bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fixed Equipment Integrity
Authors: Velasco Lorena 
Published: November 2015

Abstract
Implementation of Risk-Based Inspection, RBI in production facilities of Repsol Ecuador, is based on the API RP 580 (2009) Risk-Based Inspection, API RP 581 (2000) Risk-Based Inspection Base Resourse Document and API RP 581 (2008) Risk-Based Inspection Tecnology. This RBI methodology allows a first ranking risk level of equipment based on process conditions (qualitative risk analysis). This evaluation is complemented with a thickness analysis and remaining life estimation according to API 510 Pressure Vessel Inspection Code and the API 570 Piping Inspection Code for fixed equipment and piping respectively, and subsequent semicuantitative risk analysis.The thickness measurement and remaining life depends on damage mechanisms wich where identified in corrosion circuits in order to facilitate evaluation and monitoring.
Furthermore, the design criteria, operating conditions, frequencies, technical of inspection and maintenance at different levels of assessment, as well as the application of management policies in different areas such us management of change, risk management, process safety, etc. that are included in the management system factor. This directly affects the probability of equipment failure and allowed us to identify improvement opportunities to strengthen our fixed equipment integrity.
The RBI methodology implementation, has allowed Repsol Ecuador to optimize resources available for equipment maintenance because it prioritizes more critical equipment and allocated resources based on the risk level of each equipment and increase its operational availability to ensure its mechanical integrity since decreases the probability of failure avoiding possible injuries to people, damage of equipment and environment and to increase profitability due to a decrease on the probabilities of shut down of the facilities.
Quantifiable Costs Savings by Using 100% Raw Produced Water in Hydraulic Fracturing
Authors: Ruyle Branden , Fragachan Francisco E. 
Published: November 2015

Abstract
Conventional and unconventional well designs require 50,000 to more than 200,000 barrels of water per well during fracturing operations, generating a strain on fresh water supplies. The strain intensifies in areas where fresh water is scarce, water quality is inconsistent, or it is logistically complex to deliver water to a location. Therefore, having capabilities to reuse produced or flowback water for fracturing applications is a cost-effective option, especially when major savings in produced water disposal costs and reduced treatment requirements are achievable.
This paper comprehensively summarizes the proven benefits of using a bi-polymer crosslinking system that can be used in environments where water quality cannot be guaranteed. In addition, to the cost advantages of using a crosslink system that uses a conventional gelling agent, this paper also demonstrates the yielded cost savings per well that are achievable when reusing 100% produced and or flowback water for hydraulic fracturing operations. The costs cited in this paper are in US dollars.
Produced water typically contains large amounts of dissolved monovalent and divalent salts and other types of ions. Some of the ions present in produced water interfere in the formulation of traditional crosslinking fracturing fluids, and that creates a need in certain systems to mix produced with fresh water in specific percentages. The guar-based system discussed in this paper allows for 100% produced water reuse without filtering or treatment, representing a major environmental breakthrough in fresh water preservation. The new fluid system is a specially formulated bio-polymer crosslinking system that is not affected by produced or inconsistent water quality normally associated with fracturing applications.
The proven robust fracturing fluid system can process 100% untreated produced or flowback water with salt concentration in excess of 300,000 parts per million (ppm), between 5,000 to 30,000 ppm of divalent ions, and greater than 400 ppm of boron and 185,000 ppm of chlorides. The thermal stability of the system is proven to be unaffected by bottomhole temperatures ranging from 120°F to 300°F. The rheological profiles presented illustrate the performance of the fracturing fluid system: It yields higher viscosities than an equivalent traditional borate crosslink fluid system in fresh water. Well treatment results indicate that the bi-polymer system can be accelerated or delayed with proppant carrying/suspending properties comparable to a traditional crosslink system. Permeability tests demonstrate the benign non-damaging nature of the new system that directly represent actual field data with enhanced scale tendency reduction.
In summary, this paper comprehensively reviews the benefits of a robust fracturing fluid that can use 100% produced or flowback instead of freshwater for fracturing operations; that should become the norm as we move into a more environmental friendly paradigm.
Dynamic Under/Overbalance: A Review of the Current Practices in Block 15
Authors: Izurieta A. J. , Davila E. R. , Poveda P. E. , Garcia L. R. , Calpoviña D. E. , Cabezas J. L. , Diaz Hernandez A. , Vallejo R. , Luzuriaga A. , Castro E. 
Published: November 2015

