bluuebunny/crossref_metadata_2025_split huggingface dataset:
PENGARUH PAPARAN GELOMBANG INFRASONIK (8-12 Hz) TERHADAP KECERDASAN DAN VISKOSITAS DARAH (HEMATOKRIT) MENCIT
Authors: Qomariyah Millatul , Mulyono Agus 
Published: November 2015

Kecerdasan merupakan suatu kemampuan yang dimiliki seseorang untuk memecahkan masalah dalam kehidupannya sehari-hari. Pada era globalisasi saat ini kecerdasan menjadi semakin penting agar mampu bersaing dengan yang lain. Ada banyak cara untuk meningkatkan kecerdasan seseorang salah satunya adalah dengan melatih gelombang otak. Gelombang otak yang sangat tepat untuk belajar dan meningkatkan kecerdasan adalah pada frekuensi 8-12 Hz dan termasuk range gelombang infrasonik. Selain itu, pemanfaatan gelombang otak pada frekuensi ini telah diaplikasikan di bidang kesehatan karena dapat menghilangkan depresi klinis pada pasien. Frekuensi gelombang infrasonik (8-12 Hz) tidak mudah untuk diciptakan namun dipasaran telah beredar kaset CD gelombang alfa. Sehingga aplikasi pemanfaatannya cukup mudah.Tujuan dari penelitian ini adalah untuk mengetahui pengaruh paparan frekuensi gelombang Infrasonik (8-12 Hz) terhadap peningkatan kecerdasan mencit dan untuk mengetahui pengaruh paparan frekuensi gelombang infrasonik (8-12 Hz) terhadap viskositas darah mencit. Pengujian kecerdasan pada penelitian ini menggunakan labirin yakni dengan melihat lama waktu yang dibutuhkan mencit untuk melewati labirin, semakin cepat mencit melewati labirin maka mencit semakin cerdas. Untuk mengetahui viskositas darah mencit dengan melihat himatokrit yaitu presentase darah yang berupa sel.Analisa dalam penelitian ini menggunakan Anova dengan taraf signifikansi 5 %. Diketahui bahwa gelombang infrasonik (8-12 Hz) mempengaruhi kecerdasan dengan nilai signifikansinya sebesar 0 .000, dan gelombang infrasonik (8-12 Hz) juga mempengaruhi viskositas darah dengan nilai signifikansinya sebesar 0 .000.
PENGARUH VARIASI TEKANAN PENGEPRESAN DAN KOMPOSISI BAHAN TERHADAP SIFAT FISIS BRIKET ARANG
Authors: Setiowati Reni , Tirono Mokhamad 
Published: November 2015

<p>Bahan bakar alternatif diperlukan untuk pengganti sumber daya alam yang tidak dapat diperbarui.Salah satu bahan bakar alternatif tersebut yang dikembangkan adalah briket arang dengan memanfaatkan limbah biomassa.Pada penelitian ini dibuat briket arang dengan mengkaji pengaruh variasi tekanan pengepresan dan komposisi bahan terhadap sifat fisis briket arang. Proses karbonisasi pada tempurung kelapa 450ºC selama 15 menit. Serbuk kayu dikarbonisasi menggunakan klin drum selama 4-5 jam. Perbandingan komposisi bahan tempurung kelapa dengan serbuk kayu adalah sebagai berikut 75%:25%, 25%:75%, 50%:50%, 100%:0%, 0%: 100% dengan tekanan pengepresan 50 N/cm<sup>2</sup>, 100 N/cm<sup>2</sup>,150N/cm<sup>2</sup>. Pengeringan briket dilakukan di dalam oven dengan suhu 60°C selama 24 jam. Briket berbentuk silinder dengan diameter 5 cm.Hasil penelitian menunjukkan briket paling optimum dengan perbandingan komposisi bahan 100% tempurung kelapa menggunakan tekanan antara 100-150 N/cm<sup>2</sup> dengan nilai parameter uji sebagai berikut densitas 0.634 gr/cm<sup>3</sup>, kekuatan mekanik 43.167 N/cm<sup>2</sup> dan lama pembakaran 64,39 menit.</p>
Rherological Behavior of Water-Based Drilling Fluids Contaminated With Gypsum (CaSO4) Using Unmodified Dividivi Tannins (Caesalpinia coriaria) as Deflocculant Agent
Authors: Pérez M. A. , Colina R. A. 
Published: November 2015

