bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flowback Analysis of Acid Stimulation of Seawater Injection Wells: Case Histories
Authors: Taylor K. C. , Nasr-El-Din H. A. 
Published: December 2007

Abstract
Techniques were developed to evaluate acid stimulation treatments based on chemical analysis of the return fluids. Four acid stimulation treatments of seawater injection wells in a large carbonate reservoir in Saudi Arabia were studied in detail. Acid was bullheaded because surface washouts in the openhole section of the well did not permit the use of coiled tubing.
Each field treatment consisted of three stages. First, a pretreatment stage, driven by reservoir pressure, flushed out the wellbore. In the second stage the well was pickled to remove acid-soluble corrosion products and particulates from the wellbore. The third stage was a matrix acid stimulation of the formation. During each well treatment, more than fifty samples were collected and up to 700 chemical analyses were made on these samples.
The results provided information about formation damage mechanisms, the effectiveness of iron control additives, the volume of washout zones, the optimum flowback time, the relative amounts of carbonate minerals dissolved by the acid, and the dilution of the spent acid.
Confirmation of well damage mechanisms was obtained by analysis of dissolved and suspended solids produced during each stage of the treatment.
The amount and type of corrosion products (FeS, Fe3O4) in the wellbore were calculated from chemical analyses of the acid returns.
Results made it possible to reduce iron control chemical concentrations in the injected acid. This produced significant cost savings.
Density measurements of matrix acid flowback samples clearly identified the optimum flowback time of these treatments. The commonly used method of pH measurement does not show when all of the spent acid has returned from the formation.
Significant variations in treatment results were seen in seawater injection wells in the same formation. Iron-containing scale in the wells varied from mostly rust (Fe3O4) to primarily iron sulfide. The type of particulates present in the different stages of the treatment also differed among the wells examined.
Evolution of a Damaged Zone Caused by Water-Based Polymeric Drill-In Fluid
Authors: Queiroz João , dos Santos Renato L. 
Published: December 2007

Abstract
Open hole completion is, nowadays, the most used completion technique in horizontal wells. Many times, for operational reasons, such completions can take many days, sometimes months, to be executed. This problem leads to a questioning about what happens to the invaded area during such exposition to the drilling fluid.
To answer such question, an experimental study of invaded area aging was performed. Such procedure consisted in real-time CT-scan measurement of the invaded area by the water based polymeric drill-in fluid filtrate. The formulation used is very common at the Campos Basin, Brazil.
The tested samples were submitted to in situ conditions (pressure and temperature), during all the experiment time, which took about one year.
It was verified that the invaded filtrate area for this drill-in formulation increased about 40% in the first 34 hours, maintaining this level during the rest of the experiment. Besides, analysis done with a Scanning Electronic Microscope (SEM) in one of the tested samples, showed that the solids and salts from the drilling fluid were only present in the filtrate invaded area.
Technical/Economical Evaluation of Artificial Lift Systems for Eight Offshore Reservoirs
Authors: Ramírez Marcos , Zdenkovic Nick , Medina Edgardo 
Published: December 2007

Abstract
This paper elaborates the most appropriate AL (Artificial Lift) system for eight off shore reservoirs. First the initial screening was performed to eliminate some AL methods without deeper quantitative analysis. The remaining methods were then compared in terms of specific power (watts/Bopd) requirements. Finally the economical analysis was carried out to compare the AL systems in terms of curves showing NPV (Net Present Value) versus time. These curves were found to be very sensitive to the parameters that are usually not known with great certainty. For that reason the risk analysis was carried out to evaluate the probability of achieving the results from economical analysis.
Fractured Reservoirs: an Integrated Approach
Authors: Massonnat Gérard J. , Bockel-Rebelle Marie-Odile 
Published: December 2007

Abstract
The understanding of the flow network organization, and the ability to predict in 3D the distribution of fracture drains are hey points to enhancing well productivity, hydrocarbon recovery and therefore field productivity.
Recent advances in fractured reservoir characterization and modeling have led to construct and very sophisticated software able to model local 3D fractured networks and run one phase flow simulations on explicit fracture models.
The problem is how to take advantage of these advances and build more realistic 3D full field models to run multiple phase flow simulations.
This paper proposes and integrated approach assigning reservoir of flow properties using results from pluriscale and multi-disciplinary steps.
Its application on a case study largely contributed to a better understanding of flow behavior within reservoir.
Underbalanced Drilling Analysis of Naturally Fractured Mexican Fields through 2D Multiphase Flow
Authors: Cruz D. Velázquez , Rodríguez-Hernández H. , Cortes-Monroy I. , Azpeitia-Hernández D. , Blanco-Galan J. 
Published: December 2007

