bluuebunny/crossref_metadata_2025_split huggingface dataset:
Commercial Application of Dual Completion Technology
Authors: Garifov K.M. , Glukhoded A.V. , Ibragimov N.G. , Fadeev V.G. , Zabbarov R.G. 
Published: February 2011

Abstract
TATNEFT’s fields are, for the most part, multilayered with two and more development targets, which makes dual completion technology an optimal reservoir management solution.
The Company’s first dual completions date back to the 1960-ies, however, deficiency of oilfield hardware, especially, packers, as well as lack of production control equipment prevented commercialization of this technology.
The last decade witnessed a revived interest to dual completions.
TATNEFT has been successfully implementing dual completion technology since 2003. Different dual completion systems to meet different production conditions have been developed.
Completions with one and two strings of tubing using sucker rod pumps have found wide application. The singletubing-string completion system is used to produce from two segregated productive zones isolated with a packer. Though the well stream is commingled, methods to determine production rates, water cut, and bottomhole pressure for each target are available.
The two-tubing-string completion system has been known since 1950-ies, and in its present configuration includes the in-house dual-string wellhead equipment, parallel anchor, and M1-X production packer.
For more prolific wells two different production systems based on combination of electric submersible and sucker rod pumps are used: with commingled and non-commingled production. Production options for high viscosity oil provide for progressing cavity pumps. Also, dual completion technologies for injection using one and two packers have been developed.
By now, dual completion systems have been installed in more than 500 production and injection wells with incremental ultimate recovery exceeding one million tons of oil.
Dual completion technology has proved its efficiency for increase and stabilization of the production level, and it is one of the priority investment projects of the Company. TATNEFT plans expanding scope of the technology application, development of new dual completion systems, and improvement of existing ones.
Restimulation of Unconventional Reservoirs: When are Refracs Beneficial?
Authors: Vincent M. C. 
Published: February 2011

Abstract
Restimulation treatments have been attempted in a wide variety of reservoirs, and more than 140 papers have been published documenting the success and failure of these efforts. A database of these published examples has been compiled and analyzed to identify the mechanisms responsible for production improvement following restimulation with propped fractures (refracs). A portion of this database was recently published (Vincent 2010), and specific field examples were highlighted to demonstrate that refrac treatments can improve production by numerous mechanisms including:
– Enlarged fracture geometry – Improved pay coverage through increased fracture height in vertical wells – Greater lateral coverage in horizontal wells or initiation of more transverse fractures – Increased fracture conductivity compared to initial frac – Restoration of fracture conductivity loss due to embedment, cyclic stress, proppant degradation, gel damage, scale, asphaltene precipitation, fines plugging, etc. – Increased conductivity in previously unpropped or inadequately propped portions of fracture – Use of more suitable fracturing fluids – Reorientation due to stress field alterations, leading to contact of "new" rock
This paper will briefly review restimulation attempts in six Canadian reservoirs of interest to the local audience, and will then present a more detailed review of restimulation of horizontal wells in the unconventional Bakken oil formation. In addition to a summary of published results, this paper will introduce a significant amount of previously unpublished data regarding refrac treatments of horizontal laterals completed in the Middle Bakken. This study will identify several additional concerns and opportunities with restimulating horizontal wellbores that were not previously identified in literature reviews. This organized summary of field results and references will provide significant value to readers evaluating or designing restimulation treatments.
A Numerical Study of the Effects of Packer-Induced Stresses and Stress Shadowing on Fracture Initiation and Stimulation of Horizontal Wells
Authors: Singh I. , Miskimins J. L. 
Published: February 2011

Abstract
"Stress shadowing", where the creation of hydraulic fractures affect the stresses in certain parts of the reservoir, has the dual effect of assisting and hampering the generation of hydraulic fracture stimulation in horizontal wells. In this paper, the stress contrast and pressure profiles around the near wellbore regions of a horizontal wellbore with the presence of packers and hydraulic fractures are investigated. This was accomplished by using a finite element software package where the numerical results of the behavior of the stress envelopes and stress shadowing phenomena could be evaluated and different sensitivities analyzed.
From the results obtained, it is concluded that packers with higher pressure generation allow for easier fracture initiation as compared to packers with lower pressure generation. Additionally, modeling indicates that the weakest point for fracture initiation in a wellbore with a packer is at the ends of the packer. When two packers, with differing pressure generations, are placed in the wellbore, fracture initiation will occur near the packer with the higher pressure generation. Finally, it can be concluded that in areas of high stress concentration, the ability to generate hydraulic fractures is reduced as compared to areas of low stress concentrations.
Pseudo-components for Nigerian Heavy Oil and Bitumen
Authors: Lawal Kazeem A. , Adenuga Ademola O. 
Published: February 2011

