bluuebunny/crossref_metadata_2025 huggingface dataset:
Software Tool for the Study, Analysis and Evaluation of Enhanced Oil Recovery Processes
Authors: Delgadillo-Aya C. L. , Trujillo-Portillo M.L. , Palma-Bustamante J.M. , Niz-Velasquez E. , Rodríguez C. L. , Leon-Martinez N. E.
Published: February 2021

Software tools are becoming an important ally in making decisions on the development or implementation of an enhanced oil recovery processes from the technical, financial or risk point of view. This work, can be manually developed in some cases, but becomes more efficient and precise with the help of these tools.

In Ecopetrol was developed a tool to make technical and economic evaluation of enhanced oil recovery processes such as air injection, both cyclic and continuous steam injection, and steam assisted gravity drainage (SAGD) and hot water injection. This evaluation is performed using different types of analysis as binary screening, analogies, benchmarking, and prediction using analytical models and financial and risk analysis.

All these evaluations are supported by a comprehensive review that has allowed initially find favorable conditions for different recovery methods evaluated, and get a probability of success based on this review. Subsequently, according to the method can be used different prediction methods, given an idea of the process behavior for a given period. Based on the prediction results, it is possible to feed the software to generate a financial assessment process, in line with cash flow previously developed that incorporates all the elements to be considered during the implementation of a project. This allows for greater support to the choice or not the application of a method.

Finally the tool to evaluate the levels of risks that outlines the development of the project based on the existing internal methodology in the company, identifying the main and level of criticality and define actions for prevention, mitigation and risk elimination.
A Case Study of Integrated Asset Modeling to Support Reservoir Management Strategies for Four Dry Gas Fields Sharing Production Facilities
Authors: Espinola O. , Rocha M. , Alvarez N. C. , Ramirez J.R. , Solis A. , Guzman-Arevalo J.D.
Published: February 2021

The integrated asset modeling has gained popularity in the last years because it has a positive impact on field development, optimization and reservoir management. Especially it has become a must be to properly analyze the interaction between a reservoir and its production facilities or to predict the behavior of several fields sharing a common surface production facility (Ghorayeb, k. 2005).

As a result of the strategic development plan, PEMEX Veracruz Asset has been discovering dry gas fields which must be produced through shared production facilities in order to be economic. This poses a complex operational scenario that demands the use of technology that enables the analysis of the whole system and the interrelation of its elements to support the reservoir management strategies.

This paper describes a case study in which four reservoir models were coupled with a production network model, with the objective to maximize the recovery factor, identify operational problems along the exploitation, and also evaluate the water production impact, through the Integrated Asset Modeling (IAM) enabling the design of different exploitation strategies including compression stages and evaluate them both technically and economically.

Besides it includes a full description of the modeling process with all the assumptions, constraints, solving method and results obtained. This methodology has been successfully implemented adding value to the asset due to a proven improvement in the reservoir management, operational plans and decision making process.
Productivity Prediction of Coalbed Methane Considering the Permeability Changes in Coal
Authors: Chen H. , Li M. , Zhang Y. , Liu C. , Li Y.
Published: February 2021

This paper describes a three-dimensional numerical model for predicting the coalbed methane (CBM) production. The model describes single phase gas desorption from coal matrix, diffusion to the fracture and two-phase flow of gas and water in the natural fracture system as well as the permeability changes in coal which result from effective stress changes and matrix shrinkage due to gas desorption. The model was discretized by a finite difference method. The implicit pressure-explicit saturation (IMPES) method was used to solve the two-phase flow equations and gas desorption equation was solved implicitly.

The numerical model was validated by the field data from Qinshui basin in China. Based on the model, the impact of various reservoir and Langmuir isothermal adsorption parameters on the gas production was investigated.

