bluuebunny/crossref_metadata_2025 huggingface dataset:
Foreign Trade of Russia: Barometer Foretells Storm
Authors: Obolenskiy V.
Published: February 2021

The development of Russian foreign trade during the previous five years is analyzed. It is stated that, in terms of value, exports of services and imports of goods and services steadily grew during the first four years of the period under review. Exports of goods also rose during three years, but in 2014 both exports and imports again fell in comparison with the previous year as was the case five years ago. The composition of the Russian exports and imports of goods did not change radically during the previous years. The main items of export are, as always, mineral products, metals and fertilizers. Import is prevailed by foodstuffs, chemicals and heavy engineering equipment. The current situation is featured by the reduction of world oil prices, slump of the domestic economy and war of sanctions with the Western countries. All this substantially impairs the conditions of Russia’s foreign trade activities and inhibits its development in the upcoming years. In the author’s view, the implementation of measures worked out by the government – correction of tariff liabilities before the WTO, redirecting of trade streams from the European to the Asian markets, import substitution and export support – will unlikely improve the situation. Revision of the liabilities before the WTO in the conditions of the decrease of the internal demand and serious devaluation of Ruble is considered as inappropriate and counterproductive. “Asiatic turn” is only capable to compensate to a certain respect the loss of supplies of some food products from Europe, but cannot fully offset the loss of potentialities of the acquisition of modern technologies and equipment from the developed countries. It is doubtful that it will be possible to dramatically cut the import dependence. It is necessary to replace many kinds of foreign goods, but it is impossible to implement a frontal substitution of import in all directions. Excessive stress on the import substitution might lead to the emergence of shortages and poorer availability of some goods at the internal market and, at the worst, to self-isolation and economic autarky. The attempts to build up an effective system of export support might be successful only in the conditions of the establishment of the large-scale production of goods and services which would be comparable with the foreign analogues in respect to the criteria of price and quality. Taking this into consideration the technological renovation of production processes, first of all in the manufacturing industry, and on this basis rising up of the competitiveness of plants and factories are the most important prerequisites for encouraging export activities and formation of the new export specialization of the country.
Russia and China in the Arctic: Real or Alleged Disagreements?
Authors: Zagorskii A.
Published: February 2021

The article concentrates on two issues articulated by Xu Guangmiao in her article “China's Arctic Interests and Policy: History, Legal Ground and Implementation” published in the same issue of the Journal: Arctic Governance (and particularly the applicability of the "Common Heritage of the Mankind in the Arctic" concept), as well as the concept of the Northern Sea Route “internationalization” based on the navigation freedom principle. Both issues are considered controversial in Russia–China relations. In addressing those issues, the author seeks to separate real and alleged divergences between the two countries. He argues that apparent differences in their particular approaches do not reflect any fundamental divergences and can be transcended if handled pragmatically, with recognition of the sovereignty, sovereign rights and jurisdictions of coastal states, as well as of the non-Arctic states' rights and responsibilities under the Law of the Sea. In particular, the author argues that there is no controversy surrounding China’s expectation that an Area of the Common Heritage of the Mankind would occur in the central part of the Arctic Ocean as long as the process of the continental shelf outer limits setting by the coastal states in the Arctic Ocean takes place within the procedures established by the 1982 UN Convention on the Law of the Sea. Similarly, China accepts the regulation of vessels traffic alongside the Northern Sea Route based on the Article 234 of the Convention, and would not be able to claim the freedom of transit passage through the NSR straits unless it joined the U.S. claim that the straight baselines drawn by Russia (and Canada) effectively including those straits into their internal sea waters violate the provisions of the Convention. So far, China does not. And as long as the NSR water area remains ice-covered for most of the year, this issue remains of theoretical rather than of practical importance.
The Frontier of Network Society
Authors: Morozova E. , Miroshnichenko I. , Ryabchenko N.
Published: February 2021

In the article, the authors have integrated the network approach and the Frontier Theory, proving the heuristic potential of such a synthesis in discovering of the network society flexible borders development logic. The conceptual ideas of the Frontier Theory were revealed by the American historian F.J. Turner and his followers, later this approach was borrowed and adopted in other branches of social sciences and humanities. The authors disclose the potential of this theory with regard to the social space, including the network space. In this research, the network frontier is defined as a mobile space border of contact and mutual interpenetration between the network society social/cultural practices and those of previous times. The main stages of its development are justified and described according to several criteria. These are availability and variety of interfaces; specific technological platforms that create conditions for the networks and communities formation; centering of frontier zones around the "gravitational fields" (which are different network leaders and innovative practices in the network structures); the role of a state in implementation of control, regulatory and coordinating functions in the public network space. The researchers have identified and discussed some of the network frontier markers, such as the mobility of network border, specific features of governing system, “abuse of administrative power" and arbitrariness. The frontier demonstrates numerous examples of transgressions, first of all, in the identities formation. The directions of future research are outlined in the article: the network frontier myths and heroes, the evolution of the frontier type of personality in different social spaces, and other. Modern political processes, the growth of the developmental non-linearity and uncertainty actualize the frontier discourse in political studies. Acknowledgements. This article was prepared with fi nancial support provided by the Russian State Humanitarian Foundation (research grant № 15-03-00339 “The Frontier of Network Society as a Space of Political Interaction”).
Kandungan antinutrisi, logam berat dan cemaran biologis tepung buah Sonneratia spp dan Rhizophora mucronata dari populasi hutan mangrove di Kabupaten Kupang
Authors:   Balai Penelitian dan Pengembangan Lingkungan Hidup dan Kehutanan Kupang, E. Koeslulat Ermi
Published: February 2021

