bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analyzing Production Data from Unconventional Gas Reservoirs with Linear Flow and Apparent Skin
Authors: Nobakht M. , Mattar L. 
Published: February 2011

Abstract
Many horizontal wells with multiple fractures, producing from unconventional gas reservoirs, have been observed to exhibit linear flow. Often it is the only flow regime, and it can last several years. Classically, this flow regime is characterized by a half slope on type curves, when there is no skin effect. However, most of the time, a skin effect is observed in these wells (caused by flow convergence or finite conductivity in the fractures).
The existence of skin changes the shape of data points when plotted on log-log scales, and this can have a huge effect on the interpretation when using type curves. For example, a well with purely linear flow and with skin, in a reservoir that is infiniteacting, may appear like, and be interpreted as, a finite-acting reservoir, simply because of the "skin effect".
This paper discusses different methods that can be used to eliminate the misinterpretation caused by the presence of skin when linear flow is being analyzed using type curves. First, it is shown that among all the derivative and integral functions that are currently used, only DER (welltest-style semi-log derivative) and pressure integral-derivative are not affected by the skin. However, these two functions have other issues that usually make them unusable for production data analysis. DER is noisy most of the time and the process of integration often introduces errors at early times, which can significantly distort the shape of pressure integral-derivative. Therefore, an easier method is presented to analyze the production data from shale gas reservoirs with extended periods of linear flow and significant skin. This method uses the square root-time plot to remove the apparent skin effect from the data. Then the data (excluding skin) are used for type curve analysis. This simple procedure prevents potentially significant misinterpretation.
Breaker Enhancer for Crosslinked Borates: Novel Self-Generating Acid
Authors: Maley D. , O’Neil B. 
Published: February 2011

Abstract
Despite countless recent advances in fracturing fluids, traditional borate crosslinked guar fluids persist as a preferred fluid for hydraulic fracturing. The advantages of borate gels are numerous and include superior proppant carrying capability in difficult to fracture reservoirs, as well as high stability in high temperature and high shear conditions. However, borate fluids are not without notable disadvantages. The most obvious disadvantage is the presence of insoluble polymer residue that remains in the proppant pack after the gel has been broken with oxidizer breakers. Oxidizing breakers cleave the polymer chains at random sites resulting in a mixture of residual fragments which may remain crosslinked. These residual polymer fragments have been shown to significantly impair the proppant pack conductivity. Further compounding this problem, any residual unbroken gel at a high pH is susceptible to re-crosslinking when exposed to multivalent ions such as iron or calcium from the wellbore or formation.
Through the addition of a novel in-situ self-generating acid in combination with an oxidizing breaker, the degradation of borate crosslinked guar is notably improved. The controlled release of an acid, which is uniformly distributed throughout the gel, will lower the pH of the fluid thereby completely removing the crosslink from gel polymer fragments. This lower pH will result in an increase in solubility of the residue, improving clean-up of a proppant pack.
It has been shown that the addition of the self generating acid dramatically improves the regain conductivity of the proppant pack. Additionally the lowered pH of the fracturing fluid aids in the prevention of re-gelling upon flowback, reduces the water reactivity with water sensitive clay minerals, and aids in the removal of polymer residue from the well after treatment. Each of the mentioned benefits will aid in allowing the reservoir and conductive path to reach its full production potential.
A Conceptual study for Managing the Life of a Giant Offshore Oilfield in the UAE where Facilities and Infrastructure Mature ahead of the Reservoir
Authors: Modavi A. , Khan S. A. , Khedr O. , Muta T. , Brantferger K. , Watanabe M. , Walters J. V. , Martin W. W. , Al-Shabeeb A. N. , Al Marzouqi M. , Qotb M. 
Published: February 2011

Abstract
This conceptual study addresses the subject field which has a current expected operating life of more than 100 years, which exceeds the life of the existing facilities. As an alternative to continuing development with Well Head Platform Towers (WHPT’s), the concept of artificial islands holding drilling and production centers has been introduced [ref.1]. The island concept brings enormous flexibility in terms of managing future development uncertainties both subsurface and surface. The new subsurface development concepts include extensive utilization of ERD/MRC wells specifically designed and placed in conformance with geologically defined drainage areas. This strategy predicts significant improvement in plateau duration and sweep efficiency with fewer wells.
The new islands based surface plan allows a phased installation of facilities, and space provisions to expand facilities to cater for subsurface uncertainties. It also handles the remnant life issues associated with the existing infrastructure (Wells, WHPT’s, pipelines and trunklines, satellites, central complex). This includes provisions for future requirements in terms of Water Injection, Artificial Lift and Gas Injection and other EOR applications.
Alternative Methods in Preventing Asphaltene Deposition
Authors: Albannay Aamer , Masuzawa Tsutomu 
Published: February 2011

