bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavily Compartmentalized Reservoir: From Structural Synthesis to Optimum Development Plan
Authors: Salahuddin Andi A. , Al Naqbi Sheikha , Syofyan Syofvas , Yousef Alklih Mohamad , Al Hammadi Khaled E 
Published: November 2018

Abstract
Reservoir compartmentalization, either structural, stratigraphic, or combination, is one of key parameters for accurately characterizing the hydrocarbons distribution in the subsurface and it is an important component for optimizing hydrocarbon recovery. In order to accurately characterize its compartmentalization, structural synthesis has been applied for generating a representative structural configuration of the complex and highly faulted reservoirs of the studied field. This paper demonstrates detail structural synthesis of a Cretaceous Middle-Eastern carbonate reservoir. The studied field exhibits multiple fault blocks with different fluid composition and contacts variation. Log analysis and test results from a number of wells suggested oil rim with significant gas cap and water leg. Exploiting the oil and gas in highly faulted reservoir possesses a major challenge hence the optimum strategy of development plan was created.
Multi-tectonics history of the Arabia in the region is demonstrated by both folding and brittle deformation represented by fault system comprising en echelon faults and joint sets. The most dominant faults are N75W and N45W trending strike slip fault systems. Kinematic analysis, outcrop analogue, and nearby field analogue revealed that the two fault systems have been developed by different tectonic events. The N75W trending faults have been developed as tensile fracture shortly prior to folding when SHmax azimuth was approximately oriented 120o azimuth. The N45W trending faults have been developed at a later stage possible as splay faults by branching from the pre-existing N75W when the SHmax trend was oriented approximately 90°.
The N45W fault arrays show partitioning of displacement between the various splays, with relatively abrupt changes in the displacement at branchlines. Long ‘single faults’ are frequently shown to be segmented into en-echelon arrays. This expression defines a model of fault growth by radial propagation and linkage from a single seed fault as indicated from geometrical and kinematic evidence. Antithetic N45W fault exhibit a downward decrease in displacement towards a tip line near the N75W master fault. This suggests that the N45W faults were initially developed as Riedel shears which then propagated and linked to the pre-existing N75W system as splay faults. This has occurred by a continuous counterclockwise rotation of the causative SHmax stress from Cretaceous to present.
Quantification of the orientations, segmentation, and offset magnitudes provided a foundation for defining their implications for fluid charging, fluid flow, and pressure development within the reservoir. Thus several development scenarios were constructed in order to maintain the pressure and production rate, considering various combinations of horizontal producers and injectors, number of wells, well orientation, horizontal length, and depletion schemes.
Downhole Fluids Characterization in Middle East Unconventional Reservoirs Using NMR 2D Maps
Authors: Vican Kresimir , Jambunathan Venkat , Negm Ehab , Makarychev Gennady , Van Laer Pierre , Zeeshan Baig Muhammad 
Published: November 2018

Abstract
Unconventional and conventional reservoirs do not have much in common. They exhibit different reservoir characteristics; therefore, using conventional reservoir interpretation techniques and workflows in unconventional reservoirs could lead to incorrect conclusions.
In addition to fundamental challenges in evaluating reservoir properties, such as porosity and permeability, it is extremely important to understand reservoir fluid distribution. Downhole fluid typing and calculated volumes, together with porosity and permeability, provide more insight into reservoir potential and sweet spot zones.
Nuclear magnetic resonance (NMR) technology can be used to provide answers to some of the unknowns mentioned previously. Standard NMR measurements provide the lithology-independent porosity and permeability, and then further processing provides more details about partial porosities, volumes, and fluid types occupying the pores. Using two-dimensional maps (2D NMR) helps differentiate the reservoir fluids, especially when distinguishing hydrocarbons (HC) from water. In conventional reservoirs, it is expected to observe faster relaxation for fluid trapped in the smaller pores and longer relaxation for free fluids in the bigger pores. Industry-accepted cutoffs for T1 and T2 measurements help estimate micro, meso, and macro pores. However, for unconventional reservoirs, fluid identification using 2D maps would be different. Fluids in the small pores, such as bitumen, heavy oils, or HCs in source rock reservoir, would have a similar signature on 2D maps.
This paper presents two case studies showing how 2D NMR application was used in an unconventional reservoir for fluid typing processes and HC volumes calculation. It also shows the importance of using this method for more precise planning of further downhole activities. Core data analysis and downhole collected fluid laboratory analysis confirmed the high confidence in NMR fluid typing applications for unconventional reservoirs.
A Novel Holistic Workflow for Field Development Planning in Green Field Environment: A Case Study
Authors: Alkhatib Mohamad , Al Ali Abdulla Ali , Mukhtar Muhammad , Park Sangseok , Ghorayeb Kassem , Nasiri Amir , Shah Abdur Rahman , Ojha Aditya 
Published: November 2018