Mangrove degradation tend to increase due to excessive human activity such as land conversion, wood extraction for construction and fuel wood and nonmetallic extraction. The utilization of fruit of mangroves-in certain limits- can be an alternative way to convert the destructive utilization into more environmentally friendly one. This study aims to determine three types of flour i.e Sonneratia spp fruit flesh flour (SFFF), Rhizophora mucronata fruit skin flour (RSFF) ; and Rhizophora fruit flesh flour (RFFF). Since the utilization of SFFF is more developed in community than RSFF and RFFF, the SFFF is examined more than the two next. The analysis was conducted at the Laboratory of Center for Agro-Based Industry and Laboratory of Study Center for Biopharmaca, Bogor Agricultural Institute. The examination of SFFF covered antinutrient content (tannin and cyanide acid (HCN)), heavy metal (Pb, Mn, Cu, Hg and As) and biological contaminants (total plate count, Escherichia coli, Bacillus cereus, Salmonella sp, mold and yeast). The examination of RSFF and RFFF covered only tannin as antinutrient and Pb, Mn, Cu, Hg and As as heavy metals. The results showed that SFFF met the SNI Standards for tannin, HCN, Hg, As, E.coli, B. cereus, Salmonella sp, molds and yeasts while the Cu and Mn did not. RSFF and RFFF met the standards for tannin, Hg and As, while Pb, Cu dan Mn content did not. These content may be reduced by increasing the soaking and boiling time.
KINERJA TEORITIS, KINERJA AKTUAL DAN EFESENSI MESIN HUMMER MILL PADA PENGGILINGAN TONGKOL JAGUNG
Authors: Latief Muhammad Fadhlirrahman , Syamsu Jasmal A , Jamila . , Jamilah Jamilah
Published: February 2021

Hammer mill merupakan teknologi penggilingan bahan pakan yang bekerja dengan prinsip tumbukan. Kinerja mesin mempengaruhi dari efesiensi penggilingan. Penelitian ini bertujuan untuk mengetahui kinerja teoritis (KT), Kinerja Aktual (KA), dan efesiensi mesin hammer mill pada penggilingan tongkol jagung. Penelitian menggunakan rancangan acak lengkap (RAL) dengan 4 perlakuan dan 3 ulangan sebagai berikut  P1 (berat tongkol jagung 1 kg), P2 (berat tongkol jagung 2 kg, P3 (berat tongkol jagung 3 kg), dan P4 (berat tongkol jagung 4 kg). Total unit perlakuan yaitu 12 unit percobaan. Parameter yang diukur yaitu KT (kg/menit), KA (kg/menit), efesiensi mesin (%). Hasil penelitian menunjukkan bahwa P4 memiliki perbedaan yang nyata  (P<0,05) dengan nilai KA  0,82 ±  0,07 kg/menit dan 76 ± 0,08 kg/menit. P2 paling efesien dalam proses penggilingan dengan nilai efesiensi 99%.Kata kunci: efesiensi, hammer mill, kinerja mesin, tongkol jagung.
KONSUMSI PAKAN, KONVERSI PAKAN DAN PRODUKSI TELUR AYAM ARAB YANG DITAMBAHKAN TEPUNG DAUN MURBEI PADA PAKAN
Authors: Amiruddin . , Agustina Laily , Jamilah Jamilah
Published: February 2021

Penelitian ini bertujuan melihat pengaruh pemberian tepung daun murbei dalam pakan terhadap konsumsi pakan, konversi pakan dan produksi telur ayam arab. Ayam arab yang digunakan sebanyak 48 ekor dengan umur 10 bulan produksi CV kuda hitam perkasa Kediri. Komposisi pakan terdiri dari: tepung daun murbei, jagung kuning, dedak padi, tepung ikan, bungkil kelapa, bungkil kedelai, mineral, tepung bulu dan minyak nabati. Data yang diperoleh dianalisis menggunakan program SPSS versi 16. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) (Gaspersz, 1991) yang terdiri dari 4 perlakuan 6 ulangan, perlakuannya yaitu R1 (5% tepung daun murbei), R2 (7,5% tepung daun murbei), R3 (10% tepung daun murbei) dan R4 (12,5% tepung daun murbei), tiap perlakuan ditambahkan ramuan herbal 2,5 ml/liter air minum. Hasil penelitian menunjukkan bahwa penggunaan tepung daun murbei dengan berbagai level berpengaruh nyata (P<0,05) terhadap konsumsi pakan dan tidak berpengaruh pada konversi pakan dan produksi telur. Rata-rata konsumsi pakan yang dihasilkan berkisar antara 107,08-109,74 g/ekor/hari sedangkan rata-rata konversi pakan yang dihasilkan berkisar 2,50-2,59 sementara rata-rata produksi telur yang di peroleh berkisar 14,68-16,46%. Disimpulkan bahwa tepung daun murbei dapat di tambahkan pada pakan ayam arab sampai level 12,5%.
KANDUNGAN KALIUM DAN RASIO C/N PUPUK ORGANIK CAIR (POC) BERBAHAN DAUN-DAUNAN DAN URINE KAMBING DENGAN PENAMBAHAN BIOAKTIVATOR RAGI TAPE (Saccharomyces cerevisiae)
Authors: Rahmawati Tiwi Ika , Asriany Anie , Hasan Syamsuddin
Published: February 2021