Abstract
Asphaltene deposition reduces oil productivity in afflicted wells and- in worst case- stops the wells from flowing due to complete plugging as a result of deposition inside the tubing. Currently, wellbore soaking and wire-line clean-up jobs are implemented to deal with asphaltene deposition. However, these operations are frequent and asphaltene continues to deposit shortly after.
Three methods are currently being evaluated to control asphaltene deposition: Control of operating conditions, inhibitor squeeze treatment and continuous down hole inhibitor injection. This paper discusses the results of evaluating control of operating conditions and the preparatory work required to evaluate the latter two methods.
Integrated Reservoir Characterization Using Facies, Rock Texture and Flow Units Applying Rock Typing Approach, Upper Cretaceous Reservoir, Abu Dhabi Onshore Oil Field, UAE
Authors: Hozayen M. A. , Al Saadi H. 
Published: February 2011

Abstract
Detailed geological characterization is vital control in describing complex oil reservoirs. This work is a detailed reservoir description of a highly heterogeneous Upper Cretaceous carbonate reservoir consisting of limestone; of variable textures, and dolomite in one of Abu Dhabi onshore oil fields. The reservoir thickness ranges from 300ft to 600ft and characterized by high degree of heterogeneity with widely variable porosity and permeability. The study includes geological evaluation; detailed lithofacies description using some 7000 ft of cores and 6500 thin section descriptions on foot by foot basis, paleoenvironment interpretation, detailed High Frequency Sequence Stratigraphic interpretation using cores integrated with seismic data, and diagenesis. This is followed by a Reservoir Rock Types (RRT) study using rock textures as a driving tool and Flow Unit approach.
This comprehensive integrated multidisciplinary reservoir characterization study was conducted considering all available data including logs, cores, Mercury Injection Capillary Pressure (MICP), Flow Zone Index (FZI), Reservoir Quality Index (RQI) and Pore Throat Size Distribution (PTD) that were used to define the various Reservoir Rock Types for the reservoir characterization and description purposes. Five attempts were experienced incorporating various combinations of logs, cores parameters and MICP data to reach to a reasonable and robust rock type scheme. Eventually 9 RRT are defined in the cored wells and they will be predicted in non-cored wells as well as in between wells in 3D using specific 3D software. The outcome will be a 3D Reservoir Static Model, derived by rock texture and flow units which will be used for Reservoir Engineering Dynamic Flow Reservoir Simulation Models.
Robust Implementation of Corrosion Inhibition Squeeze CIS Program Extends the Well Completion Lifetime Case Study
Authors: Samad Saleh Abdul , Sawadi Obadah Al , Odeh Nadir , Afzal Mohamed 
Published: February 2011

Abstract
Oil producers completed with carbon steel were threatened with sweet corrosion due to early water breakthrough and the presence of carbon dioxide in the associated produced gas. In severe cases corrosion led to problems which interrupted production and put the wells in an unsafe service condition. Remediation or replacement of damaged tubing was not cost effective or not feasible. A robust corrosion inhibition program through periodic squeeze treatment was implemented. Optimized and improved through the years it provided effective protection of the downhole completion and extended well operating lifetime.
Risk Register and Risk Ranking of Non Integral Wells
Authors: Al Braiki Saleh Abdul , Al Sawadi Obadah S. , Afzal Muhammad , Khan Naeem 
Published: February 2011

Abstract
Non-Integral Wells are common in every aged field and managing their integrity is becoming a challenging issue, particularly in large fields and for complex dual completions such as the case in ZADCO operated fields. As part of the Well Integrity Management System (WIMS), integrity concerns are identified, investigated and subsequently mitigation measures are recommended to restore the well integrity, all in a systematic approach. Well barrier integrity is given the highest priority; therefore a comprehensive Risk Register and Risk Ranking process is implemented by ZADCO Well Integrity Team.
The Risk Register process utilizes every related data and integrity investigation results to evaluate the integrity of the well primary & secondary barriers for every flow path. An individual integrity assessment is performed on the different containment sections in a well such as wellhead, inner and outer annuli and zonal isolation. Based on the severity, consequences and likelihood of a barrier failure the individual containment is given a risk rank according to ADNOC/ZADCO risk matrix. The overall risk ranking of a well reflects the highest risk rank of any of its containments. To complete the risk register, existing safeguards are addressed and appropriate short and long term mitigation actions are recommended to keep the risk at ALARP.
3D OBC Seismic Survey Geometry Optimization Offshore Abu Dhabi, U.A.E.
Authors: Ishiyama Tomohide , Mercado Gary , Belaid Kamel 
Published: February 2011