Abstract
A novel workflow was developed to select the optimal field development plan (FDP) accounting for the associated uncertainties in a green onshore oil field with a limited number of wells and no production data. The FDP was then revisited in view of the performance of wells drilled during the execution phase and updated as needed based on the acquired data .
Comprehensive uncertainty analysis was performed resulting in multiple subsurface realizations. A broad set of development scenarios and options were screened under uncertainty. The viable scenarios were then economically evaluated, resulting in an optimal FDP that is robust to uncertainty and the least risk prone from an economical point of view.
The used workflow was specifically suitable to test many development concepts and explore various options including horizontal well orientation, well pattern concept, pattern acreage and spacing, length of the horizontal sections, and landing of the horizontal sections.
Following an extensive techno-economic analysis of all possible combinations (900 in total), the most robust development concept was selected and analyzed considering the viable development strategies pertaining to plateau rate, drilling schedule, phasing, water injection timing and artificial lift timings.
A phased development approach was adopted enabling acquiring necessary data to mitigate the remaining uncertainty and avoid costly consequences of significant over- or under-capacity. Data acquired in one development phase were assessed and used to update the following planned phases, if necessary.
The study demonstrated that the field development could accommodate a delay in either water injection or artificial lift implementation. Although it was not recommended at this stage to delay either of them, it is noteworthy that the long lead time that may be incurred in the implementation of artificial lift or the risk of lower injectivity would not impact the field performance or ultimate recovery if contained to a few years during initial production. These results further reinforced the robustness of the proposed development plan.
Large subsurface uncertainty combined with an extensive set of possible development scenarios and options required cutting-edge uncertainty analysis and screening workflows to select the optimal FDP. These unique workflows can be readily used in similar green fields to help arrive at the final FDP.
Integrated Petrophysics for Improved Whole-Rock Characterization: A Case Study in Vaca Muerta Formation, Argentina
Authors: Hao Zhang , Nora Alarcon , Julio Arro , Guillermo Crespo , Diego Licitra , Carlos Hernandez 
Published: November 2018

Abstract
The estimation of fluid properties and rock composition is an integral part of formation evaluation. Unconventional resources such as organic-rich shales are geologically complex, due to great variability in rock composition and post-depositional diagenetic processes. In addition, low porosities, such as those usually encountered in unconventional reservoirs, are not well defined from conventional logs due to the large influence of the rock lithological components and high uncertainties of the log measurements. The errors in estimated porosity not only relate to measurement errors, but also to the incomplete knowledge of matrix parameters. Consequently, a reliable method that integrates mineral and fluid petrophysical models is needed to determine the key formation properties in whole-rock characterization.
It is well known that the most important petrophysical parameter obtained from nuclear magnetic resonance (NMR) logging data is a lithology independent porosity. The ill-defined problem in NMR inversion requires proper regularization methods to stabilize the inversion results. The incorporation of conventional logs as penalty constraints in the NMR inversion process can lead to an improved quantification of fluid typing and formation porosity. However, the accuracy of the fluid model is also influenced by the quality of the estimated matrix properties. Geochemical logs based on pulsed neutron technology have been successfully applied to determine elements for identifying lithology and mineralogy. A probabilistic method incorporating geochemical and conventional log measurements can reliably estimate the matrix mineral composition and porosity. However, a good understanding of the fluid properties is also important for accurate results from the mineral model. The fluid and the mineral model complement each other. Consequently the integration of the two models using NMR, geochemical, and conventional logs can provide an improved whole-rock characterization.
In this work, a unified workflow that includes petrophysical relations and rock physics models is proposed. Probabilistic mineralogy inversion using geochemical and conventional logs solves for matrix properties that are used as inputs for the fluid inversion model. Simultaneous inversion using NMR echo trains and conventional logs determines pore fluid composition and formation porosity that are used as fluid parameters to improve the results in the mineral model. By using both inversion models jointly, a set of petrophysical properties that account for all available log measurements can be determined for the whole rock, and the integrated workflow can potentially reduce the uncertainty in the well log interpretation that usually applies a limited set of logs. A field example from an Argentina well in the Vaca Muerta unconventional play is presented and discussed to show the superior interpretation proficiency of the proposed methodology.
Protecting Offshore Pipelines from External Interference: Dropped and Dragged Anchors.
Authors: Bruschi Roberto , Bartolini Lorenzo 
Published: November 2018

