bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Viscosity for Xanthan Solutions in Brines
Authors: Auerbach M. H.
Published: December 2007

Loss of solution viscosity in brines of increasing ionic strength (salinity/hardness) is a major problem in the use of partially hydrolyzed Polyacrylamides for enhanced oil recovery mobility control. The solution viscosity of xanthan gum polysaccharide, however, is generally accepted to be unaffected by salt content in the water. In fact, recent work by Philips, et al1, has shown that solutions of high-pyruvate xanthan actually increase substantially in viscosity with increasing salt concentration.

Earlier papers by Ward and Martin2 and French, Stacy, and Collins3 reported results of US DOE-sponsored programs to establish relationships between total ionic strength, concentration of calcium or magnesium ion, polymer concentration, and the resulting solution viscosity for partially hydrolyzed Polyacrylamides with varying degree of hydrolysis and molecular weight. This paper presents similar work with xanthan biopolymers of varying pyruvate content. Formulae are given to enable prediction of solution viscosity for a given brine salinity and polymer concentration, and to calculate the polymer concentration needed to give a desired solution viscosity.

For both medium- and high-pyruvate xanthans, solution viscosity increased with increasing brine salinity; the presence of multivalent cations (hardness) had no additional effect on viscosity beyond their contribution to total salinity. For a given polymer concentration, xanthan solution viscosity exceeded that of hydrolyzed polycrylamides above about 0.3% total dissolved salt.
The Operator-Contractor Relationship—Contract Changes, 1982 to 1984
Authors: Warren T.
Published: December 2007

Significant changes in the oil industry have occurred during the last two years which affect both operators and drilling contractors. Operators have experienced declining demand, falling production, an oversupply of natural gas, lower oil and gas prices and the inability of most companies to replace reserves.

Drilling contractors are attempting to survive the bottom of the drilling cycle as rig supply greatly exceeds demand. Low utilization rates of 50-60% produce low prices which are not sufficient to service debt repayment or fully recover equipment replacement costs and result in a significant financial loss. Yet, bankruptcies and foreclosures are slow to reduce the number of available rigs as banks continue to disrupt the normal balancing of supply and demand by supporting contractors who should be leaving the market.

Significant, although less obvious, changes have also occurred in drilling contracts which reflect the major trends of the industry. These contractual changes need to be recognized for the way they affect the services a contractor provides, the allocation of risk, the operator-contractor relationship and the health of the industry.
Stimulating Water-Sensitive Formations at High Reservoir Temperature
Authors: Dietzel H. J. , Von Hantelmann G. A.
Published: December 2007

This paper presents a case history of a MHF-treatment on a deep gas well, situated in the North-German Ostfriesland area. From core analysis the gas-bearing formation was proven to be extremely water-sensitive. In consequence it was essential to eliminate any water content in the treating fluid, so an oil-based gel system had to be selected. To face the BHST of 270 °F (132 °C) high temperature stability of the treating fluid was required. However, the BHST was above the working limit of the gel and consequently a large cool-down pre-pad was necessary. The physical qualities of the base fluid and the rheological properties of the prepared gel system will be described. A description of the frac-design will be followed by the operation history. The use of a hydrocarbon-based treatment fluid combined with a low draw-down concept in the clean-up period resulted in an excellent back-flow performance of the treating fluid. Fracture half-length and fracture flow capacity were deduced from a post-frac pressure build-up.
Review of the Completion Practices in the Wilcox Formation in South and South Central Texas
Authors: Garbis S. J. , Brown B. J. , Mauritz S. J.
Published: December 2007

The Wilcox formation is a primary target for exploration and development of relatively low permeability tight gas reservoirs. Many operators have and will continue to drill for the Wilcox in South and South Central Texas. This formation continues to make a major economic contribution to the area's oil and gas industries. This paper will present background information on the geology of the Wilcox formation. The data presented will include lithology data derived from x-ray diffraction, and Scanning Electron Micrograph (S.E.M.) studies of whole core and/or sidewall core samples. The formation rock characteristics, such as permeability, porosity, youngs modulus, and formation water analysis are also discussed. Some of the latest completion techniques, including cementing, casing and perforating programs, are discussed in detail. Bottom hole pressure, thermal and fracture gradients are reviewed due to their important influence on completion practices.

A variety of stimulation procedures have been used very successfully on the Wilcox formations. Stimulation fluid selections, volumes and even injection rates have their influences on completion practices and resultant production. Finally, the types and size proppant selected and the volumes used are presented to maximize the production and to provide an optimum completion program.
Application of Pseudo-Steady-State Flow to Pressure-Buildup Analysis
Authors: Slider H.C.
Published: December 2007

This paper was prepared for the Society of Petroleum Engineers Regional Meeting to be held in Amarillo, Tex., Oct. 27-28,1966. Permission to copy is restricted to an a abstract of not more than 300 words. Illustrations may not be copied The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY OR THE SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting, and with the paper, may be considered for publication in one of the two SPE magazines.

