bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydraulic Fracture and Reservoir Characterization for Determining Optimal Well Spacing in the Marcellus Shale
Authors: Pankaj Piyush , Shukla Priyavrat , Kavousi Payam , Carr Timothy 
Published: October 2018

Abstract
Naturally fractured reservoirs such as the Marcellus shale require an integrated reservoir modeling approach to determine well spacing and well-to-well interference. The Marcellus Shale Energy and Environment Laboratory (MSEEL) is a joint project between universities, companies, and government to develop and test new completion technologies and acquire a robust understanding of the Marcellus shale. The study presented in this paper aims to reveal an approach to determine reservoir depletion with time through coupled geological modeling and geomechanical evaluation followed by completion and well performance history matching for a multiwell pad in the Marcellus shale.
The geomechanical model was prepared with interpreted vertical log data. A discrete natural fracture (DFN) model was created and used to determine the complexity of hydraulic fracture geometry simulated through complex fracture models on a two well pad. The microseismic data obtained during the hydraulic fracture simulations served as a constraining parameter for the hydraulic fracture footprint in these wells. Sensitivity to the DFN is realized by parametric variations of DFN properties to achieve a calibrated fracture geometry. Reservoir simulation and history matching the well production data confirmed the subsurface production response to the hydraulic fractures. Well spacing sensitivity was done to reveal the optimum distance that the wells need to be spaced to maximize recovery and number of wells per section.
Hydraulic fracture geometry was found to be a result of the calibration parameters, such as horizontal stress anisotropy, fracturing fluid leakoff, and the DFN. The availability of microseismic data and production history matching through integrated numerical simulation are therefore critical elements to bring unique representation of the subsurface reaction to the injected fracturing fluid. This approach can therefore be consistently applied to evaluate well spacing and interference in time for the subsequent wells completed in the Marcellus. With the current completion design and pumping treatments, the optimal well spacing of 990 ft was determined between the wells in this study. However, wells to be completed in the future need to be modeled due to the heterogeneity in the reservoir properties to ensure that wells are not either underspaced to cause well production interference or overspaced to create upswept hydrocarbon reserves in the formation.
By adopting the key learnings and approach followed in this paper, operators can maximize subsurface understanding and will be able to place their wellbore in a nongeometric pattern based on reservoir heterogeneity to optimize well spacing and improve recovery.
A New Model to Evaluate Polished Rod Load of Sucker Rod Pumping System
Authors: Wang Yanbo , Wang Sai , Yang Lu , Pu Hui , Ling Kegang 
Published: October 2018

Abstract
Sucker rod pumps provide mechanical energy to lift oil from bottom hole to surface when oil wells do not have enough energy to produce the oil through natural flow. It is efficient, simple, easy to be operated, and can be applied to slim holes, multiple completions, and high-temperature and viscous oils. The disadvantages include excessive friction in crooked holes, solid-sensitive problems, low efficiency in gassy wells, limited depth, and bulky volume. The load on the rod is one of the key factors that dictate the maintenance frequency of pumping unit, energy consumed to lift the fluid, and the optimization of pumping system operating parameters.
The cyclic load applied on the rod causes the fatigue and finally the failure of the rod if not designed properly. The rod load is a function of friction force, plunger acceleration/deceleration, weights of plunger, fluid being lifted, and sucker rods string, and the pressures above and below on plunger. Literature review indicates that a model to accurately calculate the load of a pumping cycle is highly desired. In this study, we couple the wellbore with reservoir performance to better analyze the dynamics of pump system, which yields more accurate results.
In this study, force balance during the pumping cycle is analyzed. Friction force due to the movement of the plunger and the rod, buoyant force, and gravity force are included in the modeling. The effects of acceleration and deceleration of the plunger on rod are considered. The sensitivity of pumping speed is investigated. This study proposed a more general model comparing with former researches because more factors that affect the load applying on rod are included. Including the friction force due to the viscous fluid is critical to rod load analysis in pumping heavy oil.
The proposed model is significant to the cyclic fatigue and failure analysis of rod in sucker rod pumping system. It can be used to predict the possible failure point for rod string by analyzing load along the whole string. It is also a useful tool to design the tapered rod string to minimize the maximum rod load while achieving optimum rod string life. Therefore, an optimization of sucker rod pumping system is implemented by balancing the tradeoff between the maximum rod string life (or rod size) and the minimum rod load (or lowest energy consumption).
Integrated Methodology for Laboratory Evaluation of Shale Plays Cuttings
Authors: Carreño P Angelica Maria , Pérez T Maria del , Marfisi Nelbett , Gomez Juan José , Pérez C Edgar Ricardo 
Published: October 2018

