bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oil in Produced Water Analysis and Monitoring in the North Sea
Authors: Yang M. 
Published: December 2007

Abstract
Oil in produced water analysis is important both for process control and reporting to the regulatory authorities. Until recently the determination of oil in produced water has been traditionally carried out using standard reference methods based on solvent extraction followed by an infrared (IR) quantification. However due to the phase-out of Freon-113 for environmental reasons, and also concerns over health and safety of its replacement solvent tetrachloroethylene (also known as Perklone or TTCE), a new reference method based on using gas chromatography has been recommended by OSPAR (Oslo-Paris Commission). The new reference method is based on a modified version of the ISO 9377-2 GC-FID (Gas Chromatography and Flame Ionization Detection), and will be implemented from 1 January 2007.
The paper will give an overview of the current practices of oil in produced water analysis / monitoring in the North Sea and the different approaches that have been adopted by the different countries. It will also examine the differences between the new and old reference methods and discuss the implications on the implementation of the new reference method.
Self-Removing Frangible Bridge and Fracture Plugs
Authors: Swor L. , Sonnefeld A. 
Published: December 2007

Abstract
Currently, the conventional method of removing mechanical fracture plugs is to drill them out with jointed tubing or mud motors on coiled tubing. This necessary procedure can be time-consuming, expensive, and damaging to sensitive formations. The objective of the project presented here was to develop a process that does not require intervention for removal of these tools. The result is self-removing frangible bridge and fracturing plugs that disintegrate from internal explosives and fall downhole into the rathole after service, requiring no removal action.
This paper discusses the development of a self-removing plug constructed of high-strength frangible materials, such as cast iron and ceramics. The frangible materials provide great compressive strengths that can still be exceeded by the shock of explosives. Explosives built into the high-strength, frangible plug are capable of targeting key areas that allow the debris of a shattered plug to pass through. When the frangible parts are exploded, they fall downhole through the targeted area, allowing the entire assembly to collapse into the rathole.
This paper also details the testing of this system in both lab and field conditions. The frangible plugs isolate zones as desired and detonate at the desired times using built-in electronic circuits.
This style plug can replace drillable plugs, thereby eliminating the need for plug removal. This application is especially helpful in sensitive frac zones where placing weighted fluids on the formation could cause production damage. The frangible plugs could potentially change a huge portion of fracturing work in much the same way that (1) composite tools reduced the drillout times of cast-iron plugs and (2) cast iron plugs with brass valves reduced drillout time from that of milling or drilling out plugs containing steel components.
Real Time Data for Structural Integrity and Stability Assessment: A GoM Case Study
Authors: Mitchell M. , Tipton E. , van Dijk Ir. Radboud R.T. , Allen B. 
Published: December 2007

Abstract
This case study illustrates how advanced data transfer and processing techniques can be applied to add value to high resolution environmental and structural monitoring data for use in operational decision making.
With hurricane Ivan in 2004 and hurricanes Katrina and Rita in 2005, the GOM operating area has suffered significant damage to its offshore structures. These experiences have shown it is essential to not only collect environmental and structural data, but to have this data readily available to stakeholders and technical experts for assessment in the aftermath of a storm or other unexpected event that threatens structural integrity.
Advanced systems for handling high frequency, high resolution data have been developed over the past decade to deal with reservoir monitoring data. The following case study from the Gulf of Mexico illustrates how this technology was adapted to provide an operational tool for filtering, transferring and accessing structural integrity and stability data. This tool is now being used to monitor asset integrity during and after hurricanes and other unexpected events that threaten the structural integrity of offshore structures.
Sewage Treatment Project
Authors: Cunha G. 
Published: December 2007