This report develops a method of analyzing pressure buildup data in a finite-acting reservoir and demonstrates the method with exemplifying calculations. It is believed that this method is, in most cases, superior to methods currently in use. Many engineers currently attempt to apply the Horner method of analysis, which is based entirely upon infinite-acting reservoir equations, to wells which have obviously been affected by the drainage limits of the reservoir and thus are finite-acting. Furthermore, the methods presently available for buildup analysis in a finite-acting reservoir are not as simple as the Horner method to apply and require a knowledge of the reservoir size, effective compressibility, effective formation thickness, porosity and fluid viscosity if the skin factor and average pressure are to be evaluated. In contrast, the method presented herein is very similar to the Horner method in that it requires similar pressure plots and uses similar equations; also, the formation capacity, the average drainage area pressure, and the skin factor can all be determined with a knowledge of only the fluid viscosity and the [re/rw] ratio. Even the Horner solution does not provide the skin factor with such limited data.

A solution based on such limited data is made possible by using the change in reservoir pressure prior to shut-in to determine the product of effective compressibility, porosity and effective formation thickness.

The application of pseudo-steady-state flow to pressure-buildup analysis is made Practical by an analytic derivation of the time when pseudo-steady-state flow begins. The development of these concepts, with a review of the basic pseudo-steady-state technology, is presented herein.

COMPARISON OF PSEUDO-STEADY-STATE FLOW WITH OTHER FLOW REGIMES

Reservoir fluid flow may be generally classified as steady-state, unsteady-state and pseudo-steady-state. This last classification, with which this report is concerned, has also been referred to as "stabilized") or as "steadystate in a bounded drainage area". This type of reservoir flow occurs much more frequently than steady-state flow or unsteady-state flow with an expanding drainage radius.
Understanding the Basics of Electrical Submersible Pump Performance
Authors: Wilson B. L.
Published: December 2007

This paper is directed at the field engineer whose responsibility is to select a proper electrical submersible pump for a given well condition. This paper develops graphic representations of the demands placed on the pump, and shows how the major pump design parameters affect the pumpperformance. By understanding the basic conceptsin pump selection, the engineer will also be able to understand and predict the change in pump performance as well conditions change. This paperalso discusses methods of modifying pump performance of an installed ESP in order that the pump approach optimum pumping conditions and will review these techniques in light of their effects on the pump itself.
Feasibility Studies for Offshore Field Development
Authors: Williams L. M.
Published: December 2007

Feasibility studies for development of offshore fields must satisfy both technical capability and economic success. To accomplish these objectives, feasibility studies are subdivided into a number of specific tasks to provide a systematic, sequential approach to developing an optimum design. The primary tasks to be performed are selectionof a project team, selection of criteria, description and evaluation of alternative concepts, preliminary design of the selected conceptual costingand economic evaluations. The method of approach to such studies, the requirements for each task and its objective are discussed.
Satellite Communications Change Drilling Operations and Procedures
Authors: Veenkant R. , Vitali J. D.
Published: December 2007

This paper describes the Critical Drilling Facility (CDF) communications system design. Different field configurations for active and semi-active operations on the north slope of Alaska, in the Anschutz Ranch of Wyoming, and on semi-submersible drilling rigs in the Bering Sea will be discussed.

Historically, oil drilling has operated without any significant communications between the personnel at the rig and the experts and supervisors in regional headquarters. This is still standard practice in the drilling industry today. A drilling system based upon complete communications and team-work has been developed. It exploits the technologies of digital satellite communications, digital video bandwidth compression, drilling data sensor and computer systems, and real-time data transmission. Full-motion video of rig operations and personnel, facsimile, voice, forms entry and access, and drilling data transmissions are available. Also, real-time cementing and well-test data are available at CDF central for resident expert analysis.

The CDF not only supports real-time drilling decisions, but provides reproducible technology transfer for drilling future wells in the same field. Although the CDF was originally designed and implemented for drilling, it has become so successful that exploration geologists and managers are finding themselves right-there at the rig without leaving headquarters.
Semi-Submersible Used as Floating Production Facility
Authors: Hammett D. S.
Published: December 2007

This paper describes the technological achievements and experiences of utilizing a semisubmersible drilling unit as a floating production facility.

The technology of using floating production facilities, where fixed platforms are less economical to deplete small offshore fields, has been proven. Fifteen (15) semi-submersibles have now accumulated 100 rig years of experience producing and shipping oil from offshore fields. The semi-submersible rigs are used as floating production facilities to which subsea wells are connected by flowline and on the floating facility, the produced fluids are separated, treated and shipped. The floating facility installations are not temporary facilities, but are designed to fully deplete the fields. Gas lift, gas and water injection equipment are installed and in operation. The facility is designed to meet local and international safety codes and regulations.

