bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanics & Effectiveness of Different Types of Diversion in Horizontal Well Fracturing
Authors: Daneshy Ali 
Published: September 2019

Abstract
Use of diverters for altering fluid distribution among created hydraulic fractures in horizontal wells has gained popularity in recent years, both for initial and re-fracturing treatments. Aims in initial fracturing treatments have included creating more uniform distribution of slurry within the created fractures, increasing stage efficiency by reducing the number of pumping stages while increasing the number of clusters per stage, increasing the number of fractures created in openhole completions, reducing interactions between fractures in adjacent horizontal wells, etc. In re-fracturing treatments, a popular application is for altering fluid distribution in wells re-treated without isolation between stages (Pump & Pray/Bullheading) with the intent of increasing the number of re-activated fractures and initiating new fractures through added perforations.
Engineering analysis of the mechanics of fluid diversion has not received the same degree of attention as its use. The reported discussions are often limited in their scope, two-dimensional in structure, and somewhat speculative in their conclusions.
This paper divides the targets of diversion into three categories; at the wellbore/perfs, near wellbore, and deeper inside the fracture. It divides the types of diverters into three categories, mechanical, solid particulate (including proppants), and chemical. The applications are divided into two categories, initial and re-fracturing, together with highlighting their differences and requirements for successful diversion. The paper discusses how presence of proppant changes the fluid distribution in favor of more conductive perforations. It considers the fracture as a three-dimensional structure, extending on both sides of the wellbore. It describes how different diverting agents cause fluid redistribution between the fractures, and the important role of proppant in some applications. It shows that as the target of fluid diversion moves away from the wellbore the chances of its success become smaller and more unpredictable, while also the time before effective diversion takes place becomes longer.
Comprehensive understanding of the mechanics of fluid diversion helps in the selection of the type of diverter and how best to deploy it for achieving specific objectives and results.
Frac Hits: Good or Bad? A Comprehensive Study in the Bakken
Authors: Krishnamurthy Jayanth , Srinivasan Karthik , Layton Neil , Drouillard Matthew 
Published: September 2019

Abstract
Frac hits are a persistent phenomenon that operators face periodically during unconventional field development. With basin maturity and infill drilling, frac hits play a major role in dictating overall production from multiwell pads. This paper focuses on the causes of frac hits and their subsequent impact on well EURs with solution methods to minimize negative impacts resulting from frac hits.
A fully numerical model-based was built around a four-well pad in Mountrail County, N.D., by integrating high-tier data including 3D sonic logs, nuclear magnetic resonance imaging and downhole spectroscopy to build a mechanical earth model of the reservoir. The parent well(s) are history-matched and geomechanical properties recalculated to changes in in situ stresses from parent well production. Infill wells are evaluated for asymmetric frac propagation toward depleted wells, and EURs are estimated to compare with thosethat of the parent wells.
The initial well stimulation program and the volume of production from the parent well has a huge impact on the degree of fracture asymmetry in infill wells. This preferential propagation creates additional stimulated surface area between wells. If the parent well was understimulated in the first place, the infill wells in general result in a positive frac hit, and additional barrels of oil are produced from the parent well with little or no impact on the infill well. However, if the parent well has been on production for a long period the hydraulic fracturing treatment deposits a huge volume of fluid and proppant in already depleted areas, and the reservoir pressure is not sufficient to flush out the excess water. This causes the parent well to experience a surge in water cut and reduction in oil rate for an extended period. In addition, the infill well's initial production will not metch the parent well IPs, and EUR can reduce drastically. This paper will categorically illustrate the timing, spacing and stimulation recommendations to minimize or mitigate these impacts.
Quantifying frac hits requires a comprehensive multiwell approach incorporating geomechanics, fracturing and production. This paper showcases case studies from the Bakken, identifying fracture asymmetry and production forecast from multiple wells, carefully considering all the physics, rock and fluid interaction in the subsurface strata. This will be a valuable tool for the engineers and geologists in the oil and gas community to effectively plan future infill development programs in unconventional reservoirs.
Triaxial Testing System for Seismic Frequencies Measurements with Laser Displacement Sensors
Authors: Lu Chuan , Brandl Jakob , Deisman Nathan , Chalaturnyk Richard 
Published: September 2019