Abstract
This work evaluates the effect of dividivi tannins (Caesalpinia coriaria) in its unmodified form in the rheological properties of standard water-based drilling fluids contaminated with gypsum (CaSO4) and its comparison with commercial tannin (reference). The plastic viscosity, yield point and gel strength of water-based drilling fluids contaminated with 5 lb/bbl gypsum was studied. The dividivi tannins contain 67.40% of hydrolyzable tannins (decomposable in water, with which they react to form other substances). The performance of dividivi tannins as deflocculant agent in water-based drilling fluids contaminated with gypsum, before and after aging, was improved, compared with commercial tannin (reference tannin). Dividivi tannins in water-based drilling fluid with gypsum achieved deflocculant efficiency of nine (9) times more than commercial tannin. On the other hand, the commercial tannin, does not improves its deflocculant efficiency with increase tannin content and temperature in water-based drilling fluids contaminated with gypsum; but shows a trend to remain constant behavior.
Transition Radial Flow in Slanted Well Test Analysis
Authors: Sousa B. R. , Moreno R. B. 
Published: November 2015

Abstract
The applicability of permanent downhole gauges (PDG) has been proved to be of great contribution to reservoir monitoring and well performance analysis. By the interpretation of any each build-up and/or fall-off from PDG readings it is possible to improve the near wellbore characterization, mainly because PDG signatures usually are not significantly affected by wellbore storage. This last advantage has motivated this work to review and further evaluates flow regimes in the wellbore surroundings that wasn't possible to be characterized due to wellbore storage effects. From this assumption, this paper presents a new study of transient pressure behavior in deviated wells. The investigation was based on an analytical solution derived for an infinite radial extent reservoir limited with both bottom-up impermeable reservoir boundary layers and uniform flow condition at the wellbore. From that, type curves were generated for different slant angles of the well and dimensionless formation thickness. The analysis showed a new flow regime called Transition Radial Flow (TRF), in a zone where, before PDG, was mainly dominated by wellbore storage. The TRF develops between early time and late time infinite acting radial flow (IARF), where the reservoir permeability can be estimated before the IARF development. Together, an alternative procedure was developed for interpreting transient pressure data using this new flow regime. This procedure was based on the TDS (Tiab's Direct Synthesis) technique, which allows interpreting the pressure data through a direct analysis of the derivative curve. The solution presented here provides a feasible alternative to the analysis of short duration pressure derivative curve in slanted wells.
Skin Damage Determination from PLT Temperature Logs in Sierra Chata Field, Argentina
Authors: Schindler M. H. , Fernández J. J. , Grill J. F. 
Published: November 2015

Abstract
This paper provides a method to estimate pressure drops due to skin damage using information from production logs (PLTs).
The analysis of the temperature measurements and flowing rates, enable calculating flowing temperatures of each layer and its differences with the natural geothermal profile.
The behavior of pressure and temperature are related according to thermodynamic functions (changes of pressures imply changes of temperatures).
Gas expansion due to formation damage or skin, occurs within a short distance of the wellbore. Due to small transient times and transfer areas, there will be no enough heat conduction from below (or above) to stabilize the gas temperature back to its corresponding natural temperature gradient.
Conversely, pressure drops due to Darcy flowing mechanism, distribute in larger zones, (especially in low permeability or fractured wells), allowing in this case significant heat conduction to reduce the associated temperature changes.
Most of the temperature changes can be allocated to the skin effect, where no significant heat transfer occurs (adiabatic) and the process can be considered isenthalpic. In this condition, the pressure drop of the gas flowing through a damaged zone can be derived from the Joule-Thomson coefficient and the temperature changes.
More than 150 PLT logs were analyzed with this method. Having compared results from all cases, particular candidates were selected for stimulation or re-perforating. The results from interventions on the selected wells were positive in strong agreement with the conclusions of this paper.
Channelling Detection Using Data-Driven Models
Authors: Moreno G. A. , Garriz A. E. 
Published: November 2015