Abstract
This current paper is intended to show the implemented methodology for integrated mineralogical, geochemical, petrophysical characterization of Shale Plays from the analysis of well cuttings at the Colombian Petroleum Institute (ICP).
The implemented methodology starts with taking drilling cuttings (Wet Trench samples) during the drilling of exploratory wells in areas of interest for production of Shale Oil & Gas in diferents Colombian basins. Then fragments are selected (picking) with stereoscopic magnifiers. Observed proportions and lithology in the Formation Evaluation Log (FEL) for a given range should be consistent.
Subsequently, the textural and compositional macroscopic description of each sample using Hydrochloric Acid (HCL) to identify carbonates is performed. This description takes into account the degree of effervescence and solid waste analysis. Finally, the percentages of every lithotype present per interval are defined, and this way samples are selected for evaluation.
The evaluation of texture and composition of samples was performed by conventional Petrography of relative abundance of elements by means of Scanning Electron Microscopy (SEM). The mineralogical evaluation of samples is performed by X-ray Diffraction (XRD).
Furthermore, geochemical analysis of TOC and pyrolysis are performed in some fragments of the selected samples. Other tests include: Mercury Injection Capillary Pressure analysis (MICP), helium porosity, nanoindentation technique. These analyzes are made to determine mechanical properties of the rock. The integrated analysis of these techniques provides information to the mineralogical, geochemical and petrophysical characterization of rocks from a shale plays.
This allows defining areas of interest for hydraulic fracturing and production in a UnConventional Reservoirs. The methodology was validated with results obtained from core samples from well Iwana-1 drilled by Ecopetrol in unconventional reservoirs in Middle Magdalena Valley Basin (MMVB). This fact provided competitive advantage to Ecopetrol in exploration and exploitation of Shale Plays. This mineralogical, geochemical and petrophysical characterization laboratory methodology for Shale Plays from well cuttings was used during 2014 at the ICP to characterize 880 ft at El Tablazo Formation in well Casabe K1, 850 ft at La Luna formation in well Golosa 1 and 5,900 ft at Gala 1K at the same formation. This methodology allowed shortening the laboratory analysis time from 120 to 60 days with respect to laboratory tests on a core of 800 ft
Application of The Technique MPD Using Automated Systems for Non-Conventional Wells Drilling with Narrow Operating Window in the Neuquén Basin
Authors: Ruiz Ismael A , Padilla Rivelino A , Pagani Alexis 
Published: October 2018

Abstract
For many years it has conducting the drilling of unconventional wells looking for optimize the operation looking for reduce risks and operational problems, additionally increasing the staff security in the complex operations of the Neuquén Basin. New technologies applied to extremely demanding scenarios contribute to reach these goals, and the MPD technique together with automated pressure control systems are a sample of these applications.
Despite the remarkable progress in the drilling of unconventional wells, through the application of UBD and MPD techniques it is observed that with the use of manual equipment continue to have operational problems, which are often associated to difficulty to maintain a proper annular pressure profile for a very narrow operating window and complex geology, which in most cases is due to human factors added to operating conditions of the equipment. As a result of this improper handling of the pressure profile while drilling or during the control of an influx, there are problems of severe admissions, collapses, trapping and presence of cross flows, generating excessive NPT and in some cases the loss of the well with the associated costs that this entail.
The content of this document will show the results of the drilling operation of horizontal wells in the Fortin De Piedra field, where is drilling by applying the MPD technique with automated systems and will demonstrate the difference with wells where techniques MPD or UBD were used with manual or semi-Automated equipment.
This article is considered of interest to those involved in drilling wells in shale gas areas with complex geology and narrow operating windows, especially Neuquén Basin, particularly for design and drilling engineers wishing to evaluate other technologies to apply to optimize drilling operations.
Lessons Learned from Bacteria Monitoring and Treatment in Marcellus Production Operations
Authors: Weaver Dalton , Densmore Zachary , Evans Paul 
Published: October 2018

Abstract
Significant effort around bacteria monitoring has been a focus since July 2016. Water testing program covers all operating areas including southwestern Pennsylvania and Marshall county, West Virginia.
The program began with most probable number (MPN); otherwise known as serial dilution testing, for sulfate reducing bacteria (SRB) and acid producing bacteria (APB). Based on the water test results, biocide treatments were performed for selected wells from October 2016. More than 300 horizontal wells from Marcellus formation were tested for SRB and APB by third quarter 2017 and biocide treatments were optimized by the end of 2017.
Bacteria DNA testing in the form of next generation sequencing (NGS) and quantitative polymerase chain reaction (qPCR) was performed on selected wells to characterize the microbial consortium present in these samples. Due to the limitations of serial dilution testing and understanding of the bacteria makeup with DNA testing, the program has evolved to utilize fieldwide adenosine triphosphate (ATP) testing and a locked-down biocide treatment procedure. Biocide treatments are prioritized during extended midstream maintenance to minimize downtime and maximize contact time and have shown to be effective for extended durations.
To investigate the root causes of bacteria, data science tools are utilized to look at the effect of the completions design and other variables on bacteria during operation. Variables under consideration include biocide type and concentration, fracturing fluid chemical additives, produced water reuse during completions, produced water chemistry, and geologic variation. Initial findings will be discussed and shared with lessons learned from production operations.
Tailored Fracture Fluid Using Nontraditional Water in Unconventional Reservoirs – Argentina Case History
Authors: Bonapace Juan Carlos , Coronel Maximiliano 
Published: October 2018