Abstract
In this study, a novel experimental system has been developed for static and dynamic elastic properties measurements at seismic frequencies under anisotropic stress and shear deformation conditions. This system focuses on static and seismic range frequencies dynamic (0.1 Hz to 20 Hz) elastic deformation properties of poorly consolidated oil sands and highly overconsolidated (clay) shales. The main body of the experimental system is a computer control servo-hydraulic system. A pair of laser displacement sensors measure nanometer scale displacement during the dynamic tests. A coarse scale and fine scale load cell system was developed for measuring force with high precision during dynamic testing. A novel triaxial cell for use with the loading system was also developed to simulate the reservoir stress and pore pressure condition during static and dynamic testing and allows permeability to be measured during testing. The loading system, dual load cell calibration procedure and results, and results for acrylic and 3D printed sand specimens are presented. The stable and reasonable results demonstrate the capacity of the new experimental system.
Can You Feel the Strain? DAS Strain Fronts for Fracture Geometry in the BC Montney, Groundbirch
Authors: Ugueto Gustavo A. , Todea Felix , Daredia Talib , Wojtaszek Magdalena , Huckabee Paul T. , Reynolds Alan , Laing Carson , Chavarria J. Andres 
Published: September 2019

Abstract
The use of Distributed Acoustic Sensing for Strain Fronts (DAS-SF) is gaining popularity as one of the tools to help characterize the geometries of hydraulic fracs and to assess the far-field efficiencies of stimulation operations in Unconventional Reservoirs. These strain fronts are caused by deformation of the rock during hydraulic fracture stimulation (HFS) which produces a characteristic strain signature measurable by interrogating a glass fiber in wells instrumented with a fiber optic (FO) cable cemented behind casing. This DAS application was first developed by Shell and OptaSense from datasets acquired in the Groundbirch Montney in Canada. In this paper we show examples of DAS-SF in wells stimulated for a variety of completion systems: plug-and-perforating (PnP), open hole packer sleeves (OHPS), as well as, data from a well completed via both ball-activated cemented single point entry sleeves (Ba-cSPES) and coil-tubing activated cemented single point entry sleeves (CTa-cSPES). By measuring the strain fronts during stimulation from nearby offset wells, it was observed that most stimulated stages produced far-field strain gradient responses in the monitor well. When mapped in space, the strain responses were found to agree with and confirm the dominant planar fracture geometry proposed for the Montney, with hydraulic fractures propagating in a direction perpendicular to the minimum stress. However; several unexpected and inconsistent off-azimuth events were also observed during the offset well stimulations in which the strain fronts were detected at locations already stimulated by previous stages. Through further integration and the analysis of multiple data sources, it was discovered that these strain events corresponded with stage isolation defects in the stimulated well, leading to "re-stimulation" of prior fracs and inefficient resource development. The strain front monitoring in the Montney has provided greater confidence in the planar fracture geometry hypothesis for this formation. The high resolution frac geometry information provided by DAS-SF away from the wellbore in the far-field has also enabled us to improve stage offsetting and well azimuth strategies. In addition, identifying the re-stimulation and loss of resource access that occurs with poor stage isolation also shows opportunities for improvement in future completion programs. This in turn, should allow us to optimize operational decisions to more effectively access the intended resource volumes. These datasets show how monitoring high-resolution deformation via FO combined with the integration of other data can provide high confidence insights about stimulation efficiency, frac geometry and well construction defects not available via other means.
Examining Hydraulic Fracture Characteristics Based on Induced Microseismicity: A Barnett Shale Case Study
Authors: Jia Suzie , Wong Ron , Eaton David 
Published: September 2019

Abstract
Microseismicity can be triggered by various dynamic processes related to a hydraulic fracturing treatment. These processes alter the in-situ stress field inside and around the stimulated reservoir volume, due to both creation of new fractures and fluid leakoff into the surrounding rock matrix. The analysis of spatiotemporal dynamics of fluid-induced seismicity can reveal important characteristics of the hydraulic fracturing process. With the knowledge of treatment data, it can be used in conjunction with the reservoir geomechanical theories in hydraulic fracture growth to investigate the fracture geometry and fluid-rock interactions. By applying these theories to a real microseismic dataset, two types of triggering front expansion patterns are evident. With the presence of a dominant hydraulic fracture, the radius of the triggering front expands linearly with time. Moreover, the microseismic event cloud forms a planar shape with low opening angles (failed by shear), indicating fracture slippages around the major hydraulic fracture. On the other hand, in the case of a complex fracture network with the absence of any major hyfraulic fracture, the triggering front grows non-linearly with time. This scenario can be treated as equivalent to a diffusion model and the microseismic events exhibit a higher fracture of tensile components (either opening or closing) and an equidimensional event cloud. In this study, two stages were analyzed and the derived fracture widths and fluid-loss coeffcients fall into a realistic range of general observations in the context of these two theories.
An Electronic Rig Action Plan - Information Carrier Equally Applicable to the Driller and the Automation Platform
Authors: Solvi Lars-Jørgen Ruså , Revheim Olav , Schaefer Serafima , Schutte Frank Johan 
Published: September 2019

