bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Multipurpose Numerical Model
Authors: Bilgesu H. I. , Ertekin T.
Published: December 2007

A multi-purpose model is developed for simulating primary, secondary, and some of the tertiary recovery processes. The simulator models the isothermal flow of oil, water, and gas in porous media in two dimensions using either rectangular or radial coordinates.

Initially, partial differential equations describing the fluid flow are approximated using finite difference technique and the resulting system of equations are solved simultaneously via alternating direction implicit procedure. The transmissibilities are calculated using explicit, semi-implicit or fully implicit formulations. Although block centered grids are used for rectangular system, a mesh centered grid is employed in the case of radial system which yields in better representation of the well block pressures. Injected fluids are tracked separately but they are accounted for within all phases using mixing parameters that empirically predict the incomplete mixing within a block. In the case of polymer injection, the modified Blake-Kozeny4 equation is used in the representation of the viscoelastic behavior of the injected fluid in the pseudoplastic region. The stripping of polymer from the injected fluid due to adsorption is represented as a function of polymer and rock properties.

A fully implicit well formulation is used where well block pressure was solved simultaneously. Multiple wells with different injection and production schemes are included in the model. In the case of rectangular coordinates, an infinite conductivity fracture is coupled with the well block.

An automatic time step selector is implemented to reduce the time truncation errors as well as reducing the computational costs. The property package used different techniques such as linear interpolation, least squares, or cubic splines for predicting fluid properties or the user supplied functions are used.

The simulator is tested using published data for several options against existing models and results are found to be in good agreement.
Oil Development Strategy in an Uncertain Market
Authors: Ausman J M
Published: December 2007

This paper contains observations about crude oil price forecasts and the way oil companies respond to oil price uncertainty. The industry is shown to act as though current oil prices are a good indicator of future prices. Industry earnings are shown to be less sensitive to low oil prices than might be expected. Strategically, it is important to recognize the inefficiency of the industry responding to rising and falling oil prices with "on/off" spending patterns.
Astute Basin Evaluation, Key to Economic Success in Hard Times
Authors: Newman Peter V
Published: December 2007

Intelligent basin evaluation, leading to identification of those basins with the greatest exploration potential, is a critically important element of the exploration process. This is especially true during times of crude price weakening, when finding costs take on somewhat greater significance. Proper basin choice is also one of the few ways in which you can gain a substantial advantage over the competition – your staff and technology are probably not much better than those of your major competitors, but it may be possible to explore a considerably more prospectize suite of basins. For these reasons, the basin selection process should be taken very seriously, with as much thought and effort going into it as into the other major segments of the exploration program.

This talk will discuss the factors that are important to basin evaluation, both geologic and nan-geologic. Non-geologic factors include not only political and economic issues, but company-specific elements that relate to company size, resource base, and operating philosophy. With geologic factors, the emphasis will be an identifying the relatively few that are critical and then predicting where those factors can be favorably combined. Modern basin classification concepts will be an aid here, especially in virgin basins.

The thesis will be advanced that, in developed basins, an entire data set is being generally ignored that could significantly improve the accuracy and quality of the basin-evaluation process. It appears that too often there is a tendency to seek out innovative exploration breakthroughs without first having utilized all the pertinent data available. In terms of cost-effectiveness and realistic results, putting these data to use may be more productive than searching for a breakthrough.

The paper will close with an example from South-east Asia of a simple but highly successful basin analysis exercise.
Impulsive Pressure of Breaking Wave on Piles
Authors: Tanimoto K , Takahashi S , Kaneko T , Shiota K
Published: December 2007

Characteristics of impulsive pressure on inclined circular piles exerted by a breaking wave were evaluated experimentally. The experiment was conducted on a model pile, which was inclined from 0° to +30° on a 1:10 bottom slope. Time histories and distributions of the impulsive pressure were observed using ten pressure transducers on the pile surface.
High-Angle, Shallow Depth Drilling in the South China Sea
Authors: Kairon Saadon bin , Schroeter D R
Published: December 2007

A substantial reduction in field development cost has been realized by using high-angle, long-reach wells to develop the shallow Semangkok Field with only two (2) platforms. An estimated savings in initial develpment costs in the order of US$60M was realized over a three (3) platform development alternative based on more conventional directional wells.

Conventional drilling equipment and methods were extended to new limits in drilling and completing wells with angles exceeding 70° to objective targets as shallow as 1250 m TVD-SS with departures exceeding 2000 m. The planning and drilling methods employed to successfully drill, survey, log, and complete these wells are presented in this paper.

