bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Rock Types With Mixed Wettability Using Log and Core Data – DOE Project Welch Field, Dawson County, Texas
Authors: Hinterlong G. D. , Taylor A. R. 
Published: December 2007

Abstract
In conjunction with the DOE Project (DE-FC22-93BC14990), the characterization of a portion of the Permian age San Andres formation under Welch Field, Dawson County, Texas was initiated. The objective of the characterization is the construction of a geologic model for the numerical simulation of a C02 flood of the reservoir. A detailed reservoir description is required because the high costs to inject and recycle C02 dictates a very efficient flood design. Identification of reservoir barriers, flow units, and prediction of continuity present the greatest challenge to the description. The productive portion of the formation is mineralogically simple, consisting of dolomite and anhydrite with very minor amounts of chert and illitic clay. Deposition occurred in a very flat shallow shelf setting ranging from supra tidal to subtidal. Depositional textures are variable ranging from fenestral mudstones to oolitic grainstones, with wackestones and packstones dominating. Diagenesis of these shallow shelf deposits has created a highly complex pore system which at times crosses depositional facies boundaries. Rock fluid interaction further complicated the descriptive process by affecting the log responses.
Porosity-permeability cross plots exhibited good correlation for a carbonate reservoir but were too coarse for simulation purposes. Special core analysis tests of capillary pressure and relative permeability provided the key for identifying the intervals of differing wettability and pore structure. A methodology has been developed to identify the varying pore systems and differing wettabilities, using multiple logs from a routine logging suite and special core analysis. The input from multiple log measurements provides a better estimation of the formation absolute permeability than by using a single porosity-permeability relation. These reservoir parameters could then be extrapolated to uncored wells, using the sequence stratigraphy framework, to build the 3-D model of the reservoir.
Pressure Transient Data Acquisition and Analysis Using Real Time Electromagnetic Telemetry
Authors: Doublet L. E. , Nevans J. W. , Fisher M. K. , Heine R. L. , Blasingame T. A. 
Published: December 2007

ABSTRACT
This paper presents the operational procedures and the results for two pressure buildup tests performed using a wireless telemetry acquisition system (TAS) tool at the North Robertson (Clearfork) Unit (NRU) in Gaines, Co. Tx. Using a single pressure gauge system downhole, we obtained real-time telemetry of pressure and temperature data at the surface, as well as a larger sampling of data that were stored in the downhole memory system.
This new wireless telemetry acquisition system was developed to provide real-time pressure and temperature data at the surface by using an electromagnetic signal to transmit these data through the formation strata. The tool is fully programmable so that a wide range of sampling frequencies can be used. The system allows pressure and temperature data to be stored downhole (as in the case of a typical "memory" gauge), or these data can be transmitted to surface data acquisition systems. This provides real-time pressure and temperature data for pressure transient tests, stimulation monitoring, and long-term reservoir surveillance.
Our objective is to demonstrate the use of this technology for pressure buildup tests in low permeability reservoirs. Our goal in utilizing this technology is to reduce the shut-in time requirements for pressure transient tcsts-which will ultimately result in a more cost-effective reservoir surveillance program as wells can be returned to production (or injection) as quickly as possible.
Once the pressure data were acquired, we performed conventional semilog and log-log analysis, and we simulated test profiles to verify the analyses of the test data. Both surface and downhole pressure data were compared for consistency, and both types of data were analyzed in exactly the same fashion. The results of these analyses were essentially identical. This approach gave consistent estimates of reservoir pressure, permeability, skin factor, and fracture half-length for both of our case histories.
How Can Selective Mobility Reduction of CO2-Foam Assist in Reservoir Floods?
Authors: Tsau Jyun-Syung , Heller John P. 
Published: December 2007

Abstract
C02-foam has been long realized as an effective mobility reducing agent for C02 flooding in oil recovery process. Recent researches indicate that some C02-foams also show an exciting additional characteristic, selective mobility reduction (SMR), in which the mobility of foam is reduced by a greater fraction in high than in low permeability cores in laboratory experiments. Examples of such an unusual property are presented first in this paper to show the mobility dependence of C02-foams on the rock permeabilities ranging from 30 to 900 md. Secondly, a simple modeling procedure is introduced to evaluate the benefits of using an SMR displacing agent in a typical oil recovery process. In this model, the mobility of the displacing fluid is considered to be proportional to the permeabilities raised to a specific exponent. This allows us, for different values of exponent from zero to one, to examine how different degrees of SMR will affect the oil recovery. The modeling results show that, as expected, the breakthrough time of the faster (higher permeability) layer is delayed and the vertical sweep efficiency of the model is improved if the mobility of the injected fluid is reduced. Furthermore, this improvement becomes even more significant when an SMR fluid is used for the displacement. Even a slightly favorable SMR fluid, that shows a slight dependence of mobility on rock permeability, can significantly reduce the number of pore volumes required to achieve the same degree of recovery as that realized with an ordinary mobility reducing agent.
Effect of Capillary Contact on CO2-Foam Mobility in Heterogeneous Core Samples
Authors: Yaghoobi Hossein , Heller John P. 
Published: December 2007

