bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonintervention Solutions to the Loss of Downhole Data in a Subsea Field
Authors: Lumsden P.J. , Batten A.H. , Phillips H.T. 
Published: December 2007

Abstract
The installation of permanent downhole pressure gauges as part of the Arkwright subsea development, was seen as the ideal solution to control escalating development costs and to satisfy reservoir performance monitoring needs. However, the failure of all nine pressure gauges, during the first seven months of field life, warranted the search for alternative methods of data gathering. This failure was compounded by the tight economic nature of the field necessitating a search for a method, or methods, outside those involving costly rig based well interventions. Initially, use was made of a combination of two-rate drawdown analysis techniques and wellhead to bottomhole extrapolations, which gave results consistent with those from earlier build-up analyses during periods when real' downhole data were available. However, this method soon became outdated with the onset of water breakthrough in two of the three production wells. An alternative method was identified which injected lift gas directly into the wellbore at the wellhead, completely displacing the in-situ reservoir fluid to the perforations. Reservoir pressures were then calculated from a static wellhead to bottomhole relationship based upon the lift gas properties and the conditions in each well. Initial testing of this method has proved encouraging.
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Drilling of an Intermediate Radius Long Lateral in the Dunbar Field
Authors: Charlez Ph.A. , Ryan M. , Brandie G. 
Published: December 2007

Abstract
This paper descrihes the drilling of an intermediate radius, long lateral side-track drain in the Dunbar field (Central Graben - North Sea) initiated from a low inclination (32.30) parent hole which had been drilled four years earlier. The main goal was to constrain the drain within the upper part of the UMS formation (Upper Massive Sand - Brent reservoir) over a distance of l000m from the parent hole. The kick-off (51 /30m DLS) was successflilly achieved in two runs and 48 hours using a short titanium downhole motor with a 30 adjustable kick-off (AKO) setting. Thereafter, 910m of horizontal drain were drilled in 4 runs (10 days) with an intermediate length motor (6 meters) and PDC bits making a total lateral length of 1000m. Actual torque and drag remained satisfactory and close to those predicted by drillstring models. The major part of the drain was drilled in rotary mode (only minor azimuth corrections in sliding mode were necessary). The lateral was logged (gamma, sonic and resistivity) in TLC mode. Finally, and according to the results of an advanced wellbore stability study (no sand production expected) the drain was kept open hole and the parent hole completed with a monobore 4 1/2" tubing.
D05z lateral is the first extremely long lateral drilled in the North Sea after such a dog-leg. The combination of high DLS (up to 51 /30m), TVD (3570m) and length (l000m) marks it as one of the most challenging wells drilled in the North Sea.
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Buoyancy Assist Extends Casing Reach in Horizontal Wells
Authors: Rogers H. E. , Bolado D. L. , Sullaway B. L. 
Published: December 2007

Abstract
This paper describes a case history of how a major operator operating offshore Louisiana, in the Gulf of Mexico, extended the casing-setting depth of a well by creating buoyancy in the leading section of the casing. The buoyancy was created when an air pocket was trapped between the float shoe on the end of the casing and drillable buoyancy-assisted casing equipment (BACE™) assembly located in the casing at a calculated distance from the float shoe.
Problems encountered when casing is run in a horizontal or highly-deviated well are compounded by the drag of the casing on the lower side of the wellbore. Adding buoyancy to the lower end of the casing string reduces friction between the casing and the wellbore, thus enabling the casing weight in the vertical section of the well to push the casing deeper into the horizontal section.
BACE assembly used to enhance buoyancy can present the following operational advantages: full casing inside diameter (ID) after releaselarge annular clearance between BACE assembly internal components outside diameter (OD) and casing IDthread-type anchoring system (no shear pins, holes in the case, etc.)
This paper presents calculations, equipment design, operational detail, and results of BACE assembly used on the operator's platform.
Multiphase Metering: Experimental Results From the Analysis of Acoustic Noise Through a Choke
Authors: Piantanida Marco , Mazzoni Agostino , Tanzi Alessandro , Hope Bjorn R. 
Published: December 2007