Abstract
The river basin that empties into the Atlantic Ocean near the Brazilian city of Aracaju is the most important in the northeast corner of this environmentally sensitive country. The river basin supplies water for Aracaju's 470,000 inhabitants, as well as for many sugar cane plantations and cattle ranches in the region.
Protecting that water supply was a major concern for Schlumberger operations based in Aracaju. The city's water is collected and treated from the Poxim River that flows close to the base. To ensure no contaminated water reaches the river, Schlumberger recently built an organically based wastewater treatment plant that has eliminated all sewage emissions.
As a result of the new wastewater treatment plant, the Schlumberger base in Aracaju achieved the following results:
Contributed to protection of local water supply Achieved significant reductions in harmful discharges Completely eliminated sewage emission into the Poxim River Received recognition from state environmental agency Eliminated odors and enhanced local vegetation
In 2003, Schlumberger built a wetland tank to collect and treat effluent water from the base, which houses up to 120 employees. The new sanitation installation was built as a requirement to comply with local regulations, established in 2002, in order to renew the state environmental license for the base.
The wetland tank replaced septic tanks that used to discharge used water into the Poxim River. The Aracaju Water Treatment Station collects its water from the river. Now, instead of being released into the river, effluent water is stored and re-oxygenated in a 37-cubic-meter cement treatment tank filled with coarse gravel in which Tabua plants live.
The water treatment plant uses no mechanical devices. Rather aerobic and anaerobic chambers are used to degrade organic material. The final effluent water is evaporated in a wetland and any excess is used to irrigate grass and trees of the base.
With this system, the treatment plant has achieved significant reductions in chemical oxygen demand, oxygen consumption and fecal coliforms. The discharge rates for these are significantly lower than those allowed by the new local environmental regulations. In addition the base has completely eliminated sewage emission into the Poxim River.
The Schlumberger base was recognized by the state environmental agency that inspected the new plant in July/2004 to issue the environmental license. The agency took photographs and requested that plant be copied at other industrial installations at Sergipe State as part of environmental licenses locations. Also, the base's neighbor, a state finance agency, congratulated the base on the elimination of foul odors. Visually, the grass at the base entrance now is continuously green.
Better Valuation of Future Information Under Uncertainty
Authors: Prange M. , Armstrongt M. , Bailey W. , Couet B. , Djikpesse H. , Wilkinson D. , Galljt A. 
Published: December 2007

Abstract
In conditions of high demand for rigs and other scarce equipment, it may be appropriate and more advantageous for a client to agree to a forward contract for a service to be performed at a future date at some specified price. In this case, the service provider is contractually bound to provide the service at the pre-agreed price within a specified time window, regardless of the prevailing price and availability.
This paper presents a mathematically consistent framework using decision trees, conditional probabilities and Monte Carlo simulation to appropriately value future information today. We assume that the client company and the service provider share information on reservoir uncertainty. The presence of multivariate reservoir uncertainties typically makes such valuations non-trivial and mostly intractable to current modeling schemes.
We demonstrate the approach with an example involving a decision to be made for a marginal asset on where to place an injector well relative to a fault. The example considers the value to the client of a future measurement of the degree of compartmentalization caused by this fault. We conclude that when faced with the possibility of obtaining new and useful information in the future, our methodology provides a quantitative valuation framework. This framework could lead, for example, to novel ways of setting up contract terms.
A New Approach to Matrix Sandstone Acidizing Using a Single-Step HF System: A Niger Delta Case Study
Authors: Uchendu C. , Nwoke L. , Akinlade O. , Arukhe J. 
Published: December 2007

Abstract
The use of unique or modified HF acid systems for matrix acidizing within the Niger Delta and some other parts of the world is still the preferred method for effective stimulation of sandstone reservoirs. The continued success of treatments done with modified HF systems in this area are due to its ability to mitigate the rapid spending of the active acid with clays and silicates; prevent matrix unconsolidation in the near wellbore region and the subsequent precipitation of acid reaction by-products within specific well applications. This success has brought about modifications to the acid system and new applications for various well scenarios.
This paper discusses the successful application of a unique sandstone acidizing process that uses a single acid stage (no preflush or postflush is required) making multiple stage treatments much simpler while still achieving both economic and technical targets for the well. It covers the non-formation stimulation treatment of several wells using this single-step method and also describes a successful approach to improving the productivity of high water cut wells with severe fines- damaged gravel packs by this system. Unique experiences acquired during the field trials carried out within the Niger Delta using this system are evaluated. The results demonstrate a significant increase in incremental hydrocarbon production for normally high risk, low reward wells and remarkable stimulation cost reduction via reduced chemical volumes, less equipment requirements and shorter job times.
Also included are a thorough analysis of actual candidate selection criteria, fluid chemistry, actual job design and operational issues during execution of treatments. Key technical and economical performance indicators including skin factors, production rates, specific productivity indices, treatment costs indicate that this system has certainly and successfully increased the application envelope for unique HF treatments within sandstone reservoirs.
Are All PSAs Good Marriages?
Authors: Dabbous S. , Macary S. , Wilson W. R. 
Published: December 2007