The cost deviations attributed to drilling at high inclinations amounted to less than 8% of the final well cost for 29 of 42 wells and two geologic side-tracks that were drilled at angles ranging from 60° to 75°.
High Temperature Drilling Fluids in the Cooper-Eromanga Basin, Australia
Authors: Aung Tun H
Published: December 2007

Several wells with bottom hole temperatures in excess of 400°F have been drilled in South Australia. Two early wells were drilled with Lignite-Lignosulfonate fluids and two recent wells used a newly introduced high temperature polymer system. A brief comparison of these high temperature wells has been made. The effects of temperature on the performance and properties of the polymer system are examined and the need for further improvements in the area of high temperature drilling fluids is also considered.
Supervisory Control and Data Acquisition System for Offshore Java Sea
Authors: Gunawan T , Thomas T P , Williams R I
Published: December 2007

Atlantic Richfield Indonesia Incorporated has started the implementation of a Supervisory Control and data Acquisition (SCADA) Sytsem for all of its offshore oil/gas production platforms in its Offshore North West Java contract area in Indonesia. This paper will outline the technical and operational requirements for the SCADA system and highlight some of the anticipated benefits for production monitoring, well testing, and management reporting.
Offshore Pipeline Transport of Waxy Crude Oils
Authors: Bomba John G
Published: December 2007

Pipeline transport of waxy crude oils can be performed effectively, both from technical and economic standpoints, through adequate system designs. Such pipeline designs must consider safety aspects, system integrity, ease of installation, and potential operating and maintenance problems. General topics which must be reviewed will include features of the waxy crudes, fluid heating and temperature loss control potential, factors influencing and methods of controlling wax accretions, and problems involved with shutdown and startup. A general review of pump effectiveness for waxy crude transport is provided. A cost comparison of pipeline transport with other methods of waxy crude movement, such as barge tow or tanker handling, is presented.

This paper is essentially a review of waxy crude oils and their features related to offshore transport. It will serve as an information source for engineers who are inexperienced in dealing with waxy crudes and as a guideline and source of ideas for more experienced engineers that must design transport facilities.

Effectively designed pipeline systems can be established to handle waxy crude oil transport. In most cases, pipelines are a cost effective method of transport when compared to other alternates such as barge or tanker shipment.
Wax Deposition in a WAG Flood
Authors: Nenniger J. E. , Cutten F. B. , Shields S. N.
Published: December 2007

Substantial deposits of a gummy material were discovered in the injection system of a water-alternating-gas (WAG) miscible flood. Capillary column gas chromatographic analyses revealed that these deposits were due to wax contamination of the natural gas liquids used to enrich the injection gas. To remove the deposits, propane was added to the injection gas. This treatment was carried out successfully at virtually no extra cost.
A Minimum Miscibility Pressure Study Using Impure CO2 and West Texas Oil Systems: Data Base, Correlations, and Compositional Simulation
Authors: Kovarik F. S.
Published: December 2007

This paper presents results from the study to improve the impure CO2 minimum miscibility pressure (MMP) prediction capability. The MMP data base was obtained from laboratory slim tube runs. Rigorous criteria for MMP determinations were established. These data were correlated as a function of mole fraction of contaminants in CO2, as a function of injection gas pseudocritical properties, and using a modified Peng-Robinson equation of state, with average errors in the range of 2 to 6 percent. The CO2 impurities were N2, C1, C2, C3, C5. Concentrations of impurities varied from 0 to 30 mole percent.

Comparisons with literature data indicate that the correlations, although developed using only West Texas oils, can be generalized to include a wide spectrum of reservoir fluids. These correlations, when compared to others in the literature, are found to be superior for injection gas mixtures which contain nitrogen and methane contaminants.

An ARCO developed compositional simulator was calibrated using slim tube and PVT data from the West Texas oil-CO2 system. The model simulates recovery curves reasonably well and predicts the pure and impure CO2 minimum miscibility pressures for West Texas oils to within 50-150 psi.
Current status of the ASEE Goals Report
Authors: LeBold W.K.
Published: December 2007

These are dramatic times of change and challenge in engineering and engineering education. New materials and energy forms are being utilized in increasing complex devices and systems. Society is making increasing demands on engineering for not only the solutions to technical problems utilizing the latest discoveries and developments in science and technology, but solutions that are economically feasible, and socially acceptable as well.

Engineering, in the past, could optimize devices and systems, on one or two parameters; today we talk in terms of n parameters where n can range anywhere from one to infinity. Fortunately in engineering, these new demands are being met by the parallel development of new techniques and methods. Custom made materials can be specified and realized rather than adapted and compromised. High speed computers make it possible to try many alternate solutions, rather than compromise on our "best guesstimate."

