bluuebunny/crossref_metadata_2025 huggingface dataset:
Oligocene Vicksburg Thin-Bed Production Optimization Derived From Oil-Based Mud Imaging: A Case Study
Authors: Fairhurst D. L. , Reynolds B. W. , Indriati S. , Morris M. D. , Hanson E. G.
Published: December 2007

The Oligocene Vicksburg formation in South Texas has been a prolific play for many years with targets of thick and stacked sand bodies. These thick sections have been primarily exploited and produced. Still existing are many previously considered uneconomical sequences. These marginal sections consist of highly laminated sand shale sequences along with disbursed clay in sand. Standard cutoffs from basic log evaluation work correctly for the disbursed clay sections. But the cutoffs are inadequate for the highly laminated sequences; many thin, high-quality sands have been overlooked. These sections can now be discerned using microresistivity measurements in oil-based mud systems and new high-resolution cutoffs can be employed.

A production prediction model is critical to enhance the chance of success. The model used here employs a petrophysically consistent high-resolution permeability estimate, fracture geometry prediction, and formation pressure. The methodology identified several sands as commercial that have been bypassed in offsets with the old cutoffs.

Over a two-year drilling program, data gathered from several field example wells were analyzed. These are presented here to illustrate how production data was utilized to continuously adjust and calibrate the high-resolution petrophysical model. The incremental revenue from the added pay exceeded the cost of this new methodology and enhanced the economic viability of the field.

This integrated process of measurement, analysis, prediction, evaluation, and model adjustment enables the operator in South Texas to make timely completion decisions as well as set-pipe decisions. This process is becoming a useful tool for further exploitation of the mature Oligocene Vicksburg formation of South Texas.
How to Apply a Blocking Gel System for Bullhead Selective Water Shutoff: from Laboratory to Field
Authors: Stavland A. , Andersen K. I. , Sandøy B. , Tjomsland T. , Mebratu A. A.
Published: December 2007

This paper describes a new method for water control by the use of bullhead injection. A water based gelant is emulsified in oil and injected into the formation. The emulsion is designed to separate into a water phase and an oil phase at static conditions in the formation. Upon reaction in the formation the water phase gels up while the oil phase remains mobile.

It has been found that the controlling parameter for disproportionate permeability reduction (DPR) is to control the fraction of gel occupying the porous media. The water fraction in the emulsion controls the reduction in relative oil and water permeabilities.

A program was undertaken to verify this DPR method in a field test, using a commercial blocking gel system. The first treatment was performed in well 30/3-A-16 T2 at the Statoil operated Veslefrikk field offshore Norway. Results show that water production was reduced by 30% after the pilot test, while maintaining the oil rate. As expected, total well productivity was reduced by more than 80%.

The treatment consisted of 124 m3 emulsion, bullheaded from surface. Step rate testing and ion water analysis were combined to study the relative change in flow contribution between the 6 perforated intervals.
The Effect of Displacement History on Three-Phase Capillary Pressure and Relative Permeability Derived from Triangular Pore Cross Sections with Contact-Angle Hysteresis
Authors: Helland J. O. , Skjœveland S. M.
Published: December 2007

We present a model of mixed-wet triangular tubes that calculates three-phase capillary pressure and relative permeability curves. Several fluid configurations may occur in triangular pore cross-sections, and capillary displacements may either occur as piston-like displacements of the fluids occupied in the bulk, or as piston-like displacements of the fluids in layers. To our knowledge, this latter type of displacement has not been analyzed before in mixed-wet pores. Using minimization of Helmholtz free energy, we derive accurate three-phase capillary entry pressures for such layer displacements, accounting for contact-angle hysteresis. Numerical examples are presented to illustrate how the entry pressures for the different possible displacements relate to each other during gas and water invasion into pores with a specific fluid configuration. It turns out that the entry pressures for related displacements are consistent. This implies that pores occupied by the same fluid in the bulk portion must have the same fluid configuration for a constant value of capillary pressure.

With this model we calculate three-phase capillary pressure and relative permeability, and explore how the saturation-dependencies of these quantities change according to saturation-reversal points. We simulate the sequence of processes primary drainage, imbibition and gas invasion, for different maximum capillary pressures Powmax er primary drainage. In the simulation results presented here, we find that the oil and gas relative permeability, and their saturation-dependencies, are sensitive to variations of Powmax, While the water relative permeability is less sensitive. Such effects are absent in cylindrical tubes. This is caused by the capillary entry pressures, which are strongly affected by hinging interfaces in the corners of angular pores when contact-angle hysteresis is assumed. Thus the choice of pore geometry is important if hysteretic capillary pressure and relative permeability relationships are simulated using network models. With respect to these findings, relative permeability and capillary pressure correlations should be formulated with parameters that strongly depend on saturation-reversal points such that different saturation-dependencies can be accounted for in subsequent invasion processes.
Dynamic FEA Models for Snubbing Buckling and Riserless Subsea Wireline Intervention
Authors: Newman K. R. , Overstreet C. C. , Beynet P. A.
Published: December 2007

