bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resistivity Logging in Conductive-Mud Environment and High Resistivity Formations. Dual Laterolog or Propagation LWD Tool?
Authors: Lander L. A. , Silva A. , Simon C. 
Published: November 2015

Abstract
Volumetric estimates are required at all stages of the field life cycle. One of the main parameters used to estimate the stock tank oil initially in place is the water saturation, which depends mainly on the true resistivity (Rt) of the formation. Correct log interpretation of LWD resistivity is a challenge in the Zuata Field due to the apparent conductive invasion profile phenomenom.
This study compares the LWD phase resistivity against Compact™ Dual Laterolog resistivity curves in the same well. The section of the well was drilled with water-based mud (WBM) in unconsolidated sandstones intercalated with shale and low conductivity formations.
The geological information for this area (core analysis and image log from two neighbor wells) indicates that there are sand/shale laminations in the surrounding formation. The area where significant differences were observed among the LWD propagation resistivity curves coincided with spiral-shaped wellbore. The interbedded formation causes the electrical anisotropy and the spiral zones amplify this effect. Compact Dual Laterolog tools on the contrary, although affected by anisotropy, can be easily borehole correted to yield an accurate Rt value.
In conclusion, when the LWD data can be correctly normalized the anisotropy effect could be reduced and the LWD propagation resistivity curves may be use for formation evaluation; however, another option is to run tools that can be properly corrected by borehole size and are less affected by anisotropy and polarization such as the Compact Dual Laterolog MDL.
Durable Yet Aggressive Conical Diamond Element Bit Increases ROP by 34% Drilling Difficult Lower Chert/Conglomerate Section, Ecuador
Authors: Rodriguez R. , Laguna A. , Caselles M. Gomez , Trapuzzano R. , Gomez J. M. , Oyatomari C. G. , Ulloa P. , Chamorro D. 
Published: November 2015

Abstract
Drilling the intermediate (12¼-in) section in Ecuador's Oriente (East) Basin involves passing through interbedded sequences of claystone and conglomerates with chert cobbles and pebbles, which generate high impact forces that damage PDC bit cutting structures. Roller-cone bits with tungsten carbide inserts (TCIs) have been the most reliable option to drill within challenging levels that are known to chip and break cutting mechanisms; however, dedicated runs through conglomerates caused additional trips to replace bits before reaching total depth of the section. To drill the entire section, PDC bits were requested with improved cutter technology and enhanced procedures to reduce damage on cutting structures. There were events, however, of destroyed bits within conglomerates without finishing all conglomerate levels, requiring another bit to drill the entire chert level, and low ROP to mitigate cutter breakage and chipping. The operator sought a new type PDC bit that could ensure drilling the entire conglomerate intervals with enhanced ROP and longer footage for the section after the chert-composed beds.
To develop a bit solution, engineers used finite element analysis–based modeling to implement a new-type hybrid bit by strategically positioning multiple conical diamond elements (CDEs) across the cutting structure from bit center to gauge. The CDE's unique geometry applies a concentrated point load to fracture high-compressive-strength formations more efficiently than flat cutters. The combination cutting structure (CDE/flat PDC) creates a high-efficiency plowing and shearing action that improves durability yet keeps the bit aggressive enough to obtain the required ROP in lithologies found after conglomerates.
The 12¼-in hybrid CDE bit was tested in three separate wells in the Shushufindi and Aguarico fields, increasing ROP in the difficult lower chert conglomerate section compared with six direct offsets drilled with 519/616-(5 bladed PDC bits with 19-mm cutters and 6 bladed bits with 16-mm cutters) standard type PDC bits and where only one bit was used to drill entire interval considering different well profiles and used drives. In one well, the CDE bit drilled the lower conglomerate at 60.2 ft/h, 34% faster than the best offset ROP of 44.7 ft/h set with a conventional 616 PDC. The hybrid CDE bit was pulled in good dull condition (1-1) with minimum damage considering the high rpm used in the lower conglomerate.
Advanced Drilling and Logging Technologies Give New Life to Aging Fields in Ecuador by Enabling Reentry Drilling
Authors: Sanchez Jose Luis , Carrizo Hector , Salgado Janine , Ordoñez Mario , Rey Fernando , Hazboun Nidal , Laguna Alfonso , Rodriguez Rogers , Larez Aquiles , Ramirez Henry , Astudillo Pedro , Sierra Fabricio , Teran Nayda , Bastidas Marisol , Camacho Gustavo , Bastidas Alejandro , Chancay Armando , Barona David , Carrion Carlos 
Published: November 2015

