bluuebunny/crossref_metadata_2025_split huggingface dataset:
From Screening to Drilling – Planning a Drilling Campaign in an Offshore Mature Field: A Case Study of TSP Field, East Coast Trinidad
Authors: Hernandez M. , Segnini C. , Grimaldi J. , Fernandez M. , Vela R. , Martinez P. 
Published: February 2021

Abstract
Repsol (operator), together with partners Petrotrin and National Gas Company of Trinidad and Tobago, took over operations of mature fields Teak, Samaan and Poui (TSP) Offshore Trinidad at the end of 2005. With the intention of planning further development in the TSP reservoirs (comprising more than 10 vertically stacked main units, highly compartmentalized reservoirs with complex tectonic geometries) an indigenous comprehensive field evaluation was required. Thus, a sand-by-sand Screening Project was carried out with the main objective of identifying the reservoirs with maximum potential so as to direct further technical effort on specific reservoirs for early monetization of reserves.
Based on the results of the sand-by-sand screening project, a prospect validation project for Teak Field was initiated – consisting of extensive field data acquisition, detailed interpretation and modeling workflows, adapted to the particular needs of mature fields. Several incremental opportunities identified during screening were validated and detailed modeling was performed to support further development. On completion of this effort, the company acquired a holistic view of the asset in terms of projects and its remaining resources, so a drilling campaign was envisioned and planning started.
The selection of drilling candidates was not a straight forward process. The number of opportunities had been reduced considerably from the opportunity category to the actual well candidates. Several disciplines developed specific workflows to overcome the challenges, for example: risk assessment for infill opportunities and probabilistic forecasting (Subsurface), trajectory designs including anti-collision, drilling through depleted sands, torque and drag analysis and selecting a suitable rig for the field and production platform conditions (Drilling Engineering); among others.
At the time of submitting this paper, two drilling rigs are moving onto the acreage to start drilling these opportunities by the end of 2013. This paper outlines the different challenges faced, as well as case studies of the evolution and maturation from the screening to the drilling stage of some of the prospects.
Adaptability Study on Plugging Thief Zones with Asphalt Particle in Polymer Flooding Offshore Field
Authors: Xiao K. , Jiang H. , Wang Q. , Wang H. , Zhao D. 
Published: February 2021

Abstract
Polymer flooding has been proved to be an effective method for improving oil recovery in offshore field of Bohai area, but thief zones with high permeability could make the effect of polymer on oil production worse. To try to minimize the negative impact brought by thief zones, we apply asphalt particle to plug the high permeability regions to compel subsequent displacement fluid change flowing direction to enhance sweep efficiency.
Its adaptability is studied by a series of parallel cores flooding. Besides, numerical simulations are carried out to optimize pattern of asphalt particle injection and evaluate the performances of asphalt flooding in a typical well group in Bohai area in a numerical model.
In addition to performances of water cut and oil recovery for the parallel core flooding, we present dynamic features of remaining oil from micro views detected by nuclear magnetic resonance. By plugging thief zone by asphalt flooding, oil production is improved. Production in small and medium pores is increased by asphalt flowing into big pores to exert strong resistance on them. Also, with numerical simulations, optimal way of injecting asphalt has been selected to lead the operation in field. Through observation of a typical well group under asphalt injection in numerical model based on real reservoir, the water-cut and oil production are decrease 9.7% and increase 29.1m3/d respectively. We conclude that asphalt particle has good capacity to plug thief zones to improve sweep efficiency of subsequent displacement fluid in polymer flooding field.
In-depth understanding such mechanisms for asphalt particle behavior may be pivotal for enhancing oil recovery in polymer flooding reservoir containing thief zones.
Reducing Latent Failure and Securing Productivity in High Risk Systems Using High Reliability Theory
Authors: Wattie J. 
Published: February 2021