A dynamic finite element analysis (FEA) calculation engine has been developed and is being used to solve specialized well intervention problems. This paper summarizes the theory used in this engine, and documents two of its applications. The first application is modeling the buckling behavior of pipe (or a bottom hole assembly) being snubbed through a packer. The second application is wireline being run from a boat to a subsea well to perform an intervention. The first step in this intervention is to jar the plug out of the tree.
Foam Mobility and Adsorption in Carbonate Core
Authors: Liu Y. , Grigg R. B. , Svec R. K.
Published: December 2007

The continued use of gas injection to improve oil recovery and the prospects for its increased use throughout the world provide impetus to improve sweep efficiency of injected gas. Work is being carried out to improve understanding and the economics of mobility control agents. This paper describes the use of foam to decrease the mobility of gas in coreflooding apparatus at reservoir conditions. Foam behavior and adsorption, two of the mechanisms required to model surfactant requirements, are studied in this project. This study uses a commercial surfactant, nitrogen gas, and reservoir conditions of 10.34 MPa (1500 psi) and 40°C (104°F), and Indiana limestone. Variables are surfactant concentration, flow rate and foam quality.

At a constant gas flow rate, gas mobility slightly decreases with increasing foam quality when below the critical foam quality (fg*) and increases with increasing foam quality above fg*. Increased surfactant concentration leads to the decrease of gas mobility. Comparing coinjected surfactant and gas (CSG) with coinjected water and gas (CWG) shows that the mobility of CSG is an order of magnitude lower than that of CWG. Also, it took more time for CSG to reach steady state compared to CWG, even with a surfactant pad conditioning the core before surfactant and gas were coinjected.
Development of a Correlation Between Performance of CO2 Flooding and the Past Performance of Waterflooding in Weyburn Oil Field
Authors: Asghari K. , Dong M. , Shire J. , Coleridge T. , Nagrampa J. , Grassick J.
Published: December 2007

Weyburn oil field, located in southeast Saskatchewan, is the location of one of the largest CO2 flooding projects in the world since September 2000.

In this paper, data of the past performance of waterflooding in the Weyburn field was used to develop empirical correlations to predict the performance of CO2 flooding. Two different correlations were developed based on CO2 injection schemes in Weyburn. The first correlation is based on a WAG process through vertical wells, and the second correlation is based on the cases in which CO2 is injected through horizontal wells and water is injected separately through vertical wells. As the first step, production data from 1958 to 2004 were collected and analyzed. Oil production rates for both waterflooding and CO2 flooding periods, water injection rates, and CO2 injection rates were used in developing the correlations. The empirical model for injecting CO2 and water through vertical wells was verified using the Kinder Morgan CO2 Scoping Model and actual field production data. The comparative analysis showed 12% error between our simple correlation and the Kinder Morgan model. For injecting CO2 in horizontal wells, the correlation could not be verified against the Kinder Morgan model, but the correlation followed the actual oil production in the field very closely.

This new model can be used effectively as a screening tool for predicting the performance of CO2 flooding in various locations in the Weyburn reservoir based on the data obtained from past waterflooding performance and the rate of CO2 injection. Hence, it can contribute significant savings in time and expense to the operating oil company. Also, this approach can be utilized for other potential CO2 flooding processes in reservoirs with histories and properties similar to those of the Weyburn field.
Does Polymer Stabilize Foam in Porous Media?
Authors: Shen C. , Nguyen Q. , Huh C. , Rossen W. R.
Published: December 2007

Addition of polymer has been proposed as a way to stabilize foam, especially in the presence of oil. This study probes the putative stabilizing effect of polymer on foam in terms of steady-state properties. Specifically, we tested the effect of polymer addition on the two steady-state foam regimes identified by Alvarez et al. (SPEJ, 2001).

For the two polymers (xanthan and partially hydrolyzed polyacrylamide), two oils (decane and 37.5° API crude oil), and an alpha-olefin sulfonate surfactant, it appears from coreflood pressure gradient that polymer de stabilizes foam modestly, raising water saturation and water relative permeability. The increased viscosity of the aqueous phase with polymer counteracts the effects of destabilization of foam. For the same polymers and surfactant, polymer does not stabilize foam in the presence of decane or 37.5 deg API crude oil relative to foam without polymer. Surface-tension measurements with these polymers and surfactant likewise showed no evidence of presence of polymer at the air-water interface that might stabilize foam lamellae between bubbles. This suggests that, for similar polymers and surfactants, addition of polymer would not give stronger foam in field application or stabilize foam against the presence of crude oil.

