bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying High-Impact Parameters in Stimulation Treatments Using a Trend Empirical Analysis Model
Authors: Grieser Bill , Stark John 
Published: December 2007

Abstract
In an effort to develop best practices for stimulation of a particular zone in a certain area, the completion engineer usually is faced with a number of choices. Ideally, experience will have shown, through production results, a preferred treatment type. However, most of the time the engineer finds conflicting results and uncertain outcomes which make choosing the proper stimulation method difficult.
This difficulty is partly due to the heterogeneity of the reservoir, reservoir-quality differences, and the seemingly infinite number of treatment techniques, sizes, and additives used.
The completion engineer must be able to recognize factors he can control, factors he cannot control, and impacts these factors have on production.
This paper tracks the completion development of 28 wells in the Frontier zone, Fontenelle field, WY. in 1996 and 1997 Descriptions of the different methodologies used and corresponding 90-day cumulative-production results are given.
A data set was created in a spreadsheet format listing pertinent data including porosity-ft, job size, total amount of proppant pumped, gel-system type, breaker amounts, type of breaker, and pH, along with ratio quantities (Ib/gal) for gel, breaker, and proppant.
This data set and production values were used as input information for a trend empirical analysis model (TEAM) to determine what factors, or combination of factors, most affected production results. There was surprise over the identification of some high-impact parameters (HIPs) by the model.
The end result is an analysis tool that helps completion engineers recognize HIPs and the magnitudes of their effects on production.
P. 581
Gas and Gas Lift Wells' Testing With Surface Shut-in
Authors: Al-Haddad S. , Fruge Mike , Frizzell D. 
Published: December 2007

Abstract
The main source for formation damage measurement is transient well testing. The formation damage measured is referred to as the skin factor. To reduce cost and operational risk, many wells are tested with surface shut-in and bottomhole pressure measurement. If properly designed, performed, and interpreted, these tests provide valuable information on the well's skin condition.
Wellbore storage becomes a very important factor with a surface shut-in. In addition to the wellbore fluids' compression and phase changes, temperature effects may be significant and extended depending on many factors including the well's depth. However, field data has shown that available analytical models do not accurately predict wellbore storage duration and pressure behavior. Moreover, extended wellbore storage pressure data may appear to behave in a way similar to radial flow as seen on the pressure derivative curve. This misinterpretation usually results in a negative skin and the creation of nearby boundaries (i.e. which results in smaller reservoirs) making high potential wells appear to be limited.
This paper will present empirical and practical field solutions to this problem. Well test, stimulation, and production field data supported by computer simulations from oil and gas wells in the Gulf of Mexico area will be presented. The data presented in this paper will demonstrate how the test design and interpretation will effect the overall reservoir and well management of the field.
P. 119
Prediction of Hysteresis Performance of Storage Reservoirs
Authors: Tek M.R. , Fegley E. , Mantia R.W. 
Published: December 2007

Abstract
Based on equations describing pressure-content performance of gas reservoirs subject to water drive, the paper presents a solution developed for prediction of hysteresis performance of storage fields. The method validated using field data form several storage reservoirs has been developed into a storage performance simulator with a number of applications of interest to the storage industry. Prognostic reservoir studies for detecting loss of storage gas due to migration or wellbore seepage, calculation of cumulative loss as a function of time, cycling of aquifers, and recoverability of cushion gas are among the applications presented.
P. 247
History Matching for Lauchstaedt Underground Gas Storage
Authors: Zakirov I. , Asti A. , Zakirov E. , Schweng K. 
Published: December 2007

Abstract
Underground gas storage Lauchstaedt (East Germany) is represented by fractured reservoir. For adequate representation of considered deposit, an idea of two-layered reservoir has been chosen. One layer was responsible for the system of fractures, whereas another one corresponded to matrix blocks description. For this storage an automatic history matching procedure has been implemented that was based upon optimal control theory approach. Objective function to be minimized included the sum of least square mismatches of observed and calculated well's reservoir pressures. A conjugate gradient method was implemented to minimize given objective function. Applied history matching algorithm implied solution of forward and adjoint boundary value problems. A set of control parameters contained porosity and permeability of fractures and matrix blocks.
The problem of reservoir petrophysical properties estimation was investigated in 3D statement. Developed history matching algorithm turned out to be very efficient. A very good fit of observed and calculated well's grid block pressures has been reached after 8 iterations of gradient search procedure, nevertheless 10 control parameters were introduced. The most sensitive parameter happened to be porosity. It resulted in initial gas in place overestimation by 15% comparing with registered one.
It was also obtained a good match of observed and calculated pressures after manual history matching procedure for reservoir described as dual porosity layer. Only two matching parameters have been introduced in this case, namely
P. 263
Determination of the Drilling Cost and Well Maintenance System in Perforacion y Mantenimiento de Pozos PPMP
Authors: Zamora Carlos Rasso , Romero Salvador Najera 
Published: December 2007