Abstract
This is a study that represents ongoing academic research into the folds of perception, organizational culture and high reliability. In the shadow of persistent industrial failures it is probable that problems with operational safety reside in abnormalities of culture. Such cultural apparitions regularly fuel failure in high risk technologies making innovation rather unreliable. As innovation grows it is worth the effort to investigate further how resilience in the face of eternal socio-technical biases can be improved. Problem solving approaches offer regressive ideas that increase the chances of deviation and the appearace of disasters.
The assumption is that resilience can be improved in critical operations using High Reliability Theory (HRT). Moreover HRT is more robust when the new constructive method of Appreciative Inquiry (AI) is applied. This early study shows that existing safety culture in a highly reliable group is positively transformed by AI and makes a more productive organization feasible.
Research was conducted from the characteristic insider perspective. A small section of a highly reliable organization was sampled. Using ethnographic methodology feedback from electronic surveying collected personal responses for discussion. While individual interviews proved difficult and the sample group was small there was enough evidence to acknowledge the influence of positive revolution. This study had two major findings a) Using AI methodology stimulates positive, resilient feelings in members and b) members readily used these positive experience to envision a more productive organization.
This study can potentially reduce over emphasis on problem solving methods to explain and change the human factors associated with failure. Cultural factors are better studied and modified by positive influence. The study here makes way for more persuasive academic discussion on resilience by constructivist perspectives. High reliability organizations are more sustainably designed on positive principles.
Asset Integrity Management – Natural Gas Slug Catcher Facility
Authors: Williams D. , Boodoosingh A. 
Published: February 2021

Abstract
Reliable operations of the Natural Gas {Slug catcher} Facility are heavily dependent on flawless operations and also the maintenance system implemented. The maintenance system is driven by the Asset Integrity Management System (AIMS), which incorporates corrosion control, equipment maintenance, pipeline operations and vessel inspection. This system is also supported by continuous monitoring and control using a Process Control System for the natural gas facility. This paper presents an integrated approach to operations of the Slug catcher facility based on AIMS and operational strategies, which are implemented to ensure efficient and effective operations. Additionally, recommendations for further improvement are documented based on a recent Asset Integrity Management Report.
Successful Single-Stage Cementing in a Weak Formation: A Case History in Spain
Authors: Bottiglieri A. , Brandl A. , Martin R.S. , Nieto Prieto R. 
Published: February 2021

Abstract
Cementing in wellbores with low fracture gradients can be challenging due to the risk of formation breakdowns when exceeding maximum allowable equivalent circulation densities (ECDs). Consequences include severe losses and formation damage, and insufficient placement of the cement slurry that necessitates time-consuming and costly remedial cementing to ensure zonal isolation.
In recent cementing operations in Spain, the formation integrity test (FIT) of the open hole section indicated that the formation would have been broken down and losses occurred based on calculated equivalent circulating densities (ECDs) if the cement slurry had been pumped in a single-stage to achieve the operator's top-of-cement goal. As a solution to this problem, cementing was performed in stages, using specialty tools. However, during these operations, the stage tool did not work properly, wasting rig time and resulting in unsuccessful cement placement.
To overcome this issue, the operator decided to cement the section in a single stage, preceded by a novel aqueous spacer system that aids in strengthening weak formations and controlling circulation losses. Before the operation, laboratory testing was conducted to ensure the spacer system's performance in weak, porous formations and better understand its mechanism. This paper will outline the laboratory testing, modeling and engineering design that preceded this successful single stage cementing job in a horizontal wellbore, with a final ECD calculated to be 0.12 g/cm3 (1.00 lb/gal) higher than the FIT-estimated figure.
Microwave Dielectric Properties of Heavy Oil and Heating of Reservoirs
Authors: Callarotti R. C. , Páez E. 
Published: February 2021