Permasalahan lingkungan di berbagai tempat, termasuk permasalahan sampah di lingkup kampus Fakultas Peternakan Universitas Hasanuddin, Makassar. Pencemaran akibat sampah di lingkungan kampus Fakultas Peternakan Universitas Hasanuddin Makassar apabila dibiarkan akan menimbulkan penyakit, bau busuk serta mengganggu estetika lingkungan. Salah satunya dengan memanfaatkan sampah daun-daunan sebagai pupuk organik cair. Penelitian ini bertujuan untuk mengetahui kandungan kalium dan C/N rasio pupuk organik cair berbahan daun-daun dan urine kambing dengan penambahan bioaktivator ragi tape (Saccharomyces cerevisiae). Penelitian terdiri dari empat perlakuan T0 (95% daun-daunan + 5% ragi tape ), T1 (70% daun-daunan + 25% urine kambing + 5% ragi tape), T2 (50% daun-daunan + 45% urine kambing + 5% ragi tape), T3 (25% daun-daunan + 70% urine kambing + 5% ragi tape). Rancangan yang digunakan adalah Rancangan Acak Lengkap (RAL) yang terdiri 4 perlakuan dan 3 ulangan. Analisis statistik memperlihatkan bahwa pembuatan pupuk organik cair berbahan daun-daunan dan urine kambing dengan penambahan bioaktivator ragi tape (Saccharomyces cerevisiae) tidak berpengaruh nyata (P>0,05) terhadap kandungan kalium dan rasio C/N. Berdasarkan hasil penelitian diperoleh kalium (T0= 0.25±0.06); (T1= 0.19±0.09); (T2= 0.33±0.08); (T3= 0.31±0.05) sedangkan untuk rasio C/N diperoleh (T0= 7.7±5.81); (T1= 8.1±2.85); (T2= 7.8±0.25); (T3= 7.3±4.52). Berdasarkan hasil penelitian dapat disimpulkan bahwa level persentase bahan baku pembuatan pupuk organik cair tidak memberikan pengaruh yang signifikan terhadap kandungan kalium dan rasio C/N pupuk organik cair.
Junk Food Consumption and Symptoms of Mental Health Problems: A Meta-Analysis for Public Health Awareness
Authors: Hafizurrachman Muhammad , Hartono Risky Kusuma
Published: February 2021

Junk food consumption increases the risk of having symptoms of mental health problems. This study aimed to conduct a meta-analysis to assess the association between junk food and symptoms of mental health problems. Six researchers, two primary researchers, and four assistant researchers, from October to December 2020 conducted a systematic literature review. The data sources were selected from Pubmed and Science Direct articles published from 2010 to 2020. Those websites were check-marked for text availability for original articles, using keywords for junk foods and mental health. This study had inclusion criteria for selecting and organizing articles using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The full-text articles were selected for conducting a meta-analysis using R Studio Software. The 5,079 article titles were obtained, seven of which met the relevant requirements for meta-analysis. The range of respondents who experienced symptoms of mental illness was 1.38%–79.8%. There was no heterogeneity based on the Tau-square test. The correlation coefficient was 0.11 (95% CI 0.09–0.14), with no publication bias based on Egger’s Regression test (0.6023 or p-value>0.05). The frequent consumption of junk food can contribute to mental illness symptoms, even with minimal effects.
Application of Computational Intelligence in Generating Synthetic Reservoir Rock Mechanical Parameters for Building Geo-Models.
Authors: Akubue L. C. , Dosunmu A. , Beka F. T.
Published: February 2021

Oil field Operations such as wellbore stability Management and variety of other activities in the upstream petroleum industry require geo-mechanical models for their analysis. Sometimes, the required subsurface measurements used to estimate rock parameters for building such models are unavailable. On this premise, past studies have offered variety of methods and investigative techniques such as empirical correlations, statistical analysis and numerical models to generate these data from available information. However, the complexity of the relationships that exists between the natural occurring variables make the aforementioned techniques limited. This work involves the application of Artificial Neural Networks (ANNs) to generating rock properties. A three-layer back-propagation neural network model was applied predicting pseudo-sonic data using conventional wireline log data as input. Four well data from a Niger-Delta field were used in this study, one for training, one for validating and the two others for generating and testing results. The network was trained with different sets of initial random weights and biases using various learning algorithms. Root mean square error (RMSE) and correlation coefficient (CC) were used as key performance indicators. This Neural-Network-Generated-Sonic-log was compared with those generated with existing correlations and statistical analysis. The results showed that the most influential input vectors with various configurations for predicting sonic log were Depth-Resistivity-Gamma ray-Density (with correlating coefficient between 0.7 and 0.9). The generated sonic was subsequently used to compute for other elastic properties needed to build mechanical earth model for evaluating the strength properties of drilled formations, hence optimise drilling performance. The models are useful in Minimizing well cost, as well as reducing Non Productive Time (NPT) caused by wellbore instability. This technique is particularly useful for mature fields, especially in situations where obtaining this well logs are usually not practicable.
Sequence Stratigraphic, Structural and Reservoir Analyses: An Integrated Approach to Exploration and Development of the Eastern Coastal Swamp Cluster, Niger Delta Basin
Authors: Dim C. I. , Onuoha K. Mosto , Okeugo C. Gabriel
Published: February 2021