The results show that the gas production rate of the coalbed methane predicted by this model is in good accordance with the field data. The permeability near the wellbore dramatically decreases as the reservoir pressure drops at the early production period while at the later production period, the permeability near the wellbore increases because of the matrix shrinkage. The permeability changes far away from the wellbore are not so remarkable. In addition, the gas production rate increases with the increased permeability, seam thickness and Langmuir pressure constant while it decreases with the increased porosity and Langmuir volume constant.

The numerical model can be used to predict and analyze the production performance of CBM reservoirs and the research results provide theoretical support for CBM production.
Probabilistic Analysis by Applying Uncertainty Worflows: A Case Study of the Teak Field, East Coast Trinidad
Authors: Segnini C.J. , Rashwan M. , Hernandez M.J. , Rojas J. A. , Infante M.A.
Published: February 2021

This paper presents a methodology for the probabilistic analysis of an infill or step-out opportunity using numerical simulation. Sensitivity and uncertainty analyses for all involved parameters were evaluated through different experimental design techniques. Subsequently, a proxy model was established to reproduce the numerical model performance. Finally, three appropriate solutions were selected from a large population of realizations corresponding to probabilistic percentiles (90%, 50%, and 10% certainty that the specified volume will be recovered).

This proposed methodology helped the asset team to evaluate the well candidates more precisely, confidently, and in less time than the current standard methodology. More knowledge about the variables and their effects on overall outcomes was also gained, which helped the team make more-informed decisions. The workflow used the same numerical modeling software, incorporating and facilitating the changes of both static and dynamic properties simultaneously.

A case study from Teak field, on the east coast of Trinidad, illustrates the applicability of the methodology and compares its results to those obtained using the standard workflow for the asset. The methodology is one of the latest developments in reservoir simulation, and it has not yet been incorporated into the operator's common practices and procedures for exploitation of the TSP fields.
Options for Monetising Deep Water Gas in Trinidad and Tobago
Authors: Alleyne N. A. , Stoute V.
Published: February 2021

Notwithstanding the global thrust to develop renewable sources of energy, fossil fuels, coal, crude oil and natural gas are expected to play a significant role in meeting the world's energy needs for decades to come. Natural gas with the highest hydrogen concentration among the fossil fuels is the preferred fossil fuel from an environmental impact standpoint. Trinidad and Tobago, like the rest of the world, is taking its petroleum exploration activities into deep water, its onshore and continental shelf provinces being fully explored. The development of petroleum reservoirs in deep water has many challenges.

This paper explores the unique challenges posed by developing deep water gas fields with a focus on the options available for monetising the natural gas produced from these fields. The options for getting gas to market are well known and include pipelines, liquefied natural gas (LNG), compressed natural gas (CNG), gas to solid petrochemicals (GTS), gas to liquids (GTL) and gas to wire (GTW). Most of these options are operating in Trinidad and Tobago. The paper evaluates the financial outcomes from applying the pipeline, LNG and CNG options, either offshore or onshore, for gas extracted from deep water fields across a range of reserve levels and well productivities. It aims to establish criteria for deciding which means of monetisation is preferred. The reserve and productivity ranges reflect typical values encountered in the deep water provinces in Latin America, North America and Africa. These provinces account for 85% of all the deep water fields and 74 % the deep water reserves which have been discovered worldwide.

Because the paper focuses on the monetisation of natural gas, its findings will be applicable to any successful deep water exploration in Trinidad and Tobago because all situations, even the discovery of oil, will require that the associated gas be handled. The handling of gas has the potential of being on the critical path in deciding on the development of deep water fields in Trinidad and Tobago.
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

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

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

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

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

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

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

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

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

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

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

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

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

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.
The Critical Role of HSSE Management and its Impact on Productivity and Corporate Social Responsibility's (CSR's) Mandate and Influence on Trinidad& Tobago's Energy Sector
Authors: David B.A. , Manswell M.N.
Published: February 2021

