bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Method To Investigate Kinetic Hydrate Inhibitors
Authors: Cingotti B. , Sinquin A. , Pic J. S. , Herri J. M. , Cournil M.
Published: December 2007

An inherent problem with natural gas, condensate and crude oil production or transportation is the formation of gas hydrates. The usual practice for avoiding the plugging of production facilities by hydrates is to add thermodynamic inhibitors such as methanol or glycol. For a few years, a lot of works have been done for the development of a new class of low dosage additives: Kinetic Inhibitors. These compounds are designed to delay nucleation and/or prevent crystal growth. The performance level of Kinetic Inhibitors can be investigated by different methods such as hydrate formation rate, subcooling, total volume of hydrates formed, plugging of a flow loop or stirred cell… but the main technique remains the determination of the induction time. Unfortunately, in rather clean conditions (without adding any impurities), the induction time is a stochastic quantity. Therefore, to obtain a significant result, experiments must be repeated until the calculated average induction time becomes constant. This procedure is consequently time consuming and rather difficult toperformed.

We have developed a semi-batch stirred reactor in which temperature and pressure are maintained at constant values. This reactor is equipped with a turbidimetric sensor which is used to characterize in-situ the methane/water system (particle size distribution of the hydrate suspension or state of dissociation of the undersaturated solution).

Using this device, a new procedure has been found which allows us to have a constant and reproducible induction time without adding any impurities. This new and very simple method enables to determine quantitatively and qualitatively the efficiency of kinetic inhibitors both from the induction time (nucleation stage) and from the quantity of hydrates formed (growth stage) in a very short time. In this paper we will describe the apparatus and the procedure applied to obtain reproducible results. This operating procedure has been successfully applied to the characterization of kinetic inhibitors.
Corrosion Inhibitor Considerations for Deepwater Systems
Authors: Ramachandran S. , Ward M. B. , Bartrip K. A. , Ahn Y. S.
Published: December 2007

Multiphase flow modeling has been used to calculate pressure and temperature profiles, gas/fluid compositions, and production rates for a specific deepwater production system. These predicted values, along with proper considerations on application and handling of corrosion inhibitors, have led to development of a laboratory test protocol. Several commercial corrosion inhibitors have been evaluated using this protocol, which is designed to limit the number of products that will pass all of the relevant tests.
Mechanisms of Anthraquinone Inhibition of Sulfate-Reducing Bacteria
Authors: Burger E. D. , Odom J. M.
Published: December 2007

This paper presents evidence that anthraquinone derivatives can be generally useful for preventing sulfide production from sulfate-reducing bacteria (SRB). We believe there is unique value for these compounds in oilfield and industrial applications where cost-effectiveness and human and environmental safety are of paramount importance.

It has been previously shown that anthraquinones inhibit sulfate respiration, but not aerobic respirations. This aspect permits safe use in wastewater treatment applications where aerobic microbial activity is required. We propose that this specificity is due to the ability of anthraquinones to randomly equilibrate electron flow in the membranes of bacteria of the genus Desulfovibrio. A consequence of this equilibration is that ATP synthesis is uncoupled from respiration. Since sulfate activation has a unique requirement for ATP, sulfate reduction halts with the depletion of ATP level. In this report a positive correlation is shown between inhibition of sulfate respiration by anthraquinones and their reactivity with cytochrome c3, which is a protein considered to be diagnostic of SRB. A model is discussed for involving anthraquinone mediated electron transfer around energy-conserving sites, resulting in a loss of ATP synthesis. This scenario is consistent with the specific inhibition of sulfate respiration in contrast to other respiration processes which do not require ATP.

Inhibition of SRB within a biofilm is dependent upon the species of the anthraquinone and the system hydraulics surrounding the biofilm. Bioavailability of anthraquinone is discussed in terms of soluble and insoluble species of anthraquinone and their mobility within the biofilm. Due to low toxicity, we believe that certain anthraquinones provide an environmentally acceptable alternative to highly toxic biocides for the control of SRB in oilfield water systems.
Application, Efficiency, and Optimisation of Chemical for Injection Water Treatment
Authors: Sevic S. , Solesa M.
Published: December 2007

Chemical injection is used in conjunction with the coalescer and filtration units to achieve the required water quality. The purpose of proper selection of water treatment chemicals in Turija sever waterflooding project is discussed. Field trials were carried out to optimize the use of chemicals. It was proved that with the help of chemicals the injection water quality could be improved significantly.
Improvement of Environmental Properties of Corrosion Inhibitors
Authors: Martin R. L. , Alink B. A. , McMahon J. A. , Weare R.
Published: December 2007

The environmental fate of specialty chemicals is now being addressed. Water soluble corrosion inhibitors which might find their way into the ocean, navigable waters, or sensitive land areas should have acceptable environmental properties. This paper outlines laboratory investigation and field evaluation methodology for assessment and improvement of these properties.

