bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geological and Engineering Assessment of Remaining Oil in a Mature Carbonate Reservoir: An Example From the Permian Basin, West Texas
Authors: Holtz M. H. , Major R. P. 
Published: December 2007

Abstract
The Jordan (San Andres) reservoir is composed of approximately 400 ft of upward-shoaling subtidal to peritidal carbonate strata that are thoroughly dolomitized and partly cemented by sulfate minerals. The reservoir is divided into four flow units on the basis of depositional facies and subsequent diagenetic alteration. Delineation of these flow units is based on the relationship between open-hole wireline log response and rock mineralogy.
Cumulative production is 68 MMSTB of 218 MMSTB original oil in place, which is a recovery efficiency of 31 percent. Forty-seven MMSTB of remaining mobile oil occurs as bypassed oil in the contacted upper part of the reservoir, which has been penetrated by well bores, and 12 MMSTB of mobile oil is in the uncontacted lower part, which has not been penetrated by well bores. The most prospective areas for increased production by waterflood profile modification in the contacted part of the reservoir are the southwest corner of the field, in low-permeability Flow Unit B, which is incompletely swept, and the eastern central part of the field, where heterogeneous permeability in Flow Unit D has resulted in an incomplete sweep. The most prospective areas for increased production through well bore deepening into the uncontacted part of the reservoir are the southeast corner of the field, where high-permeability Flow Unit C is uncontacted, and the central part of the field, where high-permeability Flow Unit A is uncontacted.
This reservoir contains 113 MMSTB of oil residual to waterflood, and reservoir properties meet preliminary screening criteria for effective carbon dioxide flooding. Thus, this reservoir is a candidate for enhanced oil recovery operations.
Application of Hydraulic Fracturing Technologies, San Andres Formation, New Mexico
Authors: Martinez A. D. , Ellis P. D. , DeAragao D. D. 
Published: December 2007

Abstract
The paper will describe the hydraulic fracturing technologies that have been applied to San Andres formation over the past two years. The use of known fracturing technologies that have been applied include minifrac analysis, fluid quality control, and the use of resin coated proppant to control proppant flowback. In addition the application of real-time fracture analysis and the use of point-source perforating will be discussed.
Results indicate that a fully integrated hydraulic fracturing well completion program can lead to improved production. These results are enhanced by incorporating various in-house departments with various departments from a single source supplier. In this way an integrated team approach is established.
Transporting Mobility Control Agents to Thief Zones
Authors: Irani C. A. , Easterly R. A. 
Published: December 2007

Abstract
This paper will present experimental results that demonstrate a novel plugging mechanism for improving the areal sweep efficiency for EOR solvents such as carbon dioxide or light hydrocarbons, or mixtures of the two. Early gas breakthrough due to thief zones or gas override is the single most significant factor affecting the sweep efficiency of miscible gas processes. WAG is routinely used and foams are being investigated for diverting gas to upswept zones. Both approaches require injecting an aqueous phase which leads to water blocking and slows gas injection, thus delaying oil recovery. Additionally, foams have a short life, are limited to near-wellbore applications due to surfactant during every cycle of surfactant injection.
The optimal solution calls for a deep penetrating plugging agent carried in the solvent phase for accurate and economical delivery to thief or override zones. Additionally, the process should be simple, safe in the wellbore region, robust, and easily activated. It has already been demonstrated that cosolvents like toluene will successfully solubilize polydimethylsiloxane-type polymers in CO2, and that polymer solubility decreases with increasing temperature and decreasing pressure. Consequently, it is feasible to define a polymer + cosolvent combination that is homogeneous at the lower temperature of the injector, but will destabilize as the injected slug moves through the formation and is subjected to higher temperatures and lower pressures.
Figure 1 represents the solubility phase boundary for a 600,000 cst polydimethylsiloxane polymer in CO2- toluene mixtures as a function of temperature, pressure, and two cosolvent concentrations. For either cosolvent concentration, a single phase condition exists for temperature and pressure combinations that would place the system above the phase boundary line, with polymer dropping out of solution once the system conditions drop below the line. Consider the specific case of a CO2 flood in a reservoir at 180°F. and 4,000 psia, where the injector is at 130 ° F., and early gas breakthrough has taken place. The working of this process would require injecting a CO2 phase enriched with 7.1 vol.% toluene and 600,000 cst polymer as a one phase system at the injector. As this mixture moves through the reservoir and increases in temperature, the stability decreases, and once the temperature at fixed pressure crosses the phase boundary line, the polymer phase separates out to plug the zone.
Cost-Effective Methods of Profile Control in Mature Waterflood Injectors
Authors: Lerma M. K. , Giuliani M. A. 
Published: December 2007