Abstract
Excellent results from a reentry campaign developed in 2014 in Ecuador have proven the benefits of implementing new drilling technologies for reentry drilling. In this campaign, rotary steerable systems (RSS) were drivers for directional control, and logging-while-drilling tools acquired critical information while drilling. Together these tools open up possibilities for giving new life to aging oil fields and to produce from unexploited drainage zones by enabling reentry drilling.
Drilling the reentry wells in Ecuador involve using the 9.625-in. casing to open an 8.5-in. window and drilling to the geological objectives in just one hole section. For this purpose, the combination of a point-the-bit RSS system, a multi depth laterolog resistivity tool with high-resolution images, and a sourceless tool that delivers density, porosity, spectroscopy, and sigma provided 100% of directional control while acquiring comprehensive formation evaluation information in real time.
Because of the casing configuration in most of the wells in Ecuador, the most commonly used reentry option is to make the window in the 9.625-in. casing and drill the 8.5-in. hole section from the Tena formation (claystone) and Napo formation (several intercalations of claystone, limestone, unstable shales, and pay zones of sandstone). This particular configuration of formation layers is a challenge for directional control and for running wireline logs.
The use of the bottomhole assembly (BHA) with the RSS and tools described above enables successfully drilling the reentries in just one 8.5-in. run, reaching the geological targets with 100% directional control, in spite of the complexity of the well trajectory, and avoiding risks such as packoff, geometrical sticking, and differential sticking. The smoother well profile obtained by use of the point-the-bit RSS and verified through the LWD measurements guaranteed the successful run of the 7-in. liner in all of the reentries drilled in the campaign.
Reentry wells provide operators with the opportunity to have new production at less than half the cost of a completely new well and in less than half of the total execution time.
Building on this reentry campaign, continued reentry drilling will be improved with implementation of the new generation of hybrid RSS (push - and point-the-bit RSS), which will enable drilling engineers to plan trajectories to deliver greater dogleg severities (DLS). This will, in turn, enable developing deeper reentries, further reducing cost and execution time.
Chemostratigraphical Characterization of Stratigraphic Sequences: Upper B Sandstones of Eocene Misoa Formation, Maracaibo Basin, Western Venezuela
Authors: Laya A. E. , Camposano L. 
Published: November 2015

Abstract
The Misoa Formation (Eocene) is characterized by a monotonous succession of sandstones and shales with scarce faunal content. This unit has been divided into several operational bodies based on its lithological, electric and radioactive log character. Its rich oil content, expressed in the wells studied in the area, leads to the need for a better knowledge and understanding of its stratigraphic development, in order to enhance its exploitation. This works is focus on the upper informal units (B1, B2, B3, B4 and B5) where their lithological content of interbedded sandstones and shales, make difficult to generate accurate chronostratigraphic correlations.
Chemical analysis of 298 samples from three wells were developed to establish concentrations of major (wt%) chemical elements expressed in oxide SiO2, TiO2, Al2O3, Fe2O3, MnO, CaO, MgO, Na2O, K2O, P2O5, minor and trace elements (ppm) Ba, Ce, Co, Cu, La, Mo, V, S, Sn, Rb, Sr, Zr, Y, Cr, Ni, Pb and Zn, by using optical emission spectrometry with inductively coupled plasma (ICP-OES). In addition, mutivariate statistical analysis was undertaken to conduct chemical characterization of informal units for each well. The use of inter-elemental ratio (V/Al) and V/(V+Ni) help to define maximum flooding surfaces (MFS) and flooding surfaces (FS), allowing to confirm the MFS-43 previously defined by seismic correlation in the study area.
These results point out those B-informal units have higher geochemical fingerprint that can be chemically correlated and used in other areas of interest at this level of the Misoa Formation. This method probe to be a valuable tool, to be applied reliably statistically in siliciclastic sequences with little or no biostratigraphic control in order to reduce the uncertainty of the stratigraphic model, also this method contributes to the definition of high-frequency stratigraphic surfaces (thirth, fourth, fifth and up to sixth order).
Pressurized Mud Cap Drilling: Feasibility Study for Application in Brazilian Pre-Salt Carbonate Reservoirs and Well Control Issues
Authors: Kuehn Andrej Luigi 
Published: November 2015