Sequence stratigraphic, structural and reservoir analytical tools have been employed in interpreting the geology of the eastern Coastal Swamp Depo-belt of the Niger Delta Basin. The aim was to understand the stratigraphic framework, structural styles and hydrocarbon reservoir distribution for improved regional hydrocarbon exploration across the onshore Niger Delta basin. This interpretative study made use of well logs, biostratigraphic (biofacies and bio-zonation) and petrophysical data obtained from twenty wellbores, integrated with recently merged and reprocessed 3D Pre-Stack Time Migrated regional seismic volume spanning across eight fields (over 960 km2). Results reveal the occurrence of nine key chronostratigraphic surfaces (five maximum flooding surfaces and four sequence boundaries) that were tied to well-established pollen and foram bio-zones for high resolution sequence stratigraphic interpretation. The sediment stacking patterns recognized from gamma ray log signatures were used in delineating the lowstand system tract (LST), transgressive system tract (TST) and highstand system tract (HST) genetic units. Well log sequence stratigraphic correlation reveals that stratal packages within the area were segmented into three depositional sequences occurring from middle to late Miocene age. Furthermore, there is thickening of stratal packages with corresponding decrease in net-to-gross thickness from north to south (basinwards). This is due possibly to the influence of syn-depositional structures on stratigraphy. The combination of reservoir sands (of LST and HST), source and seal shales (of TST and HST) and fault structures allows for good hydrocarbon accumulation and should be targeted during exploration. Reservoir evaluation studies using petrophysical parameters indicates the presence of good quality reservoir intervals, which are laterally continuous and partly compartmentalized. Structural top maps of reservoirs show good amplitude response that are stratigraphically and structurally controlled. Structural analysis revealed the occurrence of back-to-back faulting, collapsed crest structures, simple/faulted rollovers, regional foot wall and hanging wall closures and sub-detachment structures. These structural styles constitute the major hydrocarbon entrapment mechanism in the area. Overall, the study has unraveled the existence of undrilled hydrocarbon leads at deeper depths that should be further revalidated for development and production.
Production Optimization in a Marginal Field through Established Reservoir Management Techniques – A Case Study
Authors: Toluse Williams , Okolo Victor , Martey Amarquaye
Published: February 2021

The Federal Government of Nigeria in a bid to promote indigenous companies participation in the oil and gas sector, and to grow the nation’s production capacity passed legislation in 1999 to foster the exploitation of Marginal Oil Fields (MOFs). MOF is one that is considered non – commercial as a result of strategic business development philosophy of the operator, often times large oil companies. Reservoir management is central to the effective exploitation of any hydrocarbon asset; this dependence is heightened for an undeveloped marginal field. There is no ‘one-size fits all’ approach to reservoir management; this paper reviews some techniques adopted by Midwestern Oil and Gas Ltd in the development of the Umusadege marginal field.

These techniques fall under three categories: (I) subsurface study (II) well placement and spacing, (III) integrated surface production and optimization, in accordance with regulatory practices.

 The previously acquired 3-D seismic data was reprocessed and interpretation of reservoir heterogeneities within the Umusadege field concessionary boundary carried out form the basis of the initial field development plan. To optimize reservoir drainage, the general principles of non-interference well spacing were employed, and advanced well placement technology was deployed to guarantee optimum well placement within the reservoir for effective and efficient drainage.

Subsequently, 14 vertical wells and 4 horizontal wells were drilled to effectively optimize recovery from the field. Prior to bringing these wells on-stream, clean-up and Maximum Efficiency Rate (MER) tests were conducted to determine the optimum choke settings, GOR and water cut limits for all wells. An integrated approach encompassing choke sizing, gas and water production management, vessel and line sizing were implemented on the Umusadege field to maintain and optimize recovery. Crude custody transfer measurements and export were enabled by an optimized Group Gathering Facility (GGF).The above techniques combining new technologies, traditional reservoir and production strategies led to the successful development of the Umusadege field; increasing daily oil production from 2,000 bbls/d from the first well re-entry to approximately 30,000 bbls/day over a 7-year period. This case study proves that with the correct implementation of the key elements of reservoir management the value of any hydrocarbon asset can be maximized in a cost effective, safe and environmentally friendly manner.
Underbalanced MPD Technology Proved to be Effective in Drilling of Fractured Granitic Basement
Authors: Chen Peng , Wang Xi , Wu Meng
Published: February 2021

The basement hydrocarbon reservoirs have been discovered in a lot of places over the world. The remarkable characteristics of the basement reservoirs are their low pressure with narrow density windows and well developed fractures which usually resulted in probably massive losses. A case study on drilling of fractured granitic basement with application of UBD in Chad and MPD in Indonesia is presented in this paper.