Abstract
Early breakthrough and poor sweep efficiency are common problems in CO2 floods. These problems result from the large viscosity contrast between the displaced and injected fluids as well as from the heterogeneity of reservoir rock. Evidence shows the presence of an aqueous surfactant solution will produce a foam with CO2, which not only controls the gas mobility but may also selectively reduce the gas mobility through regions of differing permeabilities. Experiments were conducted to test the CO2 -foam behavior in composite parallel core samples where the two permeability regions are in capillary contact. These composite cores are more characteristic of reservoir conditions. This paper examined the effect of heterogeneity on CO2 -foam in composite cores contained coaxial zones of high and low permeability.
The results from these experiments indicate that the CO2 breakthrough was delayed in the high permeability region during the transient period when surfactant solutions were used. Without surfactant the flowing quality (fraction of CO2 in total injected fluid) was lower in the low permeability region as compared with that in the high permeability region. These results indicated the favorable fluid mobility in heterogeneous core samples when foaming agents were used.
Acid Sludge Characterization and Remediation Improve Well Productivity and Save Costs in the Permian Basin
Authors: Wong T. C. , Hwang R. J. , Beaty D. W. , Dolan J. D. , McCarty R. A. , Franzen A. L. 
Published: December 2007

Abstract
Many oil wells in the Permian Basin have reported sludging problems associated with acid stimulations. The acid sludge is similar among wells and was identified as a viscous emulsion stabilized by asphaltene-rich organic solids. The sludging tendency of the oil increased with the concentrations of asphaltenes and resins, base number of the oil, and ferric ion content in the acid. Only three out of nine commercial acid systems tested were effective in preventing acid sludge formation; they all utilize the same novel iron control technology, i.e., catalytic reduction of ferric ions. Several commercial and generic solvent systems were effective in dissolving acid sludge, including mixtures of an aromatic solvent (e.g. xylene) with either isopropyl alcohol (2:1 volume ratio) or EGMBE (2:1 to 3:1 volume ratios). Selection of acid formulations and solvent systems was based on cost effectiveness and operation safety. Field implementation proved successful. If the results of this study had been implemented earlier in the lives of some of the Permian Basin properties, the recovery of 574 BOPD of lost or deferred production from 99 wells could have been realized. This would have resulted in an estimated increased revenue of over $3 million in one year.
Hydraulic Fracture Technology in the Ozona Canyon and Penn Sands
Authors: Cipolla Craig L. 
Published: December 2007

Abstract
This paper details the acquisition and application of laboratory rock mechanical data, in situ stress measurements, dipole sonic logs, and pre- & post-fracture well test data to characterize hydraulic fracture performance in the Ozona Canyon and Penn sands, Ozona Field, Crockett County, Texas. The in situ stress measurements (micro-fracs) showed sand stresses from 0.55 to 0. 75 psi/ft, while shale stresses ranged from 0.8 to 0.85 psi/ft. These data were used to calibrate dipole sonic logs that ultimately resulted in lithology based (gamma-ray) stress profiles for fracture modeling studies. The variations in measured sand stresses using micro-frac tests indicated the need for small-volume water mini-fracs prior to many fracture treatments to measure local sand stresses.
Excessive treating pressures (high net pressures) indicated the possibility of complex fracturing (or multiple fractures) and this interpretation was supported by the short "effective" fracture half-lengths (+/- 200 ft) calculated from subsequent fracture modeling and pre- & post-fracture well tests. The post-fracture well tests unexpectedly showed very low fracture conductivity that was also attributed to complex fracturing. The inability to significantly improve "effective" fracture length with increasing fluid & proppant volumes resulted in reduced treatment sizes (and treatment costs) and improved well economics.
Field Results Demonstrate Enhanced Matrix Acidizing Through Real-Time Monitoring
Authors: Zhu Ding , Hill A. Daniel 
Published: December 2007

Abstract
The use of an inverse injectivity versus superposition time plot to diagnose the changing skin factor in a matrix acidizing treatment has been presented previously by Hill and Zhu1. The model has been extended to calculate skin factor as a function of injection time or injected volume directly to help the operator monitor and optimize the treatment. A Windows program based on the theory has been developed to provide a pretreatment test to evaluate the permeability and the initial skin factor of the formation when they are not available before the acid treatment, to calculate and plot the evolving skin during the treatment in real-time, and to evaluate treatments afterwards. It converts surface pressure, when measured, to the bottomhole pressure for the calculation, and handles fluid density and viscosity changes in real time. Several field examples showed that the technique can be used conveniently to monitor skin changes and diversion effects during matrix acidizing treatments. The program is reliable and flexible in acquiring and processing data, calculating skin, and diagnosing matrix acidizing treatments.
Simulation Studies of Waterflood Performance With Horizontal Wells
Authors: Ferreira H. , Mamora D. D. , Startzman R. A. 
Published: December 2007