Abstract
Completion with anchored guns instead of killing techniques have been used extensively in Ecuador since 2008, completing 111 works to date only in Block 15. During this process several continuous improvement practices as well as new completion techniques were implemented including:
Job design improvements: Well integrity analysisPenetration and Flow profile analysis on a foot by foot basisOptimization of the current designs by comparing dynamic under/over balance pressure recording with the simulation resultsPost audit of the calculated vs actual productivity
Operational improvements: No fluid loss control used in workover operationsUp to two days of early production due to control fluid does not go into formation.Cost reduction since no special control fluid is used when perforating with static/dynamic underbalance and anchored guns.Minimal fluid loss control when perforating with anchored guns (small overbalanced perforating).New dual concentric completion architecture with anchored guns on the lower sands.The use of anchored guns in reentry wells with 5 ½" casing.Rig time saving when running anchored guns in monobore completionNew perforating procedure in monobore completion by activating anchored guns when ESP is running in hole, then pump is placed to the designed depth, this new operational sequence helped to prevent ESP damage due to high pressure is needed to activate firing head during workover operations when a low pressure reservoir is perforated.
Productivity improvements: Significant reduction in both perforating and completion skins using static and dynamic underbalance.
This paper shows different case studies of completion and perforating designs that enabled to reduce skin as well as completion time in Block 15. A new completion procedure using anchored guns with dual concentric completion is also described.
Well Spacing Index, a New Approach for Planning the Oilfield Development
Authors: González Luís 
Published: November 2015

Abstract
The main objective of this work is to develop a methodology to relate the recoverable oil reserves, with the number of wells required for their extraction, while ensuring maximum economic efficiency and creation of value. The idea of "well spacing index", which is defined as the optimal number of wells to drill or complete per each million of barrels to recover in a specific reservoir, can achieve this goal. This optimum number of wells can be estimated from different perspectives; for example, maximizing the net present value, internal rate of return, the recovery factor or minimizing investment, among others.
This article has as its starting point in the work of R. Corrie (2001), from which the idea of well spacing index is introduced; allowing comparison with many reservoirs simultaneously, regardless of their of dimensions and is especially useful for quick calculations, management, planning, and drilling-portfolio-ranking.
The Well-Spacing-Index calculated from Corrie's equation depend on variables such as the average initial oil production rate per well, the oil prices, the average cost of drilling and completion per well and the discount rate of the operating company; in others words, has a dynamic and changing character, depending on these variables. This not static aspect, allows introducing another concept: "dynamic spacing", which is graphically illustrated in this paper.
For a wide range of data, the WSI varies between 0.3 and 1.3, and an average value of 0.7 is recommended for quick calculations.
It is also possible to determine the well spacing index, to maximize the internal rate of return or investment-efficiency. However, net present value is the objective preferred by many companies. The equations for well spacing index optimizing internal rate or return and investment efficiency is developed in appendix A
No confidential information is published in this paper and data used are from public domain.
Evaluation of Mexico's Shale Oil and Gas Potential
Authors: Stevens S. H. , Moodhe K. D. 
Published: November 2015

Abstract
Mexico has significant oil and gas resource potential in Jurassic and Cretaceous age shale formations. These shale deposits -- which correlate with productive shale plays in the USA -- appear prospective but are still in the early stage of exploration and thus remain poorly characterized. Early shale exploration wells tested mostly low rates, but a recent oil well made 500 bopd while a shale gas well reached 10.9 MMcfd.
The Mexican government plans to offer shale exploration blocks through an international auction. As part of a multi-client study, the authors have greatly expanded the geologic and reservoir data set we developed during an earlier scoping-level study conducted for the US Energy Information Administration (EIA). The additional geologic data support our initial view that Mexico has some of the largest and best quality shale potential outside the US and Canada. Risked, technically recoverable resources were estimated in the EIA/ARI study at 13.1 BBO of oil and 545 Tcf of natural gas.
Detailed geologic mapping and analysis indicates the two most prospective liquids-rich shale areas in Mexico occur within onshore portions of the Burgos and Tampico-Misantla basins, which have transport infrastructure and well services. Significant potential also exists in the Veracruz, Macuspana, Sabinas, and other onshore basins, but those areas tend to be structurally more complex and/or are mostly in the dry gas window.
The U. Cretaceous Eagle Ford Shale (in the Burgos) and correlative Agua Nueva Formation (in the Tampico-Misantla) have high TOC and brittle carbonate-rich mineralogy, but their net prospective area is reduced due to often shallow burial depth and low thermal maturity. A better target appears to be the U. Jurassic Pimienta and La Casita formations, which can be thick (~200 m), at prospective depth over much larger areas, are in the volatile oil to wet gas windows, and frequently overpressured, although TOC is lower than in the Agua Nueva.
Understanding Water Injection From a Control Engineering Approach Using the ERR-OLS Algorithm
Authors: Alvarez J. A. , Wei H. L. , Ibargüengoytia P. H. 
Published: November 2015