Abstract
Waterflooding surveillance is essential to optimize oil recovery in mature fields. Channeling or bypassing of injected brine is a common problem in mature fields. It is hard to build a reliable simulation model to predict the existence of a channel. Radioactive tracers are a practical way to reveal these high permeability zones and provide valuable information for the design of a solution strategy.
However, a method to minimize tracer injection or enhance its effectiveness in channel detection is desirable. Data driven-models are able to give a simple picture of the reservoir dynamics and often provide important information such as interwell connectivities. In this paper we show that the capacitance-resistance model (CRM) with dynamic connectivities can be used to guide the tracer test pair selection. This method requires only production and completion information and results in a straightforward screening that can be used to identify the most probable channeling path.
A field case, Chihuido de la Sierra Negra, a mature waterflood in Argentina with more than 1500 wells is presented and analyzed. In this case the model is used to reveal possible pairs with channeling problems in a time window where there exists prior information of tracer tests. The candidates selected using the model are compared with these measuremets, finding that there is good agreement with the calculated high risk set. This enables to use CRM to enhance channeling detection using tracers, also this model can be used to select a smaller set of wells where the probability of finding a connected pair is higher. In contrast to other techniques, the capacitance-resistance model with dynamic connectivities automatically takes into account dynamic boundary conditions such as new wells or shut-ins. A full-field history match and channeling detection routine can be run in minutes making this model a suitable tool for real time surveillance.
Quantitative Characterization of Porosity Partitioning from NMR Logs in Siliciclastic Reservoirs - Ecuador
Authors: Lafournére J-Paul. B. , Bringer F. , Reeder S. L. , Leon M. Naranjo , Bourge J-P. , Morales O. , Suter A. , Castillo F. , Ochoa J. , Sierra F. , Bravo J. 
Published: November 2015

Abstract
The "Oriente" basin is located in eastern Ecuador between the Andes Mountains and the Amazon rainforest. In 2012, daily oil production reached 505,000 barrels. The three main oil-bearing Cretaceous formations in the basin are the Hollin, T and U formations. Results from recent extensive coring of the U and Hollin formations showed that the pore size significantly affects oil saturation and production. Therefore, understanding pore size distribution can greatly enhance the success of a well. It is a major challenge to characterize and classify reservoir type and heterogeneity in reservoirs with pore-size variations using only well log data. We used core data from three wells in the U and Hollin formations to validate a new nuclear magnetic resonance (NMR) spectral analysis technique, applied in the echo domain, to estimate the pore-size distribution.
In certain carbonate reservoirs in the Middle East, the distribution of pore size classes can be accurately determined by fitting the NMR pulse echoe. The method was blindly tested on three siliciclastic wells from the Oriente basin, and the results were compared with pore-size analysis from mercury-injection and capillary-pressure data. Additionally, a multi-mineral petrophysical model was built for each eall from log measurements, omitting the core data. The porosity derived from the multi-mineral model was used as a porosity input to guide the time-domain inversion of the NMR echo trains. The inversion solves for continuous logs of the porosity, attributed to three pore families, representing the range of pore-body sizes from small to medium to large.
After completing the log-based classification into three pore families, the resulting porosity logs were compared to the analysis of core samples for several oilfields. For all formations and in all fields, the core-analysis inversion data was in good agreement with the time-domain NMR inversion results.
These results were used to select optimum intervals to be completed and to predict production in the studied fields.
Improved Fracture Characterization in the La Paz Field: A Case Study
Authors: Lander L. A. , Silva A. , Chiquito J. , Cadena A. 
Published: November 2015

