bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fracture Sequencing in Multi-Well Pads: Impact of Staggering and Lagging Stages in Zipper Fracturing on Well Productivity
Authors: Manchanda Ripudaman , Zheng Shuang , Sharma Mukul 
Published: January 2020

Abstract
Zipper fracturing is a method of sequencing frac jobs in multi-well pads that helps increase operational efficiency and reduce stimulation time for a pad. This technique involves stimulating several wells in a pad in a prescribed sequence of stages. In this work, we provide a thorough assessment of the various factors impacting the effectiveness of zipper fracturing treatments and provide a methodology for selecting an optimum sequence of fracture stages.
A fully implicit, parallelized, 3-D, pad-scale reservoir-fracturing simulator is used to simulate the dynamic propagation of multiple, non-planar fractures from multiple treatment wells while capturing the stress interference between fractures. This interference is captured both on an intra-well as well as an inter-well scale. Interaction between fractures propagating from different wells is found to be dependent on pad design, completion design, and reservoir parameters. We evaluate the effectiveness of the stimulation operation by comparing the impact of operation decisions on the created fracture geometries and simulated productivity of the propagated fractures using seamless fracturing-reservoir simulations.
The simulation results are used to understand the impact of well spacing, stage spacing, staggering of zipper-frac wells, lagging of stages during zipper fracturing, size of the frac job, stress contrast in the reservoir and rock properties. Using multi-cluster fracturing simulations and accurate proppant distribution calculations in the wellbore, we consider the impact of various operational decisions mentioned above on the distribution of proppant in the created fractures. We observe that fracture closure during shut-in of a stage impacts the created fracture geometries. This affects the proppant distribution in the fractured stages. The impact of the operational decisions on the fracture conductivity degradation during stimulation is also captured using seamless fracture-reservoir simulations. We show that the results obtained from these simulations can help design pad-scale operations to maximize the fracture-reservoir contact area or improve the productivity of the wells.
In this work, for the first time, we assess the impact of zipper fracturing on well productivity by performing coupled fracturing-reservoir simulations. The software is used to simulate fracture propagation and fracture closure during shut-in and production. The results obtained from these simulations recommend an optimized fracture sequencing, stage lag and staggering strategy to maximize the productivity of the pad.
Rapid Completion Optimization Using Particulate Oil-Soluble Tracers
Authors: Jones Marcus , LaRue Jon 
Published: January 2020

Abstract
Pumping multiple unique stimulation designs in a single multistage lateral combined with particulate oil-soluble tracer chemicals (OSTs) accelerates the traditional trial and error process of optimizing stimulation designs. Applying this methodology to various fracturing sand volumes provides discrete data for stimulation analysis. When compared to a large sample of wells, the data shows that OST tracer recovery may be used as a proxy to estimate oil production.
Altering fracture designs within the same wellbore with OSTs provides significant data that is useful for optimizing stimulation designs. Solid particulate OSTs differ from liquid OSTs in that the particulates remain locked in-situ in the proppant pack after the frac pressure wave has subsided. Formation pressure will not force the solid tracer back into the wellbore as sometimes occurs with liquid tracers. The unique chemistry of OSTs allows the tracing chemicals to dissolve only into produced oil, which is sampled at the surface for laboratory analysis.
Multi-stage lateral wells utilizing alternating stimulation designs with unique OSTs yield data suggesting increased proppant volumes lead to larger oil recoveries compared to lower proppant volumes. Ninety-four horizontal wells within the same bench of the Wolfcamp formation with various proppant volumes show a statistically significant correlation between proppant volumes and estimated ultimate recoveries (EURs). The OST recovery results closely match the trend of the 94 full-well completions, giving evidence that OST recoveries are a quantitative analogy for oil production over time. Increased proppant loading OST tests, beyond the range of full-well data available, show no gain in OST recovery. This suggests that adding more proppant in this specific portion of the reservoir may not add economic value to the operator.
The unique ability of OSTs to generate granular information at the individual stage level accelerates an operator's learning curve as optimizing stimulation design often requires costly investments in reservoir information. Another approach is to optimize stimulation design using empirical data if wells in a similar geological and petrophysical makeup exist. The OST alternating-stage-design methodology can be applied to other variables, providing a rapid trial-and-error process that yields significant empirical data for optimizing completion variables.
Utilizing Discrete Fracture Modeling and Microproppant to Predict and Sustain Production Improvements in Nano Darcy Rock
Authors: Montgomery Carl T. , Smith Michael B. , An Zhongfeng , Klein Hank H. , Strobel William , Myers Roger R. 
Published: January 2020

