bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Hard Rock Roller Cone Bit Technology/Operational Excellence Improves Economics in Mature East Texas Gas Fields
Authors: Martin Donnie , Jacobsen Jim 
Published: December 2007

Abstract
Because of increased demand for natural gas in the United States, the mature East Texas province is experiencing a surge in drilling activity. However, due to marginal economics of these fields, it is critical to keep drilling costs at a minimum. A typical well in this region must penetrate several sand, shale, and carbonate formations as well as the highly abrasive Travis Peak and Cotton Valley formations before reaching the reservoir target. The Travis Peak is normally topped around 6050-6400 ft, followed by the Cotton Valley at approximately 8000 – 8400 ft. Each of these formations is about 1200-1700 ft thick. Traditionally, extremely abrasive sections in these formations have severely limited the life of IADC Class 647 through 817 roller cone bits. Because of severe gauge and cutting structure wear, the bits run previously were normally pulled after drilling about 800 ft. The shortened life meant three to five bits were required to complete the two intervals.
The authors will also discuss the application and development of a new hard rock (HR) bit that is drilling up to 20% more footage than the IADC 647 and 817 types run previously. The new IADC Class 647 and 817 roller cone bits incorporate new cutting structure geometry and enhanced gauge protection along with metallurgical improvements. Today, the Travis Peak and Cotton Valley formations are being drilled with three to four bits averaging more than 1000 ft per bit. The authors will present case studies of typical Travis Peak and Cotton Valley wells in East Texas documenting significant performance improvement and reduced cost per foot.
The operator has also improved operational efficiency (incident-free) reaching bottom hole objectives quickly reducing open-hole exposure and costly "flat" time. The authors will discuss changes that allowed a specific operation to reach the target formation in record time, breaking a long-standing field record.
Seismic Measurement While Drilling in Azerbaijan and Brazil
Authors: Harrold T. , Poole A. , Nelson L. , Hawthorn A. , Underhill W. 
Published: December 2007

Abstract
This paper presents field results obtained while drilling difficult offshore wells in Azerbaijan and Brazil using a new service that delivers conventional check-shot data while drilling. The operation is similar to a conventional wireline operation in that it uses a surface-deployed source and downhole receiver. The key difference between this service and wireline seismic services is that the receiver is included in the drilling assembly; therefore, drilling does not have to be stopped to take measurements. The first case study presents results from the A-1 deviated wildcat well in the South Caspian Sea, where the service was used to reduce depth uncertainty while drilling. The tool delivered real-time check-shot data that were accurate to within 3 ms of a conventional vertical seismic profile (VSP) over the same interval (equivalent to a 10-m depth error at a 4-km depth). In the second case study, seismic data from the B-2 well in Brazil were used to set casing in a narrow window between a fault and the primary reservoir target. The data enabled safe and successful installation of the casing. Both operations were completed with zero rig downtime. Data accuracy was suitable for real-time decisions and eliminated the need to stop drilling to run intermediate wireline VSP surveys. The service offers the industry new options for reducing uncertainty in the well construction process, and it can therefore make a significant impact on cost and safety while drilling a well.
Water-Based Alternatives to Oil-Based Muds: Do They Actually Exist?
Authors: Bland R. G. , Waughman R. R. , Tomkins P. G. , Halliday W. S. , Pessier R. C. , Isbell M. R. 
Published: December 2007

Abstract
Water-based mud designs as alternatives to oil-based or synthetic-based muds are compared versus history of use. Water-soluble designs and water-insoluble designs are discussed as well as a combination approach used by Woodside Energy to drill on the Northwest Shelf, Offshore Australia. Perfornance of a water-based 2-phase polyglycol mud system containing a Drilling Enhancer with an appropriate bit design was technically and economically equivalent to that with a synthetic-based mud.
Polyurethane Grouting Geothermal Lost Circulation Zones
Authors: Mansure A. J. 
Published: December 2007