ABSTRACT
Injector profile control tends to be a challenge in any waterflood, but control problems are exacerbated in a multi-layered, heterogenous reservoir like those found in the L.A. Basin. This paper discusses the various methods of profile control used in two L.A. Basin fields; details of the methods used and the results achieved are included.
Why Water Soluble Corrosion Inhibitors Should be the Preferred Choice for Continuous Applications
Authors: Woollam R. C. , Merrett S. J. 
Published: December 2007

Abstract
Over recent years the Petroleum industry and its chemical suppliers have spent many millions of dollars searching for ever improving corrosion inhibitors for crude oil transport lines. During this time many different notations for a chemical's characterization have arisen, water soluble, oil soluble, oil soluble/water dispersible etc.
This paper argues, theoretically, that to achieve adequate protection of pipelines from continuous corrosion inhibitor addition the deployed corrosion inhibitor should be preferentially water soluble. It shows how the concentration of a product in the water phase can vary dramatically with both solubility and water cut. In addition, two other important parameters, dissociation and adsorption, are also discussed and shown to have a significant impact on product performance.
Field Evaluation of Key Liner Cementing Variables on Cement Bonding
Authors: Saleh S. T. , Pavlich J. P. 
Published: December 2007

ABSTRACT
This paper presents field evaluation results of several key variables which affect liner cementing performance in deviated and horizontal wells. The investigated variables are: displacement flowrate, cement slurry rheology, turbulators placement, and back pressure. These variables were identified based on several years of database development and analysis in the Prudhoe Bay field (PBU) in Alaska. The development of successful liner cementing practices has increased liner cementing success to 90% based on well log evaluation and production history. The results of the comprehensive field experimentation along with laboratory testing are presented.
An efficient centralization program with turbulators has evolved based on field data and experimental results derived from a flow loop model. The flow loop allowed visual observations of turbolator's effectiveness under different flow conditions. The emerging turbulator placement program was field tested and evaluated. Operational considerations and hole condition prior to cementing are discussed. Caliper logs and cement bond logs were correlated and showed the detrimental effect of hole washout on cement bonding.
Back pressure application immediately after cement slurry placement was evaluated experimentally. The experimental results supported field data, which concluded that back pressure helped prevent gas migration and obtain a better cement bonding.
Case Histories: New Horizontal Completion Designs Facilitate Development and Increase Production Capabilities in Sandstone Reservoirs
Authors: Harrison R. D. , Restarick Henry , Grigsby T. F. 
Published: December 2007

Abstract
Premature water breakthrough and sand production are problems that have plagued operators worldwide in the development of sandstone reservoirs. In many cases, these difficulties have limited the productivity of sandstone reservoirs to such an extent that operators have ignored recoverable reserves, considering them to be economically unfeasible. Today, however, horizontal technology can offer operators a viable sand control completion technique to address these issues; its capabilities of reducing formation damage by decreasing production flow velocities and drawdown pressure across the production zones while reducing the water content provides solutions to many basic sand control problems.
As demonstrated by the successes recently achieved using this technology, horizontal completions have dramatically changed operational outlook for both new wells and recompletions in a sandstone environment.
Southeast Lost Hills Hydraulic Fracturing Stimulation of the McDonald Shale Zone: Case History
Authors: Martinez A. D. , Marquez M. R. , Knauss M. E. , Shotts K. D. 
Published: December 2007