Abstract
PETROLEOS MEXICANOS and specifically PEMEX EXPLORACION y PRODUCCION has restructured the former regions around the oil fields called "assets", and this sector has focused on units of businesses, and the area of Drilling and Well Maintenance became a state-owned company which gives those services by changing its traditional technical focus to one emphasizing the technical-financial evaluation of its operations.
The present work describes the efforts to have a "Drilling Cost and Well Maintenance System", which allows transparence in the financial evaluation of the operations of the new state-owned company. The former institutional systems of PEMEX EXPLORACION y PRODUCCION used to total the information. The above way made the availability of its own financial statements difficult for the new organization to realize.
The definition of the financial structure of a new organization needs the setting of the methodology, inscriptions and the necessary concepts so that information can be reliable, useful and timely. One of these elements is the risk analysis, which has become an integral part of the decision maker in the oil industry as to know the economical feasibility of the projects. Therefore, the model of risk analysis used is shown in this work, including the "Monte Carlo" simulation with data of regional costs of the Operative Northeast Unit, statistical methods, analytic models, optimization, decision trees, sensitivity analysis and influence diagrams so that costs and required times for drilling a well can be forecast.
In a word, it has been possible to establish the "Drilling Cost and Well Maintenance System of PPMP" as a primary support of the financial structure of the new state-owned company. This will help PPMP to obtain its own financial statements and, of course, its physical-financial evaluation.
P. 453
Air Injection Technique (LTO Process) for IOR from Light Oil Reservoirs: Oxidation
Authors: Greaves M. , Ren S.R. , Rathbone R.R. 
Published: December 2007

Abstract
The feasibility of air injection into deep light oil reservoirs in the North Sea and elsewhere has been investigated. The low temperature oxidation (LTO) process removes oxygen in the injected air, to produce displacement gas (mainly nitrogen) in the reservoir in order to achieve incremental IOR. Reaction and displacement studies on four light oils have been carried out at reservoir conditions. This has involved the high pressure oxidation tube facility at Bath University as well as a small high pressure isothermal reactor.
This paper presents preliminary results on the reactivity of the oils studied in terms of oxygen consumption rate at reservoir temperature, and the oil recovery under low rate air injection.
P. 479
Effect of Coiled Tubing Initial Configuration on Buckling Behavior in a Hole of Constant Curvature
Authors: Weiyoung Qiu , Miska Stefan , Volk Leonard 
Published: December 2007

Abstract
In practical coiled tubing drilling and completion operations minor curvature always exists in coiled tubing (CT). The authors previously published that CT initial configuration results in the momentous reduction of the axial compression force required to produce helical configuration in a deviated well. In this paper the authors emphasize the effect of CT initial configuration on buckling/bending behavior in a hole of constant curvature. By utilizing the conservation of energy and the principle of virtual work, new equations are derived to predict the maximum permissible axial compression force to maintain a stable sinusoidal configuration and the axial compression force required to produce a helical configuration in a hole of constant curvature. These new equations reduce to those previously published when CT is not initially buckled. Practical examples are granted to demonstrate the effect of the initial amplitude on both sinusoidal and helical buckling behavior of CT in curved wells. The results indicate that the radius of curvature of a borehole is a governing parameter to influence CT buckling/bending behavior in a curved well. The effect of CT initial configuration on sinusoidal configuration can be neglected, whereas the effect of CT initial configuration on helical configuration is substantial. The results will help field engineer to understand CT buckling behaviors better, and consequently, to select proper CT to avoid the occurrence of lockup and to improve the prediction of the axial force transmission in horizontal and extended reach drilling. All equations manifested here can also be employed to conventional rotary drilling, slime hole drilling and tubular design.
P. 51
Electric Coiled Tubing Drilling - The First Steps Toward a Smart CT Drilling System
Authors: Head P.F. , Hanson T.J. , Yuratich M. , Turner D.R. 
Published: December 2007

Abstract
This paper describes a joint industry project to develop an electrically powered bottom hole assembly for use in coiled tubing drilling (CTD) applications.
Phase I of the project, recently completed in Aberdeen, produced a highly successful prototype assembly that recorded over 190 hours of drilling time without failure. Whilst the prototype was made almost entirely from existing technology, the success of the test has generated confidence to develop a more fit for purpose' motor.
A system overview explains the concept behind, and the advantages of, electric coiled tubing drilling (ECTD). The bottom hole assembly is described in detail, along with various surface components and the electrical power transmission system.
The testing program and operational procedures are outlined, together with some of the key results. The development plan for the technology is reviewed to highlight the ultimate goal of producing a smart' drilling system. It is envisaged that, based upon feedback from near-bit sensors, such a system would be able to automatically adjust certain parameters to optimize drilling performance.
The paper concludes that electric coiled tubing is a feasible and practical alternative to conventional CTD, although there are certain technological barriers that must be overcome.
P. 61
Development Update of an MWD Directional Drilling Package for 2-3/4" Openhole: Tiny Tools
Authors: Blount C.G. , Gantt L.L. , Hearn D.D. , Mooney M.B. , Smith B.E. , Quinn D. , Larson E.B. 
Published: December 2007