Today's energy sector has evolved by leaps and bounds in the sphere of Health, Safety, Security and the Environment. The minimization of incidents on board oil and gas platforms and by extension the energy sector continues to be the highest standards of HSSE performance companies aspire to. Our current fiscal environment has forced countries and companies to carefully consider how limited finances are to be utilized and managed to achieve outlined targets. This shrinking financial pie has also seriously impacted on the Corporate Social Responsibility (CSR) Plan for companies within the sector. Fiscal management is key in a global village where every dollar counts. In the case of Trinidad and Tobago we must seek to secure our future assets be it through acquisition, maintenance and reliability. CSR must be comprehensively managed ensuring that both the corporate entity and the various indigenous communities get full value for the relationship they might be part of. The free spending attitude is definitely a thing of the past. Proper investments into a company's CSR, particularly where it adds value to the communities where there are vested interests are of paramount importance.

This paper will advance the value of having a robust quality benchmarked HSSE portfolio/system utilizing the Plan Do Check Act (PDCA) mechanism and how it impacts on company productivity. The role, value and impact of CSR will also be scrutinized highlighting its critical importance in today's changing corporate landscape.
Analyzing Edge Water Drive Laws of Offshore Heavy Oil Reservoir with Physical Experiment and Numerical Simulation
Authors: Feng Q. , Li S. , Su Y. , Liu Y. , Han X.
Published: February 2021

The existence of edge water has both advantages and disadvantages for the development of offshore heavy oil reservoir. On one hand, edge water invasion could supplement the reservoir pressure which is in favor of the oil production, while on the other hand, the asymmetrical invasion of the edge water could result in the quick increase of water cut for production wells and the consequent low oil recovery efficiency.

For the purpose of better understanding edge water drive laws of offshore heavy oil reservoir and their effects on remaining oil distribution, several two dimensional visible physical models with different well-types, which are based on geological features and development characteristics of a certain offshore heavy oil reservoir in China, have been built to make the investigation. The experimental results are analyzed and shown as follows. Firstly, edge water mainly encroaches through areas with the maximum pressure gradient in homogeneous reservoir. But for heterogeneous reservoir, edge water would encroach through both high permeability section and areas with maximum pressure gradient. Meanwhile, compared with heterogeneous reservoir, there is more obvious water/oil front and higher reserve recovery degree in homogeneous reservoir under the same conditions. Secondly, the degree of reserve recovery obtained by double vertical wells is much higher than that obtained by single vertical well. So, increasing the number of production well is conducive to the improvement of reservoir recovery degree. Lastly, the recovery efficiency for horizontal well is much higher than that of the vertical well.

In addition, Suizhong 36-1 Oilfield, an offshore heavy oil reservoir with edge water drive, has been numerical simulated. The simulated results of edge water drive laws are consistent with the experimental results, which could provide a useful guidance for the development of offshore heavy oil reservoir with edge-water drive.
Reserves Evaluation of Dry Gas Reservoirs through Flowing Pressure Material Balance Method
Authors: Guzman J.D. , Arevalo J.A. , Espinola O.
Published: February 2021

This paper describes the practical applicacion of a method known as Flowing Gas Material Balance FGMB (L. Mattar and Mcneil, 1997) for reserve's estimation using bottomhole flowing pressure data in two dry gas fields in Mexico. The main purpose of this work is to apply the method in real cases having enough data and make a comparison with other standard methods of reserves estimation (J. Lee, 1996 and G.J. DeSorcy, 1994) such as Volumetric, Decline Curve Analysis, Conventional Material Balance and Numerical Simulation to see the results and validate the efficacy of its application.

There are some premises should be considered before its application that will be explained, besides the advantages and results of this comparison which showed differences no greater than 10% with respect to the method more trustable to report reserves for these reservoirs.
Trinidad and Tobago: Diving into the Deep but at What Cost?
Authors: Nickie A. W.
Published: February 2021

Deep-water has long been proclaimed as the hydrocarbon frontier with huge potential of resources. The offshore basins of West Africa, Gulf of Mexico and Brazil are particularly known for deep-water campaigns. Trinidad and Tobago is no stranger to deep-water activity having drilled eight deep water wells in the last decade. After a period of dormancy, it may soon rejoin its global counterparts as it prepares to dive into the deep yet again.

