bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Study of Low Cost & Effective Volume Fracturing Technology for Wells in Normal Pressure Shale Gas Play in China
Authors: Bian Xiaobing , Ding Shidong , Jiang Tingxue , Xiao Bo , Su Yuan , Li Shuangming , Wei Ran , Wang Haitao , Du Tao 
Published: January 2020

Relatively, the gas production is low for fractured horizontal wells in normal pressure shale gas plays with a quick production decrease, resulting in larger difficulty for commercial breakthrough and economic development. Accordingly fracturing technology is under study urgently.
On condition that production increased and engineering cost decreased, together with feasible and practical fracturing technology, the production potential is studied to put forward several hydraulic fracturing treatment. Firstly, cluster spacing is decreased, while increasing cluster number per stage, thus, there are more total clusters for one well with less stages, the influence of induced stress could be strengthened especially using plane perforation. Secondly, using high viscosity gel as pre fluid or flushing fluid among injecting period, to extend fracture through layers vertically. Thirdly, by use of ultra-low density small mesh proppant, increasing net pressure sharply by plugging the front of fracture. Fourthly, increasing ratio of lower viscosity slick water, small mesh proppant and higher viscosity gel, to improve hydraulic fracturing pumping pattern and technological parameter by varying viscosity, varying displacement, varying mesh proppant, so multiscale fracture propagate and propped with corresponding size of proppant. Fifthly, deminishing lower effective and non-effective clusters through studying geological and engineering sweetness.
Aiming at production increased and engineering cost decreased, the production potential is studied to put forward several hydraulic fracturing treatment, which is feasible and practical. Good result was observed in pilot application of D well and L well, providing theoretical support for developing effectively and economically in similar shale gas play.
The Application of a Fiberglass Liner in Well Tubing as Cost Effective Material Option in High Velocity Production Wells
Authors: Repetto Carmen , Gorini Simone , Nutricato Giacomo Andrea , Torri Lucia , Cavassi Paolo , Zucchetto Maria Ornella , Guglielmo Carmelo , Piccolo Aureliano , McIntosh Neil , Balistrieri Roberto 
Published: January 2020

This paper describes Eni's experience in the application of a Fibreglass liner used as a corrosion barrier in well tubing and the tests performed in high erosion conditions.
Liner is made of a Glassfibre Reinforced Epoxy (GRE) resin, inserted in Carbon Steel tubing used in both oil production and water injection wells.
Following many successful experiences in these applications, Eni decided to look at what additional requirements would be needed to prove GRE as an alternative material to high grade Corrosion Resistant Alloys (CRA's) for installation in high velocity gas wells.
The GRE liner was selected as cost effective alternative to high alloyed materials starting from 2005, where GRE was successful in reducing onshore workover costs and extending the life of Carbon Steel tubing in oil producer wells with high CO2 and water cut, to the more recent installation offshore Norway in Water Injection wells where due to high corrosiveness of the injection fluid.
The paper will summarise the testing and the appalication range of GRE in corrosive CO2 and H2S environments and also, through collaboration with Milan Polytechnic, the high flow direct impact erosional testing, utilising a continuous flow loop and nozzle directed solids impingement testing system. Various impinging angles, times and velocities were used during the testing. The results showed GRE to have a good resistance to the solid particles erosion in comparison to the similar tests carried out on Inconel Nickel Alloy material and confirms the potential use of GRE as a corrosion resistance material when combined with Carbon Steel tubulars and alternative to high CRA materials in producer wells.
Together with economic evaluations, the paper presents the characteristics of the GRE technology, the acceptable range of field conditions and will highlight feedback for the sites it has been applied.
Greenfields Production Facilities Optimization Using a Transient Multiphase Flow Simulator
Authors: Al-Qasim Abdulaziz , Al-Mudairis Fahad , Alsubhi Mutaz 
Published: January 2020

This paper discusses a method for optimizing production facilities design for onshore/offshore wells during new field development. Optimizing the development of new oil and gas fields necessitates the use of accurate predication techniques to minimize uncertainties associated with day-to-day operational challenges related to wells, pipelines and surface facilities. It involves the use of a transient multiphase flow simulator (TMFS) for designing new oil and gas production systems to determine the feasibility of its economic development.
A synthetic offshore oil field that covers a wide range of subsurface and surface facility data is considered in this paper. 32 wells and two reservoirs are considered to evaluate the effect of varying sizes of tubing, wellhead choke, flowline, riser, and transport line. A detailed investigation of the scenario of emergency shutdowns to study its effect on the system is performed using TMFS. Other scenarios are also evaluated such as startup, depressurization, pigging, wax deposition, and hydrate formation.
This paper provides a method to minimize the cost by selecting the optimum pipelines sizes and diameters, and investigating the requirements of insulation, risk of pipeline corrosions and other related flow assurance parameters. Different facility design scenarios are considered using TMFS tool to achieve operational flexibility and eliminate associated risks. Pressure and temperature conditions are evaluated under several parametric scenarios to determine the best dimensions of the production system. This paper will also provide insight into factors affecting the flow assurance of oil and gas reservoirs.
Acid Fracture Conductivity Testing on the Tight Carbonate Ratawi Limestone in the Partitioned Zone
Authors: Naik Sarvesh , Dean Mark , McDuff Darren , Ranson Andrew , Jin Xiao , Zhu Ding , Hill Alfred Dan 
Published: January 2020