Abstract
With the depletion of current oil reserves, drilling engineering is emerging to even more challenging environments. The pre-salt carbonate reservoirs is an example of that, now at the pinnacle of the Brazilian development projects, these reservoirs are located around 200km away from coast, in over 2100m water depth and up to 7000m below sealevel. Since the discovery of these huge fields in 2007 it was believed that the biggest challenge is to overcome the thick salt layer but nowadays drilling into the reservoir has become even more challenging. Carbonate formations are very heterogeneous and total losses are often experienced when fractures or vugs are encountered. The lost circulation in high rates can result in a well control issue if gas starts to flow into wellbore, manly it occurs due to loss of hydrostatic pressure. Pressurized Mud Cap Drilling (PMCD) is one of Managed Pressure Drilling (MPD) variations applied in situations where total or severe losses are experienced. This paper addresses a discussion regarding the application, fluid selection, safety consideration and well control issues using this technique.
Maintaining Production and Ensuring Asset Integrity Through Novel Inhibitor Chemistry
Authors: Salgaonkar Lalit , Belakshe Ravikant 
Published: November 2015

Abstract
This paper probes the properties of a novel naturally sourced material for the corrosion inhibition of different carbon steel alloys in the presence of mineral and organic acids as well as for the inhibition of scales. The inhibitor material is a food-grade chemical derived from a plant commonly used in medicinal formulations. It is easily available, nonpolluting, and, being of plant origin, is biodegradable. The inhibitor can be used either as a solid powder derived from the roots or as a liquid derived by means of extraction.
Corrosion inhibition of commonly used carbon steel alloy, such as N-80, was studied in the presence of corrosive media, such as 15% hydrochloric (HCl) acid and organic acid mixtures comprising acetic and formic acids, under pressurized conditions of 1,000 psi over a temperature range of 150 to 275°F. Weight loss measurements were used to evaluate the effectiveness of the inhibitor, and a corrosion loss of &lt; 0.05 lbm/ft was considered passing grade. Evaluation of inhibitor in liquid state as a scale inhibitor was performed using the testing protocol described in National Association of Corrosion Engineers (NACE) test method TM0374-2007. The inhibition tendency toward two commonly observed scales, calcium and strontium sulfate, was evaluated, which are extremely difficult to remove once formed.
The inhibitor chemical has several N, O, and S atoms containing alkaloid structures, which enhances the capacity of the chemical for adsorption and imparts corrosion inhibition properties. At 250°F, a corrosion loss of 0.03 lbm/ft was observed with 5% inhibitor in 15% HCl acid after a test duration of six hours. At 275°F, 15% inhibitor could achieve a passing grade in three hours. With formic and acetic acid mixtures (9 and 13%, respectively), solid powder (75 lbm/gal) was tested, and a passing grade (0.02 lbm/ft2) was achieved at 275°F for six hours. The inhibitor also has certain functional groups that can trap or chelate the bivalent calcium and strontium ions and prevent the formation of scales. At 0.25% v/v inhibitor concentration, 100% inhibition of calcium sulfate and 18% inhibition of strontium sulfate scale occurred. The calcium compatibility of this chemistry exceeds the performance of most commercially available scale inhibitors. For strontium sulfate, the inhibition tendency improved to 29% when 0.5% v/v inhibitor was used.
The details in this paper align with the drive of the oil and gas industry toward greener chemistries and solutions to issues. The unique corrosion inhibition chemistry exhibited by the material is sufficiently robust to function in both organic and inorganic acid environments under challenging conditions. In addition, the same material can function as a scale inhibitor. The results show the potential for inhibiting sulfate scale as well as other commonly encountered scale.
Identification of Enhanced Oil Recovery Potential in Ecuador
Authors: Tarco J. A. , Arteaga G. R. , Merino S. Achig , Estrella J. M. 
Published: November 2015