Abstract
The foundation for the relationship between a host Government and a contractor oil company in the operation of a petroleum concession is the Production Sharing Agreement (PSA). This document, versions of which have evolved over many years, should recognize that the two parties have one common goal: properly exploit the hydrocarbon resources within the defined concession area - but each has potentially diverse interests. Generally, the representing entity of the host Government is compelled to minimize financial commitment and risk and negotiates with a view to put these obligations onto the ‘Contractor’; and the Contractor, particularly if it is a publicly owned corporation, in accepting the financing and risk obligations, is compelled to seek maximization of the financial return consistent with internally established risk-return relationships.
The stage is set for serious negotiation.
If the Government terms are too restrictive, the company will take its exploration money to another opportunity in a different country. If the company is seen as too greedy, the Government will invite another company as the potential partner. Without an agreement neither wins; with a good agreement, both win. Understanding by all negotiators of the interests, goals and limitations of the other party is essential. Remember that the normal 25 year duration of a concession agreement is similar to that of a good marriage. If instead of "understanding," the parties inter into discussions with only "perceptions" regarding the forces driving decisions made, or positions taken by the other party, the negotiation process can then be unbelievably difficult, and the experience thereafter less than satisfactory, and such perceptions are created at the first reading of a revised PSA form.
This paper presents the authors' expectations about the "perceptions" that may be created by recent changes in the Production Sharing Agreement format adopted by the Egyptian General Petroleum Corporation (EGPC), the national oil company of Egypt which, we believe, is a guide for many Arab countries.
The Successful Evolution of Anton Irish Conformance Efforts
Authors: Smith D. D. , Giraud M. J. , Kemp C. C. , McBee M. , Taitano J. A. , Winfield M. S. , Portwood J. T. , Everett D. M. 
Published: December 2007

Abstract
The Anton Irish field was discovered in 1945, unitized in 1950 for a produced gas pressure maintenance project and converted to a waterflood in 1969. In 1997 CO2 flooding began and currently accounts for about 85% of the unit production. Presently, the entire field produces around 6,500 BOPD; 36.5 MMCFPD of recycled CO2, and 69,200 BWPD. Over the years of flooding, various conformance problems have been identified and many attempts have been made to address these problems with limited to no success. In 2003 a new program was initiated to re-evaluate the problems and design better solutions. This paper will outline the diagnostic efforts that were undertaken, discuss the basic findings of that effort, review the resulting solutions that were designed to resolve these problems, and show the results of this work.
New Barnett Shale Horizontal Completion Lowers Cost and Improves Efficiency
Authors: Lohoefer D. , Athans J. , Seale R. 
Published: December 2007

Abstract
Over the last few years horizontal completions of the Barnett Shale have advanced in an attempt to better stimulate the entire horizontal interval. One standard completion process, where the horizontal is cased and cemented, has emerged. Completing the well consists of running and setting a composite plug on coiled tubing (CT), perforating, stimulating, flowing the well back and repeating the process for the required number of stages for the well. This process is very costly and time consuming, with the added risks of having to remove the composite plugs, plus there is no viable method for re-stimulating these wells at a later date.
For over three years now, a new completion system has been deployed in the Barnett Shale that is fast, efficient, less costly and provides equal to or better production than what the standard completion system offers. Using specially designed mechanical open hole packers run on the production liner, mechanical diversion in the open hole section can be accomplished at predetermined points. This provides well site flexibility in completion design, so the fracturing and stimulation process can be optimized. Each stage in the horizontal section can have a specifically designed fracturing or stimulation procedure. The system has also been designed, to allow all of the fracturing or stimulation treatments to be pumped in one continuous operation with the added benefit of re-stimulating all or selected intervals at a later date if desired. This has proven to be very cost effective and efficient, while reducing the time required to bring production on line. With a multitude of jobs completed to date in the Barnett Shale, this paper will analyze the operational efficiencies, cost benefits, reliability and production data of this completion system compared to the standard completion practices being implemented today.
A Novel Approach for Determining, Evaluating, and Applying Stress Concentration Factors for Rotary-Shouldered Connections
Authors: Tang W. , Muradov A. , Chandler R. B. , Jellison M. J. , Gonzalez M. E. , Wu J. 
Published: December 2007

Abstract
This paper presents a new stress concentration factor (SCF) analysis methodology for rotary shouldered connections (RSCs). The proposed method uses finite element analysis (FEA) as a primary tool to explore the maximum peak stress trends in RSCs and calculates SCF to represent the connection performance. The paper provides a thorough discussion on the SCF analysis methodology and its application in evaluating drill string connection designs. The paper also compares peak stress trends and SCF values among various RSC designs to assist in evaluation and selection of connections for drilling, completion and intervention riser applications.
Stability Criteria for the Thermal Adaptive Implicit method
Authors: Agarwal Anshul , Moncorgé Arthur , Tchelepi Hamdi A. 
Published: December 2007

