bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wet Gas Compression – A Logical Step to Follow Multiphase Boosting
Authors: Müller-Link D. , Brandt J. U. , Reichwage M. , Schröder G. 
Published: December 2007

Abstract
Multiphase boosting in oil and gas production may typically be characterized by:
– Slug flow occurrence possible, and – GVF at inlet conditions higher than 50 %.
The physical challenge for the equipment in use is the strong variation of the GVF (Gas Void Fraction), leading to transient flow conditions at the pump's inlet. However, when the GVF during the entire operations constantly exceeds 98 %, control of heat generation becomes a further challenge. Suitable answers need to be found for the following questions like
– How can wet gas compression best be described? – Is this an efficient way to compress wet gas? – What about installation economics?
A technical issue for wet gas compression is the shaft sealing. Available standard seals can either cope with liquid or gas, but not with varying fractions of both. Other limiting factors are differential pressure, lubrication characteristics of pumped liquids, solids, and circumferential velocity.
Applied Carbonate Stimulation – An Engineering Approach
Authors: Sengul Mahmut , Remisio Luis H. A. 
Published: December 2007

Abstract
Carbonate reservoirs are quite tolerant to problems originated by poor stimulation practices. Therefore, acidizing of carbonate formations has been overlooked in many aspects. The objective of this paper is to provide a comprehensive reference material that will help the matrix stimulation designers to quantify formation damage, select optimum fluids for carbonate reservoirs, design and place proper treatment, hence stimulate the carbonate reservoirs in engineered way.
Well operations can damage the formation, from the moment the first drill bit penetrates a permeable formation to the end of its productive life of it. Most types of damage reduce the formation's natural permeability. Identifying the causes of formation damage and how to prevent it have been the subjects of much research, but well operations still continue to cause some degree of damage to the formation in the near-wellbore region. Formation damage has a dramatic, adverse effect on the flow of hydrocarbons into the wellbore, because of plugging or partial plugging of perforations, or plugging of the rock structure by debris from the well and from well operations.
Stimulation design for horizontal wells and surprises in some field results indicated the need for systematic analysis of stimulation process in ADCO fields. Therefore, an applied study has been conducted to address the issues related to carbonate stimulation and set field procedures, best practices for the carbonate reservoir stimulation. Reservoir characterization part of the project included sampling of representative cores from the producing and injection formations in all fields. A total of 287 core samples have been collected. Thin section, acid solubility, iron content, X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analysis have been performed on these samples. Existing acid recipes checked and validated against mineralogical composition, acid solubility, and iron content of particular layers and new recipes prescribed accordingly. A detailed questionnaire sent to major oil companies and service providers. Replies processed and findings of the project have been documented as Best Practices.
Lessons Learnt in Planning and Implementation of a Successful Lower Burgan Horizontal Well in North Kuwait
Authors: Azim Shaikh Abdul , Attid Juma , Smith Martin , Al Hajeri Mubarak , Moritz Lee , Ali Mohammad 
Published: December 2007

Abstract
The first horizontal well (RA-156) was successfully drilled and completed in the Lower Burgan sandstone reservoir of Raudhatain Field, North Kuwait. The objective of the well was to produce water-free (dry) oil at high rate from a difficult-to-reach portion of the reservoir. Dry production is especially desirable due to constrained wet crude processing capacity. The well successfully delivered the expected rate, making this well the highest-rate producer in the field.
Uncertainty in structure and stratigraphy are inherent in the area due to weak/noisy seismic reflections and rapid change in reservoir facies in marine-influenced channel deposits. Innovative correlation schemes and detailed reservoir description were used to reduce uncertainties. The trajectory was designed along the direction of maximum principal stress to overcome borehole instability problems. The horizontal-section was drilled with minimum overbalance to avoid potential reservoir damage.
Well-site data including logging-while-drilling (LWD), cuttings, and drilling data were used to identify faults along the well and to optimize the selection of kick-off point (KOP) and end-of-build (EOB). Subtle markers were identified while drilling, and the trajectory was geo-steered within the channel sand while maintaining maximum standoff from a rising oil-water contact (OWC). Absence of shale along 3000-ft of horizontal/high angle section was instrumental in faster drilling. Low mud weight was used to minimize potential formation damage caused by prolonged formation exposure to high-density mud.
The completion of the well was designed to deliver long-term high-rate dry oil production. The horizontal section of the well was cased and cemented to ensure zonal isolation. A perforation strategy was developed and implemented to encourage even flow from the reservoir along the productive section to avoid local water coning, facilitate future well intervention and increase productivity index (PI) by reducing potential skin. External casing Packers were used to further ensure isolation of across a fault in the horizontal section. 5-1/2" tubing with appropriate jewelry was selected to accommodate the expected high rate and to ensure well integrity.
The details of the multidisciplinary approach and the lessons learnt during planning and implementation of this horizontal well are summarized in this paper.
Research into Material Selection for Down-hole Tubing by using Dynamic Field Tester
Authors: Takabe Hideki , Ueda Masakatsu , Yamamoto Eiji , Masatomo Hiroaki , Ihara Masarou , Saito Teiji , Morsi Kamal Mohamed , Khatem Obaid Saeed , Rabti Mohamed Faraj 
Published: December 2007