Abstract
In congested districts of offshore Oil & Gas Industry, merchant ship traffic, offshore operations or fishing activity may interfere with pipelines in service, which rest exposed on the seabed. Despite the shortcomings of existing technology and knowledge, operators' concerns still emerge after yearly surveys that show new pipe damages from external mechanical interference, not to mention a few ruptures occurred in the last decade due to anchor hooking! Therefore, a question arises: do we know enough about the potential threats to offshore pipelines from external, particularly anchor, interference? The scope of this paper is to outline the rationale of pipeline protection works, both at design stage and in service, with focus on open issues influencing decisions on how and due time to intervene across busy offshore districts. In shallow waters and brown fields, e.g. in the Arabian Gulf and Gulf of Mexico, the consequences, not only economic but also safety wise, of a severe interference, might be relevant. The shallower the water depth and busier the area, the more stringent the safety targets. Sometimes, even having met acceptance criteria, backed by competent engineering modelling and use of state-of-the-art tools, field evidences from early operation may lead to rethink of purpose protection works, to be implemented with minimum impact on field operations. Marine pipeline damage prevention and awareness, from both vessel and field operators, is often a unique way to limit risks and unplanned interruptions.
Acid-Soluble Thixotropic Cement System for Lost Circulation Challenges
Authors: Jadhav Rahul , Patil Sandip 
Published: November 2018

Abstract
Lost circulation is a recurring and costly challenge for the oil and gas industry. Losses range from seepage to total and financial effects, including nonproductive time and remedial operational expenses, which can increase potential risks to the operator. To address this issue, a tunable cement-based lost circulation treatment solution has been developed that is most suitable for partial to total losses, particularly when particulate-based solutions are not effective; the solution is primarily intended to cure losses while drilling. Unlike conventional lost circulation materials (LCMs) that cure losses by mechanical bridging of particles, the thixotropic cement solution's effectiveness arises from its unique chemical composition, which is ideal when flow paths are too large to be plugged by particles.
The new lost circulation treatment solution is thixotropic with a density range of 10 to 15 lbm/gal working in temperatures up to 250°F. The formulation can be mixed with fresh water, seawater, or seawater with up to 14% NaCl. It is designed and tested in accordance with API RP 10B2 (2013) procedures for thickening time (TT), compressive strength, static gel strength, fluid loss, and rheology. During the TT on-off-on test, the formulation builds gel strength when shear is reduced and regains fluidity when shear is reapplied.
The formulation developed rapid static gel strength and an early compressive strength up to 500 psi. The reversible gelation behavior is demonstrated through multiple shear on-off cycles. This solution is operationally convenient to apply because it can be pumped through the bottomhole assembly (BHA), thus reducing trip times. Because of its acid solubility, it can be used across production zones.
The unique properties of gaining rapid gel strength reversibly and a good compressive strength render this solution effective for treating a wide range of lost circulation events during drilling. A wider density window might minimize the potential risk of inflow when treating losses.
Can We Trust the Diversion Pressure as a Decision-Making Tool: Novel Technique Reveals the Truth
Authors: Kabannik Artem , Parkhonyuk Sergey , Korkin Roman , Litvinets Fedor , Dunaeva Anna , Nikolaev Max , Usoltsev Dmitry 
Published: November 2018

Abstract
Traditionally, surface pressure is the primary tool for onsite decision making during well stimulation treatments. In multi-stage wells with multiple injection points (perforation clusters) there are several available methods for diversion efficiency evaluation: differences in pumping pressure caused by pill pumping (also referred to as diversion pressure), instantaneous shut-in pressures (ISIPs) difference, and friction pressure difference. However, these techniques rely on interpretation of friction pressure or net pressure with uncertainties related to indirect measurements of the respective parameters.
A high-frequency pressure monitoring (HFPM) service uses specially designed hardware and proprietary signal processing algorithms to determine the true location of downhole events. Bayesian algorithms are used to calculate probabilities of the interval’s stimulation. Effectiveness and applicability of the method were tested on several wells across major US shale plays. It was demonstrated that the industry standard surface pressure techniques are not always the best approach for the on-site decision making. Even when diversion is not clearly visible, it still may occur downhole. Conversely, a significant diversion pressure response does not necessarily mean adequate diversion. The effective application of the HFPM technique makes engineered decisions more confident during stimulation and diversion operations.
A Novel Hybrid Artificial Intelligence Predictive Multi-Stages Model for Gas Compressors Based on Multi-Factors
Authors: Almadhoun Wael , Alashqar Ameed 
Published: November 2018