The use of known technology to produce offshore fields utilizing Floating Production Facilities(FPF) will be extended to deplete reservoirs more economically than fixed platform development.

The conclusion of this paper presents the capability to utilize existing semi-submersible type hull forms to produce marginally economic fields that cannot justify conventional platforms installations.
The Role of Petrographic Analyses in the Design of Nondamaging Drilling, Completion, and Stimulation Programs
Authors: Kersey D. G.
Published: December 2007

Petrographic techniques that include X-ray Diffraction, thin section, and Scanning Electron Microscope analyses can assess the potential reservoir sensitivity of a formation. The results of these analyses can be used to design programs to minimize formation damage from fresh-water and acid (HCl, HF) sensitive minerals and to reduce the severity of migration of "fines" and "sand" production problems.
Prevention of Undesirable Precipitates from Acid Treating Fluids
Authors: Crowe C. W.
Published: December 2007

Precipitation of insoluble reaction products during the acid treatment of producing and injection wells is a problem which has long been recognized. These precipitates are capable of reducing the effectiveness of treatments or, in some cases, causing complete plugging of the formation. Among the precipitates which can form are iron compounds, such as ferric hydroxide and ferrous sulfide. When hydrofluoric acid is used, calcium fluoride, hydrated silica and various hexafluosilicates can precipitate. Acids also react with some crude oils to precipitate asphaltic sludges. An understanding of potential precipitates, conditions under which they form and methods of preventing or minimizing the problem is necessary to obtain optimum treatment results.
Precision Perforation Breakdown for More Effective Stimulation Jobs
Authors: Hushbeck D. F.
Published: December 2007

Operating companies are using precision perforation breakdown techniques to help achieve stimulation of their complete perforated intervals. Special packers are used to isolate one ft (.3m) sections of the perforated interval, after which a small volume of acid is pumped into the formation to make an initial breakdown. The full stimulation treatment is performed through the breakdown tool without removing it from the well.

Several benefits accrue from the use of precision breakdown techniques:

Perforations are cleanedout and the formation is broken down slightly to give the treatment an opening to begin an acid treatment or a fracture. Status of perforations is established. If some of the perforations expected are not open, the job designer can alter his treatment to allow for fewer perforations. Pumping rates and pressures are sensitive to the number and diameter of perforations. Breakdown packers can be set many hundreds of time without maintenance during the breakdown, thus saving rig time. Limited entry stimulation is aided by detailed knowledge of perforation status. Scale buildup can be spotted directly with acid.

Subject paper presents field results, job designs, and engineering detail of breakdown packers. Application and operational details are presented.
Numerical Simulation of Light Oil Steamflooding in the Buena Vista Hills Field, California
Authors: Hong K. C.
Published: December 2007

In early 1985 Chevron U.S.A. initiated a pilot steamflood of the light 27°API gravity (0.89-g/cm3) crude in the 108-ft (32.9-m) thick Wilhelm sand reservoir at the Buena Vista Hills Field in Kern County, California. The pilot project involves 12 inverted five-spot patterns over a 65-acre (263,000-m2) area with the target reservoir at an average depth of 2500 ft (762 m). A computer simulation study was performed to provide performance forecast and other information useful for the design, implementation, and operation of this first application of steamflooding to a light oil reservoir by Chevron.

A one-eighth of a five-spot, three-dimensional representation of the reservoir was simulated using a compositional steamflood simulator. The reservoir oil was represented by a three pseudo component model based on a true boiling point curve analysis of the crude.

The study showed that because of the low viscosity and high volatility of the oil, steamflooding this oil benefits from mechanisms different than those for a heavy oil. While oil viscosity reduction is the primary mechanism for production of a heavy oil, steam distillation is shown to be mainly responsible for improved production from the light oil reservoir. Whereas gravity override of steam prevails in a heavy oil reservoir, steam is seen to propagate in a more piston-like manner in the light oil reservoir, producing a more effective sweep of the reservoir. Also, the steamflooding in the low compressibility, light oil reservoir is characterized by an almost immediate production response to steam injection.

The study further showed that approximately 50% of the oil initially in place can be recovered economically by steamflooding. Over one-third of this recovery can be attributed to the steam distillation mechanism.
Production Optimization Using a Computerized Well Model
Authors: Lea J. F. , Brown K. E.
Published: December 2007

Many oil and gas wells may be producing at rates which appear to be optimum but which actually contain unnecessary restrictions to flow. These wells can be analyzed using modelling techniques to evaluate all components of a producing well system. Often this procedure will identify possible modifications in the well which if made will result in larger flow rates. This method described is often referred to as Nodal* Analysis. All components starting at the static reservoir pressure and ending at the separator are evaluated if present. This may include inflow performance, flow across the completion, flow up the tubing string including any downhole restrictions, safety valves, flow across the surface choke (if applicable) and flow through horizontal flow lines and into the separation facilities.