Saudi Arabian Chevron (SAC) partnered with the Texas A&M University Petroleum Engineering Department and Reservoir Productivity Geomechanics Team of Chevron's Energy Technology Center (ETC) to perform acid fracturing conductivity tests on the Ratawi Limestone core samples. These tests were also performed on an analog limestone from an onshore USA field and Indiana Limestone samples for comparison with the results from the Ratawi Limestone samples. This paper shows the results of the acid fracture conductivity tests using various acid treatment systems on three different limestone formations and compares the acid etching and conductivity responses between homogeneous and heterogeneous mineralogy.
The success of acid fracturing treatment depends on the creation and sustainability of fracture conductivity under reservoir conditions. The fracture conductivity depends on the reservoir rock & acid reactivity, acid-etched pattern, closure stress on the fracture face and the pore pressure depletion.
Laboratory testing shows that acid fracturing is a viable option for large-scale development of the Ratawi Limestone. Its heterogeneous mineralogy plays an important role for sustaining the fracture conductivity after acid injection. Composed primarily of calcite and dolomite, limestone dissolves positively in acid. However, the insoluble minerals, such as the clay streaks with higher mechanical properties, acted as pillars to partially prop the fractures open as closure stress was applied. Essentially, the heterogeneous mineralogy of this formation assists with sustaining fracture conductivity as the reservoir pressure depletes.
New Environmentally Friendly Solution for Iron Scale Removal
Authors: Gamal Hany , Abdelgawad Khaled , Elkatatny Salaheldin 
Published: January 2020

Iron sulfide scale is considered a big issue in the oil and gas industry and a very common problem in daily operation bases. The iron scale severely affects the production rates and field operation, as the iron scale precipitation on the well completion tools or the pipelines` inner surfaces will decrease the diameter size and cause flow restriction. Failure of the downhole completions tools will decrease the well production and it might require workover operations to cure the problem. Such workover operations add an extra cost. In addition, the iron scale is a big problem for the petroleum reservoirs as it changes the rock wettability from water-wet to oil-wet. Many studies and researches were performed to find an economical and efficient removal for the iron sulfide scale. The main objective of this study is to find a new environmentally chemical solution to be used for iron sulfide scale removal. Additionally, to study the new fluid performance in terms of solubility for an iron scale (field sample), corrosion effect, and biodegradability for environmentally safe use.
Lab solubility tests had been done at different times and concentrations to get the optimum time and concentration that provides the optimum iron scale solubility rate. Corrosion tests were performed to determine the corrosion rates for the new chemical and the results were compared with other commercial chemicals for iron scale removal.
The results from the study showed excellent performance for the scale solubility and for the corrosion rates. The iron scale solubility showed 82 % after 6 hours at 125°C for the static condition. In addition, the solubility rates ranged from 77% after 2 hours to 81% after 24 hours along the 24 hours of different time steps. The corrosion rate is 0.04 lb/ft2 which is considered a small rate compared to other used commercial fluids. The research outcomes provide an efficient chemical for iron scale removal that is environmentally safe to be used in the oil and gas fields. The new environmentally friendly acid system NEFAS provides very good performance for iron scale removal, with a lower cost than commercial chemicals. Furthermore, the new system is a biodegradable and environmentally safe system.
Designing Networks with and for Petrophysicists: Automated Grain Size Prediction from Microresistivity Logs
Authors: Basier Florian , McLean Kim , Pelling Richard 
Published: January 2020