Abstract
The objective of this paper is to build a hybrid predictive model for a gas compressor to overcome the operational challenges, optimize maintenance demand and reduce failures risks. This can be achieved by combining a multi layers multi models artificial intelligent techniques to capture all the historical events and improves the model overall accuracy. The time series statistical analytics is commonly used to early predict the potential machine failures or dip in performance in the process industry, by predicting events that occurred in the past and by monitoring the signal trend over time. Recently, other techniques are being used to perform predictive analytics. This includes the use of artificial neural network, the Naïve Bayesian and logistic regressions methods. Statistical time series forecasting methods are categorized in: exponential smoothing methods, autoregressive integrated moving average (ARIMA) methods, regression methods, or recurrent neural network (RNN) methods. Currently, a time series events are typically predicted by statistical methods or by artificial intelligent technique such as artificial neural network (ANN). A Hybrid approach combining more than one technique is applied to overcome the gaps on each method.
The Hybrid model consists of two stages and three models, model 1 and 2 are generalized, and model 3 is detailed. In the first stage, "Model 1" is nonlinear classification model using support vector machine with a Gaussian kernel, it functions as anomaly detection and a machine status classifier. The objective is to build a robust model that can be predictive, deterministic and diagnostic. Therefore, the RNN multivariate signal prediction using long-short term memory (LSTM) is added in parallel as "Model 2". Model 1 and 2 formed the first stage as overall detector. If anomalies are detected, so the algorithm will move to the second stage which consist of individual time series sensor signals. A model for each signal is added as "Model 3" in the second stage as deterministic.
The results of each model show different accuracies that varied from 70% to 96%. But the model overall confidence range is increased. The new hybrid approach provided a better understanding for each event prediction and has minimized the number of misleading alarms.
Real-Time Hydrocarbon Mapping by Time-Lapse Borehole Electric Tomography
Authors: Dell’Aversana Paolo , Servodio Raffaele , Rizzo Enzo , Cappuccio Pasquale , Carniani Carlo 
Published: November 2018

Abstract
Real-time mapping reservoir fluids distribution during hydrocarbon production, or during injection operation, represents a crucial issue and a big challenge at the same time. In this article, we present a new approach based on single-well and cross-well electric measurements. We use electrodes permanently installed on the well casing and electrically insulated from it. We tested our approach through a two-steps workflow. In the first step, we performed forward and inverse modelling on realistic production scenarios. In the second step, we acquired, processed and inverted real data acquired in laboratory, where we tested small-scale scenarios of hydrocarbon production. We acquired and inverted DC (Direct Current) data. Our objective was to reconstruct the variations of the 3D distribution of electric resistivity during the various phases of oil production. The retrieved models reproduced properly the experimental movements of fluids observed in our lab measurements. Finally, modelling and inversion of both synthetic and real data confirm that cross-hole DC method allows mapping reservoir fluid variations even in case of predominant metallic components of the well completion.
Synthesis of Adsorbent Materials by Emulsion Polymerization for Efficient Oil/Water Separation and Hydrocarbons Recovery from Produced Water
Authors: AlGhunaimi Fahd , Alsaeed Duaa , Harith Abdullah , Saleh Tawfik 
Published: November 2018

Abstract
This paper presents a novel/cost-effective hydrophobic material based 9-octadecenoic acid grafted graphene (POG) for oil/water separation. Graphene derived from graphite was modified with 9-octadecenoic acid to obtain 9-octadecenoic acid grafted graphene (OG). Then, emulsion polymerization of styrene was performed on OG to produce polystyrene branches on 9-octadecenoic acid grafted graphene (POG). Three different composites were prepared by varying the amount of 9-octadecenoic acid grafted graphene used as follows: POG25, POG50, and POG75. The three materials were characterized by using N2-physisorption and Fourier transform Infra-red (FTIR). The BET surface area of POG75 was 288 m2/g while POG50 was 225 m2/g and POG25 was 79 m2/g. These materials were evaluated for their oil/water separation efficiency using model mixture. The results showed that the higher the ratio of the 9-octadecenoic acid grafted graphene, the higher the oil removal efficiency of the material and the faster the rate of the adsorption. The materials showed not only high efficiency but also fast uptake of the certain quantity of the oil just within 1 minute. This can be explained by the high hydrophobicity nature of the materials which repel the water as confirmed by the contact angle of approximately 150°. POG75 showed promising results to be a good candidate adsorbent materials for oil removal from produced water where it displays the highest adsorption capability to organic compounds and the highest BET surface area. POG75 was regenerated and its performance was tested again. This material showed a slightly reduced adsorption rate in the first cycle compared to the fresh material. However, the adsorption rate was constant for the next several cycles. POG75 has the potential to be utilized to remove oil contaminants from produced water.