The objectives of well analysis are as follows: To determine the flow rate at which a well will produce with a given wellbore geometry and completion (first by natural flow).To determine under what flow conditions a well will cease to produce. This can be related to time as the reservoir depletes.To select the most economical time for the installation of artificial lift and to assist in the selection of the best artificial lift method.To optimize the well conditions and geometry system in order to most economically produce the objective flow rate.To analyze each component in the well system to determine if it is restricting the flow rate unnecessarily when compared to the flow capacities of the other system components.Overall, this permits quick recognition by the operator's management and engineering staff of ways and means to increase production rates. This is a very important feature of being able to graphically display the wells performance with "production optimization" or "Nodal* Analysis Techniques."

There are numerous oil and gas wells around the world that have not been optimized to achieve an objective rate in an efficient manner. In fact, many may have been routinely completed in a manner such that their maximum potential rate cannot be achieved. Also, many of the wells placed on artificial lift are not achieving the efficiency that may be possible.
Understanding Changing Wellbore Pressures Improves Sand Control Longevity
Authors: Stadalman J. R. , Novotny R. J. , Houchin L. R.
Published: December 2007

A pressure surge in a gravel packed wellbore can cause the gravel to fluidize and move. This results in damage or complete failure of the gravel pack. Two solutions are presented for this problem. The first is to allow the pressure increase to occur only over an expanded time frame. This keeps the fluid velocity rising up through the gravel in the wellbore below the "Minimum Velocity Required for Fluidization" (Vo). In many cases the required time is impractical or control over the pressure surge and shut-in time is lacking. The second solution, a consolidated gravel pack, enables the gravel to be exposed to severe pressure surges and fluid velocities without fluidization occurring.
Acidizing Sandstone Formations: A Detailed Examination of Recent Experience
Authors: Gidley J. L.
Published: December 2007

The purpose of this study was to determine how the response of sandstone formations is related to the individual components of acid treatments employed on them. Our goal was to identify the conditions that on the average lead to the greatest response. For this purpose, we collected detailed engineering data on stimulation treatments conducted within Exxon Company, U.S.A. over a three-year period, 1982–1984. During this period, more than 1,400 acid treatments were performed, of which 785 were on sandstone formations. Of the latter, 529 employed a mixture of hydrofluoric and hydrochloric acids. The response of wells treated with this formulation, commonly called mud acid, is the focus of the current study.

Mud acid, unlike hydrochloric acid alone, possesses the ability to dissolve clay materials. Its principal use in sandstone formations is to dissolve clays that have been affected by or are the result of the drilling or completion process. Such clays reduce formation permeability near the wellbore--a condition commonly called formation damage. The mechanism by which mud acid dissolves clays has been well described in the literature1–7 and is not the subject of the present work. Because of its high reactivity with clays, mud acid is spent relatively close to the wellbore (from a few inches to at most a foot or so from the sandface). Its sole value, therefore, is to remove damage near the wellbore.
Predictions of Water Floods by Graphs
Authors: Higgins R.V. , Boley D.W. , Leighton A.J.
Published: December 2007

In Part I, a method using relative permeability curves is presented to determine in about 30 min. by the use of a desk calculator and graphs the oil recovery vs cumulative water-injection of linear and 5-spot water floods. For the linear model the determinations are nearly identical to those calculated by the electronic computer used in the Higgins and Leighton technique,1 and for the 5-spot they are within an average of 2 per cent of them. The .5-spot results by the graphical method are also within an average of 5 per cent of those for presently available experimental 5-spot water floods. However, the graphical method does not give the time or rate of oil recovery.

The study shows that the recovery for the linear vs the 5-spot differs by only a small amount after about one displaceable volume is injected. This indicates that relative permeabilities are a more dominant factor in the recovery of viscous oils than pattern efficiency. This further indicates that the concept of "dead" areas in patterns is questionable. This method, with changes in the factors, is applicable to other patterns.

Part II contains material and relationships that are not as accurate as would be obtained by the electronic computer. Part II presents specific examples relating to the effect of pressure and free gas saturation on the viscosity of crude oil mixtures before and after the start of a water flood. A method to approximate the effects of initial free gas saturation and the effect of the absolute permeability variation with depth on the recovery of oil from a 5-spot water flood is also presented and illustrated.
Goal Setting and Federal Oil and Gas Leasing Policy
Authors: Zabler J. F.
Published: December 2007

Since 1979, the Department of the Interior and Congress have considered changes in oil and gas leasing. Over this period there were changes in emphasis between program goals. In pursuit of these goals many leasing methodologies have been explored. This presentation elucidates each technique within the context of those goals and elaborate on the decision process of weighing the conflicting factors involved.
Current Status of Oil Industry Congressional Tax Reform Legislation
Authors: Gage G. H.
Published: December 2007

"There doesn't seem to be any growing enthusiasm for this bill."