Abstract
We have measured the electromagnetic high frequency (~5 GHz) response of heavy oil (API density ~10). The measurements were obtained for oil samples enclosed in high purity quartz vials located in an aluminum cylindrical resonator excited at the TE011 mode by means of microwaves. The oil relative real permittivity e' is found to be of the order of 2.3 with a loss tangent ranging from 0.0005 to 0.00006 depending on the frequency and the oil sample.
We model the heating of reservoirs located at depths of the order of 1000 meters, excited through a cylindrical waveguide (a 6 inch diameter production pipe or a coiled tubing) excited in the TE01 mode. We discuss why this mode was selected and we analyze the attenuation due to various modes in cylindrical waveguides.
The reservoirs considered have variable thicknesses (of the order of several meters). We present results for oil having the permeability of free space, and relative permittivities in the range from e = 2.3-j0.001, to e = 2.3-j0.01. The losses in the metallic circular waveguide walls reduce the surface applied power of 1 Kw to some 200 watts at the top of the reservoir and the mismatch between the empty and the filled waveguide further reduces the applied power due to the impedance mismatch. The power absorbed by the oil in the reservoir increases the temperature in the range of 8 to 20 C. This increase would certainly decrease the oil viscosity, favoring an easier production, but is far too small to cause any upgrading process. We include a discussion of the EROI factor (energy return on energy input) associated with electrical heating of oil reservoirs at low (60 Hz) frequencies and for the high frequency microwave heating process described.
A Nano-Pore Scale Gas Flow Model for Shale Gas Reservoir
Authors: Li Y. , Li X. , Shi J. , Wang H. , Wu L. , Teng S. 
Published: February 2021

Abstract
Many shale/tight gas reservoirs can have pore scale values in the range from one to hundreds of nanometer. And the flow in nano-scale deviate the Darcy's law. Knudsen diffusion and/or gas slippage effects usually have modeled to character the non-Darcy flow mechanisms by many authors.
In this paper, we investigate the non-Darcy flow mechanisms in unconventional gas reservoirs, and classify these various mechanisms based on different pore scale and pressure. Then, based on the change of pore scale and pressure, the models of gas flow that consider the absorption, desorption, slip flow, transition flow, Knudsen diffusion and continuous flow in nano-pore have been proposed to evaluate the flow character. Then, the relationship between the absorbed layers and pressure or Langmuir coefficient has been built and the influences of absorption of gas molecule have been studied on the permeability change. Compared with experimental value, the model could agree with the experimental value very well. And, desorption of the absorbed layers make the pore diameter become larger. When the thickness of the absorbed layers and the pore diameter ratio is larger than 0.1, the effect of adsorbed layer becomes very significant.
With this study, the change of permeability and the gas rate on entire long term production performance could be understood better and predicted, and it is very important for the optimization of production performance and adjustment.
Reintroduction of Carbon Dioxide Supply from Central to South Trinidad via Pipeline – Perspectives and Possibilities for Using Present System
Authors: Butcher S.A. , Isaac J. , Frontin-De Peaza C. 
Published: February 2021