Since nearly all corrosion inhibitors used in petroleum recovery operations are blends, this investigation focused on solvents as well as active components. The following protocol was typically used in this investigation.

Potential components were first corrosion tested in simple kettle tests using weight loss and linear polarization for evaluation. Interesting candidates were then subjected to Microtox evaluation; this is the least time consuming of environmental evaluations and gives general prediction of toxicity. Candidates which still showed promise were often blended and tested in kettle corrosion tests. Surviving candidates and blends were then subjected to EC50 tests using Skeletonema Costatum.

Candidates which still showed promise were next subjected to biodegradability testing. Solvents of interest and commercially available inhibitors were also tested by EC50 and biodegradability methods. At this point many of the blends were evaluated as corrosion inhibitors in a laboratory flow loop.

Potential components were first chosen from commercially available compounds, then from synthesized compounds with varying degrees of oxyalklation. These were often combined with other environmentally acceptable components known to act synergistically to inhibit corrosion.

The final series of laboratory tests involved vapor pressure, environmental acceptability of vapors, and octanol/water partitioning of blends. The surviving blends were field tested first in oil wells using simple batch methods, then in continuous injection situations. This paper summarized the results of these tests plus some information for recent commercial applications.
Laboratory Studies on Polymer Gels for CO2 Mobility Control at Bat Raman Heavy Oilfield, Turkey
Authors: Topgüder Nazan N. Senol
Published: December 2007

This paper is based on the laboratory studies that are performed to establish the applicability of crosslinked polymer gels for mobility control in CO2 injection project that is going on at Bat Raman field. Two different approaches are suggested for CO2 mobility control in this field: either a small volume, strong gel treatment for near-wellbore profile modification or a large volume, weak gel treatment for in-depth reduction of CO2 permeability is considered. Regarding the 2 approaches, 2 different kinds of polyacrylamide, being Alcoflood 254 S for a strong gel and Alcoflood 935 for a weak gel; were used. Both of these polymers were crosslinked with Cr +3 acetate. The laboratory studies consist of the bottle tests to determine the gelation times and core flooding tests to evaluate the gel performance under CO2 injection conditions. The strong Alcoflood 254 S gel prohibited the gas flow under 2000 psi pressure drop and there was no breakthrough. At the other test with Alcoflood 935, there was gas breakthrough but still the CO2 permeability was reduced significantly as shown by the 1800 psi pressure drop. Consequently, both of these polymer gels behaved as expected under Bat Raman reservoir conditions. Therefore; when the economic analysis is finalized, these gel compositions may be applied in the field either for in-depth treatment or CO2 profile modification purposes.
Drilling and Completion Technology of the Deep Horizontal Well in Shixi Oilfield
Authors: Lu Xinzhong , Zhao Ziren , Chen Ping
Published: December 2007

The reservoir in the Shixi oilfield is deeply buried volcanics with multiple fracture systems and high pore pressure. It is very difficult to drill the horizontal well due to the specialty and complexity of its geological configuration, hole construction and operational requirement. Now 5 horizontal wells with 5000m MD have been drilled successfully. This paper analyzed the operational difficulties encountered during the engineering design and operations in the field. It has the positive effect on the further application of horizontal drilling in the Shixi oilfield in the future.

P. 223
New Casing Inspection Log
Authors: Cuthbert J.F. , Johnson W.M.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for the 49th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Texas, Oct. 6–9, 1974. Permission to copy is restricted to an 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 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. 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 discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A new casing-inspection log, in combination with other logs, provides for detailed evaluation of in-place well casing. The new Pipe Analysis Log employs separate tests o the total casing wall and of the inner surface. Together, these two measurements permit detection, with a high degree of resolution, of small defects and corroded areas in the pipe, and also provide the ability to discriminate between defects on provide the ability to discriminate between defects on the inner and outer walls of a single string of casing. This was not possible with just the wall-thickness information provided by the older low-frequency Electromagnetic Thickness Tool. Using the data from the new log along with the older wall-thickness measurement it is also possible to detect and locate severe corrosion or defects in the outer casing of a double string,

The following information bearing on the condition of the casing is now available from cased-hole well logs:

location of small defects or corroded areas, and discrimination between inner- and outer-walldefects (from the Pipe Analysis Log);determination of casing-wall thickness (from the Electromagnetic Thickness Tool); detection of gas accumulation behind casing in gas-storage wells(from Gamma Raj? and Neutron logs); detection of gas flow (from the High Resolution Thermometer); determination of top of cement (from Cement Top Locator); and evaluation of casingbonding (from Cement Bond Log-Variable Density Log.).

