bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vertical-to-Horizontal Permeability Relationship: Arun Reservoir
Authors: Atmadibrata R. R. M. , Joenoes Syafri 
Published: December 2007

Abstract
The purpose of this study was to investigate the relationship between horizontal and vertical permeability of the Arun Limestone reservoir in the Arun field. The study utilized core data from wells in which both horizontal and vertical permeability measurements had been made.
The Arun natural gas field, one of the world's largest gas fields, is located onshore in the North Sumatra Basin, Indonesia. This field has been producing gas and condensate since 1977. Gas production has increased since start up to the current average level of 3,300 million Standard cubic feet per day (MMSCFD). Of this total daily volume 2,230 MMSCFD is transported to the LNG plant for liquefaction and export, and after NGL recovery 145 MMSCFD is supplied for the domestic market, 55 MMSCFD is used for fuel and 870 MMSCFD is reinjected into the reservoir to maximize condensate recovery.
The current geological model, which incorporates a 7-layer zonation based on porosity trends, is the basis for input to reservoir Simulation studies. A good understanding of permeability distribution within the reservoir is critical to accurate forecasting of reservoir deliverability and injectivity performance.
The benefits from the results of the horizontal and vertical permeability relationship study are as follows: –An improved knowledge of vertical flow in the reservoir.–Improved reservoir modeling and compositional flow Simulation.–Enhanced ability to select zones for well Stimulation.
The study shows that there is a log-log linear relationship between the horizontal and vertical permeabilities in each zone.
High-Strength Coiled Tubing Assists High-Pressure Well Servicing in the Gulf of Mexico
Authors: Coats E. A. , Tatarski A. M. 
Published: December 2007

ABSTRACT
Until recently, the removal of scale from high-pressure wells in the Gulf of Mexico required the use of a conventional or hydraulic workover (snubbing) rig. The conventional methods, which mechanically removed the scale, were costly and time consuming. Although removal of scale with coiled tubing provided a cost-effective alternative, coiled tubing was only considered for applications with well pressures of 5,000 psi or less. Now, however, with the advent of high-strength coiled tubing, scale-removal operations in more hostile well conditions can be performed.
The case histories presented in this paper will provide an overview of the significant benefits that the operator was able to obtain from the use of high-strength coiled tubing in scale-removal operations in high-pressure wells.
Overview of Acid Stimulation Practices in Malaysian Oil Fields
Authors: Hashim A. M. , Yasin Z. A. M. 
Published: December 2007

ABSTRACT
Significant decline in production performance has been observed during the first few years of production in some completions in Malaysian oil fields. Near wellbore damage is thought to be the cause of this decline. Acid stimulation is the method of choice in removal of near wellbore damage and has proven to be successful in removing about 50% of this impairment.
Stringent screening criteria for acid stimulation candidates have contributed to the success of the acid jobs. Two methods viz bullheading and coiled tubing are currently being practiced. Coiled tubing has been widely used since the start of the acid campaign in 1986 while bullheading was tried only recently. Both methods give comparable results with bullheading costing about half that of coiled tubing. Standard acid formulation common to the industry together with additives has given good results at certain optimum volume of acid pumped. Nitrogen or available gas lift gas has been used to kick-off the wells.
Post acid production performance has shown improvements as substantiated by PI increases up to 200%, better gaslift efficiency, lower skin factors and average gains up to 350 STB/D. However, 20% of the candidates (with gains less than 60 STB/D) were unsuccessful due to low remaining reserves and/or high pre-stimulation water cut during the first campaign. More stringent screening criteria such as low water cut and sufficient remaining reserves have helped to reduce the rate of failures in later campaigns to 15%.
Field Evaluation of Acid Simulation Diverter Materials and Placement Methods in Arab-D Injection Wells With Openhole Completions
Authors: Ginest N. H. , Phillips J. E. , Al-Gamber A. W. A. , Wright D. W. 
Published: December 2007

SUMMARY
Hydrochloric acid (HC1) stimulation is a common method of removing shallow damage in carbonate formation completions resulting from drilling and workover operations. Current practice in the Ghawar Field is to bullhead large volumes of acid into the power water injection (PWI) wells to stimulate the long, open hole completions in the Arab-D formation. Small stages of particulate materials in a viscous carrying fluid are normally included in the treatment for diversion. This report describes the field testing and evaluation of three different acid treatment designs; (1) the conventional, bullhead treatment, (2) a coiled tubing placed, nitrogen foam diverted treatment and (3) a coiled tubing placed treatment without diverting materials. The treatment designs utilizing coiled tubing were developed in an effort to improve upon the conventional method by providing better formation damage removal throughout the entire porous interval and to reduce costs. A review of the conventional bullheading technique is presented along with case histories of wells that were stimulated with the two treatment techniques utilizing coiled tubing placement. The data presented indicates that the treatments combining coiled tubing placement and nitrogen foam diversion were more effective in stimulating the Arab-D formation and in improving injectivity than the conventional bullhead jobs.
Importance of Compression Ratio Calculations in Designing Sucker-Rod Pump Installations
Authors: McCafferty J. F. 
Published: December 2007