Abstract
Providing and sustaining fracture conductivity in secondary fracture systems created during the stimulation of very tight unconventional shale plays is critical for sustaining productivity and reducing decline rates. In this paper, a discrete fracture network model which includes proppant transport will be utilized to show the effect that an unsupported vs supported dilated fracture network has on the decline and ultimate recovery of available resources in shale. In addition, the characteristics and properties of a microproppant will be described. The physical properties of the material, the oil and water conductivity of the proppant at various fracture widths along with the resultant Fcd will be presented. Utilizing a bridging factor of 3, a comparison of the surface area propped by various proppants will be made. The proppant transport characteristics will also be described. The production benefits of utilizing very small proppants will be demonstrated utilizing production data from four different rock systems including the Barnett, Woodford, Utica, Permian Basin and Marcellus shale. Several additional operational benefits including reduced pumping pressures and far field diversion to prevent fracture hits will also be discussed. Finally, operational considerations will be described including utilizing liquid slurry's, pump wear evaluations and recommended proppant addition points will be described.
Experimental Investigation on Parameters Affecting the Coefficient of Discharge of a Perforation Hole in Hydraulic Fracturing Treatments
Authors: Loehken Joern , Yosefnejad Davood , Fricke Bernd 
Published: January 2020

Abstract
Hydraulic fracturing is the most popular well stimulation technique for extracting hydrocarbons from unconventional oil and natural gas reservoirs. During this process the stimulation fluid is injected into the reservoir from the wellbore with a pressure higher than the breakdown pressure of the reservoir in order to create fractures in the formation.
The pressures needed for hydraulic fracturing depend on many factors such as injection pressure and flow-rate, fluid density, fluid viscosity and the perforation hole. One of the important factors affecting the perforation pressure loss is the Coefficient of Discharge (Cd). This work looks deeper into the factors, which determine the magnitude of this value. Especially for a perforation hole, many of these factors are still not fully understood today and need further research.
As part of this study a new high pressure, high flow test vessel was built, which is compatible with our API19B Section IV test setup, in order to investigate some of the factors that could affect the Cd and subsequently the perforation pressure loss in the fracturing treatment. CFD simulations have been carried out to compare our experimental results with numerical models. In addition, we investigate the effect of the perforation hole size (area) by using different charges, the length of the fluid flow path, the hole geometry (shape), the effect of injecting high viscous fluid and finally the effect of Burr and Cement on the magnitude of the Cd magnitude for the perforated holes.
We developed a simple setup to deduce Cd values from perforations which were created in API19B Section II or Section IV test vessel. The values were measured for different pressure differentials, back-pressures and flow rates. The results show that the above-mentioned parameters directly affect the Cd value and subsequently the near wellbore pressure loss near the perforated hole. The values measured for real perforation holes differ significantly from simple drilled bores. Burrs on the inside and outside of the casing effect the magnitude as well as the length of the flow path.
Our new data sheds new light on the benefit of accurate measurements of Cd values for every shaped charge which helps to efficiently design the hydraulic fracturing stimulation treatment for oil and gas well.
Conventional and Eco-Friendly Hydraulic Fracturing Fluid Additives: A Review
Authors: Al-Hameedi Abo Taleb , Alkinani Husam H. , Dunn-Norman Shari , Trevino Hector A. , Al-Alwani Mustafa A. 
Published: January 2020

Abstract
The purpose of this paper is to create a starting point for research into using friendly and biodegradable waste material as supportive items for hydraulic fracturing fluids and additives. Conventional fluids and additives, although they can be effective, they pose serious threats to work personnel and public health and to the environment. Conventional fluids and additives can also be very costly. These risks and concerns should drive the oil and gas industry to pursue alternative options, safer and cheaper options, from conventional fracturing fluids and additives. Some waste materials provide this opportunity. It is apparent through many forms of research that waste materials are readily available globally making it easy and cheap to obtain. A driving force for this research was research previously done on finding alternative additives for drilling fluids. Researchers have proven that some of the waste materials, such as food waste, grass waste, palm tree waste, among many others, can and should replace or at least boost conventional drilling fluids and additives through a series of experiments and tests. Not only are these materials easier and cheaper to obtain, but they are also efficient and safer for both the environment and people. The same could be said for alternative hydraulic fracturing fluids and additives if proper research is done. The strides made in finding alternatives for drilling fluid additives have pushed the revolutionizing of the oil and gas industry, acting as a catalyst for the research into alternative hydraulic fracturing fluids and additives. In this work, a more thorough investigation into conventional fracturing fluids and their downfalls regarding price and health and environmental concerns are illustrated as well as the function of the main fracturing fluids; water fracs, linear gels, crosslinked gels, oil-based fluids, and foam/poly-emulsions. Throughout this paper, it becomes apparent that the oil and gas industry should attempt replacing or decreasing conventional fracturing fluids additives because of the negative influences they have on profit, people's health and safety, and the environment.
Pulsed Power Plasma to Enhance Near Wellbore Permeability and Improve Well Performance
Authors: Rezaei Ali , Siddiqui Fahd , Callen Nicole , Gordon Peter , House Waylon , Soliman Mohamed 
Published: January 2020