ABSTRACT
This paper is a case history of the hydraulic fracturing stimulations applied to the McDonald Shale (MS) zone in the Southeast Lost Hills (SELH) Field located in Lost Hills, CA. Approximately 25 wells have been stimulated in this naturally fractured, low permeability (.07 md), thick (+ 200 feet) reservoir since 1982. Hydraulic fracture treatments have been refined to their current design.
Approximately 65% of the wells fracture stimulated in this zone have screened out. Several design changes have been implemented which have proven successful in preventing screen outs and resulted in placing designed treatment volumes. These changes include ramping vs stair step proppant schedules, the use of higher viscosity gel pads, and smaller perforation density.
Drilling Faster and Cheaper With Dayrate Contracts in the Texas Panhandle
Authors: Riker J. E. , Reynolds G. D. , Westermark R. V. 
Published: December 2007

ABSTRACT
This paper discusses changes made in drilling practices in the Texas Panhandle resulting in increased penetration rates and less cost per foot.
Most drilling in the Texas Panhandle has been left to the drilling contractor on footage contracts. To implement ideas for improvement it was necessary to have control over the drilling operation. A change from footage contract to daywork contract was made on one rig.
Surface modifications were made to meet safety and well control standards. The mud system was modified with an additional pit and an independently driven triplex mud pump. An inspection program was initiated for the drill string.
By utilizing low solids mud, aggressive weight and RPM on new bit designs, and increased annular velocities, penetration rates have been substantially increased and cost per foot decreased.
Case History of Live Storage Cavern Snubbing Unit Work Where 100,000 bbl of Butane Were Recovered
Authors: Endacott M. S. , Buntt J. W. 
Published: December 2007

ABSTRACT
The purpose of this paper is to provide a case history of methods used to work on an underground storage cavern containing butane. This refined product had become trapped behind the casing set point. The product was recovered using a mechanical casing cutter and a snubbing unit.
Determining the Integrity of a Pipeline by Hydrotesting
Authors: Lenhoff D. A. 
Published: December 2007

ABSTRACT
One of the key methods used in determining the integrity of an existing pipeline is hydrotesting. Prior to commencing hydrotest procedures, research data such as original resurvey plats, pipeline reports, failure reports, and topographic maps are compiled to profile the pipelines characteristics. Based on this information, a practical test pressure for an unregulated pipeline can be determined by using ASME B31.8,"Gas Transmission and Distribution Piping Systems". During hydrotesting, failures resulting from metal corrosion must be anticipated so that appropriate safety and repair preparations can be undertaken. Repair of failures requires a systematic approach including the calculation of the length of piping to be replaced, development of a process by which test water from one section may be transported to another without undue delay in operations, and development of a cost effective means of test water disposal. Although hydrotest has been proven to be an accurate and dependable gauge of line integrity, the process is not yet fully defined and improvisation is still necessary to optimize both efficiency and accuracy of results.
Use of Least Squares To Estimate Gas-Well Gas Recoverable Reserves and First-Year Gas Production
Authors: Iledare W. O. 
Published: December 2007

ABSTRACT
This paper presents a statistical model of the natural gas depletion process1. The model is developed to estimate gas-well recoverable reserves and predict first-year production rate in a typical mature petroleum basin in the U.S. Our empirical results suggest that we can estimate, using least squares approach, new gas-well gas recoverable reserves and predict its first year production using our knowledge of the well's absolute open flow potential and the prevailing wellhead natural gas prices. Our results also suggest that we have no strong statistical evidence to reject the null hypothesis that per gas-well recoverable reserves and first-year gas production increase with wellhead natural gas prices. Given a set of geologic conditions, we utilized the model to determine the sensitivity of gas-well reserves and first-year production to changes in wellhead prices.
Hydrates: Significance for Design and Operation of Multiphase Pipelines
Authors: Fadnes F. H. , Schei R. S. , Majeed A. I. 
Published: December 2007