Abstract
The unconventional Vaca Muerta (VM) boom in Argentina has led operators to explore other targets, including tight-gas formations and shale oil formations, in different provinces and basins. For these projects, the primary objective was to evaluate the feasibility of using alternative sources of water for hydraulic fracturing. The customization of a fracture fluid with these types of water has had two goals. The first goal is an environmental focus, according to the geographic field locations; the second goal focuses on costs and includes both the reduction of completion costs and the improved profitability for these projects. This paper documents and summarizes three cases in which a tailored fracture fluid was developed using these nontraditional sources of water.
Case histories, including the Austral basin (Magallanes formation, a tight-gas reservoir), Golfo San Jorge basin (Diadema-129 formation, a shale oil reservoir), and Neuquina basin (VM formation, a shale oil in Mendoza province) are presented. The paper describes the scope of work for each project, sources of water evaluated, and laboratory methods applied to evaluate a customized crosslinked fracture fluid to meet the operational requirement. A summary of the total jobs performed and the total water volume used for these nontraditional water sources has been included.
A database was developed to collect the primary information required to formulate these fluids. The data are classified into three data groups. The Completion and Stimulation group provides the base information for this work and includes bottomhole temperature, pumping time, and well configuration. The second group, Water Analysis (physical-chemical), includes valuable information used to identify the deviations from the baseline standard for fresh water. The third group includes a full fluid test that consists of hydration gelling curves, a dynamic rheology test (downhole condition), a stability and break test, and a variable shear rate test.
Several types of fluid were tested for these nontraditional water sources, including a guar-borate fluid and a derivatized guar- (CMHPG) zirconate fluid. To develop a solution that would not economically affect the project, the focus was to evaluate the guar-borate system; a different type of boron crosslinker was tested. Finally, a tailored fracture fluid was developed for each project, using the different boron crosslinker, in accordance with the characteristics of the water sources.
The use of alternative water sources to formulate tailored fracture fluids enabled operators to explore or develop unconventional targets in environmentally sensitive areas. In addition, this type of solution contributes to an improved project economy, which reduces completion costs.
Coiled Tubing String Design in Extended Reach Shale Wells
Authors: Nebiolo Martin , Del Negro Ricardo , Rebasa Nicolás , Grimaldo Carmen , Valdez Martin , Prieto Agustín , Codega Dario , Bark Alejandro 
Published: October 2018

Abstract
Horizontal shale wells’ drilling has been challenging the technical limits since its beginning, and the same challenge was faced in completion phase with the Plug&Perf method. Vaca Muerta shale play in Argentina is not an exception of this. Lateral lengths in Vaca Muerta achieved 800-1000 m in the beginning of its shale operations with horizontal wells, and now they are designed to achieve more than 2500 m, even 3200 m, similar to the major laterals in the main shale plays of USA and Canada.
In Plug&Perf completion method, new materials for fracture plugs and advanced designs of perforating guns were also influenced by the technological advances of the industry.
Coiled Tubing (CT) was not an exception of this trend. CT strings for milling out plugs have been demanded to achieve longer laterals without loosing efficiency, with the required Weight on Bit (WOB).
Two main aspects must be taken into account for CT string design: Lateral reach with enough WOB depends mainly on geometrical aspects (external diameter and combination of different wall thicknesses) in order to minimize the occurance of buckling by decreasing the friction caused by the contact of the string with casing wall.Extended fatigue life
In this way, a new technology in CT manufacture was developed and patented, and introduced by the first time in the market in 2005 (R. Rolovic. M. Valdez et al, 2017). This technology employs materials with a new chemistry, and involves a heat treatment for achieving a complete microstructure transformation and homogeneous properties all along the string. Hence, bias weld, heat affected zone and longitudinal seam weld.
Field performance of this new technology in CT has gone beyond the experience achieved with conventional CT. Furthermore, testing of several strings after being removed from the field have shown a superior residual fatigue life than conventional strings, confirming the stated conclusions and pevious observations.
Optimizing Completion Operations using Latch-Functioned Tools with Full Inside Diameter Stimulation
Authors: Richardson Matt D. , Bolivar Javier 
Published: October 2018