ABSTRACT
Current sucker rod pump design procedures ignore calculating and comparing the pump's maximum available compression ratio with the required compression ratio of the installation. As a result, subsurface pumps are often installed with too small of a compression ratio for the production requirement. These pumps then experience chronic gas locking problems resulting in lost production and/or premature equipment failure.
This paper points out the need to consider compression ratio in addition to properly designed down hole gas separation as a critical part of a subsurface pump's design and installation.
Conceptual Sucker-Rod Design: An Unsolved Problem
Authors: Laine R. E. 
Published: December 2007

ABSTRACT
The available set of engineering design tools for sucker-rod pumping units is incomplete. There is no sucker-rod design tool that has the combination of speed and accuracy needed for traditional conceptual design. The existing design tools lack either speed or accuracy. The solution is to develop a simulator specifically for the conceptual design phase. A conceptual design simulator must be fast enough to evaluate hundreds of system alternatives in a short time. A conceptual simulator must be accurate enough to provide meaningful data. The new simulator achieves speed by modeling a tapered sucker-rod string as a dimensionless equivalent-uniform-diameter rod. The new simulator uses simple boundary conditions.
Hydraulic Gas Pump and Gas Well De-Watering System: Two New Artificial-Lift Systems for Oil and Gas Wells
Authors: Amani Mahmood 
Published: December 2007

ABSTRACT
This paper presents the concepts for two new artificial lift systems. The systems utilize the same operating principles. One system is for oil wells, the other unloads gas wells. The first system uses gas pressure to produce liquids through the tubing. This is called a Hydraulic Gas Pump. The other system uses gas pressure to unload gas wells and is called Gas Well De-watering System. In this system gas is produced through the tubing and liquid is produced through the casing tubing annulus.
The Hydraulic Gas Pump is suitable to pump oil wells with high gas liquid ratio and viscous crude production. The De-watering System can be used to maintain a gas well in an unloaded condition for maximizing its production rate and recoverable reserves.
Additional advantages of these systems are:
❖ They can be installed in shallow, deep, directional or offshore wells. ❖ They are wireline retrievable systems. ❖ Gas Lock and cavitation are not problems. ❖ They preform well in corrosive environments.
Vertical Permeability Determination drom Single-Well Test: Phase I—Constant Flow Rate Test
Authors: Luo Fang , Miska Stefan 
Published: December 2007

ABSTRACT
This paper presents a new method of pressure transient analysis for determining the vertical and horizontal permeabilities from a single-well test conducted on partially penetrated or perforated wells. Generally, well testing data from wells with a restricted flow entry potentially carry the information about directional permeability. It has been recognized that the test data can be characterized by two parameters: the ratio of the flow entry to the total thickness of the producing zone, and the ratio of the vertical permeability to the horizontal permeability. Fully-featured pressure drawdown data display two straight-line segments connected by a transition curve when plotted versus the logarithm of time. This paper defines a characteristic time that corresponds to the intersection point of the extrapolations of the two straight lines, and shows that the characteristic time is a function of the penetration ratio and the permeability ratio. By using the slopes of the two straight lines and the characteristic time, one can determine the vertical and horizontal permeabilities, and the net thickness of the producing zone. This paper demonstrates that the slope of the second straight line can be obtained from pressure buildup data. Hence, a full development of the pressure drawdown process is not necessary and the total testing time can be reduced. Also, by applying the real gas pseudo pressure concept, the proposed method can be extended to single-phase, highly compressible fluid flow in reservoir under Darcy's flow conditions. Examples show the test data interpretation procedure for liquid and gas flow problems.
Characterization and Prediction of Formation Damage in Two-Phase Flow Systems (Formation Damage and Filter Cake in Laboratory Core Tests - Part II: Model Assisted Analaysis)
Authors: Liu Xinqhui , Civan Faruk 
Published: December 2007