With characteristic understatement, Majority Leader Bob Dole described the prevailing attitude of the Senate towards tax reform, at a meeting of the National Governors' Association in Washington the end of February.

Nevertheless, the Finance Committee is continuing to gear up for a markup of the tax reform bill.
Wellsite Applications of Integrated MWD and Wellsite Data
Authors: Martin C. A.
Published: December 2007

The advent of a wellsite computing center utilizing a common data base for surface and downhole measurements while drilling, provides new answers regarding safety, drilling efficiency and geological evaluation.

New applications have been developed utilizing the synergistic combination of measurements made at the surface during drilling coupled with MWD measurements. These applications have demonstrated significant improvements in drilling efficiency, geological evaluation and safety. On-line drilling programs have been developed to improve hydraulics, rate of penetration and solve drilling mechanics problems. Formation evaluation software provides an immediate indication of water saturation. Safety is enhanced by on-line plotting of pressure trends from MWD resistivity, formation strength analysis and other pressure parameters. In addition real time computer programs improve safety performance of the rig crew while tripping and while controlling kicks.
Computerized Drilling Jar Placement
Authors: Askew W. E.
Published: December 2007

This paper presents information on a computer program currently in field use for determining optimum drilling jar positioning in Bottom Hole Assemblies. A finite element program models the BHA and predicts the force at the stuck point with the jar at various locations and tripping loads. Comparison of predicted impacts shows which position will produce the best response at the struck point increasing the chances of recovery.
Evaluation of Cementing Practices by Quantitative Radiotracer Measurements
Authors: Kline W. E. , Kocian E. M. , Smith W. E.
Published: December 2007

A radiotracer technique has been developed that enables quantitative, foot-by-foot measurements of cement coverage behind casing. Based on uniform tagging of the entire cement column with short half life isotopes, this new technique enables measurements of cement placement, mud displacement, and the mixing that takes place at displacement fronts. The method was used in a study of cementing practices conducted in a series of East Texas wells. Radiotracer measurements were obtained that document cement coverage in wells drilled with 9-10 ppg (1080-1200 kg/m3) mud. Variables investigated include casing movement, casing attachments, and wellbore deviation.
The Performance Characteristics and Economics of Rotary Shouldered Connection Thread Compounds
Authors: Holcomb R. T. , Wilcox V. T. , Oldiges D. A.
Published: December 2007

Tool joint and drill collar thread compounds are essential components of working drill strings. Performance of their function requires the satisfaction of a unique set of material conditions in a variable operating environment. A consideration of these, which can yield economies in the operational and capital expense of drilling operations, has gone long neglected.

The evolution of thread compound compositions and the technical literature dealing with these are reviewed. These appear, respectively, to be slow and inadequate. These deficiencies are addressed here.

A comprehensive list of functional property criteria for thread compounds is drawn which defines technical requirements-from compound application to connection breakout-and economy of use. The effects of compound material properties and drilling conditions on these are described. The diversity of compound performance is illustrated by the results of laboratory and field experience, with particular emphasis placed on the frictional characteristics of the compound/thread surface interface and the effect of temperature thereon. It is shown that the optimum combination of compound performance and economy results from products engineered to suit the specifics of particular drilling conditions.

Some of the directions of future development of compound properties are discussed.
Novel Polymeric Oil Mud Viscosifier for High-Temperature Drilling
Authors: Portnoy R. C. , Lundberg R. D. , Werlein E. R.
Published: December 2007

As part of an ongoing study of polymeric oil viscosifiers, lightly sulfonated polystyrene (SPS) has been demonstrated to provide thermally stable rheological properties to a broad range of invert emulsion oil drilling fluids. After the polymer is activated at temperatures of about 250°F or above, fluids treated with it show excellent shear thinning rheology which is stable to aging at temperatures in excess of 400°F. Laboratory testing and field drilling results have shown the product to be a valuable viscosifier for invert emulstion oil muds subjected to high temperature conditions. The product is economical, low in toxicity, easy to apply, and it causes no adverse side effects in the mud when used either alone or with conventional oil mud viscosifiers.
Designing a Next-Generation Data Acquisition System for Drilling Rigs
Authors: Jobe T. L.
Published: December 2007

Since their introduction in the mid-1970's, microprocessor-based data acquisition systems have been used to improve safety and reduce costs on drilling rigs. Recent advances in hardware and software technology now enable designers to develop data acquisition systems which are more powerful, accurate, and reliable than previously possible.