Abstract
Maintaining and increasing production are the main challenges for oil and gas companies in today's difficult market. To achieve these goals, these companies are looking for new techniques to improve fracture characterization. Open natural fractures, when present, can provide the conduit for the majority of natural gas in low porosity, hard rock environments. Therefore, a complete understanding of fracture attributes is required for optimal production, as well as cementing and completion design, well placement, and reservoir modeling.
In the La Paz field in Venezuela, previous petrophysical interpretation assumed the cementation exponent, m to be equal to 2. This assumption was made due to the absence of special core analysis and logging information such as dipolar sonic and micro resistivity image logs, increasing the uncertainty in the petrophysical model.
Using the crossplot of Ø vs. Rt on log log coordinates it was possible to determine the cement exponent, m, value for each zone. This parameter was fundamental to the estimation of the fracture and matrix porosity, fracture Intensity Index, and the Partitioning Coefficient.
The methodology applied in this case study is based on advanced acoustic analysis integrated with triple combo and borehole micro resistivity images. The triple combo (gamma ray, induction resistivity, neutron and density) and the image data allowed identification of the natural fractures, and the Stoneley wave analysis confirmed that several of the fractures observed in the borehole image data were open.
This methodology reduced the fracture characterization uncertainty of the La Paz Field and helped to more accurately estimate petrophysical properties where special core data is not available.
Well Testing Improvement Using Nitrogen Lifting in Shushufindi Field: Accelerating Well Response and Transient Data Quality
Authors: Ruiz Y. Lopez , Betancourt A. , Villanueva G. , Vargas A. , Tayo M. , Burgos J. , Vela I. , Egas A. , Loyola R. 
Published: November 2015

Abstract
Shushufindi field is the largest field in the Oriente Basin in Ecuador and is located 100 miles east of Quito. It contains 3.7 billion barrels original oil in place (OOIP) and represents 10% of country’s production. Determining reservoir properties using evaluation with hydraulic pumping for well testing has been a common practice in Shushufindi field since development in the early 1970s by Texaco Gulf Company and continuing in recent history with state company Petroamazonas.
Due to the high level of depletion and reservoir characteristics, obtaing good quality data from well testing is a challenge, and if a decision is made based on the wrong information, it could have a severe negative impact on the asset. Ambiguity in the results of well testing with a hydraulic pumping method can stem from failure on downhole shut-in that allows the development of wellbore storage, which in turn would lead to difficulties for well test interpretation, accurate flow capacity/ productivity evaluation, fluid sampling, etc.
To clarify all well testing concepts and results, a new procedure was developed for well testing in this field that uses a combination of drillstem testing tools, coiled tubing, and nitrogen lifting. With the developed method, the test is combined and continually conducted to test flow rate and drawdown buildups including downhole shut-in, providing reservoir and fluid parameters for a better evaluation and for artificial lifting design.
This paper will present a study of the implementation of this new method, covering the areas of well evaluation and the outstanding results in accelerating well response. The procedures are generally easy to follow and to understand and have an impact in reducing rig time and nonproductive time and result in a faster return of the well to production (workover). The pilot showed excellent results in obtaining reservoir property measurements that were validated by reservoir modeling and production history. The process is robust, repeatable, and applicable to other fields with similar characteristics.
A New Stimulation Method to Significantly Improve Hydrocarbon Recovery Using Temporary Beneficial Changes in Stress Anisotropy
Authors: Lewis B. J. , Surjaatmadja J. B. 
Published: November 2015

Abstract
As a result of the creation of a hydraulic fracture, transient geomechanics forces are exerted on the formation, which modify the stress landscape near the wellbore and the fracture plane. It has been observed that the potential exists for temporary reversal in the minimum stress direction, enabling a brief time interval in which a second hydraulic fracture can be created in a completely different direction. This provides hydraulic fracturing connectivity to previously unattainable locations in the formation, which can significantly improve initial hydrocarbon production and economic ultimate recovery from the formation.
This paper presents a computational validation of this multioriented hydraulic fracturing (MOHF) process. A unique transient 3D computational geomechanic fracture simulator was developed to perform this study, as traditional hydraulic fracture simulations are derived using static formation properties and steady-state assumptions. The new model incorporates cohesive zone elements to represent the fracture plane and friction elements to account for plastic energy storage of the multiple formation rock layers in the model. Time lapse stress fields show distinct windows of opportunity wherein new fractures can be influenced to extend in alternate directions.
This new stimulation method enhances the state-of-the-art in hydraulic fracturing. However, a deeper understanding of the transient geomechanic response in the treatment area is necessary to successfully design and perform the stimulation operation. Unfortunately, it also creates new complications with respect to industry standard hydraulic fracture models being incapable of modeling the transient response of the system. Furthermore, the availability of data related to the dynamic behavior of rocks is limited, and unique testing equipment and procedures must be developed to obtain such data.
Effect on Water Breakthrough When a Near-Critical Fluid Reservoir Reaches Saturation Pressure
Authors: Paredes J. E. , Perez R. , Perera L. M. , Larez C. J. 
Published: November 2015