Example logs of the -new casing-inspection tool, selected from an extensive test program and nine months of commercial application, are presented. Comparisons are made of the results from the new tool with defects observed in the pipe when out of the well.
Modern Well Testing Analysis Theory and Methods of Remaining Oil Distribution in Waterflooding Reservoir
Authors: Cheng Suimin , Su Yanchun , Lin Jiaen , Mei Qiliang
Published: December 2007

This paper presents two new methods to analyze remaining oil distribution in high-water-cut reservoir by modern well test interpretations of water injection wells and water breakthrough producers. For water injected wells, after the pressure transient behavior of two phase simultaneous flow in a water injection area is investigated the pseudo skin factor resulted from the two phase flow is determined. Oil/water relative permeability curve can be determined from the factor, combined with mobility from falloff test analysis, then remaining oil distribution can be determined. For waterbrteakthrough producers, mathematical models of flooding reservoir and their resolution are presented by approximated method of composite reservoir with multiple movable fluid interfaces. An artificial neural network was also build up to get relative permeability curve from well-test data. The two methods are examined by software to get oil distribution in large scale of whole oil field.

P. 241
A Study to Determine the Moveable Fluid Porosity Using NMR Technology in the Rock Matrix of Xiaoguai Qilfield
Authors: Wang Weimin , Miao Shen , Liu Wei , Sun Dianqin , Chaohui Ye
Published: December 2007

Xiaoguai oilfield, which is located in the north-west of China, is an oil field with typical low porosity and low permeability. It is very important to determine the recoverable reserves during the development of the oil field. The high paramagnetic mineral content and severe lithology inhomgeneity, caused by diluvial deposit, make the NMR measurement complex and difficult. This paper illustrates a low field NMR technology to determine the recoverable fluid in the rock matrix of Xiaoguai field. The NMR results are also compared with other petrophysics methods, such as mercury injection measurement and scanning electron imaging analysis. Due to the high paramagnetic material content and the serious filling of the intergranular pores by chlorite clay, the T2 cutoff of the moveable fluid is much shorter (about 5ms) and the moveable fluid amount is very low.

P. 255
Mechanism Study and Application of Preventing Water Channeling by Cementing
Authors: Yan Shicai , Luo Changji , Yang Zhiguang , Liu Ailing , Cheng Yan
Published: December 2007

This paper focuses on the mechanism of pressure decrease and gel strength of coagulated process for cementing slurry. From the study, their law and feature and their internal relation have been found. On this basis, critical condition of anti-channeling has been established. The concept of "stable press coefficient" have been proposed and used to quantitatively express the degree of stable press after cementing for the high pressure acquifer, so that it provides the basis for analysis of cementing quality and design of cementing implementation.

On the basis of mechanism study, lock-water anti-channeling agent has been developed successfully. It has been used in oil well cement of A grade, which makes the cement slurry characteristic of rapidly developing gel strength short critical time, micro-expanding volume and high bonding strength of interface etc.. So it has an obvious effect on anti-water channeling after cementing.

P. 287
Stress Sensitivity of Naturally Fractured-porous Reservoir with Dual-porosity
Authors: Duan Yuting , Meng Yingfeng , Luo Pingya , Su Wanyong
Published: December 2007

Compared with porous sandstone reservoirs, the complicated fractured (fractured-porous) reservoir is of high stress sensibility. This results in not only the difficulties of calculating transport properties of actual formations, but also problems on formation protection. The stress sensibility of the reservoir results mainly from that of fractures in the reservoir. Therefore, the topologic properties of both natural and many man-made fractures without any grinding, taking from both actual reservoirs and crops on the ground, are investigated and analyzed with elastic and elastic/plastic micro-contacting theory. Then the stress sensibility of fractures is numerically modeled on computer and tested in lab. Some conclusions different from that of publications are obtained. Consequently, a method of analyzing and evaluating stress sensibility of dual-porosity reservoir with natural fractures is made on the basis of the investigation. This can thus be applied to the calculation of in-situ transport property for naturally fractured reservior and provide basic data for the formation protection of porous fractured reservoirs.