Coupled with this technological and scientific revolution and the information explosion associated with it has been another explosion, an educational and social revolution that extends beyond local, regional and national boundaries. This is especially apparent in the contemporary American higher educational scene today. Society demands that higher education contribute not only a greater number, but a greater proportion of the educated people required in business, industry, and government; society also demands that higher educational institutions make a major contribution to the creation of new knowledge through research and to the dissemination of new knowledge through continuing education and publications. In addition, higher educational institutions are being asked in ever-increasing numbers to contribute to the contemporary problems of society including poverty and disarmament, space travel and international relations, and the Northeast Corridor and Los Angeles' smog.

The engineering profession and engineering education sit squarely in the middle of this millieu. As a result, it is both understandable and wise for us to take a moment, sit back, and ask ourselves what are we trying to do, where have we been, and where do we think we should go? The Goals of Engineering Education Project of the American Society for Engineering Education was just such an attempt, and is in its final stages now. Such studies are not new in American engineering education; indeed, we have been on about 10 year investigation cycles since the turn of the century. The general charge of the Goals Study was to conduct a comprehensive study into all aspects of engineering education and to recommend a pattern of engineering education which would result in improved undergraduate and graduate programs. This study has tried to collect information from a wide variety of sources including field studies, surveys, literature search, and study committee reports; and to obtain the views of engineering educational institutions, engineering graduates, engineering managers and personnel representatives, and technical and professional societies.
Means for Handling Gas Influx in a Marine Riser
Authors: Hall J. E. , Roche J. R. , Boulet C. G.
Published: December 2007

The deep water well-control concept described in this paper offers improved safety and reduces the risk of equipment damage and pollution. This concept could prevent the occurrence of an uncontrolled riser blowout, the danger of which is more severe as water depth increases.

The proposed riser kick control device is placed at the surface, which is conventional. The added control is achieved without making major alterations to typical, present day deep water drilling systems. Basic well bore control, surface diverter techniques, and equipment remain unchanged.
A Drilling Contractor Tests Solids Control Equipment
Authors: Froment T. D. , Rodt G. M. , Houwen O. H. , Titreville B.
Published: December 2007

In the recent years, the introduction of new expensive and sophisticated muds has changed drastically the concept of solids control in drilling muds. New equipment has appeared (decanting centrifuges), the performance of conventional equipment (shale-shakers) has improved dramatically, new regulations have forced the companies to develop and install cuttings cleaning systems.

This paper will explain the motivations of SEDCO FOREX as a drilling contractor in undertaking an extensive and full scale test campaign to assess the capacity and efficiency of each piece of solids control equipment in relation to mud characteristics. Three tests were planned: the first one, which is completed, was investigating shale-shakers, hydrocyclones and mud cleaners. The second one, which is underway, addresses the cases of the decanting centrifuges. The last one will deal with degassers.

Each time, the laboratory tests giving scientifically measured results in well controlled environment are complemented by field reports giving information such as maintenance or operation problems.

The various problems encountered while running these tests and the tools used will be described. In particular, the utilisation of the SEDCO FOREX R&E VAX 780 for storing and interpreting the results will be explained.

Finally, some information will be given on the results of the first series of tests and on the benefit that they have already produced in the field for both our company and our clients.
Moderate pH, Potassium, Polymer-Treated Mud Reduces Washout
Authors: Fleming C. N.
Published: December 2007

In the past, borehole stability and preventing hole washout have been major problems on many wells drilled in the Gulf Coast. Both of these problems have major influences on drilling efficiency and drilling cost. Two objectives were established to investigate these problems and possible solutions:

To build and maintain an inhibitive mud system. To minimize washout by contributing to borehole stability.

It is the intent of this paper to show that selected water soluble polymers and potassium hydroxide additives improve bore-hole stability and hole washout by reducing the water adsorption rate at the borehole-drilling fluid interface.

Before implementation of the fluid system on, Well #A-2, Main Pass 77, Block 151 some guidelines were established. To gauge the degree of success, directionally drilled Well #A-2 was compared with the #1 Wildcat that was drilled as a straight hole five years earlier.

The section of the wells used for comparison was the 8 1/2″ hole approximately 1100 feet in length. These sections were correlated using the D-5 and D-10 sands and divided into fourteen intervals.

The two wells were compared as to washout, mud cost to drill, hours spent drilling, hours spent washing and reaming, and total circulating time (excluding drilling). Comparisons were also made using annular velocity, jet velocity, pH, pm and pf.