Abstract
The flexibility of 3D ocean bottom cable (OBC) seismic survey design enables a variety of survey geometries. Among the infinite variations, we naturally seek higher survey efficiency within operational constraints. Therefore, it is important to consider operational constraints placed upon the geophysical requirements by equipment capability and productivity, and to discuss geometry options in order to optimize the geometry of a survey in a field, satisfying not only the geophysical requirements but also the operational constraints. We analyzed several geometry options, such as zippers between panels, source line interleave, flip-flop shooting, outboard shooting and distance separated simultaneous shooting (DS3), to solve limitations in equipment capability, to pursue higher productivity, thus to optimize the survey geometry. We show that this exercise should bring insights into higher survey efficiency within the operational constraints in order to optimize the geometry of a survey in a field.
Do You Really Need That Rotary Steerable? An Evaluation of Applications and Comparisons with High Performance Mud Motors
Authors: Malcore Eric , Murray Bruce 
Published: February 2011

Abstract
The benefits of running rotary steerable tools have been widely advertised and accepted. Borehole quality, higher ROP’s and less torque and drag are all potential benefits to running rotary steerable tools. Is the rotary steerable tool a catch all for all applications? The purpose of this paper is to review when a rotary steerable tool can be most effective and when it might be better to just run high performance mud motors.
The development of rotary steerable tools has changed the directional drilling and even performance drilling landscape forever. Rotary steerable tools can allow longer laterals than ever before. They allow casing to be run where it was difficult to run before and allow weight transfer when it was impossible to get it.
But in some applications, it might be more cost effective to use high performance mud motors. A properly engineered BHA with the right drilling tools and motor / bit combination can out drill a rotary steerable system in many applications.
This paper will review the proper application of rotary steerable tools and also present case studies where properly engineered mud motor BHA’s have out performed rotary steerable BHA’s.
Seismic Sequence Stratigraphy in Mapping Complex Reservoir Reef Build-up Geometries (Offshore Abu Dhabi field)
Authors: Bellah Samir , Shateri Abdulla Al , Kumpas Michael G. 
Published: February 2011

Summary
Reservoir zonation in a prominent offshore Abu Dhabi oil-field has been investigated by means of seismic sequence stratigraphy. The field is producing from a Rudist reef complex where only discrete zones yield high production rates. An advanced seismic sequence stratigraphy study was conducted with the objective to refine the interpretation and understanding of the extent and thickness variation of the producing zones to optimize further development of the field.
This paper presents the methodology and results of a seismic sequence stratigraphic study using innovative technique for the extraction of chronostratigraphic relationships embedded in the seismic data. The underlying concept of the method used is that all stratigraphic events are detected and placed in stratigraphic order. These chronostratigraphic events or surfaces are generated at sub-seismic resolution and tracked throughout the seismic volume within the limits of user-determined bounding surfaces – picked horizons. The integrity of the results is supported by ties to wells and good consistence with a conceptual, traditionally accepted reef complex model.
Twin-Tailed Surfactants for Creating CO2-in-Water Macroemulsions for Sweep Enhancement in CO2-EOR
Authors: Sanders Aaron W. , Nguyen Quoc P. , Nguyen Nhut M. , Adkins Stephanie S. , Johnston Keith P. 
Published: February 2011

Abstract
Several classes of surfactant have previously been reported for creating emulsions in the oilfield, but primarily these surfactants were originally designed for the interface of oil and water. We report here on the design and synthesis of a new class of twin tailed surfactants based on glycerin and designed for the supercritical (sc)CO2-water interface.
CO2-Enhanced Oil Recovery (CO2-EOR) is very efficient in terms of oil displacement, but due to the low viscosity of scCO2 suffers from poor sweep efficiency. One method of increasing sweep efficiency in CO2-EOR has been through the use of surfactants to create "foams" or more correctly CO2-in-water (C/W) macroemulsions. Traditionally surfactants have been used "off the shelf" which were designed to lower the interfacial tension (IFT) of oil and water.
The design and synthesis of twin tailed surfactants for use at the CO2/water interface is discussed. The hydrohobes for these surfactants are synthesized from epichlorohydrin and an excess alcohol. Subsequent ethoxylation of the resulting symmetrical dialkyl glycerin yields the water soluble dual tailed surfactants. The general characteristics of the surfactants in water are described. Twin tailed surfactants have been shown to be more effective at lowering the surface tension (25.6 dynes/cm at CMC) compared with secondary alcohol based surfactants such as Tergitol™ 15-S-12 (33 dynes/cm at CMC), however, due to the unfavorable packing the efficiencies of these surfactants is lower than their linear counterparts. At the CO2/water interface the lower interfacial tension is not as strong and therefore the CO2-philicity of the hydrophobe determines the surfactants ability to migrate to the interface. The higher CO2-philicity of the dialkyl glycerines leads to strong adsorption at the interface and a low interfacial tension.
In this report we compare the twin-tailed dioctylglycerine surfactants with a linear secondary alcohol surfactant in a side by side comparison in a core flood. The results show that even above the cloud point of the surfactants, the twin tailed surfactants create a significant mobility reduction, likely due to favorable partitioning into the CO2 phase. The data covers surfactant structures designed specifically for the CO2-water interface and can be used by producers and service companies in designing new CO2-floods, especially in areas that might not have been considered due to problems with reservoir inhomogeneity.
Relative Culture Strength – A Key to Sustainable World-Class Safety Performance
Authors: Van Westhuyzen Johan 
Published: February 2011