P. 295
Systematic Fracturing Technology and its Application in the Development of Low-Permeability Reservoir
Authors: Jiang T. , Shan W.W. , Ding Y.H. , Wang Y.H. , Wang Y.L.
Published: December 2007

It is an advance in hydraulic fracturing technology from single well fracturing to reservoir systematic fracturing. Taking a low-permeability reservoir as a unit, the systematic hydraulic fracturing technology is to obtain the maximum net present value by balancing producing rates, recovery efficiency and economic benefits under certain combination of hydraulic. fracture and flooding pattern. The research of systematic hydraulic fracturing involves the study of reservoir engineering and fracture mechanics of hydraulic fracturing and the optimum design of frac fluid system. The establishment of the system of systematic hydraulic fracturing technology is based on comprehensive interaction of multiple discipline.

This technology has already been executed in the marginal reservoirs of low permeability, such as Tuha Shanshan, etc., achieved important economic efficiency, and provided new way & methods for the development of low-permeability reservoirs.

P. 303
A Feasibility Research Method and Project Design on CO2 Miscible Flooding for a Small Complex Fault Block Field
Authors: Lu Lianhai , Liu Bingguan
Published: December 2007

The paper introduces the feasibility research method on how to study CO2 miscible flooding, including mechanics experiments, physical simulation experiment, numerical simulation and economic evaluation. Development plan is optimized on a pilot project based on a comprehensive evaluation of wells' conditions, equipment ability and CO2 supply ability in a small complex-fault-block, water-out, sandstone reservoir.

P. 501
Application of Sidetrack Horizontal Well in Conglomerate Reservoirs at Mid-High Water cut Stage to Improve Development Effects
Authors: Qin Jianhua , Yang Ruiqi , Chi Jianping , Cheng Shouyun , Dai Canxing , Liu Liangcai
Published: December 2007

Based on the study of remaining oil distribution and detailed reservoir description, the design optimization and field test of sidetracking horizontal drilling (SHD) in Xinjiang conglomerate reservoirs has been done. Single well production rate of two SHD wells is 2-3 times that of the average rate in the test area. That shows the technique can improve development effect of the conglomerate reservoir at mid-high water cut stage. Accurate geological description and reservoir engineering study are the key factors to the success of SHD, and to select a proper completion method is also important for the development of old field with complicated multi-bed sets. The application of SHD is limited in small ranges with small formation penetrating thickness. Therefore, we present a modified concept for the development of the aging field, SHD takes the leading role while conventional horizontal drilling and vertical drilling are the supplements.

P. 545
An Efficient Method for Enhanced Oil Production Providing an Increase in Oil Recovery Index
Authors: Shaposhnikov V.M. , Listengarten L.B. , Tseytlin S.D. , Mendelevich L.M.
Published: December 2007

V.M. Shaposhnikov, SPE, and L.B. Listengarten, and S.D. Tseytlin, SPE, and L.M. Mendelevich

PEn Technology was developed for high-GOR oil fields. The target was the optimization of well-formation system by means of maintenance of bottomhole pressure and supporting fluid lift. The technology applies an individual approach to each well, based on analysis of numerous parameters and data, computer simulation of well-formation system and sizing calculation for the technology's bottomhole tools.

P. 371
Design of Casing Strings
Authors: Bowers C.N.
Published: December 2007

Considerable economy can be effected by designing each casing string individually for the particular set of conditions involved. The paper discusses methods and procedures for incorporating all of the important variables in the design of individual strings, and step-by-step examples are given. If the casing is never empty, the problem is quite simple and can be solved very easily. While oil strings may or may not at sometime be empty, surface and intermediate strings are seldom, if ever, empty and, therefore, are not subject to collapse loads. Design charts and the usual design methods provide for collapse and tension loads occurring simultaneously. It is extremely improbable that these loads exist at the same time. A practical method of designing casing strings to provide both tensile strength and collapse resistance at the time each is needed is presented. Strings designed by this method will be much cheaper than those selected from charts or designed by the usual computation methods. This economy is realized along with adequate safety.

Introduction

The design of casing strings has long been a problem to the engineer. Many elaborate charts have been prepared to ease the task of. the designer. These charts are a form of standardization and while standardization is usually a goal much sought after, it has doubtful value in the design of casing strings. There are so many factors involved that it is impossible to include them in any set of charts. Consequently the use of available charts has resulted in thousands upon thousands of tons of steel being buried in the ground needlessly which, of course, represents dollars wasted. This can be corrected by designing strings on an individual basis. The purpose of this paper is to outline all of the required computation methods and procedures and show how the many variable factors can be incorporated into the design of individual strings. A safe, economical method for designing strings is also presented which provides for various load conditions when they occur.