The fluid system is being applied to other wells and the results are encouraging.
Drillstring Vibrations: Comparison Between Theory and Experiments on a Full-Scale Research Drilling Rig
Authors: Aarrestad T. V. , Tønnesen H. A. , Kyllingstad Å.
Published: December 2007

Extensional vibrations in drillstrings have been studied with both linear elastic theory and experiments in a 1000m deep vertical well. A hardwire MWD-tool suitable for rotary drilling has been used to transmit near bit accelerations, weight on bit and torque at a rate of 556 measurements per second. New understanding of the vibration damping process has been achieved, and the damping effects are shown to have critical influence on the vibrations. By including frequency dependent damping the theoretical results agree better with experimental results than it does with constant damping.
Cost Effective Application of Thermally Stable Synthetic Diamond Bits on Downhole Motors in the Permian Basin
Authors: McGehee D. Y. , Garnett R. B. , Rodriguez M. R.
Published: December 2007

This paper provides documentation of six cases in which Thermally Stable Diamond (TSD) bits were used in combination with downhole motors yielding economically successful results in the Permian Basin. In addition, a detailed discussion of the TSD cutting element and TSD bit design is presented. This discussion compares the TSD to natural diamonds and polycrystalline diamond compacts (PDC's) and explains why TSD bits are superior in some applications.
Charged Shales: Self-Induced Pore Pressures
Authors: Gill J. A.
Published: December 2007

Each year, a painfully significant number of drilling wells experience baffling, virtually insurmountable, prohibitively expensive pressure imbalance problems – losing mud while circulating; but gaining during trips – not explainable as simple overbalance/underbalance.

Every one of these wells seems to require as much as 17.5-18.5 ppg mud weight, and still seems on the verge of blowing out --- but. never quite does.

Pressure balance indicators are in puzzling conflict. Most of the drilling parameters indicate continued underbalance, even after – especially after – mud weights have been escalated farbeyond the natural pore pressures of, say, 16.0 ppg (as determined by well-log pressure plots and confirmed by the offset wells that have been drilled, relatively trouble-free, at the lesser mud density).

The borehole apparently balloons or breathes, slightly, when long sections of already-overpressured, wet, plastic shales are drilled this greatly in overbalance (but not by then easily recognisable as overbalance); taking 20-30 bbls of mud while circulating and giving it back (if we let it) when pumps are shut down.

This new, superimposed and "bottled-up" hydrostatic pressure in the wellbore from the (excessive) mud density is then very real.

When we push on the (16.0 ppg) shale/water mixture of the formation with 17.5 ppg mud (13,000 psi --- 1500 psi of overbalance); it can yield only slightly within its confines (the water component being virtually incompressible) before it "pressures up" and pushes right back with that same force.

We have created in the shale body a super-natural, self-induced pore pressure greater than its original, natural pore pressure. We have "charged" the shale.

Several well histories – and their "natural" pore pressure plots from well logs – are presented here, to illustrate that these impossibly delicate pressure-balance situations of our own doing can and do develop; how they can be recognized by their characteristic symptoms; and how they can be corrected, or simply avoided in the first place.
Comparison of Rheological Models in High Shear Rate Range and Experimental Relationship Between Penetration Rate and High Shear Viscosities
Authors: Sun Wanneng , Chen Jianping , Li Zhenxue
Published: December 2007

High shear viscosity at the bit nozzle is an important parameter in drilling optimization. Four rheological models were used to calculate high shear viscosity from rheometer data and the calculated viscosities were compared with viscosities measured with high pressure capillary viscometers for five types of 16 different kinds of water base non-weighted muds. The Casson model gives the best fit and rheometers can be used in the field to predict nozzle viscosities. Regression equations and experimental relationship between drilling rate and high shear viscosity were obtained from full scale laboratory drilling rig tests. The high shear viscosity has a considerable influence on drilling rate in sandstone and limestone. A lower nozzle viscosity is preferred in optimized drilling.
Artificial Lift Techniques in China
Authors: Wan Renfu , Chen Xiankan
Published: December 2007

160 oil fields have been put into development in Daqing, Shengli and other oil regions in China. The reservoir rocks of these oil fields are mainly continental sedimentation in origin characterized by multiple productive reservoirs and multiple-layers, with great difference in permeability between reservoirs and relatively insufficient natural energy supply. Reservoirs of this kind generally have a short period of flowing production, quick depletion of pressure and low primary recovery by means of natural energy. To improve the effect of oilfield development, water flooding from an initial stage of development for pressure maintenance and flowing well production has been adopted in most of oilfields. Such a system ensures that the annual crude output of China reaches one hundred million tonnes and over. However, the water cut of wells rises continuously and the capacity of flowing well production decreases gradually in the course of oilfield development. Since 1980, we have converted most of the flowing wells into the artificial lifting wells and at the same time large capacity pumps, hydraulic pumps and electric submersible pumps are gradually used to replace the conventional downhole pumps for production. Through field practice in recent years, the development result has been further improved so that crude output of our country not only remains stable but also Increases gradually year by year.