Abstract
Many oil and gas fields are being operated under severe conditions with the presence of corrosive gases such as Hydrogen Sulfide (H2S) and Carbon Dioxide (CO2). To mitigate the negative impact on operation, CRAs (Corrosion Resistant Alloys) are commonly used and getting more and more popularity. However, the selection of an appropriate CRA for a given corrosive environment requires much engineering effort, particularly for high temperature gas wells with high concentration of H2S and CO2.
In this research program, the corrosion resistance of many types of CRAs (13Cr, super 13Cr, Duplex stainless, Ni base alloy), carbon steel (L80) and low alloy (SM90SS) was evaluated in an actual gas well stream in UAE by using a Dynamic Field Tester (DFT). The DFT can permit an optimum selection of materials for tubing strings and flow-lines for use in corrosive environments. Also, concerning to these candidate materials, 4 point bent beam tests were carried out in the laboratory at elevated temperatures in 25% NaCl test solutions which were saturated with the produced gas that had been sampled from the well to evaluate the resistance of the materials to stress corrosion cracking (SCC) and general and localized corrosion.
Long-term DFT tests showed that the corrosion rate of carbon steel and low alloy steel was measured to be less than 3.1MPY and those of CRAs were less than 1MPY. Namely, all the tested materials showed lower corrosion rate than the popular criterions of an acceptable corrosion rate that are 4MPY for carbon and low alloy steel and 2MPY for CRAs. Long term laboratories tests in wet H2S environment showed that carbon steel and low alloy steel suffered from corrosion severely and corroded out partly. These tests also showed that only super 13Cr steel suffered from SCC and the other materials did not suffer SCC.
Our phase behavior study on the produced water and condensate suggested that even carbon and low alloy steels would hardly corrode when the metal surfaces were predominantly wetted with oil. However, those steels are considered to corrode severely when the metal surfaces are wetted with water in this particular UAE gas-condensate field. Therefore, there is a possibility that carbon steel is suitable material for the typical gas well in UAE, if an environment is not water wet. However, if an environment is water wet, SM2535 (25%Cr-35%Ni-3%Mo alloy) and higher grade materials are suitable material for the well.
Development of High Speed Inspection System for COS Tank Bottom Plate
Authors: Haga Hiroyuki , Ohta Masahide , Tarmoom Ihab O. 
Published: December 2007

Abstract
One of the major causes of leaks of storage tanks is thickness reduction of bottom plates due to unexpected corrosion of under surfaces of plates. And it is extremely difficult to detect such defects or analyze corrosive trend of the whole bottom plates by other inspection systems. On the other hand, it is asked for curtailment of maintenance expense. Such a background is taken into consideration. We were inquired about the method of grasping the status of the background of tank bottom plates quantitatively with high precision. We have succeeded in development of prototype inspection equipment and system. This development project was supported by Abu Dhabi National Oil Company (ADNOC) and New Energy and Industrial Technology Development Organization (NEDO) in Japan.
Developed inspection system (prototype) consisting of ultrasonic measuring unit having a 120mm of inspection width and data processing unit enables to identify such corroded condition accurately by continuous measurement of whole bottom plates of tanks. Especially, it was aimed at enabling measurement over GRP film (Maximum thickness of 6mm). This system will contribute to dedicated predictive maintenance to ensure safety operation of tanks.
Simulating Carbon Dioxide Sequestration/ECBM Production in Coal Seams: Effects of Coal Properties and Operational Parameters
Authors: Sams W. Neal , Bromhal Grant , Olufemi Olufemi , Sinisha Jikich , Ertekin Turgay , Smith Duane H. 
Published: December 2007