Abstract
In this paper we discuss the main experimental results obtained during the field verification tests of the Well Flow Analyser (WFA). The WFA is a multiphase flow meter developed by SENSORTEKNIKK (Norway) and ENI, with the support of NORSK AGIP and STATOIL. The WFA predicts the flow rates of each component (oil, water, gas) in the multiphase stream, by analysing the noise generated by the fluid when passing across a choke valve. The instrument has been tested extensively in real conditions in the Trecate test loop which is located in the Trecate - Villafortuna oil field, at about 60 Km from Milan. The system used for the tests is relatively simple: it consists of an acoustic sensor installed on a Willis choke and a signal processing unit controlled by a personal computer.
We highlight the main technical challenges that have been overcome and the performance of the instrument, as a result of the tests carried out in Trecate along 1997.
The development of the instrument required the application of advanced processing techniques, such as digital signal processing algorithms (Fast Fourier Transform, Wavelet transform), multivariate statistical analysis and the use of neural network models, to extract the information related to the multiphase flow from the acoustic spectra. The resulting instrument has been tested on a broad range of oil, gas and water flow conditions, providing flow rate estimations with an average error of 5%-15%.
Finally, we describe the benefits related to the application of the WFA to well testing measurements, as well as the problems related to its calibration.
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Development of an Oil-Soluble Scale Inhibitor for a Subsea Satellite Field
Authors: Wat Rex , Montgomerie Harry , Hagen Thomas , Børeng Raymond , Kotlar Hans Kristian , Vikane Olav 
Published: December 2007

Abstract
The formation of oilfield scales is often caused by the mixing of incompatible waters and/or by changing pressure and temperature causing a reduction in the solubility of the dissolved solids in the produced water. To inhibit scale formation chemical inhibitor typically operates by either nucleation inhibition or crystal growth modification, is added to the water. Almost all scale inhibitor chemicals are water soluble and are typically deployed continuously or by squeeze from an aqueous phase. In most circumstances water is the preferred carrier medium since it allows instantaneous mixing and rapid interaction with the scaling ions. However, for treating a water sensitive formation or a well with poor lifting energy, the application of a conventional water based scale inhibitor squeeze may have many drawbacks. These include extended clean up period, increased water saturation in the near wellbore area, cessation of production due to water ingress. Either of these can result in significant loss or deferment in the oil production. In this paper a new range of scale inhibitors which are solubilised in the hydrocarbon phase will be described. These new oil soluble scale inhibitors offer some advantages over the conventional water based products. Furthermore, unlike the oil ‘miscible’ products of the past, these new scale inhibitors do not contain any mutual solvent which sometimes can cause process upset during the backflow after the squeeze treatment. The paper will focus on the development of a product which is specifically designed for a sub-sea satellite field. Due to its unique properties some of the standard test methods and selection processes have to be modified. Special considerations on the treatment design are also needed due to the deployment constraints in the field.
Application of Computer Simulation Techniques and Solid Divertor to Improve Inhibitor Squeeze Treatments in Horizontal Wells
Authors: Jordan M. M. , Edgerton M. , Mackay E. J. 
Published: December 2007

Abstract
This paper presents field results from five scale squeeze treatments carried out on sub-sea horizontal wells from the Strathspey field in the North Sea. The development of a squeeze policy is outlined with the utilisation of laboratory coreflood data, computer simulation (SQUEEZE V Code) and the application of a novel solid divertor.
This paper outlines the practical difficulties in squeezing sub-sea horizontal wells and how some of the problems can be overcome. Some of the solutions that will be discussed include the use of variations in pump rates to encourage propagation of inhibitor along the well-bore, and the utilisation of fluid diversion techniques (both mechanical and chemical). The significance of production logging tool (PLT) data or good reservoir simulation data to evaluate the location of water production and any cross flow prior to a squeeze treatment design will also be stressed. Details of divertor selection, design simulation and the field results from the five squeeze design strategies that have been implemented will be presented.
From this series of field treatments it can be concluded that the wells have all been successfully treated with no process upset during flowback. No decline in the wells’ productivity was observed as a result of these treatments. This paper shows that by using divertor agents, and by integrating near well-bore calculations (SQUEEZE V) and PLT/reservoir simulation data, it is possible to squeeze scale inhibitors into sub-sea horizontal wells without the need for coiled tubing intervention from a diving support vessel.
Changing Chemophysical Properties of Formation and Drilling Fluid Enhances Penetration Rate and Bit Life
Authors: Hayatdavoudi A. 
Published: December 2007