Abstract
Two- and three-dimensional simulation studies have been done to evaluate waterflood oil recovery in a 40-acre 5-spot pattern using horizontal and vertical well systems. The three-dimensional simulation results indicate that the parameters considered, i.e. vertical permeability-horizontal permeability ratio, injection and production rates, and reservoir thickness have little effect on waterflood oil recovery for a particular water-oil mobility ratio. For both vertical and horizontal well systems, oil recovery decreases with increasing mobility ratio. It is concluded that the mobility ratio is the dominant parameter affecting waterflood oil recovery, in line with the experimental results of Craig, Geffen, and Morse1 for conventional waterfloods. Waterflood oil recovery using a horizontal well system is shown to be higher than that obtained by using a vertical well system. A correlation has been developed which expresses volumetric sweep efficiency in a hypothetical 5-spot pattern as a function of mobility ratio. This correlation would be useful for estimating waterflood oil recovery for the ranges of reservoir parameters considered.
Euler Loads and Measured Sucker Rod / Sinkerbar Buckling
Authors: Long Scott W. , Bennett Donald W. 
Published: December 2007

Abstract
The Petroleum Industry is experiencing anincreased awareness and understandingof sucker rod compression. This awareness has evolved during the past twelve years, from initial recognition of rod buckling, to a current desire to quantify (measure) the amount of compression required to initiate rod buckling.
Recent attention has focused on true or effective compressive loads in sucker rod strings. Measurement of these loads is being documented (1) and data collection is ongoing with improved technology.
This paper will provide a more accurate understanding of the amount of compression required to buckle sucker rods and sinkerbars of various diameters. This will be accomplished by presenting the following; Predictive compressive loads that buckle various diameters and lengths of sucker rods and sinkerbars utilizing Euler loads.Measured compressive loads that are required to buckle various diameter sucker rods and sinkerbars.A comparison of predictive compressive loads to measured compressive loads.
Knowledge regarding the amount of rod string compression required to buckle various diameter sucker rods will provide the industry better rod string design guidelines.
Use of these guidelines will help identify dangerous compressive rod string loads which initiate rod-tubing contact, provide associated wear, and result in rodand/or tubing failure.
An Integrated Study of the Grayburg/San Andres Reservoir, Cowden Fields, Ector County, Texas
Authors: Reeves J. J. , Smith W. H. , Trentham R. C. , Weinbrandt R. 
Published: December 2007

Abstract
A cooperative study of the Grayburg/San Andres reservoir is being conducted in response to the United States Department of Energy's (DOE) Class II Oil Program. The project is cost shared by Laguna Petroleum Corporation (operator), Latex Resources, Inc. (operator) and the DOE. The purpose of this study is to preserve access to existing wellbores by identifying additional reserves. Production problems associated with shallow shelf carbonate reservoirs are being evaluated by a technical team integrating subsurface geological and engineering data with 3-D seismic data. Engineering analysis, subsurface control from wireline logs, and 3-D seismic data will be integrated using a network of state-of-the-art software on a high performance computer workstation. The results of the integrated effort will be a recommendation for infill drilling locations and the design of an effective waterflood. It is expected that this study will demonstrate a methodology for reservoir characterization and subsequent development of the Grayburg and San Andres reservoirs that is feasible for even small independent operators. The integrated multi-disciplinary approach of reservoir evaluation is relevant to many shallow shelf carbonate reservoirs throughout the United States. Furthermore, this study will provide one of the first public demonstrations of the enhancement of reservoir characterization using high resolution 3-D seismic data. This paper discusses the geological makeup of the Grayburg and San Andres reservoirs and the acquisition, processing, and interpretation of the 3-D seismic data set acquired for the project. The 3-D seismic volume will be utilized for optimization of a reservoir simulation model through a quantitative study to extract reservoir properties from seismic attributes.
Predicting the Fluid Loss of Drilling, Workover, and Fracturing Fluids into a Formation With and Without Filter Cake
Authors: Carlson E. S. , Venkataraman M. , Clark P. E. , Sifferman T. R. , Coffey M. D. , Seheult J. M. 
Published: December 2007