To tackle the common problems of drilling in narrow density windows and potential problem of losses, an underbalanced drilling (UBD) technology with a micro-foam drilling fluid was used in Chad. The pore pressure coefficient of the basement of Chad was predicted as between 1.02-1.06, and the density of the micro-foam drilling fluid was designed to be 8.7ppg. While an under-balanced managed pressure drilling (MPD) technology with a synthetic based gas-to-liquid (GTL) drilling fluid was utilized in Indonesia. The formation pressure coefficient of the basement of Indonesia was estimated to be 1.04, and the density of the GTL drilling fluid was designed to be 7.4ppg.

Losses or severe losses existed in previous conventional near-balanced drilling in fractured granitic basement of buried hills of Chad. The problem of losses also encountered even UBD was later used. Losses and kicks continued almost all the time during drilling, coring and wireline logging in some wells. Losses happened as soon as pump started while overflow occurred no sooner than pump stopped. However, the potential problem of losses and kicks was completely controlled by utilization of under-balanced MPD technology in fractured granitic basement of Indonesia.

The under-balanced MPD technology, a precisely pressure controlled drilling system, is able to accurately control the annular pressure profile throughout the wellbore, therefore it could effectively achieve safe drilling in narrow density window and cut non-production time. It is proved to be effective in drilling of fractured granitic basement.
Novel Method for Real-Time Monitoring of Scale Control Products at the Site of Use
Authors: Johnstone James , Toivonen Susanna , Griffin Rick , O'Brien Ashleigh , Mundill Paul , Siivonen Joonas , Väisänen Pave , Tiittanen Satu , Lehmusto Mirva , Härmä Harri , Hänninen Pekka , Teimonen Timo
Published: February 2021

Scale inhibitors are used extensively in the oil and gas industry to provide the level of flow assurance required to maximise safe and economic hydrocarbon production. For both continuous and scale squeeze treatments, residual inhibitor concentrations need to be verified on a continual basis to assure the field operator that the implemented scale management program remains effective. To date, the analytical work required to verify residual inhibitor levels of the majority of scale inhibitor chemistries needs to be carried out onshore in a suitably equipped analytical laboratory. Often the time delay from sample collection to reporting of analytical results introduces a significant level of uncertainty with regard to effective scale control which, if removed, would substantially improve the production assurance and safety of the facility operations.

The Residual Monitoring and Analysis system is a point-of-use monitoring platform designed to measure the residual concentration of polymeric scale inhibitors with average molecular weight less than 10 000 Da in produced water, providing a timely and accurate residual scale inhibitor concentration to the facility operator. The analysis procedure can be carried out at the production location where the sample is taken, with the result obtained and recorded within 30minutes or less. The analysis method is unaffected by either the presence of other production chemicals or by the variation in typical North Sea produced water composition.

The measurement system utilises the Aqsens aqueous liquid fingerprinting technology platform (Hänninen et al. 2013) and can be designed to work with a wide range of scale inhibitor chemistries; a specific tag/label is not necessary. Unlike other systems, the analytical method is not based on immunoassay detection technology that requires modification of the scale inhibitor formulation to include tagged polymer-specific antibodies. We have deliberately reverse engineered this for a range of current scale inhibitor products to provide direct field analysis to customers on either continuous or scale squeeze application programs.

The system derives its sensitivity by combining time-resolved fluorescence with carefully optimised chemistries to quantify the product for scale inhibition levels. Performance results from laboratory testing and coreflood experiments will be presented.
Characterization of Unconventional Reservoir for Development and Production: An Integrated Approach
Authors: Pal Omprakash , Zoghbi Bilal , Razzaq Waseem Abdul
Published: February 2021

Unconventional reservoir exploration and development activities in the Middle East have increased and are expected to continue to do so. National oil companies in the Middle East have a strategy for maximizing oil exports as well as use of natural gas. This has placed emphasis on use of advanced technology to extend the lives of conventional reservoirs and more activities in terms of “unconventional gas and oil.” Understanding unconventional environments, such as shale reservoirs, requires unique processes and technologies based on reservoir properties for optimum reservoir production and well life.

The objective of this study is to provide the systematic work flow to characterize unconventional reservoir formation. This paper discusses detailed laboratory testing to determine geochemical, rock mechanical, and formation fluid properties for reservoir development. Each test is described in addition to its importance to the reservoir study. Geochemical properties, such as total organic carbon (TOC) content to evaluate potential candidates for hydrocarbon, mineralogy to determine the formation type and clay content, and kerogen typing for reservoir maturity. Formation fluid sensitivity, such as acid solubility testing of the formation, capillary suction time testing, and Brinell hardness testing, are characterized to better understand the interaction of various fluids with the formation to help optimize well development.