Abstract
Polyurethane grouting has been successfully applied to a lost circulation zone in a geothermal well at Rye Patch, NV. Previously, failure to seal this zone resulted in the temporary abandonment of the well after twenty cement plugs, including 15 conventional, two thixotropic, and three with foam cement, were unsuccessful. Advantages of polyurethane grout are that the viscosity and setting time can be controlled to fit the job. The grout can be engineered to have a low viscosity while being pumped and then gain strength in a short period, minimizing "waiting-on-cement" and the potential for the plug to be washed out. Polyurethane has been successfully used in core drilling operations (slim holes) to stop lost circulation and stabilize boreholes; however, previous attempts to apply polyurethane grouting to large diameter geothermal boreholes have not been successful. The techniques applied to grouting with polyurethane at Rye Patch were adapted from civil engineering technology where polyurethane is becoming the grout of choice for sealing high cross flows. The success of the grouting of the loss zone at Rye Patch was a result of packing off the hole and squeezing the grout, using sufficient polyurethane to sweep away the drilling mud, and controlling the gel time.
Membrane Efficiency in Shale - An Empirical Evaluation of Drilling Fluid Chemistries and Implications for Fluid Design
Authors: Schlemmer R. , Friedheim J. E. , Growcock F. B. , Bloys J. B. , Headley J. A. , Polnaszek S. C. 
Published: December 2007

Abstract
This paper describes continuing efforts to develop a water-based drilling fluid that will provide the osmotic membrane behavior and wellbore stability of an oil-based drilling fluid. A pore-pressure-transmission technique in use for several years as a tool to measure osmotic behavior has been refined for improved measurement of changes in shale permeability and pore pressure in response to fluids interactions with outcrop and preserved shale specimens. Conventional invert emulsion and water-based drilling fluids containing selected additives have been tested in this ongoing study. The data have been used to achieve an understanding of what might be called "membrane efficiency" and how that concept may relate to shale stability.
Laboratory measurements of differential pressure development and calculation of "membrane efficiency" for invert emulsion fluids have produced surprising results. Data have been collected that supports the notion that invert emulsion drilling fluids do not necessarily yield a perfect osmotic membrane. The nature of the solute in the internal phase, not just its concentration and resultant water activity, and the emulsifier package may affect the interaction of invert emulsion fluids with shales, including the transport of fluids into or out of the shale.
Observed osmotic pressure differences are compared with values predicted by osmotic theory. From this comparison arises an easy-to-understand empirical concept of membrane efficiency. The assumption that specification of a solute and its concentration in the internal phase of an invert emulsion fluid is sufficient for assuring generation of an effective drilling fluid may be incorrect.
Preliminary results are given for water-based mud formulations which achieve about ¼ to ½ the osmotic pressure of a typical oil-based mud.
Casing Deformation in a Tectonic Setting: Evaluation, Impact and Management
Authors: Last Nigel , Mujica Santiago , Pattillo Phillip , Kelso Gary 
Published: December 2007

Abstract
Ovalisation of casing strings has been detected in the tectonically active foothills of Colombia South America, initially through operational difficulties, and subsequently by extensive monitoring.
Characterising the deformation, assessing its impact on well integrity, and developing a strategy for managing the consequences to achieve improved business and operational decision making are summarized in this paper.
Extending Squeeze Lifetimes Using Miscible Displacement
Authors: Collins I. R. , Hewartson J. A. 
Published: December 2007

Abstract
As the industry moves towards increasing deepwater production, the very high cost of well intervention places large constraints upon the performance of scale control options. In particular, where scale is managed by squeeze treating, it is an absolute requirement that the treatment lasts as long as possible and efficiently utilizes the applied chemical. This paper discusses using enhanced oil recovery-type surfactant systems in conjunction with scale inhibitors to dramatically extend the squeeze treatment lifetime. It is believed that the treatment lifetime is extended by the miscible displacement of organic material from formation surfaces thereby increasing the surface area available for the scale inhibitor to adsorb onto. The efficacy of this approach, using simple to formulate packages, is demonstrated by coreflood data in which the lifetime of the treatment is extended by up to four times.
A New Model for Mineral Scale Adhesion
Authors: Collins I. R. 
Published: December 2007

Abstract
Mineral scale formation and deposition on downhole and surface equipment is a major source of cost and reduced production to the oil industry. One potential means of preventing losses due to scale is to prevent it adhering/depositing on key components in the production system (such as downhole safety valves and key parts of intelligent well systems). In general, the coatings proposed to prevent deposition of scales are made of low-surface energy materials. However, industry experience of non-adherent coatings is not good and a search of the literature suggests that there are a number of contrary reports on the effects of surface energy on solid deposition behavior. Some reports show that deposits attached preferentially to high surface energy surfaces, while others purport to show that deposits attach preferentially to surfaces with low surface energy. Numerous studies also indicate that there is little relationship between surface energy/wettability and deposition behavior. Obviously a sound theoretical explanation of the observed deposition behaviour on various surfaces is crucial for the development, and deployment, of low-deposition surfaces. In this paper, the extended DLVO theory is used to explain scale deposition behaviour on metal substrates, and on modified metal surfaces. The proposed theory is shown to agree well with the limited experimental data available and thus provides the basis for a sound theoretical approach to controlling and preventing scale adhesion on surfaces
Development and Application of a Silicate Scale Inhibitor for ASP Flooding Production Scale
Authors: Qing Jia , Bin Zhou , Ronglan Zhang , Zhongxi Chen , Yuchun Zhou 
Published: December 2007