ABSTRACT
A predictive model for formation damage resulting from particulate processes involving two-phase flow of oil and water in sandstone formations is presented. The invasion and retention of externally introduced particles, the release and capture of formation in-situ fines and the resulting formation damage in terms of permeability reduction are modeled mathematically. The release of in-situ fines, retention of external particles and in-situ fines, and interphase transfer of particles are represented by empirical rate expressions. Permeability reduction is evaluated by taking into account the effects of pore plugging and porosity variation. The effects of relative permeabilities, capillary pressure and wettability of fine particles and pore surfaces on two-phase flow formation damage are considered.
The model is first tested with laboratory data of single phase flow of water through water-sensitive sandstone cores with and without presence of residual oil, and then with two-phase flow data involving the displacement of an oil-saturated, water-sensitive sandstone core by water. It is shown that there is a reasonable agreement between model predictions and experimental data. Typical simulation results illustrating the effects of wettability of externally introduced particles on permeability impairment in two-phase flow are also presented. However, the later results could not be verified due to the lack of experimental data. The model presented in this study can be used to estimate formation damage, identify governing damage mechanisms, and provide a guide for controlling formation damage for a given rock-fluid system.
Deformation Effects on Formation Damage During Drilling and Completion Operations
Authors: Thallak S. G. , Holder Jon , Gray K. E. 
Published: December 2007

ABSTRACT
This paper deals with mechanical damage linked to stress and deformation changes associated with drilling and well completion operations and associated permeability changes. Irreversible or plastic deformations caused by pore collapse and particle rearrangement result in permanent fabric alterations due to induced anisotropy. Permeability changes are linked to damage state, anisotropic damage, dilation and stress state changes. Molecular dynamics simulations using disc assemblages and laboratory triaxial test experiments on weakly cemented sandstones clearly indicates that the induced anisotropy and deformation due to shearing significantly alters the permeability; and also its value depends on the direction in which it is measured. Severe anisotropy in permeability is the result of local heterogeneity due to damage. The molecular dynamics simulation is shown to be a powerful tool to generate insights into the physical processes of particulate behavior. The paper illustrates the implications of induced anisotropy effects on formation damage.
Numerical Evaluation of Gravel-Pack Damage
Authors: Morita Nobuo 
Published: December 2007

ABSTRACT
Oil industry statistics show that gravel-packed wells, in hydrocarbon production for more than a year from formations with permeability greater than 500 md, exhibit an average skin excess of 20. This paper utilizes laboratory and field data to investigate causes of high skin value. A finite element transient nondarcy model, simulating gravel-packed wells, was used to investigate the damage.
The Rheology of Foam
Authors: David Amiel , Marsden Sullivan S. 
Published: December 2007

Abstract
Both experimental and theoretical analyses were carried out on the rheological behavior of foam. This foam was generated by simultaneously injecting compressed air and an aqueous solution of a commercial foaming agent into a short porous medium. It then flowed into a capillary tube viscometer having four interchangeable glass tubes of different radii. A mathematical analysis was developed whereby both the very pronounced effects of fluid slippage at the tube wall and the foam compressibility were taken into consideration. The apparent viscosity was independent of foam quality but not of tube radius.
Bubble size and bubble size distribution were measured under a microscope and the change of bubble size with-time studied through photomicrographs. Both the mean bubble diameter photomicrographs. Both the mean bubble diameter and bubble size distribution were functions of foam quality. The cumulative size distribution as a function of a quality is represented by a modified Weibull function.
Although the flowing foam behaved like a pseudoplastic fluid, the static foam had a pseudoplastic fluid, the static foam had a measureable gel strength which increased with foam quality.
Introduction
Foam is a gas-liquid dispersion in which the liquid is the continuous phase and the gas is the discontinuous phase. It occurs widely and is used in many industrial applications. In the petroleum industry, foams are often encountered in gas-oil separators. In recent times, aqueous foams have been used in several oil field applications such as removal of brine from low pressure gas wells and as a drilling and completion fluid in low pressure, water sensitive reservoir rocks. Their use has also been proposed to plug thief formations and to seal caprock leaks in underground/natural gas storage reservoirs, and as a displacing agent in conjunction with water floods. Some of these applications are involved with foam flowing through tubes or pipes whereas others are concerned with the flow or retention of foam in porous media. porous media. The many physical properties of foam have been described by scientists and engineers in numerous papers and these are reviewed elsewhere. The many papers concerned with the flow properties of foam are particularly pertinent properties of foam are particularly pertinent to its use in petroleum production. In these, foam is usually considered as a fluid, which is probably a valid assumption if the bubble size is small compared to the instrument's dimensions or the size of the fluid conduit.
Characterization of Surfactant-Enhanced Cement Fluid-Loss Additives
Authors: Mueller D. T. , Bray W. S. 
Published: December 2007