Abstract
This paper documents the development and first applications of ultra-slim diameter mud-pulse-telemetry directional drilling tools for applications through 3-1/2" production tubing.
The highly successful Coiled Tubing Drilling (CTD) program at Prudhoe Bay has concentrated on equipment required to re-enter 4-1/2" and larger tubing' sizes. Typical CTD re-entry operations have sidetracked existing wells at a cost 25% to 75% of past conventional rotary operations. However, there are a significant number of wells at Prudhoc Bay, other North Slope fields, and worldwide that have been completed using 3-1/2" tubing. The development of smaller diameter directional tools allow through-tubing CTD re-entry techniques to be extended to a dramatically larger number of existing wells and also allows options for zonal isolation using small ID intermediate strings in larger tubing sizes.
Purpose built equipment needed to allow directional drilling through typical 3-1/2" tubulars has now been developed and utilized to drill the world's first directionally steered 2.75" bore holes at Prudhoe Bay. This newly developed equipment was used with CT to directionally extend the horizontal section below existing- 3 1/2" tubing strings. Economics of the first 6 wells would indicate a level of performance and cost effectiveness consistent with the larger CTD equipment.
This paper details the design criteria and covers the operational implementation of the 2-3/8" OD directional drilling assembly, referred to as "Tiny Tools" by those developing the technology. Window milling and bicenter bit performance and results will also be discussed. The problems and solutions of tool development, along with the execution of the first CTD jobs through 3" tubulars are also addressed.
P. 79
CT ESP for Yme, Converting the Yme Field Offshore Norway from a Conventional Rig-Operated Field to CT-Operated for Workover and Drilling Applications
Authors: Baklid Allan , Apeland Odd Johan , Teigen Alv Sigve 
Published: December 2007

Abstract
Conventional tubing deployed ESP was initially chosen as the artificial lift method for the Yme field offshore Norway. Two years of operational experience proved that the method chosen did not meet the original design criteria with regards to preventing fluid loss to the formation during workovers and access to the reservoir with wireline/coiled tubing. In addition, the average ESP lifetime was initially well below the target runlife.
The current ESP-completion design is described. Main operational problems experienced during two years of operation is highlighted. The revised field requirements and a re-evaluation of artificial lift methods proved the need for a change in completion philosophy. Coiled Tubing Deployed ESPs (CT-ESP) utilizing an internally installed power cable became the preferred method.
The value of installing CT-ESP in a live well is discussed. System design for true underbalanced CT-ESP installation is described. Well control and barrier philosophy during installation, production and workover mode is also assessed.
Coiled Tubing Velocity Strings - Expanding the Cases
Authors: Martinez Alec , Martinez John 
Published: December 2007

Abstract
Coiled tubing is a preferred remedial method of extending the flowing life for gas wells. but selection of a size that will accomplish the task of removing bottomhole liquids is not simple. The difficult, in predicting results that guide coiled tubing selectivity is partly caused by the changing gas to liquid flow rates in the wellbore as the accumulated liquid discharges. This paper provides a guide to the prediction making process, with emphasis on the modeling methods which are needed.
The variables that serve as indicators of the viability of each tubing size are velocity and liquid holdup. The values that should be used for criteria were reviewed in SPE 30197, Modeling Coiled Tubing Velocity Strings for Gas Wells. Those criteria are used with the prediction procedure to expand the selection process to cover a wider range of coiled tubing sizes and gas-liquid flow rates.
P. 111
The Benefits of Real-Time Coiled Tubing Diameter Measurements
Authors: Quigley M.S. , Stone L.R. 
Published: December 2007

Abstract
Coiled tubing (CT) becomes oval during normal use due to plastic bending on the reel. This ovality significantly decreases the collapse resistance of the CT, and, in extreme cases, can restrict the passage of the CT through the surface equipment. During pumping operations, the internal pressure can cause the CT to balloon as it plastically deforms on the reel and guide arch. The increase in the CT diameter causes a corresponding decrease in the wall thickness. Both effects substantially weaken the CT's collapse resistance and decrease its working life. Some CT software can estimate the ballooning and its effects on collapse and working life. However, no models exist for predicting the ever-changing ovality of CT.
A newly-developed tool can automatically measure the diameter and ovality of the tubing during actual CT operations. This real-time information is available to the CT operator for monitoring the status of the tubing and determining its suitability for continued use. Communications ports in the electronics module can feed the diameter data to a computer or data acquisition system for permanent storage or input to other monitoring software.
P. 171
Lossy Transmission Line Model of Hydrofractured Well Dynamics
Authors: Patzek Tadeusz W. , De Asoke 
Published: December 2007