Abstract
Unconventional reservoirs suffer from an ultra-low permeability, causing their drainage area to be limited to tens of feet. An efficient technique that can be used in combination with conventional hydraulic fracturing to increase the drainage area is pulse power plasma. In this study, we used an experimental approach to study the effect of pulsed power plasma discharge on the permeability change around wellbore under tri-axial confining stress conditions.
We designed and used equipment, allowing for the generation of the shock wave in a true tri-axial cell to perform the analysis in this study. The equipment has a capacity for rock samples of 14 in on each edge with 1.5 in diameter well in the center. Using the equipment, the stored electrical energy in capacitors is instantaneously released into a fusible link creating a thermite reaction, which creates a shock wave in the wellbore and is transmitted to the rock afterward. The shock wave affects the permeability of samples, even in situations where the generated stress loading is below rock strength.
Several types of material, such as limestone, sandstone, and concrete are tested in this study. Samples were investigated before and after the electrohydraulic discharge to find the extent and magnitude of the induced fractures (permeability enhancement) and their relationship with the released energy. Also, the effect of repetitive low-magnitude shock waves for creating micro-cracks in rock is studied. It is observed that even under sub-critical loading conditions, micro-cracks are generated in the rock samples that might be a result of the main shockwave or reflection of the stress wave from the boundary. These fractures were less controlled by the stress orientation as compared with hydraulic fractures. However, they contributed to the permeability enhancement around the wellbore that can be up to orders in magnitude. Finally, the optimum discharge energy for the maximum permeability enhancement is suggested.
In this study, for the first time, we tested the rock under confining stresses and imaged them using computer tomography (CT) scanning. Also, change of permeability around the wellbore using pulse power plasma is a novel use of pulse fracturing technology that can effectively be mixed with hydraulic fracturing treatment in unconventional reservoirs and maximize the stimulated reservoir volume (SRV). The results of this paper can help to maximize the EUR from the reservoir.
A Data Analytics Framework for Cored Fracture Imaging and Novel Characterization Workflow - Application on Samples from Hydraulic Fracturing Test Site HFTS in the Midland Basin
Authors: Maity Debotyam , Ciezobka Jordan 
Published: January 2020

Abstract
In this paper, we introduce a novel fracture imaging method which uses high resolution 3D laser scanning to develop detailed surface maps of the core fracture faces. The digital maps are then used to analyze fracture surface characteristics wherein observed variations provide us with meaningful insights into the fractures. We share a mathematical approach for roughness evaluation to identify morphological properties for individual fractures within rock samples. The approach is tested on core extracted at the Hydraulic Fracturing Test Site (HFTS - 1) in the Permian Basin. We characterize the roughness variations with depth across the cored section. In addition, we compare results obtained previously from core sampling and analysis to demonstrate that proppant entrapment observed within the cored interval is strongly correlated with the changes in fracture morphology. We also use calculated roughness along with the the changing behavior of roughness radially away from the center of fracture faces to predict roughness "types" such as propagational features or textural roughness characteristics.
Based on the specific fracture characterization work shared here as well as other potential uses, our paper highlights significant advantages such scanning and digital imaging of fractures may have over traditional cataloging using photographic imaging. Furthermore, as demonstrated in this study, data sampled from these detailed maps can be used to further characterize and analyze these features in a more systematic and robust manner when compared with the more traditional geological analysis of cores.
Determination of Stimulated Reservoir Volume SRV During Fracturing: A Data-Driven Approach to Improve Field Operations
Authors: Rahman Mohammad , Sankaran Sathish , Sankaran Sathish , Molinari Diego , Ben Yuxing 
Published: January 2020