Abstract
We present in this paper the theory associated with the invasion of power-law fluids in both radial and linear systems during drilling and completion operations. We have developed a computer model based on this theory, and present computational results which validate the model against analytical and experimental results. Calculations based on experimental parameters show that power-law fluids can be very effective in the control of invasion from the wellbore to the formation. Furthermore, the results show that this control does not come at the expense of long-term well damage, because it is easy to flow back the invaded fluid.
Acid Fracturing in the Warrent Unit of Southeastern New Mexico
Authors: Metcalf Steven , Ward Brian , Davis Wayne , Gray Daniel H. , Brienen Jeff , Miller Joe 
Published: December 2007

Abstract
The development of viscous acid systems has improved the effectiveness of acid fracturing. A specific case in point is the Warren Unit of Southeastern New Mexico, which produces oil and gas from the Drinkard, Tubh and Blinebry formations. The Drinkard and Tubb formations have been found to respond favorably to acid fracture stimulation through the use of gelled and crosslinked acid systems. A crosslinked 15% hydrochloric acid gel fracturing treatment provides an economic and effective initial stimulation of the Drinkard and Tubb, while re-stimulation of Tubb wells has yielded similar results independent of the treatment type.
Production results are evaluated for the different treatments. Included are comparisons of various viscous treating fluids and treatment procedures. Rotating disk reaction rate information, rheological properties of various fluids, fluid loss characteristics, formation lithological differences and well locations are also discussed. The limitations of usage of the various fluids and techniques within the Warren Unit are addressed.
Radioactive Tracers: Review of Principle Factors in Design and Application
Authors: McLaughlin James S. 
Published: December 2007

Abstract
Radioactive tracers have been successfully utilized to interpret the placement of stimulation treatments. Completion effectiveness can be verified best when stimulation operations are traced. The advances in tracer technology require a thorough understanding of all the factors that affect the design and use of tracers, including the commercial manufacture of nuclides, the economic benefits of their use, the regulatory and licensing requirements, the choice of materials and systems, exposure doses and exposure risk, procedures for well reversal (flow-back) and the technology behind multi-isotope logging (gamma spectrum analysis).
Low Cost Solutions for Well Interventions Through Advanced Slickline Services
Authors: Larimore David R. , Goiffon John J. , Bayh Russell I. 
Published: December 2007

Abstract
In the past, slickline service has been considered as an option suited only to routine mechanical well workovers. This is no longer the case. New technology has expanded slickline capabilities to include services for well interventions that have traditionally been reserved for other, more-costly alternatives. This paper will discuss the innovative equipment that has been developed to support this technological expansion, all of which plays an integral part in the expanded slickline concept, specifically: An electronic triggering device that provides a safe, efficient method for firing detonatorsA battery-operated, electro-mechanical tool that is capable of setting wellbore devices with slickline and braided line without explosives.An electronic measurement system that can automatically correct measurement inaccuracies resulting from line stretch and environmental stress factors.A collar locator that can provide verification of collar locations in a tubing or casing string.Data/job loggers or acquisition software systems that can be connected to the electronic measurement system to graphically record dynamic information that occurs during a wireline trip.A wireline inspection system that can determine integrity of both new and used mechanical wirelines during and before service.
Case histories will be used to provide comparisons of cost, operational efficiency, and enhanced safety features of traditional service options and the new advanced slickline system. Methods for service strategies that support current economic trends and well solutions will also be discussed as well as methods to determine key needs for appropriate service alternatives.
The combined use of these slickline tools provides a state-of-the-art service system that can provide efficient alternatives for the advanced service needs in the oilfield today.
Teamwork Installs Waterflood Expansion Project in West Texas on Tiime and Within Estimated Costs
Authors: Hollar E. A. 
Published: December 2007

abstract
The installation of an $18.4 million waterflood expansion project in Phillips' Goldsmith Andector Unit (Gandu) was completed in ten months and within ten percent of original cost estimates. A multi-disciplined team effort was used throughout the project, from the earliest design and planning stages throughfinal equipment installation. The project included the drilling and completion of24 infill producing wells; conversion of 28 existing producers to water injection; construction of a fully automated, 35,000 barrels of water per day injection station and 11.5 miles of injection line.
The project design stage lasted more than a year and involved regular meetings ofthe Gandu Waterflood Expansion Premise Team. Team members represented a variety of disciplines and areas of responsibility. The project was then passed to an implementation team with similar diversity. The participation and input of all groupswas solicited and utilized throughout the development and implementation of the project.
The construction of a $1.2 million water station was completed in four months and within the original cost estimate. The identification and procurement of critical path items was essential for the timely installation of this facility.Another factor contributing to quick construction time was the development of detailed construction drawings. The team identified significant difficulties encountered in past projects that were due to poor communication between facilities and electrical construction groups. The installation of five miles of electrical conduit necessary to automate the water station had to be effectively integrated into the construction process, rather than worked in as an afterthought. The electrical group was provided with piping schematics early in the design process, which enabled the planning of ditching and conduit routing before construction ever began. The finalized drawings made possible the coordination of two construction groups and the quick installation of a complex facility.