Complex behavior, some of it in contradiction to the expected two steady-state foam regimes, was observed. At the limit of, or in the place of, the high-quality regime, there was sometimes an abrupt jump upwards in pressure gradient as though from hysteresis and a change of state. In the low-quality regime, pressure gradient was not independent of liquid superficial velocity, but decreased with increasing liquid superficial velocity, as previously reported and explained by Kim et al. (SPEJ, 2005).
Reservoir Modeling for Mature Fields—Impact of Work Flow and Upscaling on Fluid-Flow Response
Authors: Meddaugh W. S.
Published: December 2007

Scoping studies using data from three mature fields suggest that simple workflows that use only essential stratigraphic and facies constraints are as good in capturing overall reservoir fluid flow response as complex, highly constrained workflows that use detailed stratigraphic and facies constraints. Thus, considerable time and cost saving may be realized during initial model building and updating if simple, but appropriate, workflows are used.

The reservoirs studied include a Permian-age carbonate reservoir in New Mexico, an Upper Miocene deepwater clastic reservoir in California, and an Eocene-age shallow water clastic reservoir in Venezuela. Two dimensional cross section models of the deepwater clastic reservoir showed that cumulative production and water breakthrough times were essentially the same for models using the two major stratigraphic picks as for models constrained by 12 detailed stratigraphic picks. Three dimensional streamline simulation was used to demonstrate that adding facies and rock type constraints had little impact on recovery factors for a carbonate reservoir scoping project area consisting of 25, 5- spot waterflood patterns. Likewise, a very complex workflow for the shallow water clastic data set from Venezuela constrained by eight facies and 16 detailed stratigraphic picks yielded the same reservoir response as a simple, two facies, and four major stratigraphic picks constrained workflow. These studies suggest that for reservoirs with moderate to high net to gross (>30-40%) or with small differences in the porosity vs. permeability trends of facies/rock types that simple geological modeling workflows are adequate for subsequent fluid flow simulation. Models generated using the shallow water clastic data sets and evaluated using three dimensional streamline simulation showed that varying the semivariogram range parameters by factors between 0.25 and 2 times the data driven range value also had little effect on reservoir response.

An important issue surrounds the impact of up-scaling on fluid flow response. Vertical up-scaling by factors commonly used for full field simulation models has little impact on fluid flow response based on studies of the New Mexico carbonate reservoir and the shallow water clastic reservoir in Venezuela. However, areal up-scaling of models generated using a very fine 50 foot areal grid significantly alters the fluid flow characteristics and warrants additional study.
Oxygen-Free Acid-Stimulation in an Underground Gas Storage Well Completed With Prepacked Screens
Authors: Yntema S. , de Boer P. , Trompert R. A. , De Jonge R. M. , van Gellekom B. J.
Published: December 2007

A well at an Underground Gas Storage location of NAM was identified to be impaired, this resulted in a significant reduction of well performance and jeopardized the integrity of the well, and as such, it classified as a stimulation candidate. However, an acid stimulation treatment in a business-critical environment such as the Grijpskerk Underground Gas Storage in the Netherlands (total peak capacity 2000 MM Scf/D), can only be executed when well and facility integrity are fully ensured.

Corrosion in wells and at production facilities due to acid stimulation treatments are being reduced by the use of appropriate corrosion inhibitors. However, due to the introduction of oxygen in the treatment fluids, for example during loading, transportation, mixing and pumping down a well, fear for corrosion still remains. In order to minimize the risk of corrosion by oxygen, a process was developed, in which all treatment fluids were prepared such that oxygen levels were considered essentially oxygen-free. The process involved the use of purging tanks, mixing the treatment fluids with nitrogen, the addition of oxygen scavengers and dilution of back-produced fluids.

The efficiency of acid treatments in pre-packed screens completions can be enhanced by the use of coiled tubing and the right choice of jetting method. Pre-packed screens generally do not resist high differential pressures, and therefore, the impact pressure of the jetting fluid on the screen needs to be kept low. At the same time, thorough treatment coverage onto the screen and into the pores of the pre-packed sand is desirable in order to achieve optimal stimulation results. A novel rotating/pulsating coiled tubing jetting tool was used that produces, apart from the non-damaging low impact pressure, hydraulic vibrations created by the pulsating effects of the jets. This pulsating effect dislodges insoluble fines in the pre-packed screen, and opens pore space normally unaffected by chemical action of the treatment fluid. The rotating nozzles ensure complete wellbore coverage.

This paper presents a case study of an oxygen-free acid stimulation treatment, performed in a well, completed with pre-packed screens, at the Grijpskerk Underground Storage facility in the Netherlands. Contributing to the success of the operation was the cross-discipline preparation, the selection of the optimum coiled tubing jetting tool, the investigation of impairment mechanism, selection of treatment recipe in combination with screen integrity tests, development of a process to create an essentially oxygen-free environment and spent-acid back production strategy. A dedicated production and test program was designed, for which chloride ions, oxygen and pH levels were monitored at the production facility against pre-set criteria.
QT-16Cr Coiled Tubing: A Review of Field Applications and Laboratory Testing
Authors: Martin J. R. , Van Arnam W. D. , Normoyle B. K.
Published: December 2007

QT-16Cr coiled tubing was introduced as a commercial product in the spring of 2004. This high strength corrosion resistant alloy product was developed to offer a cost effective coiled tubing solution for both injection and secondary production applications in wet CO2 environments where carbon steel products may not be suitable.