Abstract
In composition and behaviour, bitumen and heavy oil are more complex than conventional oil; hence they pose greater challenges for reservoir and process simulations. This notwithstanding, one practical approach for constructing efficient fluid-property models is the lumping technique, entailing the use of pseudo-components (PC). However, this is not so straight-forward, especially for these unconventional hydrocarbons whose compositions are typically available as chemical aggregates (saturates, aromatics, resins and asphaltenes) rather than the common and more convenient pure components.
This paper highlights key issues affecting construction of PC’s in general, and limits them to heavy oil and bitumen. It argues that the number and characters of PC’s should be influenced by prospective method of development, processing as well as the nature of fluids the crude would contact. Hence, process-based PC schemes are proposed for the Nigerian unconventional crudes. As an example, the number of components required for a thermal process using asphaltene-precipitating injectant (e.g. CO2) and that of a process based on steam, a non-precipitant, is shown to differ. Similar distinctions are indicated between thermal and solvent-based processes.
For some reference conditions, it is demonstrated that the Nigerian heavy crude can, in its simplest form, be reasonably represented as a single-component and up to five components where it is likely to undergo more complex processes or when greater details are necessary. With minor modifications, the proposed schemes should be adaptable to heavy crudes elsewhere.
Applied Strategic Dependability Functions and Models for Effective Asset Integrity Management in Organization
Authors: Arhagba Arierhe 
Published: February 2011

Abstracts
At a time like this, a time of Global Economic Meltdown, financial and general economic recession, is a time to be more innovative, and find new ways of adding value to our overall corporate performance portfolio. A paradym shift in areas of asset integrity management that has largely centred on systems reliability management approach becomes an imperative.
In this paper, a dependability model is formulated to enhance our asset integrity management. This is actually a re-engineering of the entire process of systems asset integrity management and it is organization specific.
A whollistic system information bank is robustly entrenched in the maintainability and availability functions which are dependability and capability functions. Then, applied strategic dependability functions and models for effective and efficient assets integrity management in organizations are a necessity for corporate survival.
The paper emphasis systems audit of all the financial elements to ensure cost effectiveness and quality assurance of such specifications. Then a thorough process re-engineering of all the existing asset integrity management processes and procedures becomes a necessity for effective and efficient system overall performance.
Prediction of Volumetric Sand Production and Stability of Well-Bore in a Niger-Delta Formation
Authors: Adeyanju O. A. , Oyekunle L. O. 
Published: February 2011

Abstract
Nigeria’s Niger-Delta province has been identified as one petroleum system- The tertiary Niger-Delta (Akata-Agbada) petroleum system. Almost all the petroleum resources currently are produced from the sandstone species within the Agbada formation. Also turbidite sand in the upper Akata formation is a potential target in deepwater offshore and currently producing interval onshore. This paper presents a mathematical model to simulate sand production from petroleum reservoir subject to an open-hole completion. A coupled reservoirgeo-mechanical model was used to predict the volumetric sand production and associated wellbore stability. The model is based on mixture theory with erosion. The Representative Elementary Volume (REV) composes of five phases - solid matrix, fluidized solids, oil, water, and gas phase was chosen. The model also incorporates the reservoir drawdown pressure, rock failure criteria, rock types and field condition. Analytical solution of sand displacement processes is also highlighted. Results show that the magnitude of sand production is strongly affected by the flow rate, the confining pressure, the pressure drawdown and the fluid viscosity. The determined ratio of the productivity index to the saturation of the fluidized solid can be correlated to determine reservoir formation type during sand production, and predicting the wellbore stability. The model has a higher degree of validity for light and medium crude oil flow which possesses moderate lubricating properties, and therefore erosion of sand particles during production highly depends on flow rate.
A Review of Water Shutoff Treatment Strategies in Oil Fields
Authors: Joseph A. , Ajienka J. A. 
Published: February 2011