Abstract
This paper describes the hydrate prevention concept for an actual North Sea subsea development, and how this concept was established.
Based on the outline of the development, an extensive program of hydrate characterisation tests was performed. These tests consist of semi-static experiments in visual high pressure PVT-cells and dynamic studies in pressurised flow loops and flow simulators. Special emphasis has been put on the investigation of the potential of hydrate blockage and the future use of unconventional hydrate inhibitors.
Technical Integrity and Continuous Improvement: Key to Survival Beyond the Nineties
Authors: Thorogood J. L. 
Published: December 2007

Abstract
Drilling decisions made before a rig reaches location make a significant contribution to an oil company's financial success. Of value to the company is not the ability to drill wells, but the ability to plan with confidence in the knowledge of what is possible. In spite of this, operators have tended to over-work day to day decisions about drilling out of proportion to their significance. Recognition of this fact has resulted in the present wave of contracting initiatives. A major challenge for the industry is to achieve the necessary transfer of responsibility without compromising the operator's licence to operate. These changes will compel the service sector to develop a new culture of technical integrity and continuous improvement. To operate safely, measure performance and manage drilling risk, the transformation will oblige the service sector to adopt many technologies presently owned by oil companies.
Rock Mechanics Aspects of Drilling and Completing Highly Inclined Wells in Weak Formations
Authors: Morita Nobuo , Whitebay Lee 
Published: December 2007

Abstract
This paper reviews how rock mechanics concepts may be used to predict borehole stability during the drilling and production phases of field development. Cases are presented to illustrate the impact of in-situ stresses on drilling, completion, and production operations. The stability of highly inclined or horizontal wells is greatly influenced by rock strength and the effective vertical stress; which increases as the pore pressure in the reservoir drops. Factoring rock mechanics data into reservoir development plans can potentially save millions of dollars by reducing drilling and completion costs, and earn additional revenue through having more productive wells.
Misunderstood or Overlooked Gas-Lift Design and Equipment Considerations
Authors: Winkler H. W. 
Published: December 2007

Abstract
Gas-lift (GL) installation design calculations and examples are presented in GL manuals, text books and other publications. Example calculations range from very simplified to detailed designs requiring accurate well information and gas-rate throughput performance for the gas-lift valves (GLV's). Unfortunately, the actual GL installation does not always operate as predicted. Certain wells will require more injection gas and produce less fluid than the other wells in the same injection-gas system. The poorer performing wells have the same fluid properties and may have similar or better productivity characteristics. The objective of this paper is to discuss several design and operating procedures that can prevent unloading a well, lead to heading and surging, and other considerations that cause excessive injection-gas usage and lower than predicted production rates.
A Multiphase Pump Application in a Low-Pressure Oilfield Fluid-Gathering System in West Texas
Authors: Oxley K. C. , Shoup G. J. 
Published: December 2007

Abstract
A multiphase pump (MPP) application in a West Texas field is discussed. The paper describes the original production system and explains the factors limiting production. Several competing concepts for increasing production are compared including a gas gathering system, separation and single-phase pumping/compression, and multiphase pumping. The paper gives a brief history of the multiphase pump project, including performance testing before installation, installed performance, response of the production system to the pump, and long-term goals of the project.
Scale Inhibition in Wellbores
Authors: Crowe Curtis , McConnell S. B. , Hinkel J. J. , Chapman Ken 
Published: December 2007