This paper focuses on the results of two years of field applications and laboratory testing with the intent of defining the suitability and limitations of QT-16Cr as a completion string subjected to varying concentrations of CO2, H2S, chlorides and pH. The combination of actual fluid and gas analysis from wells where QT-16Cr has been employed will be compared to autoclave testing which simulates downhole conditions with applied stress on the tubing.

This paper also addresses the manner in which QT-16Cr has a positive effect on production system economics using several S. Texas wells as examples.

A review of field tests utilizing QT-16Cr as work strings will be covered. Attributes will be reviewed inclusive of abrasion characteristics when run inside 13 chrome production tubulars and low cycle fatigue performance data.

Both operators and service providers that have potential applications for corrosion resistant alloy coiled tubing should have interest in this update and overview regarding the performance of QT-16Cr coiled tubing.
Redevelopment a Mature Field for Production Acceleration: Intisar 103E Field, Libya
Authors: Senturk E. , Lahwel M. , Elghmari M.
Published: December 2007

This paper presents a successful re-development and production acceleration project of Intisar E Field, Upper Girs A, B & C reservoirs of the Zueitina Oil Company in Libya. The project was implemented from 1999 to 2002 on the bases of a simulation modelling study. The re-development plan comprised drilling 6 vertical injectors and 6 horizontal producers, and re-completion of existing 8 wells as commingled and/or dual producers. As a result of this project, the oil production potential of Upper Gir reservoirs was increased almost by three folds from average of 6,400 STB/D in 1999 to 20,000 STB/D in September 2002. The incremental reserves are predicted at 33.4 MMSTB until the year 2022.
Use of Real-Time Rig-Sensor Data To Improve Daily Drilling Reporting, Benchmarking, and Planning—A Case Study
Authors: Thonhauser G. , Wallnoefer G. , Mathis W. , Ettl J.
Published: December 2007

State of the art drilling operations analysis is mostly dependent on conventional daily activity reporting. However, these activity reports are based on human observations and judgment. This fact implies a number of limitations such as the coarse level of detail and subjective coding systems. To overcome these problems a rule-based system has been applied to autonomously analyze real time surface sensor data. The system evaluates the sensor data stream and acquires crucial process information as a basis for further analysis. Scope of the system is the recognition of drilling operations, such as tripping, making connections, reaming, washing etc. to extend and enhance standard reporting. This way a standardized and objective categorization of the drilling process can be achieved at a level of accuracy and detail not reached so far.

Another benefit is the automated reporting feature. By the recognition of the rigs current state, the system is able to propose an impartial process description. This automatism leads to a reduction of the time spent on reporting and leaves more time to focus on unexpected events and lessons learned. Analysis of field data allowed introducing new key performance indicators (e.g. wellbore treatment time per depth interval) for benchmarking, which are determined automatically during the evaluation process. This type of benchmarking does not rely on company specific activity coding systems. This way cost and time-consuming data management effort e.g. to compare operated and non-operated wells are eliminated.

The new system was applied to wells drilled in the Vienna Basin during the past year. As a conclusion it can be stated that the application of this system significantly improves the accuracy and resolution of the drilling process description reducing data management effort. The objective categorization of process information is a key enabler for benchmarking specifically when identifying hidden lost time.
Development of a Tapered-OD Coiled-Tubing System
Authors: Domann R. E. , Kalman M. D. , Sharma A. , Stephens R. K. , Edmonstone G. , Chambers M. J. , Martin J. R. , McWhorter D. , Melancon J. T.
Published: December 2007

Tapered outside diameter coiled-tubing (TODCT) systems have distinct advantages in ultra-deep wells (30,000-ft range) Introduced in 2004, the TODCT system includes: (1) a modified injector that can handle more than one diameter of tubing and maintain a constant grip on the tubing throughout the length of the TODCT string, (2) an ODT "transition tube" that allows sections of tubing with different ODs to be joined together, (3) well pressure control equipment (i.e., blowout preventer and stripper) with the capability to grip and seal more than one diameter of tubing and also grip and seal the transition tube, and (4) an operator control house that allows remote control of the stripper elements and injector gripper elements to open or close to different diameters of tubing while still maintaining control of well pressures inside the wellbore and grip on the tubing.

This paper presents a review of the yard testing completed on the TODCT system equipment and then describes a subsequent field trial conducted onshore in south Texas. The end result is a tested and qualified TODCT system capable of safely running tubing strings into ultra-deep wells.
28% Chrome, 32% Nickel: A Case History on the Downhole Cutting of Exotic Completions
Authors: Portman L. N. , Blades C. J. , Laba A.
Published: December 2007

Cutting production tubing using coiled tubing-conveyed cutting tools is a relatively common practice in today’s industry. However, the move towards higher and higher chrome and nickel content in the completion metallurgy has meant that the existing tools and techniques require further revaluation and refinement. Cutting material with 28% chrome is much more difficult than cutting material with 13% chrome.