Abstract
Carbon dioxide sequestration is a promising technology for reducing anthropogenic greenhouse gas emissions while fossil fuels are still being used. The costs associated with CO2 sequestration are often high; however, in certain circumstances (e.g., enhanced oil recovery) these costs can be more than offset by the benefits of additional incremental hydrocarbon production. Primary production of coalbed methane is a well-developed technology, but secondary production, through the injection of CO2 or N2 has undergone relatively little study. Recent research suggests that carbon dioxide preferentially sorbs to coal, displacing methane, making CO2-enhanced coalbed methane production an ideal candidate for CO2 sequestration.
We use PSU-COALCOMP, a dual-porosity coalbed methane simulator, to model primary and secondary production of methane from coal, for a variety of coal properties and operational parameters. Our base well pattern consists of four horizontal production wells that form a square, with four smaller horizontal producers/injectors at the square's center. Primary production of methane and water is simulated until a specified reservoir pressure is reached, after which CO2 is injected in the center wells to displace methane, extending the reservoir's production of methane. Production continues until the CO2 concentration in the produced gas is too high. By modifying coal properties, such as permeability, porosity, degree of anisotropy, and sorption rates, we have approximated different types of coals. By varying operational parameters, such as injector length, injection well pressure, time to injection, and production well pressure, we can evaluate different production schemes to determine an optimum for each coal type.
Any optimization requires considering a tradeoff between total methane produced (or CO2 sequestered) and the rate of methane production. Values of aggregate methane production and methane production rate are presented for multiple coal types and different operational designs.
Development of Composite Progressing Cavity Pumps
Authors: Klein Steven T. 
Published: December 2007

Abstract
The newest technological advancement in the Progressing Cavity Pump (PCP) industry has been the development of composite stators and rotors. Included in this design concept is a reversing of the conventional elastomer and hard surface interface. The stator, in this design concept, is made of a hard composite material and is placed in a steel tube jacket. The rotor can be made of steel or composite material and coated with an even thickness of a soft and durable polyurethane. The urethane offers increased wear resistance and mechanical properties over conventional elastomers and the even thickness offers additional performance enhancements. Also, the elastomeric placed on the rotor offers the well-servicing advantages of the wear element being located on the end of the sucker rod string rather than on the end of the tubing string. The composite PCP becomes a low cost, highly durable PCP that incorporates the emerging even thickness elastomer technology.
Drill-String and Casing Design for Horizontal and Extended Reach Wells - Part I
Authors: Cunha J. C. 
Published: December 2007

Abstract
This paper will address some important factors that should be considered when designing drill-strings for horizontal and extended reach wells (ERW). A second paper will look into the issues of casing design for the same type of wells and present some practical field cases and examples of drill-string and casing design for ERW.
Buckling of the string and its influence on reach capability, fatigue and directional control will be emphasized.
Horizontal Water Disposal Well Performance in a High Porosity and Permeability Reservoir
Authors: Harding T. G. , Smith K. H. , Norris B. 
Published: December 2007

Abstract
Nexen Petroleum International Ltd. (Nexen) has a 52 percent interest and is operator of the Masila Block in the Republic of Yemen. Oil and water are produced mainly from the under pressured Qishn Formation, a non-marine to marine clastic sequence of Lower Cretaceous Age, which is roughly 200 feet thick and lies at a depth of 5500 feet from surface. Currently oil production is 230,000 BOPD at a water cut of about 80 percent. The one million barrels of water produced each day are currently reinjected under matrix injection pressures into 24 vertical and 4 horizontal wells. These are completed in the best quality sands (the S2/S3 members of the Upper Qishn Formation) that have average porosity and permeability of 20% and 3700 md, respectively.
Despite the exceptional disposal reservoir quality, injection problems continue to exist that have caused Nexen to study and evaluate numerous methods of improving injectivity. After extensive laboratory core and field testing, hypotheses have been developed to explain the behaviour of the water disposal wells including the so-called ‘check-valve effect’. Horizontal wells and proppant fractured wells were employed to test the hypotheses and to improve injectivity.
This paper reviews the laboratory results and discusses the placement of horizontal injectors along with the drilling and completion details of the wells. The performance of the horizontal disposal wells under matrix injection is compared to conventional vertical disposal wells and proppant fractured vertical wells. Produced water is expected to reach 1.5 MMBWPD and improvements in disposal well performance will reduce the number of wells that will need to be drilled to handle this volume, thereby improving overall project value.
Effect of Scale Dependent Data Correlations in an Integrated History Matching Loop Combining Production Data and 4D Seismic Data
Authors: Aanonsen S. I. , Aavatsmark I. , Barkve T. , Cominelli A. , Gonard R. , Gosselin O. , Kolasinski M. , Reme H. 
Published: December 2007

