bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design Optimization of Plunger Lift Systems
Authors: Avery D. J. , Evans R. D. 
Published: December 2007

ABSTRACT
A general dynamic plunger lift model is presented which can be used to predict optimum design of a plunger lift system for wells which are producing by any reservoir mechanism. The upstroke and downstroke plunger models are coupled to a generalized inflow performance relationship thereby matching the production capability of the reservoir to the plunger dynamics. By matching reservoir performance and plunger dynamics the optimum slug size and cycle time can be determined which will maximize the liquid production for a given well.
A discussion of the development of the dynamic plunger lift model is presented and performance comparisons are made with other models available in the literature.
Conclusions are stated and potential improvements addressed concerning future work in plunger lift technology.
Computer Modeling and Optimization for Submersible Pump Lifted Wells
Authors: Lee H. K. 
Published: December 2007

SUMMARY
A computer simulation procedure is presented for evaluation and design of an electrical submersible pump (ESP). The System Nodal Analysis technique is also presented for modeling ESP lifted wells. The pump performance can be analyzed using the System Nodal Analysis technique by examining the well production rate versus wellhead back pressure, percentage of water cut and different motor speed as monitored by the Variable Speed Controller. The final goal of the computer simulation is to optimize the well production. Examples will be presented to illustrate the optimization procedure.
Coiled Tubing Non-Rig Workovers at Prudhoe Bay
Authors: Cobb D. O. , Bragg J. A. , Haines J. R. , Putnam J. S. 
Published: December 2007

ABSTRACT
Arctic rig workover operations to perform reservoir control and remedial cement squeezes have been replaced by cost effective, state of the art coiled tubing technology at Prudhoe Bay. This non-rig workover (NRWO) approach is used to reduce high GOR and high watercut production without spotting a kill pill, pulling production tubing or drilling cement. The technique was implemented in the Prudhoe Bay Unit (PBU) Western Operating Area (WOA) during September, 1985, and includes 99 NRWO squeezes completed through December, 1987, by Standard Alaska Production Company (SAPC). This paper reviews the Production Operations and Engineering developments responsible for a successful NRWO program that has aided in extending plateau oil production and deferring decline point.
The Production Operations sections of the paper review field procedures and equipment used to perform low pressure squeeze techniques with low fluid loss cement slurries in an arctic environment. Discussion of field procedures include: cement slurry testing, pre-squeeze acid wash, sump cleanout, pressure control, wellbore liquid packing, Coiled Tubing Unit (CTU) depth control, pumping cement through coiled tubing and contaminating excess cement in the production liner to allow wellbore cleanout without drilling operations.
The Production Engineering sections of the paper review the candidate selection and evaluation process, general design considerations, program benefits and production results of WOA non-rig workover operations. As of year-end 1987, 57 gas shut-off (GSO), 23 water shut-off (WSO), 2 GS0/WS0 combination, 6 profile control, 2 plug & abandon and 9 pre-rig workover squeeze jobs have been completed. Program costs, incremental oil rate, additional recovery and repair longevity are also discussed.
Successful Application of Drilling Technology Extends EMPI’s Directional Capacity
Authors: Schroeter D. R. , Wah C. H. 
Published: December 2007

ABSTRACT
This paper summarizes recent drilling performance on EPM’s Tabu, Palas, and Guntong platforms where a top-drive drilling system, PDC bits, MWD equipment, and low-toxicity oil base mud have been used to drill EPM’s deepest directional wells. These wells are as deep as 3750 meters (measured depth) with hole angles up to 73 degrees. More than two thirds of the wells are dual completions, each with two to three directional targets. The paper describes how this technology was used to overcome the usual problems in wells of this type, especially high torque and stuck pipe.
How Successful Acid-Frac Program Could Require Drastic Changes in Both Drilling and Completion Design
Authors: Despax D. , Bladier C. , Charlez P. 
Published: December 2007

Abstract
This article is based on five years experience in acid fracturing on a Middle East offshore field operated by TOTAL-CFP.
The field in question is a highly stratified formation containing dolomitic reservoirs which are separated by very compact and almost impermeable anhydritic interbeds. [FIG. 1]
The producing layers (A, B, C, D and E) vary in thickness and two of these are of particular interest: «A», which has already been considerably depleted with a fairly high matrix permeability (150 to 200 mD) and «E» only slightly depleted, and with a much lower matrix permeability (25 to 30 mD).
Estimating Rock Properties by Statistical Methods
Authors: Rodriguez E. , Tetzlaff D. M. , Mezzatesta A. , Frost E. 
Published: December 2007