Abstract
The fully implicit method (FIM) is widely used due to its unconditional stability (even with possibly large time steps). However, FIM is computationally expensive per time step, especially for large number of components. IM-PES (Implicit Pressure, Explicit Saturations), on the other hand, is computationally inexpensive, but only conditionally stable. For large-scale heterogeneous models, the allowable stable time step of IMPES may be extremely small. In the Adaptive Implicit Method (AIM), only a subset of the primary variables is treated implicitly. AIM offers a balance between FIM and IMPES by employing implicit treatment only where necessary. The challenge with AIM is to find a robust and sharp stability criteria that can be used to choose an optimal time step size. The objective here is to derive and verify the stability criteria for a given time step selection in simulations based on a Thermal Adaptive Implicit Method (TAIM). Our linear stability analysis accounts for mass and heat convection, heat conduction, capillary mixing and compressibility. The TAIM stability criteria are obtained using a von Neumann approach. We found the stability criteria to be sharp. That is, mild violations of the stability limits lead to unstable solutions both in the saturation and temperature profiles. The instabilities lead to significant deviations from reference solutions for small CFL (Courant-Friedrichs-Lewy) violations and oscillations for larger CFL violations. Our analysis indicates that, overall, a TAIM-base approach is a promising candidate for simulation of thermal displacement processes of practical interest.
A Retrievable and Reseatable Propagation Resistivity Tool for Logging While Drilling and Logging While Tripping
Authors: Frey M. T. , Argentier L. , Ross M. , Varveropoulos V. 
Published: December 2007

Abstract
A new while-drilling propagation resistivity system with a novel architecture has been developed that greatly reduces lost-in-hole exposure and provides increased operational efficiency and flexibility. The downhole electronics, antennas, and battery are mounted in a retrievable and reseatable tool unit with a 1.75-in. outer diameter. This unit is seated in a 4.75-in., 6.75-in., or 8.25-in. special stainless steel collar that is engineered to be electromagnetically transparent. The tool measures phase shift and attenuation resistivity at 2 MHz and 400 KHz to provide borehole-compensated resistivity measurements at four independent depths of investigation. This service can be run with an existing measurement-while-drilling (MWD) system to provide real-time data such that the combination is retrievable and reseatable in one operation. Alternately, the collar alone can be run while drilling, the tool unit can be lowered through the drill string into the collar, and measurements can be recorded while tripping out at speeds up to 1800 ft/hr. Combination of the data with cased-hole logs can be used to save operational time and improve logging success in difficult environments. The system has completed extensive field-testing. Several field examples and comparisons with while-drilling and wireline logs will be shown.
Customized Reperforating With New Technologies for Optimal Field Drainage and Productivity Enhancement: East Venezuela Applications
Authors: Rodríguez H. , Molina O. , Salazar A. , Rondón A. K. , Méndez M. , Fayard A. , Gama C. , Smitheman C. , Mármol A. , Cervantes E. 
Published: December 2007

AbstractThis paper describes a new methodology and technologies applied for re-perforating production wells in a development field in East Venezuela. Subsequent well tests and production logs demonstrated significant skin reductions and improved flow profiles, delivering up to threefold increase in productivity index and enhancing reservoir drainage efficiency. These results exceeded normal expectations for this type of job.El Furrial field is located in Northeast Venezuela. The wells typically produce from multiple intervals having widely heterogeneous flow capacities. In order to avoid asphaltene production and water-gas channeling, downhole pressure drawdown has to be limited leading to restricted production. These conditions are further complicated by severe formation damage caused by deep mud filtrate invasion and plugging of existing perforation tunnels with crushed rock material left over from conventional perforating. This environment motivated the team to try a novel re-perforating methodology to overcome these combined challenges.In these cases, rather than follow the common practice of treating all intervals as having the same average reservoir properties, the reperforation program was customized, taking into account the individual properties and skin of each layer.Post re-perforation analysis, presented in this paper, clearly shows that the two main causes of formation damage (skin) i.e.: deep mud filtrate invasion and perforation tunnels lined with crushed rock material, were effectively minimized by using new deeper penetrating charges and a controlled dynamic underbalance perforating technique.El Furrial field success has renewed interest in re-perforation as an important tool for optimizing reserves recovery. This new customized approach used by PDVSA has generated a much higher effective return on investment.