Abstract
Management of unproductive water has been a major challenge facing the hydrocarbon industry. It was estimated that about 210 million barrels of water are produced daily accompanied with 75 million barrels (11.9 million m3) of oil worldwide. Consequently, mechanical, chemical shutoff and other water reduction techniques have been developed and deployed to curb the menace in the hydrocarbon industry.
In this study, a review of the water shutoff treatment methods and reduction techniques in the industry was made. The major sources of water problems were identified and categorized into four major groups in order of treatment difficulties. A mechanism for attacking excess water production is also developed to enhance the application and success rates of water shutoff treatments and the latest technological advancements to make water shutoff treatments most viable is highlighted as well.
Five case studies were evaluated with published data to investigate success and failures after treatment using WOR, water cut, productivity change, oil gain and the period of sustenance.
The study reveals that the level of success is not just a function of the type of treatment deployed but routine diagnosis of the problem and that combined treatment proved to be the most efficient and sustained method.
Unhealthy Effects of Gas Flaring and Wayforward to Actualize the Stopping of Gas Flaring in Nigeria
Authors: Anosike Chikaodi R. 
Published: February 2011

Abstract
Nigeria flares more natural gas associated with oil extraction than any other country on the planet, with estimates suggesting that of the 3.5 billion cubic feet (100,000,000 m3) of associated gas (AG) produced annually, 2.5 billion cubic feet (70,000,000 m3), or about 70% is wasted via flaring. One of the greatest is the release of large amount of methane which has very high global warming potentials. The methane is accompanied by the other major greenhouse gas, carbon dioxide of which Nigeria was estimated to help emitted more than 3,438 metric tons in 2002, accounting for about 50% of all Industrial emissions in the country and 30% of the total CO2 emissions. This paper discussed some of the harmful effect of the gas flared on the livelihood of the communities and solution to actualize the stopping of gas flaring in Nigeria. Some of the harmful effects on the health and livelihood of the communities includes the release of variety of poisonous chemicals, just some of combustion by-products include nitrogen dioxides, sulphur dioxide, volatile organic compounds like benzene, toluene, xylene and hydrogen sulfide as well as carcinogens like benzapyrene and dioxin. Humans exposed to such substances can suffer from a variety of respiratory problems. Therefore in other for Nigeria as the giant of Africa to meet the worlds energy demand and supply, a quick response to utilizing natural gas should be made at least by concentrating in the liquefied natural gas LNG project which is targeted at foreign and local market, as a source of energy, also can be used as community projects and as well as re-injecting to enhance oil recovery.
Using an Automated Approach To Reservoir History Matching and Property Selection in Material Balance Modeling
Authors: Chinedu Onyeizu , Jye Collins , Tuitjer Eric 
Published: February 2011

Abstract
Petroleum engineers use material balance modeling and analysis for a high level understanding of the reservoir performance, drive mechanism and estimation of volumes in place. An intrinsic aspect of this analysis is to obtain a close match of the reservoir pressure behavior based on knowledge of production history, reservoir rock and fluid properties.
Material balance (MBAL) is a one dimensional approach and therefore difficult to generate a unique solution. This is especially the case when the field is in its early production life or there is significant uncertainty surrounding variables such as fluid properties and aquifer influence. To deal with this challenge, an automated concept has been developed using Petroleum Experts MBAL™ software. The concept processes a combination of subsurface scenarios to determine a range of solutions that mimic the reservoir pressure behavior. It uses a batch fit approach to generate multiple solutions within a given uncertainty range. The quality of each solution can be quantified through an automated calculation of the percentage error with history data at specific time steps.
In this paper, reservoirs within Benin River and Opuekeba fields are used to demonstrate the capability of the tool to select a number of history matched solutions. Each providing an outcome for Stock Tank Oil Initially In place (STOIIP). Current Oil-Water Contact (COWC) and Transmissibility.
Practical Guidelines for Predicting Sand Production
Authors: Osisanya Samuel O. 
Published: February 2011