Abstract
Three ASP (Alkaline, surfactant and polymer) flooding projects and one multicomponent foam flooding project have been carried out in Daqing Oilfield. The increases of oil recovery rates are all above 20% (OOIP). One of the major troubles that happened during the three ASP flooding projects and the multicomponent foam flooding project was silicate scale deposition in the tubings of production wells which caused frequent downhole operation failure. To prevent scale deposition in production wells, a scale inhibitor, which works well in brines of pH values as high as 12 was developed. The scale inhibitor is effective both on carbonate scale and on the mixed scale of carbonate and silicate. The scale inhibitor was tested on 6 production wells in two ASP flooding project zones. The pull-out period of the tested production wells were elongated from 1 month to 9 month during the test.
Modelling of In-Situ Scale Deposition: The Impact of Reservoir and Well Geometries and Kinetic Reaction Rates
Authors: Mackay E. J. 
Published: December 2007

Abstract
Previous work has demonstrated how and where the mixing of incompatible brines occurs in waterflooded reservoirs, and what the impact would be on scale prevention strategies in terms of timing and placement of squeeze treatments. This paper extends this work, by modelling the resulting in-situ deposition process. The location of maximum scale deposition and the resulting brine compositions at the production well are calculated for a range of sensitivities, including reservoir geometry (1D, 2D areal, 2D vertical, 3D), well geometry (location and orientation within field and with respect to other wells and the aquifer), and reaction rate (ranging from no precipitation to equilibrium).
In conventional systems with no aquifer, it is demonstrated that maximum scale deposition occurs in the immediate vicinity of the production wellbore, and therefore low produced cation concentrations indicate inadequate squeeze treatments. In systems where water injection is into the aquifer, low cation concentrations may also result from deposition deeper within the reservoir. Maximum scale dropout still occurs as the fluids approach the production well, but sufficiently far from the wellbore to be unaffected by squeeze treatments, or to have any major impact on productivity. The reaction rate is critical in determining the amount of scale deposition, but even under equilibrium conditions, sufficient concentrations of scaling ions are delivered to the production well to necessitate squeezing the well, although using lower volumes of inhibitor. Once cation concentrations have been reduced, it is predicted that they will never pick up again.
This paper also discusses some of the limitations of modelling such systems, which include the determination of the kinetic reaction rates, size of the mixing zone, and the impact on permeability. Although the thermodynamics are fairly well understood, the kinetics are much more difficult. The size of the mixing zone is affected by numerical dispersion, and computationally intensive techniques are required to overcome this problem. Previous experience shows that formation damage factors are very difficult to extrapolate from coreflood data because there is a great difference between the dimensions of the mixing zone in the reservoir and the core plug.
Managing Workplace Health and Welfare-related Issues in the Shadows of HIV/AIDS: The Way Forward in the Oil and Gas Industries
Authors: Faleyimu B. xsL. , Ajayi PA , Fagade O. A. , IH Jonathan , Kpiasi E. O. 
Published: December 2007

Abstract
HIV/AIDS has become an unprecedented epidemic and public health emergency. Globally, about 36 million people are infected with HIV, and over 21 million have died of AIDS-related illnesses and the number of new HIV infections continues to rise. In some countries in Africa, AIDS-related morbidity and mortality are causing major reversals in development, childhood mortality, and survival and life expectancy.
HIV/AIDS presents a major obstacle to economic growth and stability in the workforce and the epidemic has affected most business with prolonged staff illness, absenteeism and death, thereby impacting on productivity, employee benefits, occupational health and safety, production costs and workplace morale.
Both private and public sectors now have strong economic and social reasons for becoming active in promoting HIV/AIDS prevention both in the workplace and in the community if they are to protect the "bottom-line".
In pursuing this obligation, one area of controversy is Pre-Employment and Workplace HIV testing as it affects job placement, disengagement, employee benefits and co-workers fears. The AIDS epidemic has introduced a potentially complex conflict between the doctrine of strict confidentiality, beliefs of human right activists, employee's future and the dictates of business interest, with serious ramification for the individual, the family, employers and the community.
As the HIV/AIDS epidemic progresses, companies continue to face increasing numbers of HIV-positive employees and will have to deal with a variety of employee-related health and benefit issues.
One of the most effective ways of reducing and managing the impact of HIV/AIDS in the workplace is through the implementation of an HIV/AIDS Workplace policy and Prevention programs. This paper will therefore attempt to review HIV/AIDS in the Workplace, the Health and Welfare-related issues especially as it affects the Oil and Gas Industries and drawing from the experience of the Chevron's Workplace AIDS Prevention program, proffer a way forward.
Flow Behavior of Fracturing Slurries in Coiled Tubing
Authors: Shah S. N. , Zhou Y. , Goel Naval 
Published: December 2007