Abstract
The commerciality of unconventional field development depends on generating highly productive stimulated reservoir volumes (SRV) in an economical manner, but there is no reliable method to estimate SRV consistently during or immediately after fracturing operations. The SRV achieved during fracturing can be inferred through multiple techniques, including production data analysis, modeling (analytical or numerical, including various treatments of geomechanics), and/or microseismic monitoring, all of which have several limitations. Using production data, we need at least several months of well production history to establish a pseudo-boundary dominated flow regime. Additionally, the production-derived total SRV is a composite of all the stages lumped together, as it is difficult to evaluate the performance of individual fracture stages due to the reservoir heterogeneity. Furthermore, production rates are measured as a total aggregate for all the fractures, while production contributions from each stage cannot be obtained pragmatically for most wells. Full physics modeling, besides being time-consuming and requiring specialized expertise, requires proper reservoir characterization including geomechanical parameters and calibration, which are not routinely captured for most wells, and even when they are acquired, they are difficult to measure accurately. Microseismic, though informative, doesn't indicate actual SRV, and often it is only available for a small percentage of the wells. It is desirable to have a scalable method to estimate SRV evolution consistently during injection using commonly available fracture treatment data for all wells, and it should be practically applicable in a typical unconventional field.
A novel asymptotic analysis of the diffusivity equation has been proposed by other researchers like Datta-Gupta et al. (2011), Yang et al. (2015), and King et al. (2016) to estimate the production drainage volume in unconventional reservoirs based on diffusive time of flight (DTOF). We have extended this methodology to estimate injection SRV (iSRV) quickly from routinely collected fracture treatment data after each stage has been pumped. Further, we have benchmarked stage-wise stimulated reservoir volumes to other available production performance measures or aggregated stage volumes with total well production drainage volume.
Understanding the Role of Well Sequencing in Managing Reservoir Stress Response in the Permian: Implications for Child-Well Completions Using High-Resolution Microseismic Analysis
Authors: Chittenden Hannah , Cannon Dave , Jeziorski Katie , Bowman-Young Sheri , Smith-Boughner Lindsay 
Published: January 2020

Abstract
In this case study, three sequential well pads were designed, stimulated and monitored to evaluate 1. Treatment order of stacked wells across multiple benches, 2. Completions optimization in proximity to a parent well and 3. The efficacy of treatment sequence in proximity to parent wells. Microseismic data were evaluated in conjunction with tracer and pressure data to provide a more detailed understanding of reservoir deformation and well connectivity using statistical approaches that consider the collective behavior of seismicity. High-resolution microseismic involves analyzing spatio-temporal trends in seismicity rather than reliance on microseismic event clouds to provide more meaningful assessment of hydraulically-linked seismicity vs. stress-driven seismicity. The findings of the first two case studies were applied to the stimulation of the third well pad to demonstrate the role of well sequencing in proximity to depleted zones and the impacts of completions design in managing well communication. Here we discuss the benefit of high-resolution microseismic in assessing perceived well interference by delineating the difference between hydraulically-linked and stress-driven seismicity recorded during multi-well hydraulic fracturing programs. In applying knowledge of reservoir deformation processes to customize stimulation programs, operators have additional tools to help manage reservoir stress, limit unwanted well communication and optimize production.
Experimental Study of Proppant Transport in Complex Fractures with Horizontal Bedding Planes for Slickwater Fracturing
Authors: Chun Troy , Zhu Dawei , Zhang Zhuo , Mao Shaowen , Wu Kan 
Published: January 2020

Summary
The use of hydraulic fracturing has taken off over the past decade, and the importance of efficient proppant placement in fractures has increased accordingly. Connection with weak-formation bedding planes brings about distinctive fracture propagation and development. This might hinder hydraulic fractures from extending in a vertical direction, yet they might instead propagate in a horizontal direction after the existing bedding planes. The bedding plane introduces additional hydrocarbon flow path during the recovery process. This naturally leads to proppants traveling in the horizontal section of the fractures. Optimal proppant delivery and conductivity in bedding planes directly relate with effective fracture height and well performance. This paper focuses on understanding horizontal movement and delivery of proppants and their distribution in vertical and horizontal fractures on the basis of experimental work.
The size of proppants is one of the key determining parameters when calculating uplift and settling velocity. They travel farther into the fracture because they settle slower with less gravitational effect. Fine mesh is highly recommended to effectively deliver proppant to the horizontal bedding plane. Large proppants have to rely on the critical bed height to move into the bedding plane sitting on top of the vertical fracture. A higher injection rate promoted bedding-plane proppant delivery in the inverted T-shape case because it opened up a longer and larger area for particles to settle. Excessively strong turbulent flow generated by two inlet cases prevented proppants from settling and seeping into the bedding plane. Continuous mixing and agitation disturb proppants from settling. They limited additional coverage area expansion in the bedding plane. Moreover, inlet design shows little effect in the T-shape, yet having more injection points improves proppant placement in the bedding plane. Direct injection to the bedding plane surprisingly did not affect much in the T-shape case. Overall, only a small percentage of proppant can travel into the bedding plane for both T-shape and inverted T-shape-fracture geometries.