A major international operator in Malaysia recently had a requirement to remove two production strings of 28-chrome tubing from two offshore wells. The two wells were to be worked over, requiring that the tubing be retrieved.

High-chrome tubulars present problems for not only mechanical cutting techniques, but also chemical and explosive techniques. This paper lists the considerations that led to the adoption of the mechanical cut method. Because of the technical difficulties of the operations, significant equipment testing was carried out prior to the work. This paper further details the results of that testing and describes the execution of the work offshore.

Finally, the findings and learnings derived from the interventions will be discussed.
Experimental and Simulation Studies of SAGD Process in Fractured Reservoirs
Authors: Bagci A. S.
Published: December 2007

Experimental studies present the effect of horizontal and vertical fractures and well configurations on the SAGD process in a three-dimensional model using 12.4 ° and 18 °API gravity crude oils. A total of eleven runs were conducted, using a 30 cm x 30 cm x 10 cm rectangular-shaped box model. Temperature distributions, the rise and growth of the initial steam chamber were observed by using 25 thermocouples. Three different well configurations were investigated – a horizontal injection and production well pair, a vertical injection – vertical production well pair and a vertical injection – horizontal production well pair with and without fractures that provided a vertical path through the horizontal producer for 12.4 °API gravity crude oil. The effect of fracture orientation (vertical or horizontal) on steam-oil ratio (SOR) and oil recovery was studied using horizontal well pair scheme.

The experimental results indicated that vertical fractures improved SAGD. Maximum oil recovery was observed during the horizontal injection – horizontal production well scheme with a fractured model, because of the favourable steam-chamber geometry. Runs showed that the location of the fractures affects the performance of the process. During the early stages of the runs, the fractured model gave significantly higher SORs than those observed in the uniform permeability reservoir. The fractures were successful in shortening the time to generate near breakthrough condition between the two wells.

In this study, numerical simulation of the SAGD process is performed. The CMG-STARS thermal simulator was used to simulate the data from the present SAGD experiments for fractured reservoirs. The simulation uses a two-component (water and heavy oil) black oil, three-phase (water, heavy oil and steam) and three-dimensional numerical model. The results from the history-matched numerical simulation are found to be in reasonable agreement with those of the experiment for oil production rate, cumulative oil production, steam chamber and temperature profiles in the model. The numerical simulation using STARS has provided relatively good result for the history matching of the experimental SAGD process using with scaled reservoir model.
Openhole Completion Options: The Niger Delta Experience
Authors: Arukhe J. , Nwoke L. , Uchendu C. , Imie S.
Published: December 2007

Within the Niger Delta clastic environment, horizontal well completions have been widely used with success. Although, conventional wells have been applied to drain reservoirs in Niger-Delta extensively, in recent years, horizontal wells have also gained acceptance as a proven reservoir management and well completion method. Production improvement factors (compared to conventional wells) of two or higher is not uncommon. To make decisions on the correct completion type to select, it is important to be aware of the many sand control issues and the relative strengths/weaknesses of the systems available. Production hotspots arising from partially plugged screens are often a problem, giving rise to the challenge of installing rugged sand face completions, which again could also compromise production.

When it comes to selecting a sand face completion strategy, several operators have a number of concerns. This paper examines sand control options (barefoot, standalone predrilled liner / screens or slotted liners, gravel pack and expandables) for the Niger-Delta, a high activity region in openhole applications. Typical key learning is presented. The openhole completions are preffered over casedhole completions in the relatively high transmissibility reservoirs of the Niger Delta as they will allow higher well productivity to be attained and their greater inflow area is also advantageous in solutions where scaling can occur like in water injection for pressure maintenance.

Wells drilled and completed with a fully integrated study were profitable, emphasing that planning drilling and completion as a discrete system, performing drill-in-fluids QA/QC, ensuring a stable hole, and that all engineers take active roles to make proactive decisions / choices that can impact operations are keys to success for a typical completion method.

Small independents that operate marginal oil wells will find openhole completion on horizontal wells useful to enhance production rates. Even the majors will agree that prevention based on experience and sound engineering practices is better than cure for most sand control problems. A common score card item, irrespective of the category of well owner is to deliver best-in class producers that quickly pay back investment capital.
Buoyancy-Dominated Multiphase Flow and Its Impact on Geological Sequestration of CO2
Authors: Bryant S. L. , Lakshminarasimhan S. , Pope G. A.
Published: December 2007