Factors To Be Considered

In the past most casing strings, whether selected from charts or designed by computation methods, have been based on the assumption that the casing is empty (and, therefore subjected to a full head of mud) and at the same time is hanging in air. Obviously this is an inconsistency. The effect of tension on collapse resistance is considered, but the effect of buoyancy is neglected and yet if collapse acts on an empty string, a buoyant force in excess of the total weight of mud displaced by the casing wall must exist. Buoyancy puts at least some of the casing at the bottom of the string in compression. Compression stresses increase the collapse resistance just as tension stresses decrease it.
New, Low Viscosity Acid in Oil Emulsions
Authors: Crowe C.W. , Miller B.D.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for the 49th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Texas, Oct. 6–9, 1974. Permission to copy is restricted to an 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 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. 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 discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A highly retarded acid emulsion has proven extremely effective in the stimulation of hot limestone and dolomite formations. The level of reaction rate retardation achieved with this acid is much greater than previously possible and is obtained through use of a unique surfactant system which both emulsifies the acid and forms a chemical barrier on the surface of the rock. Acid reaction rate studies performed in the laboratory under both static and flowing conditions demonstrate its high level of retardation.

In contrast to previous emulsified acids, which depend upon high viscosity for retardation, this emulsion has a viscosity of only 30 cps, thus greatly reducing pumping pressure and allowing increased injection rate. Due to its slow reaction rate and improved pumpability, acid penetration distance is greatly increased. penetration distance is greatly increased. Comparative well results clearly demonstrate the increased effectiveness of this type retarded acid.

Introduction

Most acid treatments can generally be classified as either fracture or matrix acidizing. Matrix treatments are performed at pressures below that required to produce pressures below that required to produce hydraulic fracturing and have as their main purpose the removal of formation damage in the purpose the removal of formation damage in the area immediately around the wellbore. Acid fracturing treatments are performed at pressures above fracturing pressures, usually at greatly increased injection rates. These treatments are designed primarily to improve the natural flow characteristics of the well by the creation of artificial flow channels deep into the formation. In contrast to ordinary hydraulic fracturing where fracture conductivity is produced by the placement of sand or other propping agents acid fracturing achieves conductivity by the nonuniform etching of the fracture faces.
Chemical Composition of Deep Subsurface Waters of the Western Anadarko Basin
Authors: Dickey Parke A. , Soto Carlos
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

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

Five different chemical types of water are found in the Oklahoma panhandle area, each type characteristic of a particular geological zone. The Permian of the Hugoton-Panhandle field contains concentrated chloride-calcium brine, which resembles normal connate water except that it is unusually rich in sulfate (Type V). The Pennsylvanian sands above the Morrow (Lansing, Pennsylvanian sands above the Morrow (Lansing, Tonkawa, and Toronto) contain normal chloride-calcium connate water (Type Y). The Oswego sands contain similar water, somewhat less concentrated (Type W). The Morrow sands contain three different types: in Cimarron County, Okla., a high-sulfate, chloride-calcium brine resembling Type V (Type X); in Texas County, the normal chloride-calcium brine (Type Y); and in Beaver County eastward to Blaine County, a very strange, dilute water containing appreciable amounts of carbonate and sulfate (Type Z).

The origin of the different chemical types is quite puzzling. The dilute waters of Type Z are especially anomalous, for they resemble meteoric waters chemically, although there is no hydrodynamic circulation at the present time. They may be ancient meteoric waters trapped by the uplift of the Amarillo-Wichita mountains shortly after deposition of the Morrow sediment or they may be "immature" connote waters similar to those reported from the abnormally pressured areas of the Gulf Coast Tertiary.

Introduction

Deep subsurface waters associated with the oil and gas of the Texas and Oklahoma panhandles vary widely in their chemical composition. Those of the Morrow are especially interesting because they range from strong chloride-calcium brine with the total solids content of 100,000 to 200,000 mg/liter, to relatively fresh bicarbonate-sodium waters with a total solids content of 10,000 to 30,000 mg,/liter.

Connote waters have been defined as waters that have been removed from the hydrologic cycle by burial in sediments for substantial periods of geologic time. They must be remains of ancient sea water, but their composition is drastically altered. Normally they lack bicarbonate and sulfate, and are much more concentrated than sea water. The concentration often increases with depth and age.