A continuous rise of water cut, an increase in borehole fluid gradient, a rise of flowing pressure causes a decrease of production pressure differential, resulting in a decline of the crude output. For example, in 1980, there were 3872 flowing wells in Daqing Oilfield with an overall water cut of 60%. The chokes of producing wells had been enlarged continuously but the producing pressure differential did not increase strikingly. Generally a rise in the producing pressure differential of 0.4 atm will occur for each water cut increase of 1%. Although the water flooding has been strengthened to restore the reservoir pressure, it could not match with the rising speed of flowing pressure. So, the producing pressure differential might not be increased and even further decreased in some cases.

There are two ways to increase the producing pressure differential at the water cut production stage. One way is to restore or increase the reservoir pressure and the other is to reduce the flowing pressure. The change of the mode of production from flowing to artificial lift is, in fact, to take the second way, i.e., water injection for pressure maintenance at a given level to ensure a sufficient supply of the fluid to the wells, while the flowing bottom hole pressure is greatly reduced by means of artificial lift techniques so that the aim of increasing the producing pressure differential to maintain a steady crude output is achieved.
Well Testing Analysis in a Double Porosity Reservoir
Authors: Zhu Yadong
Published: December 2007

Our research results and their application on well testing analysis in the reservoir with double porosity in recent years are summarized in this paper. In the field of theoretical research, on the basis of analytical solution of flow equation for the double porosity reservoir1, calculation methods under three boundary conditions, a closed reservoir with constant external pressure, a closed reservoir and an infinite boundary are given in this paper. The theoretical pressure change curves under these boundary conditions are constructed, and the effect of interporosity flow parameter λ, storage capacity ratio w and dimensionless outer boundary radius RD on the curves are analyzed. While in practical application, on the basis of the above research results, two analytical methods, that is, optimum matching and semilog straight line, are given in this paper for single well testing in a naturally fractured reservoir to obtain the related parameters: As for the interference test between wells in a naturally fractured reservoir, a set of type curves is given, which could be used in the interpretation of interference pressure testing data to obtain the inter-well parameters in such a reservoir. These methods have been used in fractured carbonate reservoirs in North China Oilfield and Shengli Oilfield.
The Flow Effect of Mud in Annulus and the Selection of Rheological Parameters
Authors: Wang Zhongying , Tang Songran
Published: December 2007

The flow of mud is closely related with the anomaly of well-bore diameter, the density of cuttings in the mud and the annular pressure loss. This paper discusses the annular flow effect, puts forward the three flow effect criteria of erosion, lifting and dynamic pressure, defines the similitude rule of annular effect, and derives formulas representing the three criteria. It also recommends the index for evaluating the annular effects, and presents how to select the rheological parameters and the circulation rate.
Adjustment of Surfactant/Polymer Interaction in Surfactant/Polymer Flooding With Polyelectrolytes
Authors: Yang C. Z.
Published: December 2007

The aim of this paper is to make a systematic analysis of surfactant-polymer interaction in the process of chemical flooding. In determining the influence of the salinity of the solution, the degree of hydrolysis, the molecular weight and the concentration of polymer as well as the surfactant concentration and the type and concentraction of alcohol on the incompatibility of the surfactant-polymer system. We find that salinity is the main cause of miscibility loss by the mixture, thus leading to phase separation and to an appreciable variation in surfactant distribution in the solution and in phase properties. When inorganic polyanions are introduced, e.g. phosphate (SP-6) and silicate (SS-3), the compatibility of the system is considerably improved, and salinity, which causes phase separation, increases. The incompatibility phenomenon can be explained by considering the micelle-polymer system as a colloidal system according to the DLVO theory for the stability of colloids.
The Status and Potential of Enhanced Oil Recovery
Authors: Kuuskraa V. A.
Published: December 2007

The search for tomorrow's oil reserves has directed the energy industry to new frontiers. Traditionally, this term "new frontiers" connotes hostile and challenging geographical terrain -- the deep waters of the offshore, the harsh environment of the Arctic, or deeper, more subtle oil traps. In the past few decades a fourth "new frontier" has evolved -- a frontier defined not by geography or geology but rather by technology. This fourth frontier is a collection of technologies -- involving the use of thermal, gas, and chemical means for producing more oil -- that fall under the broad umbrella called enhanced oil recovery (EOR).
Slim-Tube Investigation of CO2 Foams
Authors: Irani C. A. , Solomon C.
Published: December 2007

Formation and propagation of foams at considerable distance from the injection point is not well understood. In this study a 100-ft slim tube packed with 50/70 Ottawa sand was used to investigate foam behavior over long distances at reservoir temperatures and pressures. Both simultaneous and alternate modes for surfactant and CO2 injection were found to be inadequate. The liquid surfactant phase has a much lower linear velocity in the formation relative to the gas phase, and consequently there is a steady buildup of surfactant concentration in the vicinity of the injection point. Additionally, foams were found not to propagate, but rather to form spontaneously where CO2 and surfactant contact each other. As a result, in either the simultaneous or alternate injection modes, the foam front was found to have a very low frontal velocity, while unnecessarily high pressure drops were generated behind the foam front.