Abstract
Modified surfactants, in the form of ethoxylate-coated resins (ECR), serve as the foundation for fluid loss additive systems that are functional in a wide range of applications and environments. ECR's, when combined with polyvinyl alcohol, produce fluid loss additives that: (1) are minimally retardive, (2) can be placed in turbulent flow, and (3) possess anti-gas properties. Blending ECR with hydroxyethylcellulose yields a multi-purpose fluid loss agent with higher efficiency, greater salt tolerance, and improved thermal stability as compared to conventional fluid loss additive systems.
Presented are the laboratory data substantiating the use of surfactant enhanced fluid loss additives, as well as supportive case histories demonstrating the utility of these systems in field cementing operations.
Gas-Lift Valve Performance Testing
Authors: Decker K. L. 
Published: December 2007

Abstract
Gas lift valves are used in many producing wells to increase or maintain production. The spacing of valves in the well, calculation of opening or closing pressures, and selection of port size all play an integral role in the success of unloading and lifting operations. The design procedures that have been developed through the years include many safety factors; however, some of these were based on erroneous assumptions concerning the flow performance of gas lift valves; subsequently, many problems resulted.
Now that recent developments in gas lift valve mechanics have addressed the importance of using gas lift valve performance testing in predicting a valve's true flow performance, considerably more interest is being shown in this topic. One gas lift valve manufacturer has been furnishing gas lift valve performance data and using the data to perform gas lift valve spacing designs since 1962.
This paper will answer the questions of what constitutes performance data, why there is a need for this data and what types of testing techniques must be conducted to obtain a valve's true flow performance when subjected to subsurface conditions. The methods for performing the tests will also be discussed.
Simplified Computer-Aided Analysis of Electrical Current in Motors Used for Beam Pumping Systems
Authors: McCoy J. N. , Podio A. L. , Jennings J. W. , Capps K. S. , West Jerry 
Published: December 2007

Abstract
A substantial cost for operating most oil properties is the monthly electricity charge. Analyzing the motor current in a beam pumping system is a difficult task in that the current is normally changing from consumption to generation during each pump stroke. A gear "slap" will occur during a pump cycle when the motor changes from driving the pumping system to being driven by the counterbalance and the unit's inertial forces. Conventional clamp-on current meters indicate the magnitude of the current flow in the wire but do not indicate whether the motor is consuming or generating electricity.
A new computerized technique for acquiring motor current using a clamp-on probe permits the acquisition of apparent current and the calculation of real ( or active) current. The apparent current is acquired at a one kilohertz rate. These data are processed to obtain real current A plot of the active current ( showing consumption and generation) along with the apparent current is presented to the user. This plot is extremely beneficial for determining electricity costs, pumping unit balance, cost per barrel of oil lifted and other power consumption factors.
An Efficient Semianalytic Reservoir Model for Complex Reservoirs
Authors: Poe B. D. , Dube H. G. , Holditch S. A. 
Published: December 2007

Abstract
This paper presents a summary of the development of a semi-analytic reservoir model for gas reservoirs with various reservoir complexities. The types of reservoir complexities that have been considered in this study include; multiple reservoir layers in which the reservoir layers may be infinite or finite in extent, dual or single porosity systems, and wells that have been fractured. The reservoir model that has been developed and used in this study was constructed with the appropriate Laplace domain pressure and rate-transient solutions that are available in well testing literature.
This reservoir model was developed to provide a more detailed and accurate means of analyzing or predicting the performance of a gas reservoir than is possible with a simple "type Curve" approach, yet would be more computationally efficient than a finite difference reservoir model. The results of the semi-analytic reservoir model have been validated with the reference solutions generated with a commercial finite difference reservoir simulator. The results of the semi-analytic reservoir model are comparable to the results of the finite difference simulator, yet require substantially less computation time and computer memory.
Generalized Inflow Performance Relationships for Three-Phase Flow
Authors: Wiggins M. L. 
Published: December 2007

Abstract
Generalized three-phase inflow performance relationships (IPRs) for the oil and water phases are presented in this paper. These relationships yield adequate estimates of the production-pressure behavior of oil wells producing from homogeneous, bounded reservoirs during boundary-dominated flow. The IPRs are empirical relationships based on linear regression analysis of simulator results and cover a wide range of reservoir fluid and rock properties. Methods to study the effects of changes in flow efficiency and to predict future performance are also presented.