We have previously proposed the "inject low and let rise" strategy of storing CO2 in deep saline aquifers. The idea is to maximize the amount of CO2 stored in immobile forms by letting CO2 rise toward the top seal of the aquifer but not reach it. The distance that the CO2 rises depends on the uniformity of the displacement front. In this paper, we address the question of whether the intrinsic instability of a buoyancy-driven immiscible displacement leads to fingering. Fingers could reach the top seal of the aquifer, leading to an accumulation of CO2 at large saturations. We study the mechanisms governing this type of displacement in a series of very fine-grid numerical simulations. Each simulation begins with a finite volume of CO2 placed at large saturation at the bottom of a two-dimensional aquifer. Boundaries are closed, so that CO2 rises and brine falls as the simulation proceeds. Several fine-scale geostatistical realizations of permeability are considered, and the effects of capillary pressure, anisotropy and dip angle are examined. In these simulations, buoyant instability has very little effect on the uniformity of the displacement front. Instead, the CO2 rises along preferential flow paths that are the consequence of spatially heterogeneous rock properties (permeability, drainage capillary pressure curve, and anisotropy). Capillary pressure broadens the lateral extent of the flow paths. If the formation beds are not horizontal, capillary pressure and anisotropy can cause the CO2 to move predominantly along the bedding plane, rather than vertically. Accurate assessment of CO2 migration after injection ends will therefore require accurate characterization of the spatial correlation of permeability in the target formation, and of the capillary pressure and relative permeability curves.
Simulation While Drilling: Utopia or Reality?
Authors: Primera A. , Perez-Damas C. , Kumar S. , Rodriguez J. E.
Published: December 2007

Numerical Reservoir Simulation has been used in the industry as a powerful production planning tool over the last 20 years, and its efficiency for reservoir production forecasts is very well known. Nevertheless, simulation models are the final result of multiple data sources representing considerable time efforts in model building and updating. This restricts the technique to processes and decisions that can only be held inside level of days, weeks and even months; and depending on the resolution of the geological description and the complexity of the fluid behavior, simulation runs could be very time consuming.

This paper address the possibility to use reservoir simulation while drilling to simulate the reservoir conditions in real-time and dynamically improve the well trajectory and completion strategy based on the well performance predictions. During this study a critical review of the techniques that can improve the reservoir simulation speed and the real-time model updates is presented.

To better quantify the impact of this technique, a synthetic model based on real information from a North Sea Field was used and the reservoir model was continuously updated by assuming new information from well logs and structural markers. Advanced simulation techniques, as boundary conditions and grid refinement, were combined to improve the speed of the simulation runs while preserving an acceptable level of accuracy in the well performance predictions. Multiple wells deviations and configurations can be planned using this methodology while drilling a well.
Case History of a Successful Pipe-Cutting Campaign in the Adriatic Sea
Authors: Mayol J. , MacKinlay G. , Sportelli M. , Baccon G.
Published: December 2007

This paper will present the results of an extensive pipe cutting campaign in the Adriatic Sea for a major Italian operator, where previous pipe cutting tools failed and where explosive severing tools were not permitted for offshore operations.

The main objective of the pipe cutting campaign was to sever the 2 3/8-inch dual string completions on platforms in the Adriatic Sea. Most of these strings are stressed during the production stage due to buckling. All the cutting operations were to be conducted using the Coiled Tubing (CT) conveyed 1 11/16-inch hydraulic pipe cutter in highly deviated zones, on the order of 45 to 70 degrees, with the production strings in compression.

The new CT conveyed hydraulic pipe cutter has proven to be an excellent alternative to conventional severing options which can be ineffective or are not permitted due to offshore regulations.

The pipe cutter features durable knives dressed with specially designed tungsten carbide inserts to engage and quickly sever tubing, casing or drill pipe. The knife design produces lower point loading across the cutting surface resulting in longer life, completing cutting operations in a single run.

A detailed description of the CT conveyed hydraulic pipe cutter, the challenges and results of this campaign will be presented in this paper.
Model-Based Framework for Oil Production Forecasting and Optimization: A Case Study in Integrated Asset Management
Authors: Zhang C. , Orangi A. , Bakshi A. , Da Sie W. , Prasanna V. K.
Published: December 2007

This paper describes the design and implementation of a prototype toolkit that demonstrates Integrated Asset Management (IAM) functionality through an integrated production and forecasting workflow. A graphical modeling environment specially configured for this domain is used to instantiate the asset model. Automatic conversion of legacy data into structured model representations is facilitated through a model synthesis tool. The actual optimization is performed using a commercially available solver. For an oilfield with about 75 wells, the tool requires only a few seconds to read the model information and produce the forecast. The time required to generate the forecast output in the desired format depends on the duration of forecasting, the size of the field, and whether the output is to be produced as a text file or a Microsoft Excel spreadsheet.
Factors From Damaged Sperm Affect Its DNA Integrity and Its Ability to Promote Embryo Implantation in Mice
Authors: Pérez‐Crespo M. , Moreira P. , Pintado B. , Gutiérrez‐Adán A.
Published: December 2007