In 2011 and 2012, two deep water bid rounds were held and ten companies/consortia dared to venture into the deep but only three won the opportunity. Eleven thousand, six hundred and fifty seven square kilometres (11, 657 km2) was awarded out of a total acreage of twelve thousand, eight hundred and six square kilometres (12, 806 km2) for the past two bid rounds. With such potential activity, Trinidad and Tobago's commercial success in the deep may seem to be imminent but this is far from certain as exploration and development costs are substantially higher than those in our shallower areas. While commercial success is dependent on government share, hydrocarbon volumes and project costs, this paper focuses only on the latter.

This paper compares and analyses Trinidad and Tobago's proposed Deep-water development project costs with other global deep-water field development costs, by investigating scenarios in terms of estimated development capital and operational expenditure and associated volumes. Capex and Opex of USD 12-14 Bn was required for developments between 500-750 mmbbl and the average global sample estimated for this volume range was USD 13 Bn. The paper concludes that Trinidad and Tobago's proposed project costs are indeed in line with other global developments.

Undoubtedly, deep water exploration and development demands huge investments. Trinidad and Tobago's deep-water venture will soon commence and understanding these proposed costs would shed some light on its position in the deep and help prepare for what lies ahead.
New PDC Bit Technology Sets the Standards in Drilling Hard and Abrasive Formations in Oman - Case Study
Authors: Maouche Z. , Al-Rawahi F. , Agapie I. , Parasher M. , Al Nahwi Talal
Published: February 2021

Historically, the hardest and most abrasive rock formations in Oman have been drilled using either diamond-protected, roller-cone insert bits or impregnated bits in combination with high-speed drives. Polycrystalline diamond compact (PDC) bits have been successfuly used to drill soft and non-abrasive formations to depths of approximately 2, 500 m. Within this region, all previous attempts to drill deeper into the hard and abrasive intervals have resulted in rapid bit wear, poor rate of penetration (ROP), and repetitive trips for bit change. A new PDC cutter technology combined with a novel multi-level cutting structure force balancing has extended the PDC bit footprint, setting new records for drilling the longest intervals of hard and abrasive sandstone formation in Oman. This new technology is the result of a program committed to two years of research, which focused on the improvement of PDC cutter wear and impact resistance, as well as addressing bit vibration and wear distribution issues. As a result, Halliburton DBS PDC bits have become the standard for drilling hard and abrasive rock in the Middle East, providing significant improvement with respect to distances drilled and ROP. In rotary mode, or in combination with low-cost drives, this new technology has drastically reduced the operational cost per foot drilled in Oman.
Application of Multistage Hydrajet-Fracturing Technology in Horizontal Wells with Slotted Liner Completion in China
Authors: Hai Qu , Xiaoxiang Zhao
Published: February 2021

Multistage hydrajet-fracturing combines hydrajet perforating and hydraulic fracturing to perform separate, sequential fracture stimulations without mechanical packers. It can reasonably place fractures according to geological condition, and then accurately treat them. Without packer, it uses dynamic isolation to seal flow into target, saving operating time and lowering operating risk. Therefore, the process not only especially adapts to stimulate open hole, but effectively treats slotted liner completion.

The mechanisms and fluid dynamics of multistage hydrajet-fracturing technology are investigated with numerical simulation and laboratory experiments. More than 70 oil and gas wells have been successfully treated using this technology since 2009. On average, three hydraulic fractures with total 120m3 proppants were placed at strategically selected locations in well, typically several hundred meters apart without sealing equipments. The deepest treatment in oil well 203-19 in Zhongyuan oilfield, using tubing string, was 3692m, and surface pressure reached 88MPa. Significant stimulation results were achieved in these wells. For example, production increased by more than 50 times after stimulation to the gas well XS311H in Sichuan oilfield. The oil well 92-2 in the Zhongyuan oilfield, which had been a dead horizontal well, has been revived using this technology with average oil production of 15 tons per day.