ABSTRACT
A statistical method for estimating rock properties from well logs has been developed and implemented in two computer programs: OPTIMA and OPTIMA-RT. Both programs use the set of available logs to estimate best values and confidence intervals of rock properties.
These programs are based on a non-linear weighted least-squares method, which combines actual measurements, theoretical values, and uncertainties into an objective function whose minimum yields the most probable set of results. The OPTIMA-RT program utilizes resistivity logs from devices having different depths of investigation to estimate diameter of invasion (d { ) and true resistivities of the virgin (R t ) and flushed (R xo ) zones. The OPTIMA package combines different types of log data to estimate porosity, fluid saturations, and mineral volumes.
We have applied the OPTIMA and OPTIMA-RT programs to a well located in the northern North Sea. Acoustic, radioactivity, and resistivity logs covering a depth of about 1000 ft were available for the study. Geologic information from the area indicates the presence of feldspar-bearing sands, silts, clays, mica, and other accessory minerals.
Resistivities calculated with the OPTIMA-RT program are used as input for OPTIMA. In spite of the lithologic complexity, mineral compositions calculated by OPTIMA agree with available geologic data. Variations in the confidence interval of the calculated values emphasize the importance of being able to measure the reliability of the estimation.
Stratigraphie Correlation of Well Logs Using Relational Tree Representation
Authors: Tsay F. S. , Lai P. F. 
Published: December 2007

ABSTRACT
A new method of well log stratigraphie correlation is being described. The method is based on a heuristic waveform correlation scheme uisng relational tree data structure. The relational tree is used to provide a complete description of the contexture relationaships of the waveforms and a distance measuring process incorporated with a cross-over and multiple- links elimination procedure is impletmented to optimize the waveform correlation. Results have shown that the method is capable of handling the thickening, thinning and the missing strata which normally occur in stratigraphie correlation using well log data.
The Effects of Vertical Fractures on Areal Sweep Efficiency in Adverse Mobility Ratio Floods
Authors: Bargas C. L. , Yanosik J. L. 
Published: December 2007

ABSTRACT
The industry has recognized for many years that the creation of hydraulic fractures is an excellent means of improving well productivity and injectivity. These induced fractures, however, can have a significant impact on sweep efficiency. This paper presents the results of a simulation study using a finite element model to determine the effects of hydraulic fractures on the areal sweep efficiency of contact miscible displacements in five-spot and line-drive patterns. The influence of fracture orientation, length, and conductivity for mobility ratios ranging from one to ten is reported for patterns where either the producer or injector, or both the producer and injector are fracture stimulated.
For favorably oriented fractures, the relative amount of improvement in areal sweep efficiency increases as the mobility ratio increases. Long highly conductive fractures at both the injector and producer are required to improve sweep for a five-spot pattern. Areal sweep in a line-drive pattern is more sensitive to fractures and can be improved by stimulating either or both wells. The greatest improvement occurs when both the injector and producer are fractured, while the smallest improvement occurs when only the producer is stimulated. Low conductivity fractures should be avoided because they can severely restrict the sweep improvement resulting from favorably oriented fractures.
Care must be taken to ensure that fractures are oriented in a favorable direction, however, because a significant reduction in areal sweep efficiency occurs if the fractures are oriented in an unfavorable direction. Since fracture orientation is not always known or cannot always be controlled, this study also identifies which length fractures prevent detrimental effects to sweep for unit and adverse mobility ratio floods with unknown fracture orientation.
Knowledge-Based Well Data Management and Graphical Interface
Authors: Citerne A. , Yu K. 
Published: December 2007

ABSTRACT
Well log data including information about the wells from which the data was acquired, the tools by which the data was obtained, and the operations that were performed on this data, are best represented taxonomically by objects in a knowledge base for property inheritance. However, there are important non-taxonomical links between those objects. To be applicable, information must be presented and used according to different classification principles (philogenetic, phenetic, and teleologic).
The Graphic Log Data Manager (GLDM) is a graphical application that is designed to display these objects in a phylogenetic tree on a log analyst’s terminal. This tree can be adjusted (purged, annexed, etc.) to focus on only those data objects that a user wishes to examine. Furthermore, the GLDM uses different (but generic) trees, menus, tables, piano charts, curves, and the like to allow a log analyst to browse and edit the well data knowledge base and view, the log data in a desired structure during computer log analysis. Data access in the GLDM combines a frame-based, object-oriented facility and a declarative, adaptable non-taxonomical scheme. The purpose of the GLDM is, ultimately, to provide any log interpretation program with a visually flexible and adaptable data environment for log analysis.
The implementation of the GLDM depends not only on a comprehensive understanding of well log data, but also on a sophisticated information layout scheme and a comprehensive set of human interface tools.
It turns out that the artificial intelligence workstation programming environment and frame-based knowledge representation are appropriate and powerful vehicles to accomplish this.
Water-Base Mud System Having Most of the Advantages of Any Oil-Base System Plus Ecological Advantages
Authors: Carney L. L. , Güven N. , Panfil D. S. 
Published: December 2007