Abstract
Increasing oil production in Trinidad and Tobago (T&T) by means such as Enhanced Oil Recovery (EOR) may be a more cost effective and less risky pathway, when compared to the drilling of exploration and appraisal wells. This is because the fields and reservoirs that would be considered for EOR projects are generally in an advanced state of delineation and there has been experience derived from production data for some time. Considering the scope/applicability of carbon dioxide EOR (CO2-EOR), the revitalization of such projects in T&T would aid in extending the use of CO2 to another purpose, given its useful properties and behaviour, before being emitted to the atmosphere.
Five CO2 EOR pilot projects were implemented in South Trinidad, starting in the early 1970's. At that time, as it is now, Trinidad had abundant CO2 available as a waste product from the ammonia manufacturing operations at the Point Lisas Industrial Estate (PLIE), Central Trinidad. At present, consideration is being made for the reintroduction of CO2 pipeline transport, directed to suitable EOR candidate sites mainly in South Trinidad, focusing once more on CO2 sourced from the PLIE.
Det Norske Veritas (DNV) has introduced a Recommended Practice (RP) on the Design and Operation of CO2 Pipelines (RP-J202), incorporating lessons learned from existing CO2 pipelines around the world. This RP provides guidance for managing risks and uncertainties during the lifecycle of a CO2 pipeline, including design, testing, inspection, operation, maintenance, and de-commissioning.
This paper will use DNV-RP-J202 to present a guiding framework for the possible re-qualification of sections of the existing CO2 pipeline network in Trinidad for the reintroduction of safe and efficient CO2 pipeline operations. The re-qualification process entails the following steps: Initiation, Integrity Assessment, Hydraulic Analysis, Safety Evaluation, Premises, Re-assessment, Modification Alternative(s), Documentation and Implementation.
On completion of the re-qualification process, the majority of the pipeline system may not be acceptable for reintroduction of CO2. Options for consideration can be an adjustment of the pipeline routes where sections of pipeline network are not in acceptable condition, or the development of a completely new pipeline network and/or new routes.
Application of an Integrated Methodology for Pre-Filtering of EOR Technologies
Authors: Nnang-Avomo T. , León-Carrera M. F. , Escobar-Alvarez E. , Rodríguez-Morillas N. , Mancera-González A. , Guitian-López J. 
Published: February 2021

Abstract
This paper presents a new methodology developed in the Repsol Technology Center (CTR), to perform the prescreening of Enhanced Oil Recovery (EOR) processes in an innovate and integrated way. The methodology consists in four stages adapted to different levels of available information: 1) an analogous reservoir identification step, where it is analyzed the experience in terms of EOR applications in similar reservoirs; 2) a go/no go pre-screening scheme of EOR technologies based on average reservoir and fluid properties; 3) a more detailed screening using reservoir and fluid properties distribution defined in 3D geological model, where areas of EOR application are identified and the volumetric impact is estimated; and 4) a qualitative ranking of the pre-selected EOR technologies, considering three main factors: the oil recovery, the success factor and the estimated cost of the process including the environmental impact.
This methodology has been successfully applied in real fields. In this paper, we will present four different cases showing the flexibility of CTR workflow. Case A and Case B are examples of offshore, brown, light- medium oil fields, of sandstone and carbonates respectively. Cases C and D are illustrations of onshore, sandstone, heavy and extra-heavy oil fields correspondingly.
Determination of Bubble-Point and Dew-Point Pressure Without a Visual Cell
Authors: Hosein R. , Mayrhoo R. , McCain W. D. 
Published: February 2021

Abstract
Bubble-point and dew-point pressures of oil and gas condensate reservoir fluids are used for planning the production profile of these reservoirs. Usually the best method for determination of these saturation pressures is by visual observation when a Constant Mass Expansion (CME) test is performed on a sample in a high pressure cell fitted with a glass window. In this test the cell pressure is reduced in steps and the pressure at which the first sign of gas bubbles is observed is recorded as bubble-point pressure for the oil samples and the first sign of liquid droplets is recorded as the dew-point pressure for the gas condensate samples.
The experimental determination of saturation pressure especially for volatile oil and gas condensate require many small pressure reduction steps which make the observation method tedious, time consuming and expensive. In this study we have extended the Y-function which is often used to smooth out CME data for black oils below the bubble-point to determine saturation pressure of reservoir fluids. We started from the initial measured pressure and volume and by plotting log of the extended Y function which we call the YEXT function, with the corresponding pressure, two straight lines were obtained; one in the single phase region and the other in the two phase region. The point at which these two lines intersect is the saturation pressure.
The differences between the saturation pressures determined by our proposed YEXT function method and the observation method was less than ± 4.0 % for the gas condensate, black oil and volatile oil samples studied. This extension of the Y function to determine dew-point and bubble-point pressures was not found elsewhere in the open literature. With this graphical method the determination of saturation pressures is less tedious and time consuming and expensive windowed cells are not required.
Systems Approach to Fluid Sampling for Real-Time Testing without Sticking
Authors: Galvan-Sanchez F. , Hinkle A. , Solomon H. 
Published: February 2021