AbstractHydraulic fracturing through coiled tubing (CT) has become an effective and economical stimulation technique for wells with multiple zones to be fractured. Yet, prediction of friction pressure losses of fracturing slurries in coiled tubing presents a unique challenge in the fracturing job design.This paper presents an experimental study of friction pressure losses of fracturing slurries in coiled tubing using a full-scale coiled tubing test loop which consists of 1000 ft 2–3/8″ coiled tubing and 200 ft 2–3/8″ straight tubing sections. The fracturing slurries were prepared with guar-based gels at various polymer and sand concentrations. Based on the experimental results, the characteristics of the flow behavior of fracturing slurries as affected by sand concentration, base gel rheology and centrifugal forces are discussed. A new correlation has been developed and can be used to predict the friction loss increase over base gel friction.The coiled tubing erosion mechanisms (sliding abrasion, random particle impact, and directional particle impact) have been discussed. The abrasion by sliding sand bed is believed to be the dominant erosion mechanism.
Practical Application Of Spherical Flow Transient Analysis
Authors: Abbott W.A. , Collins T. , Tippie D.B. 
Published: December 2007

Introduction
Spherical flow is not a new concept, and its occurrence has long been recognized. Muskat derived equations for the steady-state fluid velocity, potential function and productivity for wells producing from partially penetrated strata. Transient spherical flow theory has been described by Chatas, Culham and others. This paper attempts to demonstrate the practical uses for spherical flow analysis based practical uses for spherical flow analysis based on the theory developed by others. Examples of field data are used to demonstrate how this analysis can aid in well test interpretation and provide data and insight for reservoir and provide data and insight for reservoir and production studies. production studies. CONDITIONS CREATING SPHERICAL FLOW Ideally spherical flow is flow along the radii of a sphere. Concentric spheres are equipotential surfaces. The center of the sphere is either a point sink or point source. Figure 1 shows the ideal geometry of spherical flow. Hemispherical flow, also shown in Figure 1 is identical to spherical flow with the obvious exception that the flow is contained within a hemisphere. Analysis is the same for spherical and hemispherical flow, The term "spherical flow" will be used herein and is meant to include hemispherical flow. Spherical flow is created -in petroleum production when massive reservoirs are partially production when massive reservoirs are partially completed or partially penetrated. Figure 2 shows these two conditions. For these two cases, the flow is not purely spherical because the completion interval is not a true point sink. However, the flow is spherical in a practical sense if the completion interval is very short relative to the net pay. It can be seen from these Figures that any condition forcing flow toward a single "sink" will promote spherical flow. Data obtained from a wireline tester are analyzed using spherical techniques. Plugged perforations or blockage of a large part of an open-hole interval may also promote spherical flow. promote spherical flow.
Miscible Gas Injection in Fractured Reservoirs
Authors: Uleberg Knut , Høier Lars 
Published: December 2007

Abstract
This paper discusses miscible gas injection in fractured reservoirs, based on compositional reservoir modeling. Developed miscibility in conventional one-dimensional systems is dependent on fluid properties alone, and can be estimated by well known experimental and numerical procedures. This is not the case for heterogeneous and multi-dimensional systems such as fractured reservoirs.
Based on a multi-cell algorithm a method is proposed to determine conditions of developed miscibility in fractured reservoirs. The proposed method makes it possible to evaluate gas injection processes, and developed miscibility in particular, in specific regions of the reservoir.
A systematic step-by-step extension from a single one-dimensional matrix block to more complex matrix-fracture systems shows that the minimum miscibility pressure/enrichment (MMP/MME) level in a fractured reservoir is significantly higher than for a conventional one-dimensional single-porosity system. This is mainly due to multi-dimensional flow and molecular diffusion.
On the other hand, even at pressures significantly below the fracture system MMP, substantial enhancements in the recovery rate and ultimate oil recovery can be expected by non-equilibrium gas injection. It is shown that reduction of the gas-oil interfacial tension and internal Darcy flow induced by interfacial tension gradients play a key role. This capillary driven process may lead to accelerated production and very high ultimate recoveries.