Abstract
As operators continue drilling longer laterals, current completion methods present challenges in maximizing stage counts while maintaining operational efficiency and minimizing operational risk. This paper will discuss recently developed completion systems, the Ultra-High Stage Count and the Latch-and-Perf Systems, and results in addressing completion challenges from field trials.
Some of the inherent risks and challenges associated with the current completion methods include: (i) reaching the toe of long laterals with coiled tubing and wireline for setting, stimulation and millout operations; (ii) maintaining a full inside diameter during stimulation for an effective treatment; (iii) time and cost efficiencies; and (iv) logistics. The pros and cons of multiple completion technologies will be highlighted, including various sliding sleeve completion methods in both openhole and cemented applications, as well as plug-and-perf completions.
Design considerations, bench testing and field trials related to the Ultra-High Stage Count System and the Latch-and-Perf System will be presented. The Ultra-High Stage Count System uses pump down sleeve activation tools that build on the efficiency and cost savings associated with continuous pumping operations, requiring no downtime between stages as a unique latch-functioned sleeve actuation tool is pumped from surface to land and shift a corresponding sliding sleeve in the wellbore. Using full diameter sliding sleeves provides no restriction in the wellbore during treatment, maximizing pump rates. The Latch-and-Perf System also provides a full diameter during stimulation and uses a latch isolation tool deployed on wireline to isolate a stage for perforating and treatment, eliminating the requirement for plug setting and millout operations. Both systems are currently in field trials.
The novel Ultra-High Stage Count System presents a step-change in completion design as it overcomes challenges presented by drilling longer laterals without comprising any of the efficiencies and benefits from today's current completion technologies.
Application of Natural Gas for Foamed Fracturing Fluid in Unconventional Reservoirs
Authors: Pankaj Piyush , Phatak Alhad , Verma Sandeep 
Published: October 2018

Abstract
Foamed fracturing fluids have been used in unconventional reservoirs to reduce the water use and minimize deleterious impact on water-sensitive formations. As part of a Department of Energy (DOE) sponsored program, we previously identified an optimal thermodynamic pathway to transform wellhead natural gas (NG) into pressurized NG suitable for use as the internal phase in a foamed fracturing fluid. This study now aims to extend that work by determining the impact of using NG foam fracturing fluids on hydraulic fracture geometry and on productivity from the unconventional reservoirs.
The current study is focused on investigating the impact of the NG-based foam of various foam qualities in hydraulic fracture geometries and their production through simulation models. Field data and laboratory based measurements for NG foam fluid properties are incorporated in the study. In addition, the transient response of the fluid flowback from foam based fluid is studied using numerical simulation. Comparative analysis is done with typical slickwater, linear gel, and crosslinked fluid application for hydraulic fracturing using 3D-complex hydraulic fracture models. 1D and 2D particle transport models have been used to verify the differences in proppant distribution in the hydraulic fractures.
Rapid wellbore clean-up, low formation damage, and effect of the relative permeability improvement are added advantages apart from reducing the water requirements for hydraulic fracturing. In addition to providing the logistical benefit of using wellsite liberated low pressure gas, NG foamed fracturing fluid has a dynamic fluid leak-off behavior and increased effective viscosity over the base fluid that allows pumping and transporting proppant at least 10% farther in the hydraulic fractures than linear gel. Slickwater displays poor proppant transport and hence poses inability to pump higher concentrations of sand. NG foam fracturing fluid on the other hand displays improved proppant transport and has been shown to create more complexity than slickwater in our simulations.
Use of NG foamed fracturing fluid has not been practiced widely yet. Application of NG Foamin field test and reaping the economic benefit from simplified logistics and improved production would enables operators to invest in creating a safer handling environment for wellsite application of NG foam.
Aggressive or Not? Experimenting with Fracturing Design and Fluids in Pursuit of Better Return
Authors: Nikolaev Max , Zhao Haiyan , Christanti Yenny , Makarychev-Mikhailov Sergey 
Published: October 2018

Abstract
Unconventional plays in the US continue to be the biggest experiment in the history of the oil and gas industry. Particularly in the current market conditions of volatile oil prices, operators continue to introduce methods to maximize the efficiency of their operations. We examined the methods of adopting an aggressive approach to optimizing stimulation design to lower the breakeven level of operations and evaluated the results.
Public data were deciphered in a way they could be interpreted to the level of granularity sufficient to conclude an effect of certain fracturing techniques of different operators and to compare on a similar scale measures that had been taken to improve fracturing design. Various analytical and statistical tools were employed to handle the large amount of data in both unaltered and normalized ways to demonstrate the trends in different US basins.
Operators made significant improvement in production by changing parameters in the fracturing and completion design strategy, including, but not limited to, the amount of water used, the amount of sand pumped, stage spacing, maximum sand concentration, and fracturing fluid selection. However, the challenge remains of determining whether the design is indeed optimum. This paper addresses the importance of aggressive design, its evolution, and enablement technologies.