This paper describes the goals, design features, and implementation of an advanced, ruggedized data acquisition system for use by drilling contractors on both offshore and onshore drilling rigs.

The results will show that substantial technical improvements can be made in designing such a system. These improvements will allow the drilling contractor and operator to be better equipped for reducing drilling costs and providing a greater safety margin.
New Sidewall Core Analysis Techniques Improve Gravel Pack Design
Authors: Himes R. E. , Ruiz S. J.
Published: December 2007

The increased use of sidewall core samples for gravel pack design can lead to the improper selection of gravel pack sand size if analyzed by standard sieve analysis techniques. Sidewall cores, which are obtained from the near wellbore region after drilling, are usually contaminated with drilling mud material lost to the formation as filter cake buildup occurs. This artificially introduced material is fine in particle size and can skew a sieve analysis of the sample, indicating a smaller median particle size than that of the true formation.

A commercial particle size analyzer, which operates by the light blockage principle has been used to successfully analyze sidewall core samples while excluding the major effects of mud contamination. This results in a more representative size distribution of the formation sand and a more accurate basis for selection of the proper gravel pack sand size. Its ability to rapidly analyze small amounts of sample means a larger number of samples can be evaluated in a comparatively shorter period of time.

Results of field application of the analyzer has shown that larger, and therefore more productive, gravel pack sands have been recommended for several wells where finer sands were indicated by conventional sieve analysis. Production reports have shown that these wells show high productivity with no evidence of significant sand production or gravel pack plugging by formation material.
Development of a Two-Stage Sand Consolidation Technique
Authors: Poston S. W. , Turner S. E. , Tobola D. P. , Barger B. R.
Published: December 2007

Sand production in conjunction with oil and gas production has been a major problem in the unconsolidated and poorly consolidated sands of the Gulf Coast. Chemical methods of sand consolidation are often used to prevent sand production. These sand consolidation treatments often fail because the in-situ permeability may be highly variable. These variable permeabilities cause fluid channeling through the high permeability streaks. The region around the wellbore will not be uniformly treated.

A two-stage sand consolidation treatment has been found to provide a more uniformly consolidated interval. The inital high injection rate treatment forces most of the fluids into the zone of highest permeability. This stage will reduce the in-situ permeability of the high permeability streak. A second, and similar, consolidation treatment at a reduced injection rate is then conducted to uniformly treat the entire interval.
The Prediction, Evaluation, and Treatment of Formation Damage Caused by Organic Deposition
Authors: Houchin L. R. , Hudson L. M.
Published: December 2007

Extensive work has been conducted in the past on organic deposition in upper tubing, surface equipment, and pipelines. Although many analytical test methods are available to evaluate organic damage, new procedures were required to establish the means by which organic formation damage can be predicted. A statistical study performed on 361 wells is presented here to provide new insight into evaluation criteria and treatment design utilizing these predictor methods.
Asphaltene Precipitation During Acid Stimulation Treatments
Authors: Jacobs I. C. , Thorne M. A.
Published: December 2007

Iron contaminated acid has recently been found to promote the precipitation of asphaltenes when acidizing certain oil bearing zones. This can cause severe formation damage. Standard anti-sludging agents, normally used to prevent this, are no longer effective in the presence of iron. Commonly used iron sequesterants are found not to prevent the asphaltic sludging. Proposed mechanisms to explain these observations are presented along with a new iron control additive that does prevent the precipitaton when used with conventional anti-sludging agents. Some recommendations are made for acidizing practices when asphaltic crudes are encountered.
A Brief Introduction to Oil Production Technology in China
Authors: Liu Xiangou
Published: December 2007

This paper gives a brief description of the general situation of characteristics of oil production technologies in China and the results of application. A forecast of future development of these technologies has been made also.

In China, most of the oil-fields developed and exploited are sandstone-oilfields. In Eastern China, apart from Daqing Oilfield, most oilfields are complexly block-faulted. The sandstone-oilfields are, generally, featured with multiple reservoirs, long production intervals, great variations in permeability vertically, high wax content and high crude viscosity.

Huabei oilfield is a fractured carbonate reservoir. The reservoir is characterized by high temperature, and high well productivity. The reservoir is featured with double porosity by having both fractures and pores in the rock matrix. In the western part of China, the Kalamai, Changqing oilfields and others are low permeability reservoirs. These reservoirs are conglomeratic and sandstone reservoirs. In the 1980s, a series of heavy oil reservoirs have been put into development and some high viscosity reservoirs and buried hill reservoirs are to be exploited. According to the geological and development characteristics, the oil production technologies in China and its relevant infrastructure have been developed.
Technical Measures for Improving Oilfield Development by Waterflooding in a Large Multi-Layered Heterogeneous Sandstone Reservoir
Authors: Tang Zengxiong , Lui Heng , Jiang Chengzao
Published: December 2007

Daqing, a large sandstone oilfield with an oil-bearing area of nearly 1000 sq.km, is in an anticlinal structure with a long axis. The oil reservoir formations lie at depths of 800-1200m. The max. thickness of oil-bearing intervals is up to some 500m. The oil reservoir is a Lower Cretaceous nonmarine fluvial-deltaic sedimentary system. The reservoir rocks are from middle, finegrained to silt sandstones.