Multistage hydrajet-fracturing stimulation shows promising feature for horizontal, vertical, deviated, and even multilateral wells.
An outbreak report of vancomycin-resistant Enterococcus faecium outbreak in a Dutch general hospital, 2014-2017: successful control with a low impact strategy
Authors: Weterings Veronica , Oosten Anita Van , Nieuwkoop Ellen , Nelson Jolande , Voss Andreas , Wintermans Bas , Lieshout Joris Van , Kluytmans Jan , Veenemans Jacobien
Published: February 2021

Background
We describe the control of a large VRE outbreak in a Dutch general hospital in 2014–2017.
Methods
After the outbreak was identified, a screening policy consisting of a single rectal swab culture (with enrichment broth) to identify VRE carriage in high risk patients, was implemented. In addition to screening, measures to improve compliance with standard infection control precautions and enhanced environmental cleaning were implemented to control the outbreak.
Results
Between September, 2014 and February, 2017, 140 patients were identified to be colonised by vanA mediated vancomycin-resistant Enterococcus faecium (VREfm). Three of these patients developed bacteraemia. AFLP typing showed that the outbreak was caused by a single clone. Extensive environmental contamination was found in multiple wards. Within nine months after the detection of the outbreak no new VRE cases were detected.
Conclusion
We implemented a control strategy based on targeted screening and isolation in combination with implementation of general precautions and environmental cleaning. The strategy was less stringent than the Dutch national guideline for VRE control. This strategy successfully controlled the outbreak, while it was associated with a reduction in the number of isolation days and the number of cultures taken.
Differential mitochondrial proteomic analysis of A549 cells infected with avian influenza virus subtypes H5 and H9
Authors: Yang Yuting , Zhang Yun , Yang Changcheng , Fang Fang , Wang Ying , Chang Haiyan , Chen Ze , Chen Ping
Published: February 2021

Background
In the past 20–30 years, both the highly pathogenic avian influenza (HPAI) H5N1 and low pathogenic avian influenza (LPAI) H9N2 viruses have been reported to cross species barriers to infect humans. However, H5N1 viruses could cause severe damage and a high death rate, but H9N2 viruses could not. In this study, we use H9N2 virus infection as a control to investigate the differential expression of mitochondrial-related proteins caused by H5N1 and H9N2 virus infections in A549 cells.
Methods
According to the determined viral infection titer, A549 cells were infected with 1 MOI (multiplicity of infection) virus, and the mitochondria were extracted after 24 hours of incubation. The lysed mitochondrial protein was analyzed by BCA method for protein concentration, SDS-PAGE preliminary analysis, two-dimensional gel electrophoresis, and mass spectrometry. Select different protein spots, perform Western Blot to verify the proteomics results, and then perform GO and KEGG analysis.
Results
In the 2-D gel electrophoresis analysis, 227 protein spots were detected in the H5N1-infected group, and 169 protein spots were detected in the H9N2-infected group. After further MS identification and removal of redundancy, 32 differentially expressed proteins were identified. Compared with the H9N2 group, the H5N1-infected group had 16 upregulated mitochondrial proteins and 16 downregulated proteins. The 70 kDa heat shock protein analogs, short-chain enoyl-CoA hydratase, malate dehydrogenase, and ATP synthase were verified by Western Blot, and the results were consistent with proteomics.
Conclusions
Functional analysis indicated that these differentially expressed proteins were involved mainly in apoptosis, metabolism and the cytoskeleton. The differential expression of eight mitochondrial proteins in H5N1-infected cells resulted in decreased T cell activation, decreased antigen presentation and stress response, reduced ATP synthesis, and decreased induction of apoptosis, resulting in the higher pathogenicity of H5N1 virus than H9N2 virus.These finding may provide a basis for analyzing the pathogenesis of influenza viruses with different virulence levels, identifying anti-influenza host targets and developing new influenza vaccines.