Abstract
Two-dimension multi-phase fluid flow numerical simulations which include drilling fluid, injected gas, formation fluids and cuttings were carried out for different well geometry taking into account both inlets and outlets throughout boundary system. Simulations were made for fields whose formation and fracture pressure profiles are characteristic of the naturally fractured Mexican fields. During simulations different gas injection systems to get underbalanced conditions such as parasite tubing string, annular gas injection and drill-pipe gas injection were proved in order to establish their feasibility for application in the case of study. Pressure and velocity fields together with phase distribution along the well are analyzed in each case to determine their technical and operative applicability as well as to evaluate advantages or disadvantages of this technique respect to the present circumstances during drilling. From the results it is possible affirm that drill-pipe gas injection is the best option to get underbalanced conditions during drilling as is explain in the extent work. A comparative survey against other model results (R.R. Angel, Machado-Ikoku, Poettmann & Berman and Okpöribi) is realized in the final of this work from which it is possible to observe the improvements of this work in regarding those of obtained by mentioned models. According to observed results underbalanced drilling is a good-available solution to total lost circulation and formation damage problems faced presently during drilling-wells in the naturally fractured low-pressure Mexican fields. The main contributions of this work consist of its capability to design drilling performance and quantify lost circulation by means of numerical simulation of volume-average general mass and momentum conservation equations.
Improved Zonal Isolation Through the Use of Sealants Before Primary Cementing Operations
Authors: East Loyd E. , McIntyre Kenneth W. , Tucker James , Covington Rick , Duell Alan 
Published: December 2007

Abstract
Zonal isolation in injection, geothermal, and producing wells is critical both to reservoir evaluation efforts and to operations, but often, cementing between the casing and the wellbore is still the only method of zonal isolation performed in many wells. Although zonal isolation and well diagnostics techniques have improved, primary cementing techniques may be inadequate for some reservoir conditions, resulting in undesirable water flows, gas flows, or both. If zonal isolation is inadequate, then expensive, often complicated remedial cementing work will be needed for improved well and reservoir performance.
If conformance technology is applied during the drilling phase, it can improve the performance of primary cementing processes, making them safe and economical. Conformance treatments seal problem intervals before primary cementing, thereby alleviating potential well-control problems. These treatments also help ensure successful primary cementing operations and prevent isolation loss caused by the casing expanding and contracting during production-pressure cycles. The formation itself, rather that the cement sheath alone, becomes the zonal isolation mechanism.
During the drilling phase, zonal isolation requires the use of coiled tubing, a hydrajetting device, a depth-correlation device, and a sealant. The sealant should be water-thin during placement, and should become an elastic polymer only after it is set in place. This zonal isolation technique requires an understanding of (1) depth correlation to openhole logs, through the use of mud-pulse technology, and (2) hydrajetting techniques that remove mud filter cake while placing the sealant. This paper presents examples of this technique for a 7 ⅞-in. wellbore and a 13 ½-in. wellbore.
Foaming Cement as a Deterrent to Compaction Damage in Deepwater Production
Authors: White J. , Moore S. , Miller M. , Faul R. 
Published: December 2007

Abstract
This case-history paper presents the results of a foam cementing process used during construction on four primary casing strings. The process was initiated to help prevent compaction damage associated with deepwater production.
Europa is a four-well, deepwater, subsea development project drilled in 3,500 ft of water at Mississippi Canyon, southeast of New Orleans, LA, in the Gulf of Mexico. Several issues related to effective primary cementing during well construction are addressed in this paper. Special spacer designs were also used because of the synthetic oil-based mud (SBM) used on two of the casing strings, which included production liners.
The main focus of the paper is on the planning, preparation, and execution of the primary cementing on the critical production liner. Because of the highly unconsolidated formations above the producing zone, the reservoir will experience compaction caused by depletion. The critical issues for the production liner are proper casing design, effective cement placement, and mechanical properties needed to help resist the forces imposed on the wellbore and cement sheath. Minimizing the effects of these forces caused by transverse loading helps to prevent the casing from buckling. The unique properties of foamed cement make it best suited for this application.
Casing Centralization in Horizontal and Highly Inclined Wellbores
Authors: Blanco A. , Ciccola V. , Limongi E. 
Published: December 2007