Abstract
Using existing production/injection rates is convenient for analysing a mature field as the access to relevant historical records does not cause any extra cost and a large amount of significant information can be extracted from the dataset by means of good analysis methods.
In the proposed work, each of the production wells is considered as an output variable while injection rates from other wells, which have an effect on the outputs, are treated as input variables. Control and System Engineering Approaches motivate such considerations.
Since injection and production are time dependent variables, time delays were considered in the analysis. This consideration allows recognition of how long it takes for the injection on a certain well to affect production.
The Error Reduction Ratio (ERR) algorithm, along with the Orthogonal Least Squares (OLS) method is used to determine how each of the injection wells affects production; this is achieved by sequentially orthogonalising input variables according to the order of their contribution to production.
The algorithm can be customised to explain a certain variance threshold in production resulting from injection wells. For the present case study, a 19-year monthly dataset from Beatrice, an operating field in the North Sea is studied.
It is observed that the historical datasets contain missing values. In order to address this problem, missing values are predicted by using an autoregressive linear model.
Horizontal Well Landing Optimization Combining Rotary Steerable Technology and Deep Azimuthal Measurements in Block 7, Ecuador
Authors: Sierra F. , Teran N. , Bastidas M. , Soria G. , Rojas E. , Villalva R. , Sanchez J. L. , Castro B. 
Published: November 2015

Abstract
Horizontal well landing in block 7 presents several challenges including reservoir vertical position uncertainty, which is generally anticipated based on seismic models, local formation dip at wellbore position and well path construction following strict directional objectives.
To support landing decisions, a logging-while-drilling (LWD) technology based on deep azimuthal electromagnetic measurements was introduced in the project, not only for conventional well-to-well correlation, but to remotely detect the approaching of the latest geological markers and adjust the trajectory inclination and landing point accordingly. In addition, a real-time gamma-ray borehole image was used to qualitatively identify local formation dip for a more effective planning of the further lateral section. Landing section has also been optimized with the use of a point-the-bit rotary steerable system (RSS), which allowed improved directional control, safer operation and higher build rates, minimizing the need of an additional mud motor run to achieve navigation inclination.
This paper presents case studies of the implementation of well placement and directional technologies to optimize horizontal well landing, and the introduction of a novel deep directional resistivity system to eliminate the need of of drilling a pilot hole.
State of the Art in 3D Reservoir Characterization: Palo Azul Field, Ecuador
Authors: Sandoval J. , Gaibor J. , Benalcazar E. , Jimenez L. 
Published: November 2015

Abstract
Redevelopment of mature oil fields is becoming increasingly important, both in Ecuador and worldwide. This paper describes the results of the integration of disciplines in the Palo Azul mature field where leading edge techniques were applied to develop high-definition static and dynamic models, change previous interpretations, and improve the understanding and characterization of the Hollin reservoir to estimate the remaining reserves.
An advanced 3D method was developed that integrates the well log signature, petrophysical analysis, seismic calibration with well logs, horizon correlation, and structural mapping using seismic attributes. Based on this approach, an area of high potential in the northern side of the structure was defined. The Hollin formation was subdivided into three depositional environments: fluvial, tidal-dominated, and marine. For each environment, three primary static parameters were modeled in detail. These parameters include net sand distribution, geometry of the sandstone bodies, and reservoir connectivity.
The static model was critical in providing more meaningful structural information, opening up adjoining areas, and identifying new pay horizons and bypassed reserves. A simulation model was developed to demonstrate the potential of the Hollin formation in Ecuador. Within this formation, defining the location of vertical transmissibility barriers and seal zones was a critical factor in the achievement of good history matching. Based on integrated work between the geology and reservoir engineering teams, several wells were reviewed and updated in the geostatistical model to reproduce, as closely as possible, the historical field behavior. This approach provided a better understanding of reservoir distribution. It enabled the optimization of new drilling locations in the northern area and infill drilling plans for the southern Palo Azul field, reduced the cost of new wells, improved the recovery factor, and enhanced reservoir management.
Multibowl Wellhead
Authors: Mora Esteban 
Published: November 2015