Abstract
The real-time detection of hydrofracture growth is crucial to the successful operation of water, CO2 or steam injection wells in low-permeability reservoirs and to the prevention of subsidence and well failure. In this paper, we describe propagation of very low frequency (1-10 to 100 Hz) Stoneley waves in a fluid-filled wellbore and their interactions with the fundamental wave mode in a vertical hydrofracture. We demonstrate that Stoneley-wave loses energy to the fracture and that energy transfer from the wellbore to the fracture opening is most efficient in soft rocks. We conclude that placing the wave source and receivers beneath the injection packer provides the most efficient means of hydrofracture monitoring. We then present the lossy transmission line model of wellbore and fracture for the detection and characterization of fracture state and volume. We show that this model captures the wellbore and fracture geometry, the physical properties of injected fluid and the wellbore-fracture system dynamics. The model is then compared with experimentally measured well responses. The simulated responses are in good agreement with published experimental data from several water injection wells with depths ranging from 1000 ft to 9000 ft. Hence, we conclude that the transmission line model of water injectors adequately captures wellbore and fracture dynamics. Using an extensive data set for the South Belridge Diatomite waterfloods, we demonstrate that even for very shallow wells the fracture size and state can be adequately recognized at wellhead. Finally, we simulate the effects of hydrofracture extension on the transient response to a pulse signal generated at wellhead. We show that hydrofracture extensions can indeed be detected by monitoring the wellhead pressure at sufficiently low frequencies.
Evaluation of Geochemical Approaches to Heavy Oil Viscosity Mapping in San Joaquin Valley, California
Authors: Henshaw P.C. , Carlson R.M.K. , Pena M.M. , Boduszynski M.M. , Rechsteiner C.E. , Shafizadeh A.S.G. 
Published: December 2007

Abstract
Areal and vertical distributions of petroleum viscosities within heavy oil reservoirs are important in designing well completions, optimizing field development and planning thermal and other recovery operations. Viscosities of oils in closely-spaced reservoir zones in heavy oil fields can vary substantially. Unfortunately, oil samples are often unavailable or too small for conventional laboratory viscosity measurements. In such cases, correlations between heavy oil viscosity and geochemical, chemical and physical parameters can be valuable for estimating working viscosities. Various geochemical-viscosity correlations were evaluated using a suite of heavy crude oils (API gravities &lt; 150) from fields in the San Joaquin Valley, California. Whole, dewatered, crude oils where studied. Kinematic viscosities were measured at multiple temperatures. Elemental, organic acid, pour point and gravity analyses were completed, followed by compound class separations and gas chromatographic analyses. Statistical methods were used to assess correlations of various parameters with viscosity. Results were compared with correlations reported in the literature and evaluated in terms of linkage to models of field-wide degradation processes believed to account for formation of the heavy oils, with the goal of assessing these predictive models for viscosity variations with applications to viscosity mapping.
A Study of Steam-Water Relative Permeability
Authors: Satik Cengiz 
Published: December 2007

Abstract
In this paper we report on experimental efforts to measure accurate steam-water relative permeability functions under steady-state and non-adiabatic conditions. We conducted a steady-state flow experiment in which a mixture of superheated steam and liquid hot water was injected at varying fractions into a Berea sandstone core sample and steam-water relative permeability was calculated. These experimental results show that the relative permeabilities for both steam and water phases in porous media vary with saturation in a curvilinear fashion. The saturations in this experiment were measured by using an X-ray computer tomography scanner. Pressure gradients were obtained from accurate measurements over regions with flat saturation profiles. These two issues constitute a major improvement in the experimental method compared to those used in the past. Numerical simulations were also carried out for the simultaneous injection of steam and water into a core by using STARS simulator. At steady- state conditions, the effects of steam quality, total injection rate and the type of relative permeability curve on saturation profiles were investigated. To extend the results to general steam-water flows in porous media, similar experiments will be conducted at higher temperatures and with rock samples having different permeability and wettability characteristics.
Foam Cementing Cyclic-Steam, Producing Wells: Cymric Field Case Study
Authors: Miller Larry S. , Frank William E. 
Published: December 2007

Abstract
Primary cementing of production casing for cyclic-steam wells in shallow, weak formations presents several challenges. This paper discusses the application and optimization of foamed cement that was done to solve the primary cementing problems in an ongoing developmental drilling project in a portion of the Cymric field in California's San Joaquin Valley. Improvements in cement placement and reductions in well damage from operational stresses are shown.