Abstract
Many factors affect water movement within the reservoir; it's already known that petrophysical characteristics of the porous media, reservoir fracture networks and exploitation rhythm are some of them. In naturally fractured reservoirs containing near-critical fluids (oil systems) there is evidence that fluid properties have a direct effect in the strong water breakthrough at the time that the saturation pressure is reached in the reservoir.
These reservoirs undergo substantial changes in volume and composition, due to its high oil formation volume factors that cause a sudden advance oil water contact that is aided by the presence of fracture networks. This semi-instantaneous variation can be up to 40% loss of liquid saturation and it will depend on the characteristics of the fluid itself. This effect is usually confused by channeling or water coning when conventional techniques are used to diagnose water breakthrough.
This work was developed in order to demonstrate the effects and consequences of reaching the saturation pressure in the advancement of water oil contact in naturally fractured reservoirs (NFR) that contains near-critical fluids, using traditional reservoir engineering analysis, novel diagnostic plots and numerical simulation.
Selection of Customized Polymers to Enhance Oil Recovery from High Temperature Reservoirs
Authors: Gaillard N. , Giovannetti B. , Leblanc T. , Thomas A. , Braun O. , Favero C. 
Published: November 2015

Abstract
While polymer flooding has proven to be an effective technique to improve oil recovery from mature reservoirs, the new objective pursued by the main stakeholders consists now in optimizing the overall costs and decrease the risks associated to the implementation of chemical enhanced oil recovery methods. This is particularly true for reservoir conditions with high temperatures (above 85°C) using injection brine with high hardness.
In such conditions, using specific robust polymers is necessary to ensure stability over months during propagation in reservoirs. These polymers containing Acrylamido-Tert-Butyl-Sulfonate (ATBS) and N- Vinyl Pyrrolidone (NVP) are more expensive than regular HPAM and have to be overdosed to reach target viscosities since their molecular weights are low. In extreme cases, the project can be aborted for economic reasons. However, many fields, especially in South America, have access to very soft injection brines with a total dissolved salt lower than 3000 ppm in many cases. Using such brine is a tremendous advantage for polymer flooding since less robust polymers can be selected and target viscosity can be achieved with low dosages.
This paper describes the selection and evaluation of polymers dedicated to high temperature reservoir conditions (from 85°C to 140°C) using very low salinity brine in comparison with harder brine. A series of rheological, shear and thermal stability tests have been performed to select the most appropriate polymer for each case. The impact of the chemical composition and the microstructure shows that the incorporation of NVP is not necessarily required to ensure stability over 6 months above 100°C in soft brines. Results show as well that ATBS improves shear and thermal stability in both soft and hard brine conditions. Besides, the incorporation of thermo-responsive moieties in the polymer improves viscosity properties resulting in a lower dosage even at high temperature to reach target viscosity.
The objective of the study is also to demonstrate the possibility to develop innovative and cost-effective polymers for each reservoir condition. It encompasses an early and particularly close cooperation between the polymer manufacturer and the company willing to improve oil recovery from its reservoirs.
Elastic Seismic Inversion for Sandstone Prediction: Lower U Sandstone Reservoir, Limoncocha Oilfield - Ecuador Case Study
Authors: Galárraga M. F. , Pazos J. C. , Izurieta A. J. 
Published: November 2015

Abstract
This paper shows the results of the Lower U Sandstone prediction of Limoncocha Oilfield using the pre-stack elastic seismic inversion method, based on available well and seismic data. This study was focused to reduce the uncertainty in the location of new wells. The Poisson's Ratio (PR) is the most sensitive elastic parameter for discriminating lithology. Data of 49 wells were used in this study and the cross-plots analysis between mean PR obtained of seismic inversion and sand net thickness gotten of the wells show the best correlation (90%). Based on the results of this study 21 new wells were located and drilled, including horizontal and sidetrack wells. Currently, the cross-plots between these parameters in the Lower U Sandstone, including the new wells, keep a high correlation (83%). These results show the validity of this method for predicting the net sand thickness of the Lower U reservoir in the Limoncocha Oilfield. Production data were also correlated with the mean PR, and the best production matches with thickest sand development. Maybe this method could be applied in other Oilfields with similar results.