Abstract
Success of primary cementation is highly improved by use of centralizers. They are fixed along the casing or liner to keep it away from borehole walls. To be effective use, the placement of centralizers with respect to spacing and location must be optimized through consideration and evaluation of all parameters and forces involved. At present, all models have been developed to evaluate the casing deflection based on lateral an axial loading. However, some approximations made in the estimation of axial load, leading to standoff values that can be very different from actually expected. The present study demonstrates that a more realistic determination of axial load is achieved by applying a new method, when considering, in a more realistic way, the effects due to fluid forces. In API model, the effect of fluid action is limited to the buoyancy forces on the casing. In this paper a model is presented, in which fluid effect is evaluated in a global way, integrating both buoyancy effect and horizontal force component acting on the casing. Also, corrections are made to estimate casing deflection caused by compression. The results obtained using the new model vary significantly from API-10D, especially in highly inclined and horizontal wellbores.
The Evolution and Application of Formate Brines in High-Temperature/High-Pressure Operations
Authors: Bungert D. , Maikranz S. , Sundermann R. , Downs J. , Benton W. , Dick M. A. 
Published: December 2007

AbstractHigh-density formate brine-based drilling fluid systems have emerged as viable reservoir drilling and completion fluid options for deep high-temperature wells. Upon their commercialization in the early 1990's, these systems were shown to possess a unique combination of properties that could be exploited to engineer high-density fluids that would comprise minimal solids, maintain rheological stability at high temperatures, minimize reservoir damage and satisfy environmental requirements.This paper describes the evolution of these systems and their recent application in the drilling of deep wells in Northern Germany and other areas. Not only did the formate-based systems exhibit faster penetration rates than the water-based fluids used previously; they also eliminated the solids sag problems experienced with water-based drilling fluids used in technically and economically demanding high-temperature environments. Furthermore, the formate brine-based systems were shown to improve well productivity.Through an examination of 15 deep gas wells in Germany and other formate-based applications, the authors review the performance of formate brines as reservoir drilling, completion and workover fluids. Particular attention is given to drilling and eventual well performance, as compared to offset wells drilled and/or completed with alternative systems.
Development of an Open Hole Sidetracking System
Authors: Stokley C. O. "Doc" , Seale Rocky 
Published: December 2007

Abstract
Sidetracking in an open hole environment has been accomplished for many years using time drilling techniques, cement plugs, and permanent whipstocks. However, problems have been identified in certain applications that warrant alternative sidetracking methods or techniques. For example, in time drilling applications, harder formations can prevent the lateral hole from being initiated, and softer formations may allow ghost holes to develop. Each condition is time consuming and costly.
To address these problems, an open hole retrievable sidetracking system was developed and tested. Design considerations revolved around anchoring and retrieving in the open hole, while maintaining integrity through the drilling process. The iterative steps taken for this design project are covered in detail.
Well Control in Campos Basin - Brazil
Authors: Martins F. S. B. , Santos O. L. A. , de Paula I. L. 
Published: December 2007

Abstract
This article presents the actions taken in Campos Basin, offshore Brazil, in order to make drilling, completion and workover operations safer, especially in deep waters. Firstly, the paper describes the pioneer work called Safety Program for Dynamic Positioning Vessels (DPPS) in terms of well control that has been implementing in Brazil since 1993. This program consists of operational procedures, equipment requirements and practical recommendations for well control in deepwater locations. The paper also shows the current status of the program implementation and the benefits and good results associated with its application in Campos Basin.
Afterwards, the paper presents the structure and the most important aspects of the Blowout Contingency Plan for Campos Basin. The management structure to be established and the responsibilities and assignments of each person involved in a deepwater blowout and during its killing operations are listed. Also are presented the operational aspects related to the three phases of the blowout control operations: immediate actions, blowout containment procedures and blowout control.
Next, the paper presents the huge effort that has been developing in Campos Basin in order to train and certify in well control all personnel directly involved in drilling, completion and workover operations. The paper shows the criteria, statistics and control items of the well control certification system currently in use in Campos Basin. The kick detection and well shut-in drills to be implemented on the rig are also presented and discussed in the paper.
Finally, an analysis of the rig downtime due to BOP repair in the Campos Basin is presented.
Foam Propagation in the Absence and Presence of Oil
Authors: Vassenden F. , Holt T. , Moen A. , Ghaderi A. 
Published: December 2007