Abstract
By use of the proposed method for digitilizing operation procedures and activities, the rig action plan can become the dynamic information exchange platform between planning and execution phase. Digitilizing the workflow and structuring the information in a rig action plan enables engineers to plan operations and transmit procedures and related parameters in a consistent form applicable to the driller and the drilling control system's automation platform.
The paper reviews existing rig action plans and activities to demonstrate how structuring of information using the new methodology allows planned procedures to be readable by a drilling automation platform. A new data structure with multiple activity levels is proposed for the rig action plan. The requirements and concept of a new application program interface (API) is discussed. The result of applying the proposed methodology to an actual rig action plan is presented along with an overview of a pilot project. The benefits of digitalizing the workflow and implementing an open, structured, machine readable rig action plan demonstrate how the new approach will contribute to the oil and gas technologies ambition to automate operation.
Paradox of Control in Large Project Organizations
Authors: Duhon Howard , Braathen Petter 
Published: September 2019

Abstract
Most major projects fail(Merrow, 2011). Failure results from a lack of control
Failures occur most often and most ruinously on our largest and most important projects. But these are the projects that are subjected to the most rigorous management oversight and control. There appears to be a paradox here: Those projects that we control the most rigorously appear to be the most out-of-control.
We argue that this paradox is caused by control models rooted in the reductionist/Newtonian worldview that is not suitable for understanding and controlling today's complex projects.
We argue that management control models can be improved by making them more like the control models extant in naturally occurring complex systems which do not experience any paradox of control.
A Case Study Demonstrating Single Relief Well Contingency for a Prolific Gas Well in Ultra-Deepwater
Authors: Oskarsen Ray T. , Paknejad Amir , Chantose Prasongsit , Emilsen Morten , Morry Brett 
Published: September 2019

Abstract
A blowout contingency plan was made for a gas field in a remote area with water depth exceeding 1600 m. The worst-case discharge analysis for a representative well in the field concluded that the reservoir is capable of producing at a highly prolific rate, which posed a challenge when developing a source control contingency plan that complies with governing regulators’ and operators’ internal requirements. Simulations using a transient multiphase flow simulator showed that the kill requirements could exceed the capability of a single conventional relief well; however, planning to intersect and coordinate a dynamic kill using multiple relief wells involved unacceptable operations risks. Furthermore, considering rig availability, limited pumping resources, and long mobilization times for this region, planning to use multiple relief wells is not a feasable option.
A recently developed subsea flow spool system can eliminate the need for multiple relief wells in the case of potentially hard-to-kill blowouts, especially where a dynamic kill using multiple relief wells would involve unacceptable operations risks. Dynamic kill simulation shows that the subsea flow spool, coupled with a supporting mobile offshore drilling unit (MODU), flexible flow lines, a supplementary flow spool, and a casing string placed inside the riser will be able to achieve a successful kill if needed. Furthermore, detailed engineering analysis of triaxial loads, fatigue, and erosion were done for critical hardware components to ensure all potential failure points were addressed. In conclusion, the subsea flow spool is a key component of demonstrating a single-relief well contingency for potentially hard-to-kill blowouts
An Industry Look at the Petroleum Engineering Curricula
Authors: Rietz Dean , Soliman Mohamed , Cagle Adam 
Published: September 2019