Abstract
This paper focuses on solving drilling problems that includes slow penetration rate, hole tightening, and short bit life. The goals are achieved through the alteration of chemophysical properties of the plastic, troublesome shales (i.e. "gumbo" shale.) Our studies of these issues show that most efforts of the past concentrated more on enhancing the penetration rate through the manipulation of weight on the bit, rotary speed, and other variables rather than by changing the chemistry of rock and drilling fluid and their interaction. As evidenced by setting two world drilling records in 1997, we were able to drill deeper and cheaper by designing and using a new Modular Drilling Fluid System, (MDFS) for the purpose of solving costly drilling problems. The properties and functions of MDSF are as follows. (1) It contains, through a reaction, a host of "anion" radicals linked to esters. Having a low surface tension, the mud filtrate with these radicals diffuses in the shale/rock capillaries rapidly like an "Anionic Wedge." The excess anionic charge adsorbed on the clay fraction of shales and mud particles cause strong repulsive forces within the shale capillaries. These forces in the rock/fluid interaction area weaken the rock shear resistance which result in the enhanced penetration rate due to the removal of the "sticky balling" material from the drill bit. (2) Unlike ordinary surfactants, the MDSF deposits a long lasting and lubricating coat on the shale and mud particles. The chemical "coat" changes physical properties oft the shale and mud particles (i.e. the particles with low friction cause enhanced bit life and less abrasion of drilling equipment).
By applying the new technique of changing chemophysical properties of formation and drilling fluids to the modern drilling technology, the contractors have successfully drilled more than 400,000 ft of hole over the last two years. Both the contractors and the operators have realized the considerable savings over the comparable footage drilled in the past.
Injection Water Treatment at the Source: Biocide-Enhanced Corrosion Inhibitor Squeeze Treatments of Water Supply Wells in a Central Arabia Oilfield
Authors: Rosser H. R. , Nasr-El-Din H. A , Al-Shammari N. A. , Al-Dhafeeri A. M. 
Published: December 2007

Abstract
A novel inhibitor squeeze program has been applied to control SRB (sulfate-reducing bacteria) and microbially-influenced corrosion (MIC) in the injection water supply wells of a sweet, Arab Superlight oilfield located in Central Saudi Arabia. The treatment is based on a biocide-enhanced corrosion inhibitor squeeze, spear-headed by concentrated biocide, and is unique in attempting to affect control of SRB and MIC from within the aquifer supplying injection water to the system. Applications of the treatment were intensively monitored in the field to assess the rate of return of the chemical, and their effects on microbial populations in the wells. Non-surface active biocide components were produced back in short, concentrated slugs comparable to shock doses in pipeline treatment programs, providing effective short-term control of SRB activity in the water supply wells. Regrowth, however, resumes once the chemicals are flushed from the wells during normal production, limiting the effective life of the biocide treatment in these wells to 2–3 weeks. Amines are extensively adsorbed on clay minerals, and are produced back at low concentrations for extended periods of time. The data provide insight into the range of rock-chemical interactions that can occur when squeezing multi-component oilfield chemicals into a sandstone aquifer containing significant quantities of clay minerals. The investigation highlights the importance of effective microbiological control during initial drilling and completion operations, and the difficulty in treating established microbial populations in porous media with biocides developed primarily for pipeline systems.
Advances in Observation of Asphaltene Destabilization
Authors: Wang J. X. , Brower K. R. , Buckley J. S. 
Published: December 2007