AbstractThe use of time-lapse data, or 4D seismic, in conjunction with production data in computer aided history matching of reservoir models requires that the various types of data are incorporated in a single objective function measuring the mismatch between the simulated and measured data. In the context of linear maximum likelihood estimation, the contribution of seismic data and production data to the objective function can be balanced on the basis of the sum of the inverse of the data and model error covariance matrices. Methods to estimate these covariance matrices for the combined set of production data and seismic impedance are presented. Generally, the seismic data will be correlated leading to a nondiagonal error covariance matrix. This matrix will also be very large, and efficient methods to invert this matrix are required. This is done using a very fast discrete convolution inverse based on multiplication of block Toeplitz matrices. It is shown that the regression may converge to a wrong solution if incorrect values for the data correlations are used.The presented methodology is applied to an actual history-matching project using data from a North Sea oil field, and a procedure for mapping the time-lapse seismic data and covariance matrix from the seismic grid to the simulation grid is presented. The data seems to contain information about distribution of gas and oil not recovered by history matching to production data only. However, it turned out to be difficult to obtain a good match to the time-lapse seismic data in the regression. It is not clear whether this is due to large uncertainties in the data, incorrect petroelastic model, or incorrect parameterization. This should be investigated in future work.
A New Method for Calculating Well Indexes for Multiple Wellblocks with Arbitrary Rates in Numerical Reservoir Simulation
Authors: Peaceman Donald W. 
Published: December 2007

Abstract
In numerical reservoir simulation, the well index is used to relate the flowing well pressure to the numerical wellblock pressure. The well index is usually calculated from the equivalent wellblock radius. A previous paper presented an exact relationship for the equivalent wellblock radius for multiple wells with arbitrary rates.
In this paper, a new, simpler, and more general, equation is presented for calculating the well index for all nw wellblocks in a reservoir. Arbitrary wellblock flow rates and interactions between wellblocks are fully accounted for. The data required for the new equation may be obtained in a preprocessor by calculating nw single-phase pressure distributions. Then an accurate WI can be calculated for each wellblock at each timestep, even under conditions where well rates vary with time.
Compositional Streamline Simulation of Field Scale Condensate Vaporization by Gas Injection
Authors: Seto C. J. , Jessen K. , Orr F. M. 
Published: December 2007

Abstract
This paper presents an application of compositional streamline simulation in modeling enhanced condensate recovery via gas injection. These processes are inherently compositional and detailed compositional fluid descriptions must be use to represent the flow behavior accurately. Compositional streamline simulation results are compared to those of conventional finite-difference (FD) simulation for evaluation of gas injection schemes in condensate reservoirs.
We present and compare streamline and FD results for two-dimensional (2D) and three-dimensional (3D) examples, to show that the compositional streamline method is a way to obtain efficiently estimates of reasonable accuracy for condensate recovery by gas injection.
A New Formulation for the Implicit Compositional Simulation of Miscible Gas Injection Processes
Authors: Bowen Garf , Crumpton Paul 
Published: December 2007

Abstract
Compositional simulation is an important tool in gas injections studies. Often the aim of a gas injection project is to enhance the sweep efficiency by generating miscible displacement, either by utilizing a first contact or multiple-contact process. The compositional simulator is the only tool available to quantitatively study this behavior in a field setting.
The paper introduces the concept of treating a single-phase hydrocarbon as a separate distinct phase. This has the effect of reducing discretisation non-linearities in single-phase regions and allowing an implicit solution to converge efficiently. A number of small illustrative models will be used to demonstrate the technique, where the effect of varying degrees of implicitness will be reported, these being fully implicit, IMPES and AIM. In several of the example cases the standard implicit solutions are shown to fail entirely. The CPU advantage of the reduced non-linearity will be illustrated using a field scale example solved with an adaptive implicit method.
Streamline Methodology using An Efficient Operator Splitting for Accurate Modelling of Capillarity and Gravity Effects
Authors: Rodriguez Pedro González , Segurat Manuel Kindelan , Morenot Francisco J. Mustieles 
Published: December 2007

Abstract
The flow of hydrocarbons in a reservoir is a very complex process involving the interaction of several fluids and rock. Accurate and fast modelling of this complex flow is crucial to optimize reservoir exploitation.
We have developed a 3D streamline based reservoir simulator for two phase (water and oil) incompressible flow. In this case, the model simplifies to a non-linear elliptic equation for the pressure, coupled to an equation for the evolution of saturation. The streamline method assumes that displacement along any streamline follows a one-dimensional solution, and that there is no communication among streamlines, so that the 3D saturation equation is decomposed into a set of one-dimensional problems. It takes advantage of the fact that the pressure varies slowly compared to saturation and therefore needs to be updated after several steps in the saturation equation.
The decoupling of the pressure equation from the saturation equation speeds up the simulation orders of magnitude with respect to the conventional finite difference method, and this increase in speed is very important in modern reservoir engineering.
The method is best suited to problems dominated by displacement as opposed to gravity and capillarity. However, these effects can be taken into account in the model and we will show how to use operator splitting techniques to this end.
We will describe the main characteristics of the streamline method, analyze different numerical methods to solve the non-linear hyperbolic equation along streamlines, and present numerical results to show the effects of capillarity in the production of the reservoir.