Abstract
Downhole fluid samples enable better quantification of condensate-to-gas ratios that are required for effective reservoir estimation and forecasting. Quality of samples directly affect the measured properties, i.e., fluid compressibility and viscosity, that provide the supplemental information necessary for planning prospective wells through improved understanding of the reservoir.
An industry-leading, logging-while-drilling (LWD) fluid analysis and sampling tool was successfully deployed on 21 jobs with 46 runs to date, and completed 400 pressure tests with 109 samples recovered worldwide in shelf and deepwater projects. This paper highlights a new systems application for this technology to acquire single-phase fluid samples for a major operator in Trinidad. The acquired data was used for early investigation of reservoir connectivity.
The technology was introduced to the oil and gas industry in 2011. High sample quality, testing without sticking, and sample acquisition in complex well geometries and designs differentiates this technology for fluid analysis and sampling from existing wireline alternatives. Benefits of the LWD method include improved cleanup time due to reduced invasion, reduced overall sample acquisition costs, and reduced risk of stuck pipe. This method enables sampling in extended-reach wells and enables accurate fluid identification of oil, gas or water.
This paper describes the learning and the innovative systems methodology employed to successfully attain information pertinent to evaluating and understanding reservoirs.
The Study of CO2 Flooding of Horizontal Well with SRV in Tight Oil Reservoir
Authors: Wang H. , Liao X. , Zhao X. , Ye H. , Dou X. , Zhao D. , Lu N. , Zhang Q. 
Published: February 2021

Abstract
As one kind of unconventional reservoirs, tight oil reservoir has become one of the main forces of oil reserves and production growth. The characteristics of tight oil reservoir are low porosity and ultra-low permeability, thus stimulated reservoir volume (SRV) should be conducted whether applying the mode of vertical wells or horizontal wells production. Tight oil reservoir is mostly developed by natural depletion or water flooding recently, but the problems are existed, including low recovery factor with natural depletion and the difficulty of water injection. To further improve the development effect of tight oil reservoir, CO2 flooding is proposed.
Based on chang-8 tight oil reservoir in Ordos Basin, an oil sample of typical block is selected. The PVT experiments are conducted. The compositional numerical model of five-spot pattern is established with a horizontal well in the middle and 4 vertical wells on the edge. Based on the model, several CO2 flooding scenarios of horizontal well with different completion measures are studied. Furthermore, parameters such as the formation pressure, production rate, shut-in gas-oil ratio and total gas injection volume are optimized.
The results of this study show that the recovery factor of horizontal well with SRV is higher than those of horizontal well and conventional fractured horizontal well. The minimum miscible pressure (MMP) and the total gas injection volume are two key factors of CO2 flooding effect. CO2 flooding of volume fractured horizontal well in tight oil reservoir can not only improve oil recovery, but also realize CO2 geological sequestration. It plays dual benefits of economy and environment.
The study gives new ideas of CO2 flooding with volume fractured horizontal well for the Ordos Basin tight oil reservoir. It can be helpful for rapid and effective development of tight oil reservoirs in Ordos Basin.
Multiclient 3D Seismic Surveys in Trinidad and Tobago – Towards a Policy
Authors: De Landro-Clarke W. , Bradshaw-Niles P. 
Published: February 2021

Abstract
It is said that it is politics not science that finds oil, by this is meant that the policies of governments create the conditions conducive to the exploration for petroleum. The converse is also true; lack of policy can also remove incentive to explore. The government of Trinidad and Tobago has applied many policies with respect to the petroleum sector, some with great success but there is always a need for dynamism in policy making to keep pace with changing industry conditions and to remain competitive. This paper is aimed at moving policy forward for obtaining new seismic data on open marine acreage through the use of 3D multiclient surveys.