Abstract
During the last few years, the petroleum industry has been experiencing significant changes in various areas including, workforce, targets of exploration, application of (new) technologies, and general operational areas of focus. A prolonged depression of oil prices, changes in geopolitical atmosphere, the rise of investment in unconventional resources, as well as the implementation of emerging technologies (including digital) have been the primary catalysts of change within the industry. In terms of workforce, these changes have produced leaner organizations, along with the unintended consequence of losing some critical expertise and creating knowledge-gaps at many organizations. The changes, particularly in technology, necessitate a look at the need for the acquisition of new skills, for current and future petroleum engineers, that match new areas of interest – such as data analytics and artificial intelligence.
As the oil industry continues to evolve, it is imperative for academic organizations to consider these changing dynamics and be responsive. This paper outlines the results of a recent survey that targeted industry managers or supervisors who have direct experience with newly minted petroleum engineering graduates (less than five years of experience). The survey asked the participants their opinions regarding the preparedness of recent graduates as they enter the workforce. The survey's intent was to identify the potential need to modify the skills and knowledge currently acquired in academic institutions during the undergraduate study.
A comprehensive survey that posed questions regarding classical and contemplated new petroleum engineering curriculum was sent to recipients, primarily within the reserves and reservoir-engineering sector. The recipients were industry professionals working in operating, service, financial, and consulting sectors of the petroleum industry. More than 200 responses were received. The tabulated results are presented in the paper, along with interpretation of the results. The raw data will be made available through OnePetro as an accompaniment to the published paper.
The paper presents the survey conclusions, proposed action items, and discusses plans for a follow-up survey.
An Assessment Of The Current Regulatory Frameworks For Onshore, Upstream, Unconventional Well Integrity And Strategies For Improvement
Authors: Thomas Tim , Johnson Jr. Raymond L. 
Published: September 2019

Abstract
This paper reviews existing analysis of well integrity related regulation in upstream unconventional oil and gas projects and proposes a methodology to enhance such regulation in the future. This paper has compiled findings from a number of peer-reviewed sources assessing regulatory systems across a number of jurisdictions. These findings were based around four key questions that this paper has assessed (1) what is the overall assessment of current regulatory systems; (2) where to-date are the key areas that current research have focused on; (3) what are the key strengths identified in current research; and (4) what are the key gaps in current research?
This paper demonstrates that the body of work provides a wide array of assessments and conclusions. Whilst some are quite explicit in their judgment of a particular system’s effectiveness, many refrain from making a holistic assessment in a particular jurisdiction. Much of the research involves the application of prisms, such as environmental risks or local government jurisprudence. Along with these prisms, a number of common aspects of research are identified that strengthen the analyses, such as the use of ‘as drilled’ data and the use of relevant data samples. Some research gaps remain despite these strengths.
The majority of previous researchers can identify some degree of ineffectiveness in various regulatory regimes. Further, a number of gaps exist as a result of regulatory systems being incomplete or inadequate, potentially masking other inadequacies. To address these gaps, this paper proposes a methodology to improve and clarify knowledge and practical recommendations to improve the effectiveness of assurance activities by both regulatory agencies and operators. Specifically, this methodology focuses on a typological assessment of written rules in a number of jurisdictions. As an example, we present an ‘as built’ dataset to assess compliance with rules and identify means of assurance. This methodology proposes surveying of regulatory agencies and operators to validate the assertion that gaps can be identified and corrected and provide more insight into how regulatory systems function and the systematic causes of gaps.
Collapse Ratings of Cold Expanded Line Pipe Used as Casing
Authors: Miller Rich , Stewart Craig , Owoeye Oladele , King Abe , Long Xin , McGill Randy 
Published: September 2019

Abstract
API Specification 5L (2018) pipe is commonly used as surface casing. Recent deepwater failures have led to a review of collapse performance of 5L pipe as part of the larger root cause investigation.
A survey of pipeline industry publications generated a database of over 80 collapse tests of cold-expanded line pipe. The data are compared to casing collapse ratings per API Technical Report 5C3 (2018) and to alternative ratings included in API Recommended Practice 1111 (2015) for offshore pipelines and in the submarine pipeline standard DNVGL-ST-F101 (2017). The comparison showed that the pipeline ratings provide a better fit to the collapse data and that API TR 5C3 overpredicts collapse performance of the subject pipe.
Further investigation revealed that, for two operators, the vast majority of offshore surface casing is line pipe that has been cold-expanded without stress relief. Several risk mitigation alternatives were considered. In the short term, the risk can be managed through learning bulletins, design guidelines and operational procedures. The preferred mitigation is to change the collapse rating for cold-expanded line pipe used as casing. This is a long-term solution involving industry standards and the subsequent adoption through commercial design software.
The work described in this paper has led to a ballot change for the next edition of API TR 5C3. This paper is presented to provide drilling industry awareness of the lower collapse performance of cold-expanded line pipe and to add context for selection of an appropriate alternative rating.