Meteoric waters may be defined as waters that have been part of the hydrologic cycle recently, geologically speaking. They are usually circulating, entering the aquifer (waterbearing permeable formation) at an outcrop of high elevation and leaving it at a low elevation. Chemically, they are comparatively fresh and vary widely in composition.
Coiled Tubing Hangoffs: A Simple, Yet Effective Tool for the Future
Authors: Allbee James D.
Published: December 2007

During the life of most gas wells, lifting technology is needed to help produce gas. There are a lot of reasons for this. As reservoirs deplete and pressures drop, the energy of the reservoirs may not be sufficient to unload gas and liquids in a consistent fashion. In addition to natural production declines, the produced oil and water may serve to choke the well as the well loads up and hydrostatic pressure at the producing zone increases. Operators may try various things to keep their wells producing when this is the case. For instance, compressors are installed to lower minimum line pressures, and downhole pumps and gas-lift are installed to remove liquids. Temporary measures may include workovers to swab liquids or blow liquids out of the well with nitrogen, dropping soap sticks and venting the wells to the atmosphere. One of the simplest permanent measures to control this loading phenomenon in wells is the installation of velocity strings.

Twenty-one velocity strings were installed for one operator between June 1996 and August 1997. These wells are in various regions of Oklahoma, producing from different formations and depths. In an attempt to classify the success and viability of these installations, ten of these wells were studied. The project concentrated on obtaining a good reservoir and well model which, first, predicted the necessity of these services and, second, modeled post-job production. A thorough documentation of the methodology for this study is included along with the results. The average project well had 4100 cumulative days on production before the coiled tubing hangoffs were installed. 8 of the 10 wells had positive net present values, with the cumulative net present value of the 10 wells analyzed to be $238,000 in 250 days. Pay-outs for the wells averaged 130 days. The study shows the importance of looking at each candidate well individually, and confirms the economic viability of hanging coiled tubing as a permanent, hassle-free completion.
Formation Sand Liquefaction: A New Mechanism for Explaining Fines Migration and Well Sanding
Authors: Hayatdavoudi A.
Published: December 2007

An exhausting review of oil field literature showed us a wide range of causes for fines migration. Conspicuous among these causes was the existence of kaolinite clay mineral in the pores and the intensity of mass and momentum transfer of the fluid within the wetted perimeter of pores or pore throats. However, the field production operation personnel have taught us that when the water cut rises, the fines migration and well sanding becomes a serious, costly issue for the operators. It appears that neither researcher in the laboratory nor field researchers have offered clear reasons for the fines migration when the water-cut increases above and beyond a certain threshold. This paper addresses this issue with some examples. These examples may be used as bases of recommendations for resolving the fine migration issue. To understand the issue first, (for the purpose of offering some remedial measures), our works led us to examine a new mechanism, sand liquefaction. In this effort, we discovered that as the original water-oil contact plane rose above the original plane of contact resulting from water conning or very high rate production, the formation sands began to liquefy. It appeared that five important parameters controlled the sand liquefaction process. They were the fine particle buoyancy, changes in the effective bulk density of sand, high pore pressure build-up near the well bore due to transient pressure (equivalent to transient shear stress), lack of adequate cohesive cement between sand grains, and a low angle of internal friction. Our calculations lead us to conclusion that if the fine particles accelerate above the threshold limit of 0.190 g, where "g" is the acceleration of gravity, the sand liquefaction begins. The obvious outcome of this process is well sanding, fines migration, or both. Although not discussed in this paper, we detected that if the amount of natural cementing material, such as calcite, dolomite, and siderite, reached a level of about 5 percent or more, the sand would not liquefy easily. Our recommendation for remedial works like gravel packing, frac packing, selectively perforating the sand, trajectory planning for well re-entries, and other measures is largely based on these conclusions and microscopic determination of the sand shear strength.
Well Optimization Package for Progressive Cavity Pumping Systems
Authors: Klein S. T. , Thrasher W. B. , Mena L. , Quijada E. , Brunings C.
Published: December 2007

The subject Progressive Cavity Pump Optimization System (PCPOS) continuously analyzes analog system values from several components at the surface to determine the operating fluid level of a well. One major component is a load-measuring device integral to the surface drive system. No down-hole sensors and/or wires are required. Analyses of the input values by the PCPOS software provide optimum pump operation criteria related to the dynamics of the producing well.
Finite Element and Neural Network Modeling of Extreme Overbalance Perforating
Authors: Azari Mehdi , Asadi Mahmoud , Schultz Roger , Ghalambor Ali
Published: December 2007

Finite element modeling (FEM) was used to study the micro-fracture propagation around perforation tunnels created after an extreme overbalanced perforating (EOBP). The effectiveness of the EOBP as a function of formation permeability and the overbalanced pressure was investigated.