ABSTRACT: Endogenous nucleases in mouse sperm can be activated by freeze‐thawing the spermatozoa in media without cryoprotection and cleaving spermatozoa DNA. The role of sperm chromatin integrity during intracytoplasmic sperm injection (ICSI) is of critical importance. We analyzed in the B6D2 mouse the proportion of DNA‐fragmented spermatozoa (DFS) produced by incubation in conditioned medium (CM) generated by freeze‐thawing sperm in the absence of cryoprotection. We then examined the subsequent development, implantation, and offspring obtained after ICSI with incubated spermatozoa. When fresh sperm cells were incubated for 90 minutes in this CM, a significant increase in the amount of DFS was detected by the terminal deoxynucleotidyl transferase biotin‐dUTP nick end labeling assay (27% vs 4.5% in fresh sperm). After ICSI of fresh and incubated spermatozoa, embryos were cultured in vitro to either the 2‐cell or blastocyst stage before they were transferred into pseudopregnant CD1 females. On day 14, recipients were sacrificed, and implantation rates, estimated as the number of live fetuses plus resorptions, were determined. When ICSI was performed with sperm incubated in CM, no effects on fertilization, embryo cleavage, blastocyst rate, or blastocyst morphology were detected; however, the quality of the embryos was affected because the total implantation rate decreased significantly (P < .05) when 2‐cell embryos or blastocysts were transferred. Independently of sperm pretreatment, in vitro cultures significantly affected the percentage of live fetuses present on day 14 of pregnancy. These results demonstrated that there are factors released from fragmented spermatozoa capable of inducing DNA fragmentation in intact sperm that may compromise, to some extent, birth rates after ICSI.
Intracellular Sodium Increase Induced by External Calcium Removal in Human Sperm
Authors: Torres‐Flores Víctor , García‐Sánchez Norma L. , González‐Martínez Marco T.
Published: December 2007

ABSTRACT: In human sperm, removal of external calcium produces a fast Na+‐dependent depolarization that is presumably due to sodium permeation through calcium channels. Calcium restoration produces a ouabain‐sensitive hyperpolarization that brings the membrane potential to values frequently more negative than resting. In this work, we show evidence indicating that external calcium removal induces an increase in the intracellular sodium ([Na+]i) and that this phenomenon is related to the Na+‐dependent depolarization. Calcium restoration blocked the [Na+]i increase and then produced a slow decrease that was inhibited by ouabain. The [Na+]i increase was inhibited by nanomolar—micromolar calcium or by millimolar magnesium, which has been previously shown to inhibit the Na+‐dependent depolarization. This evidence supports the hypothesis that, in zero‐calcium medium, a calcium channel that would contribute to resting intracellular calcium levels allows sodium permeation, producing depolarization and a significant [Na+]i increase. Sodium loading would stimulate the Na+,K+‐ATPase, the activity of which contributes to the sperm hyperpolarization observed upon calcium restoration.
Marital Interaction in Middle and Old Age: A Predictor of Marital Satisfaction?
Authors: Schmitt Marina , Kliegel Matthias , Shapiro Adam
Published: January 2008

Many studies point out the importance of marital satisfaction for well-being. However, although being married is still the norm in middle and old age, research on the determinants of marital satisfaction has neglected long-term marriages. While research on short-term marriages mainly focuses on partner fit (e.g., in personality traits and socio-economic status), marital interactions should be more important for marital satisfaction in long-term marriages. In this article we examine the role of both stable, dispositional factors and of marital interaction in predicting marital satisfaction in long-term marriages in middle and old age. With data from 588 married women and men in middle and old age who participated in the Interdisciplinary Longitudinal Study of Adult Development (ILSE), we examined age and gender differences in the role of socio-economic status, personality, and marital interaction as predictors of marital satisfaction. Results showed a) that socio-economic factors and personality played a minor role in predicting marital satisfaction, and b) that a high quality of dyadic interaction was particularly important for the marital satisfaction of women. The implications of these findings for future research and interventions on marital interaction in middle and old age are discussed.
The Relationship of Worldviews of Advisors and Students and Satisfaction with Advising: A Case of Homogenous Group Impact
Authors: Coll Jose E. , Zalaquett Carlos
Published: January 2008

The purpose of this study was to investigate whether differences in worldviews between academic advisors and their advisees (both traditional and non-traditional students) impact students' use of and satisfaction with the advising process. This study surveyed 115 students and 5 advisors from a four-year liberal arts university in southeastern United States. Analyses of the data revealed no significant differences among traditional and non-traditional students' worldviews. However the degree of match between advisees and their advisors on two components of worldviews (self-worth and meaningfulness) was related to students' use of and satisfaction with the advising process. There was a significant difference ( F = 4.398, p < .0148) between students' self-worth and their perception of whether their advisors understood them. There was also a significant difference ( F = 4.172, p < .0183) between student self-worth ratings and their commitment to actively seeking advising. In addition, there was a significant difference ( F = 3.57, p < .0336) between student perceptions of “meaningfulness” and how students perceived the importance of advising. These findings suggest that a) students who have a similar self-worth value as their advisor have a sense that they are being understood, b) students who scored high or were within the means of their advisors self-worth tended to actively seek advising, and c) students who scored high or above their advisors mean score in meaningfulness, felt that advising was an important activity tor them. Implications for how understanding students' worldviews might improve academic advising are also discussed.
A Business Marketing Strategy Applied to Student Retention: A Higher Education Initiative
Authors: Ackerman Robert , Schibrowsky John
Published: January 2008