In a cross section, there are up to over 100 single layers with a minimum thickness of 0.2m. and a max. of 20m. or more. There are great variations in the extent of the distribution sandbodies and in inter-layer and in-layer permeabilities (1)(2).

The field was put on stream in 1960, and with the progressive extension of the productive area by 1975, the main parts of the field had already been fully developed, oil output entering a stable peak stage from a rising stage. In 1976 annual output reached more than 50 million tons and 55 million tons are expected in 1985. Since then, the field has kept a stable or slightly rising production for 10 years in succession.
A Study of Optimum Programs and Decision-Making Methods for the Development of Cluster Gas Fields
Authors: Jiali Ge , Liyan Zao
Published: December 2007

On the basis of the study of optimum theory of system engineering, theory of decision-making and the theory of optimum control, a set of methods of static programmings, and methods of decision-making and dynamic optimum control for the development of a cluster of gas fields have been presented. A study of the case history of a cluster of seven gas fields has been carried out, and fruitful results have been obtained.

The study of static programming, theory of decision-making and corresponding methods has been conducted for the development of cluster fields gas fields in this paper. A technical and economic model of development programs of individual gas fields has been proposed. The characteristics of this model are to use provisional technical indexes of subsurface development together with the process of surface oil and gas gathering and treatment with which economic indexes are integrated as an issue of system engineering, all of which are studied using the common "techno- economic model". On such base, the techno- economic models of several gas fields were combined together to work out a "mixed integer programming model with multiple objectives for cluster gas field development" and such a model was solved using the method of non-linear mixed integer programming. This model can be applied for the optimum production allocation of each gas field after the total production of cluster of gasfields has been determined. This paper also describes the comprehensive evaluation methods used for cluster gas fields. These methods are used to work out various development schemes among which the best scheme can be sorted out. The above-mentioned results of study have been used for development of a cluster of seven gas fields in the central part of China, in solving the problems of optimum development speed of this cluster of gas fields and their production allocation programming, as well as the optimum development scheme and order of development of different gas fields. Therefore, an overall optimum program has been obtained and satisfactory results have been achieved.
An Analysis of Properties of Laminar Flow Field of Power-Law Fluid in Annular Space
Authors: Liu Xisheng , Zhai Yinghu
Published: December 2007

A group of simultaneous equations have been developed to describe the helical laminar flow of viscous non-Newtonian fluids in an annulus space. A theoretical analysis of the field of helical flow and axial flow of power-law fluid has been made. The axial velocity profiles of helical laminar flow and axial laminar flow are given for five aqueous solutions of polyacrylamide to verify the theoretical analysis, which shows good agreement with experimental data.

The helical flow pattern may serve as a better model to simulate the flow field in borehole. The methods used in this paper may be useful in the study of annular hydraulics.
A Study of Pore Structure by Image Processing Method and its Application
Authors: Gao Yaming , Shen Pingping , Tu Fuhua
Published: December 2007

Pore characteristic was drawn from thin sections of dye casted sandstone samples using an image analyzer. Pore size distribution of the sample and its characteristic values were obtained with section-chord technique.

The following items have been obtained from the samples studied:

The same core sample may have different curves of throat size distribution and the pore size distribution. For the two samples with basically identical throat size distribution curves, their pore size distribution curves may be different. And for the two samples with basically identical pore size distribution curves, a large difference between the two throat size distribution curves may occur. Therefore, pore size, throat size and their distributions must be studied simultaneously in order to have a complete study on pore structures.

The throat diameters have a larger effect on permeability than those of pores. Pore and throat sizes as well as their sortings almost have no effect on porosity.

Water displacement recovery efficiency is affected by both pore and throat sortings, however, pore-to-throat size ratio has even larger effects on the recovery efficiency. The smaller the pore-to-throat size ratio is the better the pore and throat sortings, and the higher the recovery efficiency will be; and vice versa.
Injectivity Losses Under Particle Cake Buildup and Particle Invasion
Authors: Ershaghi I. , Hashemi R. , Caothien S. C. , Abdassah D.
Published: December 2007

A series of laboratory flow experiments were conducted to examine the relative effects of various factors causing gradual losses in injectivities in fieldwide water injection operations. Injectivity losses were measured on a small scale during radial flow injection of carefully prepared particle suspensions with KCl as a base fluid.