An additional parameter in unconventional reservoirs is to plan ahead when implementing the proper fracturing stimulation technique and treatment design, which requires determining the geomechanical properties of the reservoir as well as the fluid to be used for stimulation. Properties of each reservoir are unique and require unique approaches to design and conduct fracturing solutions. The importance of geomechanical properties is discussed here.

This paper can be used to help operators obtain a broad overview of the reservoir to determine the best completion and stimulation approaches for unconventional development.
Required Understanding for the Development of Shale Reservoirs in the Middle East in Light of Developments in North America
Authors: Sayed Mohammed A. , Al-Muntasheri Ghaithan A. , Liang Feng
Published: February 2021

The ever-increasing international energy demands require exploration of new fossil energy resources. Unconventional oil and gas have received a great deal of attention in recent years as the technological advancements have made their production possible and more economical. Most of the shale developments took place in North America where the learning curve is being developed. Although shales still require lots of understanding and more advanced technologies, a substantial experience has been developed in North America. This paper presents an effort to summarize the current experience in shales of North America from different angles: rock mechanics, rock/fluids interaction, gas flow mechanisms through shale rocks, proppant embedment and water recovery after shale fracturing.

Three prospective areas for unconventional gas were found in the Kingdom of Saudi Arabia: in the Northwest, South Ghawar and condensate-rich shale gas in the Rub' Al-Khali area. The main targeted formations for unconventional natural gas are: the Ordovician Sarah, Silurian Qulibah, Qusaiba hot shale, Devonian Jauf and Permian Unayzah formations. The Qusaiba shale is located at depths of 7,500 to 20,000 ft throughout Saudi Arabia's basins. The Qusaiba Hot Shale in the Northwest area is relatively thick and it is considered to be the richest in all possible source rocks with a maximum total organic content of 6.15%.

Shales are composed of: kerogen, rock matrix and natural fractures. The mineralogy of shale varies from one field to another. Literature has confirmed that for Haynesville shale, the rock becomes more ductile with the increase in its clay content. Similar trends were seen for Lower Bakken shale. While other shale reservoirs, like Eagle Ford, Barnett and Middle Bakken are harder since they contain more quartz and calcite. The exposure of these clay-sensitive rocks to fracturing fluids does change their rock mechanical properties. This has been confirmed in literature where Middle Bakken shale lost 52% of its Young's modulus after exposure to 2 wt% KCl slickwater at 300°F for 48 hours.

The use of slickwater in fracturing represents a major challenge as it consumes huge volumes of this valuable resource. Recycling of produced water has been attempted in North America in Marcellus. An average amount of 3 to 8 million gallons of water are used in fracturing one well in Marcellus shale formation. In one application, re-use of the flowback water resulted in 25% reduction in the fresh water volumes and it reduced the cost of disposing produced water by 45 to 55%. The paper presents a summary of all of these findings from North America. A comprehensive understanding and analysis on unconventional reservoirs is required for the Middle Eastern reservoirs.
Predicting Hydraulic Fracturing in a Carbonate Gas Reservoir in Abu Dhabi Using 1D Mechanical Earth Model: Uncertainty and Constraints
Authors: Sirat Manhal , Ahmed Mujahed , Zhang Xing
Published: February 2021

In-situ stress state plays an important role in controlling fracture growth and containment in hydraulic fracturing managements. It is evident that the mechanical properties, existing stress regime and the natural fracture network of its reservoir rocks and the surrounding formations mainly control the geometry, size and containments of produced hydraulic fractures. Furthermore, the three principal in situ stresses' axes swap directions and magnitudes at different depths giving rise to identifying different mechanical bedrocks with corresponding stress regimes at different depths. Hence predicting the hydro-fractures can be theoretically achieved once all the above data are available. This is particularly difficult in unconventional and tight carbonate reservoirs, where heterogeneity and highly stress variation, in terms of magnitude and orientation, are expected.

To optimize the field development plan (FDP) of a tight carbonate gas reservoir in Abu Dhabi, 1D Mechanical Earth Models (MEMs), involving generating the three principal in-situ stresses' profiles and mechanical property characterization with depth, have been constructed for four vertical wells. The results reveal the swap of stress magnitudes at different mechanical layers, which controls the dimension and orientation of the produced hydro-fractures. Predicted containment of the Hydro-fractures within the specific zones is likely with inevitable high uncertainty when the stress contrast between Sv, SHmax with Shmin respectively as well as Young's modulus and Poisson's Ratio variations cannot be estimated accurately.