Abstract
Multibowl Wellhead equipment was designed to reduce rig non-productive time and to improve safety during wellhead installation. Nevertheless, this paper presents additional advantages like to use this system in any kind of completion.
The patent pending from Válvulas del Pacífico S.A. goes beyond the advantages of reducing rig nonproductive because it gives the opportunity to the customer in use this any kind of completion in a Multibowl Wellhead and to change one kind completion after evaluation of the well without changing the wellhead basis. For example, change from a single production to a dual system without changing the basis of the wellhead. This is possible thanks to the converter kits.
The Multibowl Wellhead significantly reduces time during drilling of an oil well; time savings are about 18 hours, which implies a significant cost savings. This optimization in time is given by comparing a standard wellhead installation (which is installed in two individual sections) to Multibowl Wellhead installation where both sections are installed altogether. It also improves personnel safety during field operations. Additionally, it is relevant to highlight the versatility of its running tools, since they accomplish at least two functions at once.
Multibowl Wellhead is fully compatible with any type of extraction system; this converter kit can facilitate conversion to an Injector, Re-injector or Dual Concentric. It is compatible with any type and brand of electrical connector used for electro-submersible pumping, as well.
Multibowl Wellhead offers the opportunity to be more cost-effective because it can be used to complete wells where 3 or 4 casing and tubing strings are used, without disconnecting BOP and test it in each section of the wellhead installed and also provides the versatility to use any kind of well completion equipment, like: BES, PowerOil, Natural Flow, Injector, Dual, etc. This innovation has proven been a source of saving for Operators in the range of 5% in rig time per drilled well.
Competitive Analysis of Latin American Oil and Gas Fiscal Regimes
Authors: Vargas J. C. , Quintana S. 
Published: November 2015

Abstract
Mexico's new open market, Brazil's pre-salt discoveries, Argentina's unconventional potential and Colombia's unexplored offshore areas among other examples make Latin America a focal point to global upstream investors. However, in the current low oil price environment resources have become scarce and geological prospectivity is not the only factor to attract investment. Countries are therefore fiercily competing to secure foreign investment and fiscal terms play a key role. This study presents a comprehensive analysis of current fiscal regimes of oil and gas producing countries in the region.
Typical upstream onshore, offshore, heavy oil and unconventional projects are evaluated applying the fiscal terms of each particular country for low, mid and high scenarios (i.e. P90, P50, P10) under identical conditions. Economic indicators such as net present value, profitability index and rate of return for both contractor and government are calculated. Sensitivy analysis is then conducted for low and high price and investment ranges. Government take is calculated depending on the corresponding fiscal system (i.e. Royalty Tax, Profit Sharing Contract and Service Contract) and broken down by its compounded elements (i.e. taxes, royalties, profit oil).
Based on the analysis described above, fiscal regimes of producing countries in the region are compared and ranked by Contractor and Government take. Their behaviour is understood under low and high price and cost conditions in order to estimate the share of the potential upside/downside on extreme cases and subsequently indentify which regimes are more competitive from the fiscal point of view to investors. Finally, elements like fiscal stability and state participation are also incorporated into the analysis.
Recent changes in fiscal terms implemented by governments to either protect their finances against the oil price drop, attract new investors or encourage new developments (i.e. offshore and unconventional exploration) are captured in the present study. Frontier regions such as Uruguay and the Falkland Islands are also included in the analysis.
Work Inclusion Breaking Down Barriers
Authors: Bocchicchio F. , Paz M. 
Published: November 2015

Abstract
SEED is an expression of the spirit of integral and ethical service that the oilfield services company has with its clients and community. The SEED (Schlumberger Excellence in Educational Development) program focuses on education and inclusion for the common good, especially in the vulnerable sectors of society, such as children, youth and people with special needs, and Down syndrome and mental disabilities. Ecuadorian legislation requires that 4% of company staff be people with special needs; nevertheless, the oilfield services company goes further than hiring people from this vulnerable sector. We create true inclusion of people with mental disabilities and Down syndrome in the work, social, educational and professional environment. The Company works with 6 institutions that accept people with various disabilities, and focuses on various aspects of inclusion in education with 3 special education schools in the amazon region. It has provided these schools with technology and training for teachers in technological areas, and how to create projects that focus on solutions for students with special needs and improving teaching for their day-to-day learning. In the case of the Special Needs School, "3 de Diciembre" in Lago Agrio, it has provided them with a physical rehabilitation room with equipment such as: stationary bicycles, electro-stimulation equipment, physical therapy and hydro massage, etc. Regarding inclusion in the work area, along with Fundación General Ecuatoriana and the Vice President's Office of the Republic of Ecuador, and Fundación El Triángulo, we currently have 26 youth with mental disabilities and Down syndrome on our local payroll, and 7 of them work directly in the main offices with the same guarantees and benefits as all of our workers. Regarding sports inclusion, we work with the "School of wheelchair tennis" in Quito. This school provides a space for people with physical, mental and visual disabilities to practice sports.