used to predict upcoming stages within the well that would be difficult to treat. Another perforation placement plan was developed for the second half of the well to avoid perforating natural fractures as an attempt to mitigate operational issues due to natural fracture dominated distribution. Over the past several years, the industry's growing understanding of geomechanical and well construction variability has created new limited-entry design considerations to optimize completion economics and reduce the variability in cluster slurry volumes. Completion engineers working in naturally fractured fields, such as the Marcellus, should consider the impact the natural fractures have on slurry distribution when optimizing their limited-entry designs and stage plan.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

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