Abstract
Foam propagation in co-injection was studied in a 10 m long porous medium, equipped with pressure ports for every 1 m. The porous medium had been characterized by flooding experiments on the core scale. In the absence of oil, propagation on the 10 m scale could be understood by corescale, steady-state foam properties. In the presence of oil, however, the foam front propagated significantly slower than the injected fluid front. An extraction mechanism for oil combined with foam oil sensitivity can explain the delayed propagation. These effects were included in a foam simulator that reproduced the slow foam propagation.
Simulating Foam Processes at High and Low Foam Qualities
Authors: Cheng L. , Reme A. B. , Shan D. , Coombe D. A. , Rossen W. R. 
Published: December 2007

Abstract
Foams used for gas or acid diversion exhibit two flow regimes, depending on foam quality. Two foam simulators, one the most widely used commercial foam simulator and the other developed at our university, fit steady-state foam behavior in both regimes. A simple procedure is described for fitting simulator parameters to a set of steady-state coreflood data and examples are shown. Fitting model parameters to a single coreflood data can err by fitting this datum to the wrong flow regime.
Shear-thinning reported in the "low-quality regime" can increase foam injectivity in radial flow. Foams in low-quality regime fit the same correlation for overcoming gravity override previously derived for foam in the high-quality regime. The flow regime does greatly affect the effect of capillary crossflow on foam diversion between layers differing in permeability, however. Capillary crossflow harms diversion between adjacent layers, as found earlier, but the magnitude of the effect is much less for foam in the low-quality regime, and no single correlation matches all the results. Capillary crossflow can actually increase (by a small amount) diversion from adjacent layers differing somewhat in permeability to distant layers with much-different permeability.
An Improved Three Phase Flow Model Incorporating Compositional Variance
Authors: Fayers F. J. , Foakes A. P. , Lin C. Y. , Puckett D. A. 
Published: December 2007

Abstract
A consistent set of procedures for calculating 3 phase relative permeabilities (3PRPs) and the capillary pressures (3PCPs), referred to as the rescaled Interpolation Method (RIM), is described. The intention is to provide an approach for mixed-wet systems which is compatible with the likely availability of immiscible 2P measured data, which honours the basic physics of 3P displacement processes, and at the same time avoids undue complexity in the simulator and excessive overheads in computing efficiency. For 3PRPs the starting point rests on the use of the Baker saturation weighted interpolation method for the three phases, but modified for the oil phase through saturation rescaling to give compatibility with a general form for the residual saturation function Som(Sg, Sw). Comparisons with experimental data show the benefits of this approach as opposed to Stone's I. A practical procedure for including 3P hysteresis is described. This is then extended to allow for compositional changes in the oil and gas phases, including the limiting miscibility conditions. The model for 3PCPs is based on simple assumptions concerning the division of the pore space between water-wet and oil-wet pores and comparing this with the phase occupancies of pores in the corresponding 2PCP-measurements. The mixed-wet pore space division is found from the cross over saturation in the water/oil 2PCP.
Evaluation of Gelation Systems for Conformance Control
Authors: Prada Alvaro , Civan Faruk , Dalrymple E. Dwyann 
Published: December 2007

Abstract
This paper presents the results of laboratory tests measuring typical gel system effectiveness in conformance control. The evaluated gel systems are a metal-complexed polymer system, an organic crosslinked-polymer system, and an in-situ polymerized system. All the systems are typical, commercially available systems used for water control in sandstone formations. The effects of temperature, differential pressure vs. permeability, and adsorption are investigated and quantified.
The first set of core-flood experiments was performed with 1-ft long, 2-in. diameter Brown sandstone cores. The test temperatures were 140° and 240°F. The second set of experiments was run in a composite system with two 6-in. long, 1-in. diameter parallel coreholders. One coreholder contained a Brown sandstone core and the other coreholder held a Berea sandstone core. The permeability of the Brown sandstone core was 5 to 10 times greater than that of the Berea sandstone.
The parametric studies carried out with these gels show
the effect of differential pressure vs. permeability behavior of the water-control systems during placement adsorption characteristics the effect of the gel systems on nontargeted intervals when placed without zonal isolation
The organic crosslinked-polymer system provided the highest gel-threshold pressure. The test results indicate an improved injectivity profile after an in-situ gelation treatment. The permeability of the untargeted intervals was also affected during nonselective treatments. A larger slug had a larger impact on nontargeted zones proportional to the zones’ permeabilities. Therefore, zonal isolation is strongly recommended. Polymer adsorption on rock surfaces and sensitivity of the metal-based crosslinker to the chemical environment can reduce gel-system effectiveness.