Abstract
The objective of this paper is to identify the EOR potential of the Ecuadorian Amazon Region also known as Oriente Basin. The EOR methods are grouped into three: gas injection, enhanced waterflooding, and thermal. 150 oilfields and 410 reservoirs were studied as part of this work.
This study first evaluates the type of EOR method applicable to the oilfields located in the Ecuadorian Amazon Region, also known as screening. The EOR methods evaluated were:
Nitrogen injection CO2 injection Hydrocarbon injection Immiscible injection Polymer flood SP / ASP injection Steam injection, and Combustion in situ
The reservoirs analyzed for all 150 oilfields were:
Basal Tena Napo M-1 Sand Napo M-2 Sand Napo U Upper, Middle, and Lower Napo T Sand Hollin
The necessary inputs or reservoir data for this evaluation came from the Petroleum Information Databank or BIPE, a project from Secretariat of Hydrocarbons of Ecuador (SHE).
The evaluation is not detailed since the objective of this study is to provide a first guide of the theoretical potential of EOR methods in Ecuador. Those fields with more potential than others can go for further details. Due to the reservoir characteristics in the Ecuadorian Amazon Region, the most applicable EOR methods are immiscible gas followed by chemicals (Polymers and surfactants). Additional analyses should be done in order to identify the effects of the waterdrive mechanism in most of the oilfields. The CO2 miscible flood could work, but there are no near natural or anthropogenic sources. The results of this study do not cover either the economic-finance or the legal issues that can affect the implementation of the EOR technology. A second stage of a similar study should evaluate these aspects.
This study is the first work available to public based on data provided by official sources of the Ecuadorian Government. This study can be used for industry, government, and academy as guide for developing or modifying current hydrocarbon legislation.
Fluid Logging and Analysis in Real Time, an Application for Shushufindi-Aguarico
Authors: Navarrete J. , Gordon C. , Garcia M. , Bolanos M. J. , Vega J. , Lafournere J. P. , Naranjo M. , Paladines A. , Bourge J. P. , Suter A. , Henson R. , Delgado P. , Fornasier I. , Morales O. , Badillo V. 
Published: November 2015

Abstract
The Oriente Basin is located in eastern Ecuador at the Amazon rainforest. Shushufindi-Aguarico field is one of the most important fields in Oriente Basin with over 12% of the national production; the main hydrocarbon reservoirs are located inside the Cretaceous formations Napo and Tena. In spite of being a mature field in production since the beginning of 1970s, Shushufindi-Aguarico field still presents various formation evaluation challenges that can potentially be explored to enhance its productivity.
In order to improve fluids characterization in a recently developed area at NorthWest of the field, a new reservoir evaluation technology, Fluid Logging and Analysis in Real Time, is introduced to obtain a continuous log of quantitative composition of hydrocarbon and an improving in the pay zones analysis from gas presence in the mud while drilling.
The prospective intervals determination within the productive reservoirs is performed while drilling with cuttings analysis and chromatography evaluation in real time. This evaluation is based on Gas Ratio Method, which uses the relation between heavy, medium and light gases to identify porous rocks with hydrocarbon presence. The prospective intervals determination using Advanced Surface Fluid Logging technology gives more precision to identify thin beds by eliminating the recycled gas effect than conventional mud logging. In addition, the Advanced Surface Fluid Logging provides fluid composition in the C1-C5 range analogous to the PVT single phase composition. The fluid composition achieved in the main target zone exhibited a close correlation with a convention PVT from a recent offset well.
This paper presents a case study where ASFL technology was tested on a Shushufindi well highlighting valuable benefits, with better pay zones definition in the challenging geological environments encountered in the Shushufindi-Aguarico field. The reliability of the data provided is demonstrated by the good correlation amongst the Fluid Logging and Analysis in Real Time composition recorded in the main target zone and a recent PVT composition from a nearby offset well.
Production Optimization Based on Data Acquisition and Real-Time Monitoring Infrastructure
Authors: Mariach R. , Torres J. , Crespo C. , Gabarron R. J. 
Published: November 2015