Image logs such as Microresistivity give the interpreter an indication of bedding patterns and depositional environments. This allows him, after correlation with an analysis of selected curve shapes (SP, GR) to interpret the grain size along the well. Both image analysis (from image logs) and data aggregation are areas where Deep Neural Networks have proven efficient, but their accuracy in the field of grain size prediction is still limited, hence not useful yet for an interpreter. Since relevant and complete log data is usually only available on small intervals, networks are overly trained on hand-picked well sections, while ultimately predicting a softmax-activated vector of all grain size "probabilities".
Working with data from deepwater wells off the Gulf of Mexico, we have been able to account for uncertainties and scattering in the training data to produce a set of single-tasked, multi-input, multi-output classification CNNs. Combined, these networks produced more accurate results than their multi-category counterparts, with accuracy over 87% on test wells. Using the computed metrics (recall, precision) of these single networks, a confidence curve of the overall algorithm is produced, highlighting high-confidence high-accuracy areas (85% of test wells), as well as areas where human interpretation is required.
This approach combines Machine Learning prediction and uncertainty analysis to reshape, using deterministic methods, the "black box" predictions of the Neural Network. This provides a methodology which is more accurate than conventional Machine Learning, while also being aware of its own inaccuracies and highlighting them. It uses complex network architectures and data ingestion mechanisms, designed to generate results that can be exploited by a petrophysicist in charge of log interpretation.
Blockchain Applications in Midstream Oil and Gas Industry
Authors: Kadry Heba 
Published: January 2020

Blockchain is believed to be a foundational technology that will create foundations in the economic and financial systems in a way that will revolutionize the business models and the organizational structures. Blockchain has opened a series of possibilities for blockchain-based innovative applications that are extended to midstream Oil and Gas industry.
In the era of the digital revolution, the need for an advanced information and communication technology has become crucial in midstream oil and gas industry to be able support increased challenges of decarbonization, decentralization, digitalization, and security. Blockchain is proposed to be an integrated platform through a series of different applications, such as, metering, billing, carbon trading, security, supply chain management, and performance-based contracts. The opportunities and impacts of utilizing blockchain-based applications will be demonstrated including economic, environmental, operational and social related benefits. Blockchain is disruptive technology, however, the current applications are in early development phase. Key improvement areas have to be assessed to reach the desired levels of scalability, decentralization and security. The paper concludes that this technology has significant potential to enhance the efficiency and maximize the profit that needs further digging from both research and industry. This work provides an overview of the blockchain technology and working principles. It describes the novelty and innovation that blockchains brings to industry, especially when combined with smart contracts. Also, the paper explores blockchain potential for the midstream oil and gas industry and investigates the state-of-the-art current business cases. To the best of our knowledge, this is one of the earliest works to explore blockchain-based applications in midstream oil and gas industry.
Combining 1C & 3C Sensors: An Evolution in Passive LFS Low Frequency Seismic Exploration
Authors: Al Jadani Mohammad , Birialtcev Evgenii , Ryzhov Vasilii , Feofilov Sergey , Mokshin Evgenii 
Published: January 2020

Passive low frequency seismic exploration is a technology for specifying the geological attributes of the earth's interior. Known examples of its application for tasks, for example, determining of the contour of hydrocarbon deposits (direct hydrocarbon indicator DHI) [2, 4, 8, 14, 18, 21, 23, 26, 35, 36, 37]. However, most of the results are qualitative.
In this paper, we propose a physic-mathematical method for interpreting this phenomenon, based on the recognized approaches of extracting the Green function from passive observations [27, 45, 46] and methods for solving the partial problem of full-wave inversion [16]. It is known that the correlation function of observations of a random field carries information about the Green function, which is a response to the structure of the geological setting [15]. We additional filter out Rayleigh surface waves and inclined waves using linear prediction algorithms [10].
It is assumed that the properties of the medium are known; it is necessary to determine the location of a small-thickness formation with anomalous absorption. Hydrocarbon deposits with high permeability are recognized with high absorption. Abnormal absorption at low frequencies occurs as a result of friction of the liquid phase of hydrocarbons on the skeleton of the rock during the passage of longitudinal waves [7, 10]. Contrast of anomalous absorptions can cause additional reflections (resonance).
The task is reduced to a one-dimensional partial task of the full-wave inversion, when the base model is generally known, and it is necessary to find individual deviations (oil-saturated reservoirs). A numerical simulation is performed with different possible placements of a search object. Field record spectra, after applying filtering procedures, are matched with synthetic ones. We solve this problem in the Born approximation of single scattering with regularization in the form of restrictions on the coefficients, this problem is solved by quadratic programming. The proposed method has been applied to solve problems of hydrocarbon prospecting [41].
Combining 1C (single component) sensors and 3C (three components) ones is considered as an evolution to solve problems concerning scarcity of passive LFS data due to our long-time reliance on 3C sensors only to collect such valuable data. Quantitative approaches will merge soon!
A Novel, Cost Effective and Easily Scaled Solution for On-Site Treatment of Oily Wastes
Authors: Thomas David , Bireta Paul , McVey Kevin , Segal Daniel , Hudson Matt , Sami Bu-Hulaiyem , Gabriel Sabadell 
Published: January 2020