The results of the FEM were used to train and generate an artificial neural network (ANN) for EOBP conditions. This neural network model may then be used to quickly investigate the effects of using different overbalanced pressures and various formation permeabilities on flow rate.
Effect of Drill Pipe/Coiled Tubing Initial Configuration on Contact Force
Authors: Qiu Weiyong
Published: December 2007

The contact force between the drill pipe and the wall of a bore hole has been studied intensively in the past1–6. Formulas have been provided to predict the contact force for the drill pipe which is initially straight and finally changes into either a sinusoidal configuration or a helical configuration. Recent publications7, 8 indicate that the residual bending of the drill pipe has significant effect on the post buckling behaviors of the drill pipe in deviated and curved well bores. No papers has been published regarding the effect of the residual bending of the drill pipe and CT on contact force.

This paper presents a novel approach to investigate the effect of the initial drill pipe/coiled tubing (CT) configuration on the contact force between the drill pipe and the wall of a bore hole. The initial drill pipe configuration is assumed to be a sinusoidal configuration. In order to simplify the problem, only the helical configuration is assumed to be the final drill pipe configuration. By using the Lagrange Multiplier method, the change in the total potential of the conservative system is formulated. Setting the first order variation of the change in the total potential to zero yields the force equilibrium equations. The contact force for a drill pipe constrained within a well bore (vertical, inclined, and curved) can be achieved by solving the equilibrium equations simultaneously. Numerical examples are presented for the drill pipe and CT in vertical, deviated, and curved wells, respectively. The results show that the residual bending of the drill pipe increases the contact force.
A Novel Program for Processing Acid-Stimulated Well Returns on Offshore Platforms
Authors: Brown J. Mike
Published: December 2007

Offshore oil and gas wells sometimes require stimulation to remove formation damage and improve production. The chemicals used in stimulation packages and the low pH of the fluids can cause a difficult to resolve emulsion that creates upsets in the operation of the platform crude oil and water treating systems. These upsets result in oil that does not meet pipeline specifications and water that cannot be discharged overboard. Out-of-spec oil is temporarily stored in a wet oil tank; however, on offshore platforms storage is limited and when the capacity is exceeded the entire production from the platform must be shut in until the out-of-spec fluids can be processed or shipped to a land-based handling facility. The low pH and high organic content of the water from the stimulated well returns can cause upsets in the water treatment system resulting in overboard water discharge that is out of compliance. This also can result in a shut down of production.

A novel program has been developed which eliminates the difficult to resolve emulsion resulting from stimulated wells by using a unique combination of products custom tailored for each offshore production platform. The program prevents out-of-spec oil by allowing for complete emulsion resolution in the test separator. This eliminates the possibility of a complete production shut-in period. The water from the test separator is processed in a two step treatment which removes free oil and dissolved organics to a level that is acceptable for overboard discharge. This system generates no waste byproducts. The oil and gas production of a platform can be maximized by pursuing more aggressive stimulation schedules on single or multiple wells without risking an out of compliance operation or excessive disposal costs.
Identifying Opportunities to Increase Oil Recovery from Fluvial-dominated Deltaic Reservoirs in Oklahoma
Authors: Knapp R. M. , Yang X.
Published: December 2007

U.S. Department of Energy data suggest that previously discovered Oklahoma reservoirs contain approximately six billion stock tank barrels of mobile oil that will not be recovered using current production practices. This mobile oil should be recovered using current technology. A significant amount of this oil is believed to be in reservoirs deposited in fluvial-deltaic (FDD) environments. These FDD reservoirs have low recovery factors because they generally have substantial heterogeneity.

This paper presents results of nine case studies of Pennsylvanian FDD reservoirs. The case studies were part of the University of Oklahoma's U.S. DOE Class I project completed in 1997. The project was funded by the Department of Energy to determine if reservoir management and production strategies could be altered to increase expected recovery from the reservoirs. The FDD reservoirs studied were relatively small and thin. Some of them were associated with aquifers and had water drive. Because of the small reservoir sizes, most were developed with a limited number of wells. The largest reservoir studied had 36 wells. Expected primary recoveries for most of the reservoirs studied were less than 20%. Most wells were producing less than five barrels of oil per day at times of the studies.

The simulation studies reviewed in this paper combined available geological and engineering information to develop new geological models for the reservoir. The models were translated into input data files for black-oil reservoir simulators. The models were validated by matching past reservoir behavior. After the models were validated, alternate production strategies were investigated. The alternate strategies generally included an extrapolation of the current strategy (a base case), well completion changes, infill drilling, and water injection. In one case, gas injection was studied. The alternate strategies were compared with the base case. For almost all reservoirs, it appears that recovery could be fifty per cent larger than can be expected from the base case. One reservoir had an estimated recovery eight times larger than the current policy and for one reservoir it did not appear that any alternate exploitation strategy could increase recovery. The authors used commercial, ECLIPSE, and public domain, BOAST3, reservoir simulators in the simulation studies.
A New Stabilized Method for Use in IMPRES-Type Numerical Reservoir Simulators
Authors: Meijerink J.A.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

The stabilized IMPES technique for solving reservoir fluid flow equations allows larger timesteps and uses less calculation time than the standard IMPES method if stability control is the limiting factor. Otherwise it reduces to the standard IMPES method. This technique can easily be implemented in existing IMPES type simulators, and can be combined with both 1-point and 2-point upstream approximations If the stability problem is not too severe, it can easily compete with implicit simulators in computer time and storage.