Abstract
The purpose of this project is to demonstrate how the real-time infrastructure implemented by ORNCEM as a part of its automation and technical data acquisition architectures is supporting a continuous improvement for production optimization processes.
ORNCEM is responsible for Sacha oilfield exploration and production activities in Ecuador, which is the location of this project and where the entire infrastructure has been deployed and implemented, including software, hardware, telecommunications, personnel, and facilities.
The ORNCEM technical platform is based on a robust telecommunications infrastructure that provides enough accessibility for real-time data acquisition from installed devices throughout the field. Optical fiber is the technology applied to develop the industrial network to improve response time. Hardware is implemented based on the actual and future operational requirements to provide stability and scalability. Specialized applications are implemented to provide tools that help users execute complex tasks, integrate activities into workflows, and store data in a centralized repository where access can be configured based on specific requirements defined by user roles.
The oil industry has experienced drastic changes that have modified business rules, and the optimization resource is one of the parameters to evaluate efficiency in this industry. Aligned to this fact, ORNCEM is working to achieve improvement in three main areas: response time in critical situations, electric submersible pump (ESP) cycle and runtime life, and ESP performance analysis. Real-time monitoring activities enable production personnel to detect any abnormal behavior in wells that can affect production rates and to deploy a correct response for the event in record times. By evaluating ESP features and its optimal performance range and by analyzing well behavior data and well test information, it is possible to increase pump efficiency, lifetime, and runtime cycle. Also, managing electric power consumption compared with volume of fluid produced in wells and working with ESP artificial lift are important factors to determine and evaluate efficiency of production activities and to optimize cost per produced oil barrel.
Heavy Oil Reserve Development by Cycle Steam Stimulation + Gas Process in Bach-01 Reservoir
Authors: Boscán H. , Chourio G. 
Published: November 2015

Abstract
The Bach-01 reservoir has one of Heavy Oil Reserves (12° API) the most importan West Venezuela with an OOIP 6621 MMSTB. Stratigraphically the reservoir is comprised of Miocene sediments (Member Bachaquero, Lagunillas Fm) with a thickness of 750ft, the product of sedimentation prograding fluvial-deltaic domain, being divided into 8 intervals informal (AP, H, G, F, E, D, C, AB), which are marked differences in thickness, rock quality, facies and distribution of fluids. On the other hand, the development plan of the field horizontal wells has been based only on exploiting the upper sand (AP unit), which represents 75% of the OOIP. In this research, we have visualized and conceptualized new opportunities for development of heavy oil reserves, by optimizing steam injection in horizontal wells, through gas injection during the soaking period (CSS+GAS).
The work integrates geological and reservoir of upper-lower sands and thermal evaluation of the optimal parameters of steam injection and rock-fluid characterization. In this research were used field data for making model pit that is the representation of the behavior of production wells, subjected the process of css+gas and weighted data reservoir, for performing a pseudo-compositional thermal simulation black oil system, through which were evaluated the effects caused in the reservoir, by css+gas process. The most outstanding results concerning this process were: increase oil accumulated by cycle, increased volume of the steam chamber in horizontal wells and, decreased viscosity.