Treatment and management of oil-impacted wastes (e.g. tank bottoms, clarifier or pit sludge, oil-impacted soils) poses significant technical and financial challenges at exploration and production (E&P) facilities. Often these materials are distant from waste disposal or treatment facilities or are inaccessible to the equipment necessary for treatment. Further, the size of treatment facilities and associated costs may make treatment of these wastes unviable.
Heated Overland Thermal Treatment Pad (Hottpad), is a novel, cost-effective and easily scaled solution for oil impacted wastes at E&P sites that has been developed and field demonstrated. Hottpad consists of a metal pad with metal or dirt-bermed walls, which is then covered with oily waste material or oil-impacted soil for subsequent treatment via smouldering combustion. Since initial deployment in 2016, the technology has been further improved and refined to target two applications of interest; i) small, portable systems designed for treatment of stranded wastes and ii) centralized, bespoke scale treatment facilities. Both systems are designed for on-site treatment with conversion of wastes to materials suitable for reuse.
The current Hottpad configuration is the culmination of more than 8 years of collaborative research, technology development, refinement and improvement. Hottpad has been demonstrated to be highly effective at meeting remediation goals, is cost-effective, and is a more sustainable and lower risk alternative to the traditional means of treatment that rely on off-site transport of impacted materials.
Productivity Evaluation of Radial Multi-Branch Horizontal Well in Unconventional Gas Reservoirs Considering Permeability Variation: Model Establishment and Sensitivity Analyses
Authors: Shi Juntai , Fang Yexin , Wu Jiayi , Sun Zheng , Tang Jizhou , Li Qian , Chen Zan , Lu Jiaguo , Ke Wenqi , Jia Yanran , Wang Yabing , Lu Wenming 
Published: January 2020

The low permeability of unconventional gas reservoir makes it difficult to achieve good development effect. Hydraulic fracturing technology and multi-lateral well technology are usually adopted to increase the gas production. What's more, the permeability may change dynamically during the production process because of the effective stress, gas slippage and matrix shrinkage effect.
In this paper, we first establish the productivity equation of radial multi-branch horizontal (RMBH) well in unconventional natural gas reservoirs, considering the dynamic change of permeability during the production process. Then, the productivity equation of radial horizontal well with 2 branches is compared with fractured vertical well and conventional horizontal well productivity equations proposed by former researchers. Finally, main factors influencing the productivity of unconventional natural gas RMBH well are analyzed, including well structure parameters, gas formation properties and production stage.
Results show that the productivity equation of degenerated RMBH well with 2 branches is proven to be reasonable by comparison with those of vertically fractured well and horizontal well. RMBH well shows more advantage in the formation with relatively large difference between maximum and minimum stresses, indicating that this type of well configuration may be an alternative technique for improving gas production in unconventional gas reservoirs. Sensitivity analyses demonstrate that the gas production rate of RMBH well is sensitive to branch length, branch number, build-up section horizontal distance, and stress dependence effect. The radial horizontal well with 4 branches can achieve a best development effect and economical benefit.
Delayed Oil Swell Packer for Openhole Zonal Isolation of Long Laterals Wells
Authors: Sadana Anil , Kovalchuk Anton , Cook Christopher 
Published: January 2020

Swellable elastomer packers are the preferred choice for openhole zonal isolation for many applications due to their cost-effective and interventionless deployment. For drilling long laterals, customers prefer to drill in oil-based muds (OBM) because the OBM acts as a lubricant and helps deeper and faster drilling.
The swell packers are deployed in OBMs up to total depths (TD) of 36,000ft and require sufficient time to run liner to bottom, pull out of hole with running string, and run a displacement string to total depth (TD) to displace the OBM mud to a completion brine and breaker prior to the swell packer contacting the 8.5-in. open hole. Thereafter, upon exposure to produced or injected fluid, the packer must hold pressure to a wash out an openhole diameter of 9 in. &gt; 1,000psi. Commercial oil swell packers meet the differential pressure requirements, however, their fast swell rate, especially in high-temperature applications, presents a significant challenge in getting these packers to the required depth/distance.
In this paper we report the development and testing of 11-day delay oil swell packers to compartmentalize an 8.5-in. openhole, seal a 9.25-in. washout zone, and hold a minimum differential pressure of 1000psi at 220° F. Swell delay was conducted on 20-in. × 8.15-in. OD donuts (dunk packers) on a base pipe 6.625-in. OD in oil-based mud (NAF) at 200 to 207° F. Pressure testing was performed as per API190H standard on packers (4 ft × 8.15 in. and 5.5 ft × 8.15 in.) on a 6.625-in. base pipe that was pressure tested at 225° F by applying pressure from top and bottom annulus. These packers held a steady differential pressure of 1100 to 1300 psi for 30 minutes.
This development enhances the ability to reliably compartmentalize larger open holes with potential washout sections by using a delayed swell oil packer.