The uncertainty associated with this analysis is mainly related to the lacking of the calibration of the stress profiles of the 1D MEMs with minifrac and/or XLOT data, and both mechanical and elastic properties with rock mechanic testing results. This study investigates the uncertainty in predicting hydraulic fracture containment due to lacking such calibration, which highlights that a complete suite of data, including calibration of 1D MEMs, is crucial in hydraulic fracture treatment.
Fracture Identification and Comprehensive Evaluation of the Parameters by Dual Laterolog Data
Authors: Saboorian-Jooybari H.. , Dejam M.. , Chen Z.. , Pourafshary P..
Published: February 2021

Quality and productivity of tight formations are heavily dependent on the degree of fracture development. In fact, hard and dense carbonate formations may not be considered as net pay without presence of fractures which conduct fluids towards wellbore. The evaluation of fractures is a key to reservoir effectiveness characterization for well drilling, completion, development and simulation of fractured reservoirs. Although new imaging technologies such as Formation Micro-Scanners and Imagers (FMS and FMI) provide the information of fracture properties (dip angle, porosity, aperture and permeability), image logs are very expensive and cannot be available in all wells. In this paper, fracture parameters are estimated using conventional Dual Laterolog (DLL) resistivity, which includes shallow (LLS) and deep (LLD) responses. This technique is based on electrical resistivity anomalies because of separation of shallow and deep laterolog curves. Fracture parameters that can be calculated by DLL include dip angle, aperture, porosity, permeability and cementation factor. The accuracy of the calculated parameters using DLL is validated by the results of FMI in one well in one of Iranian fractured reservoirs. Despite the image logs, the conventional DLL is routinely run in all of the drilled wells. This makes the constructed fracture model on the basis of DLLs more reliable than the corresponding model founded on limited and insufficient image logs. Furthermore, DLL has an advantage of much deeper evaluation of fractures in comparison with the immediate borehole investigation of image logs.
Non-Darcy Flow Effect in Fractured Tight Reservoirs: How Significant Is It at Low Flow Rates and Away from Wellbores?
Authors: Saboorian-Jooybari Hadi , Pourafshary Peyman
Published: February 2021

Reservoir development is increasingly moving towards unconventional resources such as tight reservoirs due to the rapid decline in conventional reserves. Several researches have been done in the petroleum industry addressing significant influence of non-Darcy flow behavior on well deliverability and reservoir performance. In all of the previous works, it is generally believed that the non-Darcy flow in a reservoir, if occurs, becomes considerable within a few feet around the wellbores beyond which it is negligible. Furthermore, when mentioned non-Darcy effect in the literature, attentions are usually attracted to gas wells with high production rates (i.e. rates higher than 10 MMSCF / day).

In this paper, correlations that are typically used for determination of non-Darcy coefficient are reviewed. Then, it is shown that the correlations are distinct and lead to considerably different values of the non-Darcy coefficient for the same rock sample. A simple guideline is also presented for choosing the most appropriate correlation for a reservoir. Main body of this paper is directed at accurate description of non-Darcy flow in fractured tight reservoirs. This study evaluates the validity of a widely accepted assumption, which considers non-Darcy effect significant only within a few feet around wellbore of gas wells producing at high rates. A synthetic simulation model is made using the data of a well from one of the Iranian fractured tight reservoirs. A full feature compositional simulator is used for the computations in this study. The distance out of the wellbore is subdivided into a number of regions, and then the necessity of including the non-Darcy component in each of the regions for better performance predictions is investigated. The effect of accounting the non-Darcy term in each of the regions on the simulation results such as production rate, final recovery and pressure behavior is studied. Furthermore, three distinct reservoir fluid types including dry gas, gas condensate and black oil are used with the objective well model to evaluate dependence of non-Darcy effect on the type of flowing fluid. The study results are used to provide guidelines about the necessity of global consideration of the non-Darcy term in simulation of different fluid systems even at low production rates. The results highlight that contribution of the non-Darcy component to flow can be significant even far away from wellbores, thus it must be considered globally in the bulk of reservoirs. Additionally, the study demonstrates that the role of non-Darcy component can be crucial even at low production rates regardless of reservoir fluid type. Therefore, in order to have accurate modeling, design and successful implementation of projects, simulations of fractured tight reservoirs must be performed with the global inclusion of the non-Darcy flow formulations regardless of the type of flowing stream and levels of production rate.
Unconventional Shale Play in Oman: Preliminary Assessment of the Shale Oil / Shale Gas Potential of the Silurian Hot Shale of the Southern Rub al-Khali Basin
Authors: Madi Jamal A. , Belhadj Elhadi M.
Published: February 2021

Oman's petroleum systems are related to four known source rocks: the Precambrian-Lower Cambrian Huqf, the Lower Silurian Sahmah, the Late Jurassic Shuaiba-Tuwaiq and the Cretaceous Natih. The Huqf and the Natih have sourced almost all the discovered fields in the country. This study examines the shale-gas and shale-oil potential of the Lower Silurian Sahmah in the Omani side of the Rub al Khali basin along the Saudi border. The prospective area exceeds 12,000 square miles (31,300 km2).

The Silurian hot shale at the base of the Sahmah shale is equivalent to the known world-class source rock, widespread throughout North Africa (Tannezouft) and the Arabian Peninsula (Sahmah/Qusaiba). Both thickness and thermal maturities increase northward toward Saudi Arabia, with an apparent depocentre extending southward into Oman Block 36 where the hot shale is up to 55 m thick and reached 1.4% vitrinite reflectance (in Burkanah-1 and ATA-1 wells).

The present-day measured TOC and estimated from log signatures range from 0.8 to 9%. 1D thermal modeling and burial history of the Sahmah source rock in some wells indicate that, depending on the used kinetics, hydrocarbon generation/expulsion began from the Early Jurassic (ca 160 M.a.b.p) to Cretaceous.