Abstract
The control of formation sand is the principal producing problem of oil and gas fields producing from recent clastic sediments. Sand control is very important as the value of non-renewable oil reserves increases and cost of remedial work skyrockets. Sediments of the Pliocene and younger Tertiary ages are particularly troublesome, and sand production problems may be expected whenever wells are completed in unconsolidated reservoirs. Sand failures may also occur in older formations when in-situ rock strength is reduced by poor completion and production practices.
Several factors lead to sand production. The most critical factors are formation strength, changing in-situ stresses, and fluid production rate. The problems resulting from sand influx include abrasion of downhole tubular/casing, subsurface safety valve and surface equipment; casing/tubing buckling, failure of casing or liners from removal of surrounding formation, compaction and erosion; and loss of production caused by sand bridging in tubing and/or flow lines. Also, the cost of handling and disposing of produced sand is expensive and troublesome, especially offshore, where solids must be removed from surface facilities on platforms and transported to approved disposal sites to mention a few.
There are several methods for predicting sand production. The methods include use of production data, well logs, laboratory testing, acoustic, intrusive sand monitoring devices, and analogy. The methodologies are described in details and the data needed for predicting sand production are enumerated. The techniques described in this paper are supported with examples and case studies from regions around the world known for sand production.
Effect of Cementation on Mechanical Properties of Reservoir Rocks and Hydrocarbon Production
Authors: Ghadami Jegarluei S. , Moazzeni A. R. 
Published: February 2011

Abstract
Porosity and permeability are two important reservoir rock properties intensively affect quality of the reservoir. Various parameters affect these two factors which cementation is the more important. Measuring cementation accurately the place of entrance of hydrocarbon to the reservoir can be determined and permeability and porosity of the reservoir rock can be qualified. Since rock mechanical properties of reservoir rocks are severely impacted by cementation and rock mechanical properties of the rock are the important parameters for the mechanical reservoir modeling, which is used for well bore stability analysis, sand production prediction and finally studying the compaction of reservoir rock importance of this phenomena can be denoted. In this study diagenesis of lime stone and sand stone, effect of cementation on oil production and methods of increasing production when cementation is poor would be considered.
Experimental Investigation Of Specific Energy Of Rocks By Low Power Laser Drilling
Authors: Ashena Rahman , Ashena Rahim , Nabaei M. , Habibnia B. , Taee B. 
Published: February 2011

Abstract
Specific energy is the amount of energy required for a specified volume of rock to be destroyed. This is a normalization method used to compare the efficiency of destruction of rocks. Low power laser beam of Free Electron Laser (FEL) has been shown in literature to be used to penetrate different reservoir carbonate rocks and shales. The corresponding specific energies and ROPs are measured when a work in this field is performed.
laser beam is shown to be capable of drilling boreholes because of the high energy it can create. Laser is shown to drill shales while preventing the clay swelling problem prevailing when water is in contact with shales. Laser can also increase the accuracy of perforation of casing strings. In works like, the core samples to be tested are usually taken from fields and analyzed.
Comparison of different laser modes in terms of specific energy and ROP increase has been investigated and presented as a literature review which has not been accounted for in many previous works. As the future work, shape and rock type should be considered although there exists many works in literature wherein these parameters have been neglected.
Modeling the Perforation Stress Profile for Analyzing Hydraulic Fracture Initiation in a Cased Hole
Authors: Fallahzadeh S. H. , Shadizadeh S. R. , Pourafshary P. , Zare M. R. 
Published: February 2011

Abstract
Hydraulic fracturing has been used for many years in order to stimulate the oil and gas wells for improving the reservoir production. Many investments are allocated for hydraulic fracturing all around the world to develop hydrocarbon resources. Most of them are done for cased holes which some of them do not significantly improve the hydrocarbon production. The main reason is improper fracture initiation and complex near-wellbore fracture geometry which is a challenging problem.
In cased holes, the perforations are the only connection between the well and the reservoir, therefore the fracture initiates somewhere in the perforation. Understanding the stress distribution around the perforations is the key for analyzing the fracture initiation mechanism and thereby the near-wellbore fracture geometry. In this paper new analytical formulas are derived and applied along with numerical methods to simulate the stress profile around the perforations.
Having analyzed the perforation stress distribution, it is possible to understand the mechanism of fracture initiation and consequently improving the near-wellbore fracture geometry. Results of this model are presented at some in-situ stress regimes, cement and rock properties, and also perforation and well parameters. It is concluded that, at any specific stress regime, there is an optimum well design and completion, and also perforation orientation, which leads to lower fracture initiation pressure as well as better fracture orientation geometry in terms of less near-wellbore fracture tortuosity. Therefore, better connection can be developed between the borehole and the reservoir formation.
The importance of this model is its ability in analyzing the stress profile along the perforation tunnel, so more realistic fracture initiation pressure and fracture geometry can be estimated for better well completion and perforation design.