An alternate approach referred to as the dual slug injection method is proposed. This method calls for injecting all the necessary surfactant as a single, large, dilute slug and then chasing it with CO2. This approach demonstrated almost plug-like displacement of the foam front through the slim tube, resulted in optimum use of the surfactant and maximized foam penetration. For some surfactants the presence of crude oil is detrimental to foaming action and oil recovery is hampered. Additional testing of this methodology is necessary in order to verify the improved efficiency of this approach relative to conventional injection schemes.
Anadarko Basin Completion Overview
Authors: Clement C. C. , Maness S. F. , Mason C. M.
Published: December 2007

Completion methods used in the deep Anadarko Basin have varied a great deal over the past several years.

Due to an active exploration program in the basin, Sohio Petroleum Co. formed a Springer task force group to evaluate past methods and to develop and refine deep completion techniques in the Morrow and Springer formations. This group formulated guidelines based upon published literature and past experience of the group members.

The guidelines were implemented in the field and modified as more data and knowledge were obtained, resulting in a specific set of guidelines now used on all Morrow and Springer completions.

There are a number of case histories that illustrate the evolution and reasons behind the specific guidelines, which will be listed.
Using Fiberglass Sucker Rods in Deep Wells
Authors: Hicks A. W.
Published: December 2007

When a flowing well no longer produces adequate volumes of oil, it is wise to use the most economical method of artificial lift to produce the wellbore fluids. When all forms of artificial lift are considered and the cost of producing oil exceeds the value of the produced oil, it becomes uneconomical to operate the well and the well is usually plugged and abandoned. Beam pumping systems utilizing fiberglass sucker rods are producing oil from wells that had previously been uneconomical and are now profitable operations. Beam pumping systems using fiberglass sucker rods in deep wells are producing fluid more economically than systems using steel sucker rods.

In contrast to standard steel sucker rods where relatively heavy weight and corrosion are inherent, fiberglass sucker rod bodies are much lighter in weight and are not susceptible to corrosion.

The author presents this paper in an effort to provide an in-depth study using fiberglass sucker rods in deep wells. Consideration is given to rod string design, pumping unit design, energy consumption, and production capability.

This paper will present conclusions from studies of beam pumped wells with seating nipple depths in excess of 11,000 feet. The overall results have meant a considerable increase in production while reducing working stress on surface and sub-surface equipment.

In conclusion, fiberglass sucker rod strings, when properly designed, reduce peak polished rod loads, torque requirements and energy consumption.
Saving Money: The Real Aim of Quality Assurance Systems
Authors: Gookin L. E.
Published: December 2007

Deep drilling requires detailed planning, procurement, and operations over a relatively long time span as compared to normal well operations. However, like all drilling ventures, the ultimate goal of a deep oil or gas well is to make a profitable well as cheaply as possible. Consequently, a quality system that assures efficient activities and cost effective methods is required to optimize this goal. This paper presents the basis of a Quality Assurance System which can be established to improve efficiency and reduce costs.
Numerical Analysis of Helical Buckling
Authors: Mitchell Robert F.
Published: December 2007

The equilibrium equations for a helically buckled tubing with weight are solved by an approximate method that produces a generalized form of Lubinski's force-pitch relationship. This new solution provides a method for evaluating the range of application of Lubinski's results. A new definition of the neutral point is derived based on a contact force criterion. A numerical analysis of a cantilever end constraint at the packer is used to evaluate the generalized buckling solution. This analysis puts the Lubinski solution in a technical context that allows further developments, such as tapered strings, inclined wellbores, and friction.
Automatic Density Control System Improves Cement Slurry Performance
Authors: Edgley K. D.
Published: December 2007

Correlation of anticipated and actual cement slurry performance has been improved by combining microprocessor-based density control with a recirculating cement mixer. After desired density is set from a membrane keypad, the system's electrically and pneumatically operated controls keep the slurry density within ±.1 lb/gal of selected density. Density setpoint may be changed during the job.

The density of cement slurry as mixed on the surface is critical to the ultimate performance of the slurry downhole. In deep, hot holes, density control is especially critical, and the need for dependable performance is intensified. Accuracy of the automated system exceeds human capabilities to maintain slurry density throughout an entire cement job.

Subject paper presents operating description and specifications of the system, including schematic diagrams. The manual backup system is described.