Systematic matching of rocks mean pore sizes and the mean particle sizes in the suspension pointed out their effect and control on the mechanism of injectivity impairment.

Additional factors studied included the impact of prefiltration using microfilters and the role of differential pressure in enhancing the injectivities.
A Versatile Phase Equilibrium Package for Compositional Simulation
Authors: Obüt S. T. , Ertekin T. , Geisbrecht R. A.
Published: December 2007

Modeling of enhanced oil recovery applications such as miscible gas injection requires careful consideration of phase equilibria, especially between multiple liquid phases. This paper addresses the problem of phase equilibria when more than two phases are present.

A cubic equation of state approach is used and both Peng-Robinson and Soave-Redlich-Kwong equations of state are considered. Solution methods implemented for finding the roots of the nonlinear system of equations include successive substitution method (SSM), accelerated and stabilized successive substitution method (ASSM), and minimum variable Newton-Raphson (MVNR) method.

In the process of finding interaction coefficients for the mixing parameters a linear optimization routine is used to obtain the first set of constants which pertain to mixture energy of interaction while the second set, which pertain to mixture volume, are held equal to zero. To initialize the optimization search, the first set of interaction coefficients are supplied from the available literature. Randomly generated numbers are then used as scaling factors to obtain additional sets of interaction coefficients in the process of constructing an error matrix. Constraints are determined with the aid of a least squares routine, and by using a revised two-phase procedure, best estimates to the interaction coefficients are obtained. The proposed phase equilibria package is also capable of collapsing a number of components into a pseudo component, which in turn requires less computational work. Furthermore, it is also capable of splitting a C7+ fraction into hypothetical components, which will subsequently give a better phase behavior prediction.

The phase equilibrium prediction progresses in a stepwise manner and during this process, the method of Heidemann and Khalil for critical point determination in multi-component systems is utilized to distinguish the types of the phases.

The phase behavior routine has been tested on various three- or four-phase systems and has been found flexible and satisfactory for phase equilibria prediction of multiple liquid phase mixtures.
Coiled Tubing Cement Squeeze Technique at Prudhoe Bay, Alaska
Authors: Harrison T. W. , Blount C. G.
Published: December 2007

A non-rig Coiled Tubing Unit (CTU) cement squeeze technique has been developed and proven in the Prudhoe Bay field. This new technique does not require that the well be killed. The channel and perforations remain clean and unobstructed allowing easy placement of cement. This process utilizes in-situ contamination of cement left in the well bore after the squeeze. The contaminated cement is then circulated or reversed out of the wellbore after the squeezed cement has set, eliminating the need for drilling. The technique has been used to shut off channels in the primary cement to both the aquifer and the gas cap, to squeeze off unwanted production perforations, and to alter injection profiles. Workover costs for these types of jobs have been reduced an average of 85% by utilizing the CTU technique. Scale modeling, fullscale testing, and field operating experience were drawn upon in developing this technique.
A Core-Log Study of the Hartselle Sandstone in North Alabama With Emphasis in Log Interpretation Problems in Tight Gas Sands
Authors: Tsay F. S. , Fang J. H.
Published: December 2007

The correlations among the physical properties of core samples taken from the Hartselle Sandstone formation were examined, porosity, permeability, formation factor, cementation factor, saturation exponent, caly mineralogy and cation exchange capacity were determined. Constants such as, a, a*, m, m*, n, n* and no were found to be unique and significantly different from those for normal shaly sands. The cation exchange capacities (CEC) were determined by the strontium exchange technique. The curvelinear equation correlating CEC vs. Gamma Ray has been proven to be useful for the prediction of CEC for the Hartselle Sandstone. It has been found that water saturation calculation using Dual-Water and Waxman-Smits models are very sensitive to the values of m*, n* and the clay content, particularlly when water saturation excees 50 percent and Vsh exceeds 15 percent. Therefore accurate determination of these constants is necessary. It was also found that Fertl-Hamm ck equation can be used as a suitable alternative for the tight gas sands, with an accuracy similar to Waximan-Smits model, when the core data is not available
Advances in the Microseismic Method of Hydraulic Fracture Azimuth Estimation
Authors: Sorrells G. G. , Mulcahy C. C.
Published: December 2007

Research during the past two years into the triaxial borehole seismic method of fracture azimuth estimation has led to the development of new data processing and analysis procedures. Applications of these techniques to data acquired in a variety of treatment zones and under a variety of treatment conditions have successfully yielded precise estimates of seismic polarization planes which exist in the microseismic data. Methods have also been developed, or are being developed, to unambiguously relate the polarization planes to real fractures in the earth. In addition, an advanced system of instrumentation has been developed and tested to simultaneously acquire bottom-hole pressure, microseismicity and temperature data in the treatment well.