Shale oil/gas resource density estimates, particularly in countries and plays outside North America remain highly uncertain, due to the lack of geochemical data, the lack of history of shale oil/gas production, and the valuation method undertaken. Based on available geological and geochemical data, we applied both Jarvie (2007) and Talukdar (2010) methods for the resource estimation of: (1) the amount of hydrocarbon generated and expelled into conventional reservoirs and (2) the amount of hydrocarbon retained within the Silurian hot shale.

Preliminary results show that the hydrocarbon potential is distributed equally between wet natural gas and oil within an area of 11,000 square mile. The Silurian Sahmah shale has generated and expelled (and/or partly lost) about 116.8 billion of oil and 275.6 TCF of gas. Likewise, our estimates indicate that 56 billion of oil and 273.4 TCF of gas are potentially retained within the Sahmah source rock, making this interval a future unconventional resource play. The average calculated retained oil and gas yields are estimated to be 6 MMbbl/mi2 (or 117 bbl oil/ac-ft) and 25.3 bcf/mi2 (or 403 mcf gas/ac-ft) respectively.

To better compare our estimates with Advanced Resources International (EIA/ARI) studies on several Silurian shale plays, we also carried out estimates based on the volumetric method. The total oil in-place is 50.2 billion barrels, while the total gas in-place is 107.6 TCF. The average oil and gas yield is respectively 7 MMbbl/mi2 and 15.5 bcf/mi2.

Our findings, in term of oil and gas concentration, are in line or often smaller than all the shale oil/gas plays assessed by EIA/ARI and others.
Impact of Geomechanics on Well Completion and Asset Development in the Bakken Formation
Authors: Ganpule Sameer , Srinivasan Karthik , Izykowski Tyler , Luneau Barbara , Gomez Ernest
Published: February 2021

In-situ stress variability within a reservoir is a primary parameter that controls hydraulic fracture initiation, growth, connectivity, and ultimately drainage and well spacing. This paper highlights the importance of characterizing the variability of in-situ stress and demonstrates the risk of underestimating stimulation treatment size when a treatment design is applied in a “copy-paste” fashion without any modifications to account for variation in pore pressure and in-situ stress across a basin. Thermal maturity and hydrocarbon generation from unconventional shales has a direct effect on pore pressure and the in-situ stress distribution in reservoir and barrier rocks. An examination of the Bakken Petroleum System (BPS) identifies regions of thermal maturity and higher pore pressure due to hydrocarbon expulsion. Consequently, the elevated pore pressure and the resulting in-situ stress vary vertically and laterally within the basin.

Multiple pore pressure profiles and corresponding stress profiles across the BPS were considered to quantify the impact of in-situ stress variability on hydraulic fracture geometry. These profiles include effects of normal pore pressure regime, over-pressure regime or pressure profiles transitioning from over pressure to normal pressure regimes. For a given stress profile, hydraulic fracture geometries are estimated using a fracture simulator, with multiple calibration points. The hydraulic fracture system and reservoir interactions are simulated in a subsequent production modeling phase which estimates drainage area characteristics, recovery forecasts and optimum well spacing for developing an asset.

Results from stress profile sensitivity emphasize the need to address variability of in-situ stress as it directly impacts well spacing considerations in an asset development plan. For example, stress profile with a normal pore pressure regime results in longer hydraulic fracture lengths in the Middle Bakken (MB) thus requiring three wells per section to infill the asset. Conversely, stress profile with over-pressure regime in MB results in much shorter hydraulic fracture lengths thus requiring more than three wells per section to develop the asset. Incorrectly assuming overpressure in a normally pressured zone could lead to over-engineering of wells and unnecessary costs, whereas incorrectly assuming normal pressure in zones that are in fact overpressured could lead to sub-optimal completions and/or a reduction in overall production.
Application of Linear Flow Volume to Rate Transient Analysis
Authors: Acuña Jorge A.
Published: February 2021

This paper explores the application of two techniques to rate and pressure transient analysis of fractured wells in tight reservoirs. The first one is the Linear Flow Volume (LFV), defined as a region with size determined by a characteristic distance proportional to but smaller than the radius of investigation. Similarly to it, this distance and the LFV increase with time without dependence on flow rate or pressure. The LFV can be calculated analytically for an infinite linear system. It can also be calculated in terms of cumulative production, pressure change and compressibility. When calculated this way, it gives results that are useful to characterize the well and reservoir before and after linear flow. It gives fracture storage volume for early time and reservoir volume when there is boundary dominated flow. It can also be used to help assess whether there is a closed or open boundary condition. The second technique is a normalization method for tests with variable pressure and flow. This is an alternative to the conventional approach of using p/qB with equivalent time (Q/q) as normalizing variables. The alternative technique is simple and provides normalized variables with much less noise and a better defined straight line in linear flow plots with clear indication of the end of linear flow when present. More importantly, it retains dependence on actual production time as opposed to equivalent time. This eliminates distortions caused by the use of equivalent time. The combined use of LFV and the alternative normalization technique provides an improved methodology for analysis of fractured wells in tight reservoirs. Validation with simulated examples is presented and application to actual cases is discussed.