Density control documentation from actual cement jobs is presented.
Minimizing Reservoir Damage by Insuring Proper Additive Performance in Stimulation Fluids
Authors: Holcomb D. L.
Published: December 2007

Specific aspects of reservoir damage, particularly associated with clays are well defined but are seldom considered in total with respect to loss of additive effectiveness due to possible negative reactions in a clay environment.

Significant losses of additives and subsequent additive effectiveness are suggested and documented with emphasis on various clay control methods in the presence of various key clay families.

Tendencies for additive incompatibilities in various clay and fines environments within sensitive reservoirs will be outlined. Various methods to prevent damage when using these additives will be discussed including overcoming loss of performance in situ due to adsorption onto high surface area clay coatings.

Finally, methods for removing damage from immediate wellbore regions will be discussed and a new technique using specific pH buffered alcohols will be discussed with respect to system description and mechanism.
Laboratory Study of Lost Circulation Materials for Use in Oil-Base Drilling Muds
Authors: Nayberg T. M. , Petty B. R.
Published: December 2007

Lost circulation problems encountered in drilling are magnified when using expensive oil-base muds. There are many lost circulation materials (LCM's) that perform effectively in water-base drilling muds, but very few that work, well in oil-base muds. Those that do work well are effective in controlling seepage loss only.

A laboratory study was undertaken to compare the performance of conventional lost circulation materials with a new material composed of thermoset rubber in different oil-base drilling muds. Laboratory data are presented comparing the effectiveness of mica, modified hydrocarbons, cellulose fibers, ground walnut shells, a blend of fibers, flakes and granules, and thermoset rubber in controlling mud loss to simulated medium-size fractured formations. Included in the evaluation were tests performed in a low toxicity mineral oil-base mud, two invert emulsion oil-base muds, and two other oil-base muds (one heavily weighted).

It is shown that the LCM's specifically designed to combat lost circulation in oil-base drilling muds such as mica, modified hydrocarbons and cellulose fibers failed at all tested concentrations in all five oil-base muds. The other conventional materials such as walnut shells-coarse, a 2:1 blend of walnut shells-coarse and walnut shells-medium performed satisfactorily only at high concentrations in the five oil-base muds. The coarse blend of fibers, flakes and granules worked satisfactorily at high concentrations in one mud only. The thermoset rubber performed effectively at tested concentrations in all five oil-base muds.

Two interesting results were observed during this study. It was found that granular type LCM's, such as walnut shells-coarse and thermoset rubber-medium, sometimes exhibit a phenomenon called channeling effect. This channeling effect occurs when a high pressure differential and insufficient solids concentration in the mud (that cannot build and sustain a bridge at the formation face, or within the formation matrix) causes many channels to form within the LCM deposit, thus leading to mud or gas migration through the channels and, finally, to a test failure. It was also found in some drilling muds that high concentrations of walnut shells or thermoset rubber contribute to poorer performance than at lower LCM concentrations.

The effectiveness of the thermoset rubber LCM in oil-base drilling muds is believed to be due to: optimized particle size distribution, oil wettability, combination of particle strength and deformability, thermal stability and mud compatibility. Based on the results of this study, a solution to the problem of controlling the loss of oil-base muds to fractured formations is proposed. Comparative performance data are also presented to facilitate the use of the conventional LCM's as well as the thermoset rubber material in oil-base drilling muds.
A Simple Segregated Flow Model for a WAG Process
Authors: Hopkins C. W. , Wu C. H. , Poston S. W.
Published: December 2007

A simple segregated flow model was developed to describe an alternate water and gas (WAG) injection process in a linear reservoir system. The model was developed based on the geometries of segregated fluid interfaces and on a volume balance of the injectants and the initial reservoir fluids. Results obtained from the model showed good agreement with published experimental and field data.

Assumptions in the model development includes immiscible water and gas phases, incompressible fluid flow, no trapped oil volumes and a uniform initial water saturation. Segregated flow interfaces depict the injected gas channeling to the top and the injected water channeling to the bottom of the oil zone. It assumes a pistonlike displacement and a fully segregated flow process.

The model tracks the progress of the respective interfaces and estimates the cumulative injection required to gas and water breakthrough. The model considers the fillup of initial free gas volume. The model can be easily extended to a five spot pattern by utilizing a streamtube approach, or by using an independently determined areal sweep efficiency.