ABSTRACT
A medium pH range water base mud system designed as a result of high temperature high pressure studies on various clays and polymers has been laboratory developed and field tested. This type of system has proven to have advantages over water base mud systems previously used.
After detailed laboratory studies of attapulgite, bentonite, sepiolite and saponite clays in conjunction with polymers and various salts, a system using a mixture of saponite/sepiolite for the primary viscosifier has been developed.
The rheology of most clay slurries can be controlled by high molecular weight and low molecular weight temperature stable polymers. Potassium salts such as potassium bicarbonate and potassium carbonate are used instead of the sodium salts to control the alkalinity and chemical base exchange of clays. Potassium salts of the polymers are also used instead of sodium salts in order to maximize the potassium availability and minimize the sodium content.
These systems can be used in almost any type of make-up water and can be increased in density for control of high pressure-high temperature environments. They have been used for drilling in both shallow and deep wells, including wells of total depths below 17,000 ft. In addition to small diameter holes; these systems also show excellent hole cleaning ability and borehole stability in large diameter holes drilled for mine shafts.
These systems have temperature stability above the 500°F (254°C) range and with correctly chosen chemicals, show inhibition to water sensitive clays when run at intermediate pH range. They are easy to test and maintain and can result in faster drilling rates, improve hole cleaning, better cement jobs and minimal formation damage; and, add a more economical approach to drilling fluids. In addition, the environmental aspect is extremely appealing.
A Single Technique Solves Gas Migration Problems Across a Wide Range of Conditions
Authors: Drecq P. , Parcevaux P. A. 
Published: December 2007

ABSTRACT
The problem of annular gas migration following primary cementing is analyzed, and the main mechanisms responsible for its occurence within the cement matrix or at the cement to formation interface are described.
The emphasis is put on a special technique that has proved, through extensive field usage, to solve the problem in widely varying conditions, such as shallow gas from weak zones, very high pressure formations, interlayered gas and water sensitive zones. Such conditions involve slurry density from 10 to 22 lbm/gal, downhole temperature from 10 to 180° C, and mix water from fresh to 18% NaCl.
This technique is based first on the proper displacement of the drilling mud through good cementing practices, and then on the placement in the annulus of a well dispersed, non gelling, impermeable cement. The key of this system is a latex additive, that, through its film forming property, locks the cement permeability to gas when the gas attempts to permeate under a differential pressure.
For such a system to perform optimally, cement pore pressure drop is delayed as much as possible, through the use of proper dispersants that inhibit premature cement gelation. Then the transition time between the liquid and the set state is shortened by chemical stabilizers of the latex. Finally, cement permeability to gas is controlled during cement thickening and setting, and cement to pipe and to formation bonds stay durable for the whole life of the well, and this is achieved through the latex itself.
Field applications of this system are presented through several case histories illustrating typified normal and extreme situations.
Preparation of Two Polymer Pilot Tests in Daqing Oil Field
Authors: Chauveteau G. , Combe J. , Dong Han 
Published: December 2007

ABSTRACT
Information relative to the preparation of two polymer flood pilots in the West Central Saertu area of the giant Daqing oil field in China is presented.
The reservoir features of the West Central area of the field contribute to suggest polymer injection as an attractive process. Numerical simulations as well as economical calculations based on anticipated optimum operational conditions have confirmed this interest.
The primary scope of the reported laboratory study is the use of a new methodology for selecting the most appropriate polymer chemical structure. Three main selection criteria, namely maximum intrinsic viscosity, minimum adsorption and absence of attractive polymer-polymer interactions were considered and a Polyacrylamide containing 20% of acrylate group was chosen. This polymer was found to show high effective viscosity and low retention in core flows. A xanthan sample also suitable according to these technical criteria was not considered due to economical reasons.
The two pilot tests are being designed on these bases. The first one aims at checking the ability of polymers to reduce vertical channeling within a single layer. The second will evaluate the improvement of vertical sweep efficiency when two separate layers open in wells with single completions are subjected simultaneously to polymer injection. The well layout of each pilot and the type of information expected from the observation wells are described.
Field Experience with the GRI Rheology Unit
Authors: Ely J. W. , Haskett S. E. , Holditch S. A. 
Published: December 2007