Abstract
Adsorption is considered the primary mechanism of scale inhibitor retention during squeeze treatments of sandstone formations. Steps are often taken to avoid inhibitor precipitation for fear of formation damage. In limestone and dolomite formations, phosphonic acid inhibitors are deliberately allowed to react with the formation and precipitate as the slightly soluble calcium salt. This can result in longer scale protection times. Even neutralized inhibitors react with limestone to form precipitates.
This paper investigates the factors that affect the inhibitor precipitation and retention in carbonate formations. Core tests show an absence of damage during inhibitor injection but good retention. A slow rate of inhibitor return is observed during brine backflow. In formation brines containing Ca++, inhibitor dissolution is slowed by the common ion effect.
Deepwater Activities Offshore Brazil: Evolution on Drilling Technology
Authors: Barcelos André , Awad S. P. , Assunção R. B. 
Published: December 2007

Abstract
Petrobrás started drilling deep water wells offshore Brazil in the mid-eighties. Nowadays, after ten years of experience, 180 wells have been drilled in water depths ranging from 400 m to 1800 m. Several records have been broken since the Marlim Field Pilot System came on stream. Recent activities and new prospects are pushing on limits into even deeper waters, where Petrobrás is committed to drill and produce wells in the near future.
This paper addresses main problems faced in the Campos Basin area, southeast Brazil, during the deep water exploratory program and the solutions achieved to solve them. A a brief description of the current field developments is also given. Finally, a point about the future challenges to be overcome is made.
Influence of Composition and Texture on the Failure Properties of Clastic Rocks
Authors: Plumb R. A. 
Published: December 2007

Abstract
New relationships are identified between the composition and texture of clastic rocks and their Coulomb failure parameters, unconfined compressive strength and friction angle. Rocks examined in this study have porosities that vary from 0% to 40% and the volume fraction of clay minerals varies from 0% to 72%. Results show that unconfined compressive strength depends on porosity, clay content and the degree of cementation. Young's modulus was found to be a better indicator of unconfined compressive strength than porosity. Friction angle depends on porosity, clay content and effective confining pressure. These results indicate that measurements of porosity, clay content, cementation and in-situ stress are required to evaluate strength variations among rocks typically encountered in a single well.
Measuring Compaction and Compressibilities In Unconsolidated Reservoir Materials Via Time-Scaling Creep
Authors: Dudley John W. , Myers Michael T. , Shew Roger D. , Arasteh Mike M. 
Published: December 2007

Abstract
A testing procedure and analysis method is proposed that gives compaction and compressibility data that are independent of test duration for unconsolidated sands. Compaction data on unconsolidated sand material (including several Gulf of Mexico reservoirs) using this method are presented. Tests on twin plugs give essentially the same stress-strain data for test durations from 1 day to three months. This occurs because of a fundamental time-scaling property of these unconsolidated materials. The creep behavior is modeled using a fractional power law dependence with time, which represents the Voigt material model having an extremely broad distribution of relaxation times. This analysis indicates that the characteristic relaxation times of these materials are measured in decades or longer. ‘Creep equilibrated’ tests are therefore impractical and not relevant to a reservoir that will be depleted in one or two decades. Analysis of the power law creep parameters indicates the creep behavior is consistent at higher stresses among the materials tested. The creep parameters scale with stress and provide a means of decoupling the time-dependent behavior from the stress-strain behavior.
Basin scale rock mechanics: Logs and core measurements
Authors: Marsala A. F. , Ragazzini G. , Meazza O. , Brignoli M. , Santarelli F. J. 
Published: December 2007

Abstract
The Northern Adriatic basin contains a great number of developed fields at depth ranging between 1000 and 4000 meters, and a comprehensive geophysical, petrophysical and mechanical characterization of these weakly consolidated formations was carried out. For 15 wells cored in the pay zones, a systematic campaign of core measurements was undertaken and comparison between logs and cores made. Typical log programmes contained porosity, gamma ray, resistivity and sonic, including full waveforms and dipole. In the laboratory typical core measurements consisted of density, porosity, permeability, residual oil saturation, formation resistivity factor, granulometry, clay content, ultrasonic velocity measurements along with triaxial and oedometric tests. Empirical correlations and statistical analysis of this entire database at the scale of a geological unit is presented.