Relationship marketing, a concept that focuses on attracting, maintaining, and building business relationships, has enhanced the profitability of businesses. The core of the relationship marketing approach in business is that resources are directed toward strengthening ties to existing customers on the proven premise that maintaining existing customers is less costly than is attracting new ones. Relationship marketing models have been developed in a wide range of settings and evidence exists suggesting that it is a successful approach. This article explores the concept of adapting the business relationship marketing framework to the challenges of college student retention. The student retention and relationships marketing literatures are reviewed and parallels are drawn. The relationship marketing model presents a different way of viewing student retention, provides a different perspective on retention strategies, and provides an economic justification for implementing retention programs. Retaining students in post secondary programs has been a national concern for decades (Braxton, 2000). However, doing so remains a challenge (Habley & McClanahan, 2004; Maldonado, Rhoads, & Buenavista, 2005). Improving student retention is a worthwhile goal for a variety of individual, social, and economic reasons (Institute for Higher Education Policy, 2005; Schuh, 2005; Tinto, 1993). And, while not everyone will be comfortable applying concepts from business to an issue in education, adapting the customer retention model to student retention is appropriate given the emphasis both place on quality of services. We include a formula for determining the economic benefits to the institution of retaining students.
Shaping Retention from Research to Practice
Authors: Braxton John M. , Brier Ellen M. , Steele Stephanie Lee
Published: January 2008

This article presents seven guidelines to direct professional practice aimed toward the improvement of institutional student retention rates. For each of the seven guidelines, specific recommendations to provide direction to the enactment of the focal guideline are described. These seven guidelines spring from empirical studies of campus-based interventions and from recommendations for policy and practice advanced in empirical studies of college student retention.
McDonald's — Much Maligned, But an Engine of Economic Development
Authors: Tschoegl Adrian E.
Published: December 2007

Critics have excoriated the US fast-food industry in general, and McDonald's most particularly, both per se and as a symbol of the United States. However, examining McDonald's internationalization and development abroad suggests that McDonald's and the others of its ilk are sources of development for mid-range countries. McDonald's brings training in management, encourages entrepreneurship directly through franchises and indirectly through demonstration effects, creates backward linkages that develop local suppliers, fosters exports by their suppliers, and has positive external effects on productivity and standards of service, cleanliness, and quality in the host economies.
Fuel Ethanol Subsidies and Farm Price Support
Authors: Gardner Bruce
Published: December 2007

Ethanol subsidies are well established in U.S. policy and have high priority in corn growers' political agenda. This paper develops a vertical market model of ethanol, byproducts, and corn which is used to analyze whether corn growers would prefer the government's subsidy dollar to be spent directly on corn subsidies (though deficiency payments) rather than on a subsidy on ethanol made from corn. Because the subsidy dollar has to be shared with ethanol manufacturers under the ethanol subsidy, it is to be expected, and the model confirms, that a dollar spent on a direct corn subsidy increases corn growers' producer surplus more than an a dollar spent on an ethanol subsidy under many plausible values of the relevant parameters. But there are equally plausible parameter values under which the ethanol subsidy is preferred by corn growers. The economics of this result turn mainly on the price discrimination an ethanol subsidy creates between ethanol and corn used for feed and export purposes, reducing the buyers' price of ethanol and byproducts but increasing the price of corn fed and exported. This enables producers of corn and ethanol to increase their joint producer surpluses above the total value of subsidies paid. The paper also analyzes the social cost (deadweight loss) of these subsidies, and finds the ethanol subsidy to generate deadweight losses likely to be in the billions of dollars annually.
Policy Alternatives for the Future Biofuels Industry
Authors: Tyner Wallace E.
Published: December 2007

US and state governments have subsidized ethanol since 1978, and the rationale for these subsidies has varied over time from supporting farm prices and income, to environmental quality, and more recently to energy security and reduction of greenhouse gas emissions. The recent boom in ethanol investment and production can be considered as an unintended consequence of an ethanol subsidy keyed to $20 crude oil and fixed at 51 cents per gallon combined with oil surging to $70/bbl. Thus, in the 2005-07 period, ethanol was extremely profitable inducing substantial new investment. For the future, different political action groups and political figures propose renewable fuels targets or standards ranging from 35 to 100 billion gallons per year. To achieve anything like these levels, it is likely that the current policy set will need to be reconsidered. In addition to the current policy, this paper considers using a subsidy tied to the energy security gains and greenhouse gas emission reductions provided by renewable fuels, subsidies targeted specifically at cellulose ethanol, and different versions of a renewable fuel standard such as the one passed by the US Senate. It is clear that we must develop a better understanding of the consequences of these alternative policy pathways.