Introduction

In simulators of the IMPES-type the nearly elliptic pressure equation is solved implicitly saturation equations, ranging between parabolic and hyperbolic, are solved explicitly. The explicit solution of the saturation equations dictates a maximum for the timestep to preserve stability and non-oscillatory behaviour. This maximum is regularly less than the limitations for control of the truncation error, especially if the mobility ratios are large and the fluid velocities are high in comparison with the pore volumes of the grid blocks.

In this paper we shall describe a time-discretisation method that allows a k2 times larger timestep for k times more calculations while the solution remains stable and/or non-oscillatory. When the truncation error is the limiting quantity, the method becomes equal to the commonly used forward-explicit time discretisation method.

THE STABILIZED EXPLICIT METHOD

For simplicity we shall restrict ourselves to a simplified linear partial differential equation for the saturation, given by:

dS(x,y,t) ————— = dt

d2S(x,y,t) d2S(s,y,t dS(x,y,t) dS(x,y,t) ————— + ————- - ————— - ————- dx2 dy2 dx dy

(1)

The boundary conditions are given by:

S(x,y,0) = 0

S(0,y,t) = 1

S(x,0,t) = 1 (2)

To solve this equation we use finite difference analogs. The continuous domain is replaced by an (n + 1) × (n + 1) equidistant grid system, with grid spacing h, central differences approximating the second-order spatial derivatives and 1-point upstream differences being used to approximate the first-order spatial derivatives. The latter can also be represented by two-point upstream differences.

In both cases this leads to a set of n2 ordinary differential equations given by:

ds -- = - As + g (3) dt
Fine Particulate Matter: How Dirty is Clean Combustion?
Authors: Christy Roger H. , Ziman Stephen D.
Published: December 2007

Changes in the Federal health-based ozone and fine particulate (PM2.5) standards will cause many regions of the United States to be declared "non-attainment." Attainment plans, which include emission control strategies, will be required by the year 2007. In late 1997, the U.S. Department of Energy began funding a study to determine real-time particulate matter concentrations from various combustion sources. Both the current Federal, and the more stringent California ozone standards have required significant emissions controls for ozone precursors such as nitrogen oxides and volatile hydrocarbons. One goal of the investigators was to determine if control technologies presently in place for meeting state and federal ozone requirements also minimize emissions of fine aerosols from combustion. A second goal was to provide new information about fine aerosol emissions from combustion sources, as the present information is old, and questionable. The study's selected technologies, reflecting the current state-of-the-art, could represent common controls when the new particulate standards take effect.

This paper will review the selection process of the various equipment, discuss the test methods used, and summarize the results. The selections included a rich-burn internal combustion engine with non-selective catalytic reduction, a steam generator with flue-gas recirculation, and two different sized turbines, both with water injection. Test methods included laser-induced breakdown spectroscopy (LIBS), laser aerosol spectroscopy (LAS), EPA Method 5, and a real-time particle-bound PAH monitor. Preliminary data indicates that the best emission controls for ozone precursors currently in place, along with the appropriate fuel selection, have exceptionally low PM2.5 levels, and would be expected to have insignificant impact on PM2.5 concentrations. Therefore, a need for additional fine particulate emission controls on these combustion sources is not anticipated.
Pipeline Management Program
Authors: Winkler William R. , Hesson Bruce H. , Shemaria Mark A.
Published: December 2007

Due to a spill from an unregulated pipeline in 1993 the legislature granted the Department of Conservation's Division of Oil, Gas, and Geothermal Resources (Division) jurisdiction over oil and gas production pipelines. As a result new pipeline regulations were promulgated in 1994 and 1998. The first regulations were broad construction standards and the second were a two tiered risk based system that included construction, maintenance, and testing requirements. Part of the regulation adoption process included statistics on oil spill frequency and clean-up cost estimates of between $15 and $25 million. Combining these statistics with a case study that demonstrates the potential reduction in the spill frequency clearly shows the benefit of initiating an integrated pipeline management plan. This is especially important in urban areas and environmentally sensitive areas when considering the potential for penalties imposed by any one of a number of regulatory agencies.