A comparison of published experimental production data for different gas/water injection ratios with that predicted from the model showed excellent agreement. The model was satisfactorily used to predict the production performance of a field WAG process.
Extension of the Dykstra-Parsons Method to Layered-Composite Reservoirs
Authors: Tiab D. , Osman M. E.
Published: December 2007

The Dykstra-Parsons method is often used to study the displacement of oil by water or gas in stratified reservoirs. These strata of different permeability are assumed to exhibit lateral continuity throughout the reservoir. In the proposed model, these strata are assumed to consist of several blocks with differenl transmissibility, kh/μ, and storage, ϕcth. According to Dykstra and Parsons, the displacing fluid sweeps faster through the more permeable zones so that much of the oil in the less permeable layers must be produced over a long period of time at high WOR. In this study, it is found that this is not necessarily true. It simply depends on the rock characteristics from layer-to-layer and from block-to-block. It is also found that waterflooding performance in layered-composite reservoirs is essentially controlled by the mobility ratio.

Equations giving the pressure drop, time of breakthrough, water-front location, coverage, WOR and cumulative oil recovery in a layered-composite reservoir are presented. Application of these equations to the case of constant injection pressure, which was not treated by the original Dykstra-Parsons method, is discussed.
A Method for Predicting Solution Gas-Drive Production Decline
Authors: Cummings C. A. , Gentry R. W.
Published: December 2007

This study deals with projecting production decline curves. It examines a generalized relationship of cumulative production versus time presented in the literature by Gentry1. A production rate versus time relationship is derived from this general equation. Four methods of determining the constants appearing in both equations is presented. The equations are used to model solution-gas drive production (simulated and actual field case studies). The goal is to determine the uti1ity of using the equations to evaluate solution-gas drive reservoirs.
Densitometers for Mass Flow Determination of CO2
Authors: Ord R.
Published: December 2007

Density is widely used in mass flow computations for custody transfer of supercritical CO2. Determination of density from densitometers is shown to be more reliable than estimation from temperature and pressure. Three types of vibrating element densitometers are described, and typical installation schemes are outlined. Advantages and disadvantages of each densitometer type are reviewed.
Corrosion Control in Enhanced Oil Recovery Wells
Authors: Martin R. L. , Braga T. G.
Published: December 2007

Results of laboratory and field investigations are presented which illustrate corrosion identification and control in several types of EOR projects. Primary emphasis is given to producing wells in CO2 floods, in polymer or micell-polymer floods, and insitu combustion wells. Injection wells in these projects are considered briefly.

Based on corrosion measurements and measurements of sulfide, bicarbonate, and dissolved CO2 in produced fluids, effective corrosion inhibitors can be selected for corrosion control in all of the above conditions.
Interpretation of Temperature Profiles from the Steam-Stimulated Cold Lake Reservoir
Authors: Vittoratos E.
Published: December 2007

Steam stimulation of the Cold Lake bitumen reservoir causes fracturing of the formation. Steam enters via convection along the fracture plane, and heat propagates perpendicular to this plane by conduction, which in some cases may be enhanced by convection. Temperature profiles from observation wells located around stimulated wells directly give the energy distribution at those locations. The analysis can be extended beyond energy distribution by distinguishing regions of convective and conductive heat transfer in the temperature profiles. Simple analytical models can then yield important insights into the cyclic steam stimulation process, such as fracture geometry and fluid flow velocity. Eight field cases are discussed representing profiles from the injection, shut-in, and production phases of the process.
A Comparison of Methods for the Representation of Three-Phase Relative Permeability Data
Authors: Parmeswar R. , Maerefat N. L.
Published: December 2007

With the advent of enhanced oil recovery (EOR) methods such as chemical flooding, miscible gas displacement and thermal methods, three-phase relative permeability data are needed to predict performances of field applications. Complexity of experimental and calculation procedures for three-phase relative permeability measurements is a primary reason why published data in this area are limited. Furthermore, arbitrary methods used for analysis and graphical representation of these experimental data are affected to some extent by subjective bias.

In this study, three-phase relative permeability data, reported previously by five other investigators are represented by a power law functional form with seven parameters to be estimated for each of the phases present. In this new approach, it is assumed that the relative permeability of a given phase is a function of the three fluid saturations. Results from the seven-parameter equations fit the experimental data throughout the three-phase range within experimental error (0.52%). To illustrate the accuracy of the isoperms predicted by the parametric method, these isoperms were compared with isoperms obtained by a graphical contouring technique. The graphical contouring technique uses a collection of local interpolation functions to calculate isoperms from experimental data and to plot on a triangular graph. This procedure eliminates errors resulting from subjective bias and is a true representation of the experimental data since it passes through all data points.

Comparison of the isoperms obtained by the parametric method with the isoperms plotted by the graphical contouring technique show that: (1) the parametric method gives a more reliable fit to the data points than manual techniques, because it is based on mathematical optimization and therefore eliminates subjective bias and (2) the graphical contouring method reveals the fluctuation in the original data points and possible smaller scale trends that may be significant. The functional form presented in this paper can be used to estimate three-phase relative permeability from displacement (unsteady state) core flood experimental results.