Abstract
During the past five years, the Gas Research Institute has developed a comprehensive fracture fluid evaluation laboratory that is portable and is used in the field to monitor actual fracture fluid systems. Although many components of the GRI Rheology Unit are available elsewhere, no other organization offers a system that can be used in the field to fully characterize a fracture fluid before and during an actual fracture treatment.
One of the objectives of the GRI research effort is to run 3-D fracture models in real time to improve our understanding and control of hydraulic fracture treatments. The 3-D fracture models are used to history match the values of excess pressure vs. time in order to determine fracture size and shape. We have found that unless one can fully characterize the fracture fluid viscosity vs. time, temperature and shear rate, then the fracture shape computed using a 3-D fracture model will be non-unique.
To more fully explain this concept, one must understand the mechanisms that affect the excess pressure in a fracture during the treatment. The excess pressure is dominated by friction pressure as the fluid flows down the fracture. The friction pressure is affected by both the viscous properties of the gel and the shape of the fracture. We can only determine the shape if we know the viscous properties of the gel beforehand. Therefore, to improve our use of 3-D models in this research, we have determined that we must go to the field and accurately measure the viscous properties of the fracture fluid.
In the early stages of the program, most of our efforts involved surface quality control and real time monitoring of fluid parameters during the pumping operation. Although the importance of quality control and pre- and post-job materials inventory cannot be overemphasized, we have found that a more intense effort is required to quantify the viscous properties of the actual fluid on site.
Acoustic Emission Interpretation for Estimating Hydraulic Fracture Extent
Authors: Sarda J-P. , Perreau P. J. , Deflandre J-P. 
Published: December 2007

Abstract
It is useful to map hydraulic fractures in order to improve the rate of success of such operations and to optimize the pattern of stimulated wells. The proposed method can be used during a minifracturing or prefracturing operation and necessitates a downhole 3D acoustic detector clamped in the well. A few to a few dozen cubic meters of gel being injected during fracturing phases, the acoustic activity is recorded after every injection, then signals containing apparent P and S waves are analyzed to determine the directions and distances of the emitting sources. A number of arrivals cannot be easily interpreted, in particular those corresponding to refractions along the casing. Two field examples corresponding to a vertical and an inclined fracture are given. Knowing the P and S wave velocities in the different layers and a careful choice of the tool position are essential to the success of the method.
Improved Rock Property Measurements Using Core from the Travis Peak Formation
Authors: Narahara G. M. , Holditch S. A. 
Published: December 2007

ABSTRACT
The advancement of technology in producing tight gas sands requires rock property measurements involving the flow of fluids in cores. The purpose of this paper is to present measurements of absolute permeability, total porosity, capillary pressure, and gas relative permeability on several Travis Peak cores. Even though such measurements are difficult to obtain, the resulting values are needed to accurately model gas flow in such reservoirs.
A transient test method developed in the early portions of this research has been used to measure absolute permeability and total porosity as a function of net stress. The net stress on the cores was increased to simulate the depletion of the reservoir pressure, and the results can be used to observe the effect of formation compressibility on permeability and porosity.
A study of gas slippage was performed using the transient test method. Several parameters, including gas molecular weight, net stress, and flow rate, were varied to determine their relationship with gas slippage. It was found that gas slippage can be affected by the slot-pore geometry found in highly cemented, low permeability formations.
Since water is pumped into low permeability formations during stimulation treatments, two-phase rock property measurements are important if one wishes to model the effects of the water upon gas recovery. The measurement of capillary pressure and gas relative permeability have been investigated in this study.
The ultracentrifuge presents a practical method for determining capillary pressures in low permeability cores. Several cores were run and the capillary pressure data are presented. Saturation equilibrium was determined by monitoring each centrifuge speed over a 24 hour period. An analysis of the continuity of the displaced phase has also been performed.
A new method recently developed in this research has been used to measure the gas relative permeability and water saturation simultaneously. The new method presents a rapid means of generating the entire gas relative permeability curve. The results from two Travis Peak cores are presented.
In summary the results of these measurements on absolute permeability, total porosity, capillary pressure, and relative permeability present a description of the rock properties for studying fluid flow in a typical tight gas formation. The system of measurements can be performed on any low permeability core on a routine bases.
The Impact of System Capacitance on Gas Pipeline Facility Design
Authors: Richwine T. E. , Schroeder D. W. 
Published: December 2007

ABSTRACT
In the design of natural gas transmission facilities it is important to consider the time-varying nature of most gas demands. Steady-state analysis may or may not be adequate depending on both the characteristics of the demands and the transportation system. This paper attempts to point out the factors that are of importance as system loads change and quantify them where possible. Criteria for determining the appropriate analysis techniques are discussed along with an example of the relative impact of adding in-line compression versus additional pipeline.