Abstract
While workers in the oil and gas industry tend to work safely, in general, most enforcement mechanisms are compliance-based, often focusing on safe conditions rather than safe behaviours. As a result, the frequency of injuries and accidents remains static, with several incidences per year. By embracing a behaviour-based system, in which employees are trained to think consequentially and work safely, companies can cultivate a self-reinforcing safety culture that has the potential to make the goal of zero injuries and accidents a reality. Intrinsic to success is the ability to quantify and measure progress towards a sustainable safety culture, one that allows companies to chart progress and adapt strategies to ensure a positive outcome.
To this point, DuPont initiated a survey in 1999 to determine why one plant site might have outstanding safety performance while another in the same business has poor performance. Though much qualitative analysis had been conducted on this issue, no quantitative analysis had been performed to validate the relationship between safety culture and safety performance. As such, the goal of this survey was to evaluate employees’ perceptions of their safety programme and identify behaviours, attitudes and other factors that have the potential to undermine a safety programme.
Results from the survey were analyzed, specifically focusing on how the safety culture varied between organizations with poorer safety performance and those with excellent performance. The Total Recordable Injury Rate based on the US Occupational Safety and Health Administration (OSHA) model was used as the measure of safety performance. Using collected data, the value of Relative Culture Strength was determined to normalize question responses in reference to its benchmark poor and benchmark best values.
Ultimately, the data showed a pronounced relationship between safety culture and safety performance, with leadership as a key variable. The number of injuries is inversely proportional to Relative Culture Strength. The development of this metric thus allows for the quantification of qualitative data pertaining to safety culture, making it possible to benchmark safety culture within a company, an industry and across industries. As such, the metric has proven an effective measure for assessing and catalyzing safety culture improvement. This paper will review the data provided by the Safety Perception Survey, sharing insights, trends and analysis pertaining to safety culture. Moreover, it will serve to assist managers in better understanding the utility of a safety culture, as well as its role in improving safety performance.
Redevelopment of the Cardium Formation Using Fractured Horizontal Wells: Reservoir Engineering Perspectives and Early Case Histories
Authors: Omatsone E. N. , Bagheri M. A. , Galas C. M. , Curtis B. , Frankiw K. 
Published: February 2011

Abstract
According to the Alberta Energy Resources Conservation Board, the Cardium Formation holds about 25% of Alberta's total discovered conventional oil resource, amounting to over 10 billion barrels of oil-in-place. In spite of its enviable size, oil quality (36 to 40 degrees API) and significant dissolved gas content, the cumulative production from this clastic play, as of December 2009, was approximately 1.75 billion barrels (since the onset of oil production in 1957). This represents an achieved Recovery Factor of only 17%, from a combination of primary, secondary and tertiary recovery schemes with predominantly vertical drilling in various parts of the formation. Since late 2008, however, operators have shown that redeveloping the Cardium Formation with multi-stage hydraulically fractured horizontal wells has the potential to significantly increase production by increasing reservoir contact in the undeveloped and under-developed areas.
This paper presents a brief review of the historical performance of vertical wells in the low reservoir quality areas of the Cardium and then describes the impact of placing multi-stage fractured horizontal producers in these areas. The paper deals with the redevelopment of the Cardium Formation from a primary recovery perspective only – with a focus on the fringe areas around the super-giant Pembina field as well as the development of the largely untapped resource in the "A" lobe of the Cardium in the Garrington/Caroline areas. The development of these portions of the Cardium constitutes an extension to previous estimates of Original Oil-In-Place and significant additional recovery potential. The performance of the over 120 multi-stage fractured horizontals that have been placed on production (as of June 2010) is discussed from geologic, reservoir engineering, development modeling and economic analyses perspectives. The authors include some proposals for "typical" Cardium horizontal well performance profiles for reserves assignment purposes and, in closing, they present some data-gathering and forward-modeling recommendations for Cardium operators/stake-holders that would enable them to maximize the near- and long-term values of their assets.