Abstract
An optical observation cell was added to a mercury-free PVT apparatus to extend studies of the onset of asphaltene precipitation to elevated temperatures and pressures. Observations for asphaltic, paraffinic, and light to medium gravity crude oils are reported as a function of temperature, pressure, and mixing time. Precipitants ranged from heptane to propane.
Studies at ambient conditions have shown that the refractive index at the onset of precipitation is an important characteristic of oil/precipitant mixtures. Calculated values of refractive index as a function of temperature, pressure, and composition are being correlated to observations of asphaltene separation at elevated temperature and pressure, as a predictive test.
Interfacial Studies on Dissolved Gas Flotation
Authors: Oliveira R. C. G. , González G. , Oliveira J. F. 
Published: December 2007

Abstract
The removal of emulsified residual oil from water is an important issue due to the increasing concern with the environment. In the present paper various surface chemistry aspects of dissolved gas flotation were studied aiming at a better understanding of the mechanisms of the process. These studies included surface and interfacial tension measurements of a model system composed of n-dodecane in the presence and absence of nonyl-phenol.
After bubble/drop contact and rupture of the water film, oil drops have a tendency to spread over the bubble surfaces. Critical micelle concentration and spreading coefficients determinations were undertaken at different NaCl concentrations. The spreading coefficient proved to be a critical parameter in oil droplets flotation. The spreading coefficient increased with increasing salt concentration.
An experimental setup was designed to measure the induction contact time between single n-dodecane droplets and air bubbles. Induction time decreased with increasing salt concentration. In the presence of the nonyl-phenol aqueous solution, induction time decreased with time of stabilization. On the other hand, induction time increased with time of stabilization when nonyl-phenol was added to the organic phase. The mechanisms involved are discussed and some results obtained in a dissolved air flotation batch unit in which bubbles size was measured and controlled are also presented.
The Influence of Divalent Cations on the Performance of BaSO4 Scale Inhibitor Species
Authors: Boak L. S. , Graham G. M. , Sorbie K. S. 
Published: December 2007

Abstract
One of the most common methods of preventing downhole and topside mineral scale formation in oilfields is through the use of chemical scale inhibitors. Several aspects of the brine composition may affect the performance of the various scale inhibitors used in oilfield applications. In this paper, we focus on the influence of divalent cations such as calcium and magnesium. The concentration of such divalent cations is shown to effect the barium sulphate inhibition efficiency of generically different species of scale inhibitors by varying degrees, and in different directions. In previous work,1 the effect of calcium cations on the performance of various inhibitor species was demonstrated. In this paper, these observations are extended to include the effects of the magnesium cations in solution.
The influence of divalent cations such as Ca2+ and Mg2+ on the barium sulphate inhibition efficiency of generically different inhibitor species has been examined here in a variety of brine systems including low scaling "Brent type" and medium scaling "Forties type" brines. In addition, low salinity "ideal" brine systems have also been examined. The scale inhibitors studied include: penta-phosphonate (DETPMP), hexa-phosphonate (TETHMP), phosphino-poly carboxylate (PPCA) and poly-vinyl sulphonate (PVS). Results are presented from a series of static barium sulphate inhibition efficiency tests conducted at 95°C over 2 and 22 hour residence times.
The results presented here demonstrate how phosphonate inhibitors are significantly improved in the presence of [Ca2+] and also that their effectiveness is considerably reduced, or poisoned by increased [Mg2+]. The performance of the phos-phonate species are shown to be controlled by the performance of inhibitor/Ca2+ complexes, whereas the formation of inhibitor/Mg2+ complexes effectively poisons the phosphonate species ability to inhibit. The polymeric species (PPCA and PVS) are shown to be less influenced by increased [Mg2+]; indeed, marginally improved performance is obtained. This paper significantly extends the findings reported previously in SPE 37273.1
Application of a Mineral-Dispersion System to EOR
Authors: Li Jiyong 
Published: December 2007

Abstract
This paper presents a new technology for oil recovery enhancement in heterogeneous waterflooding under high tempterature and high water salinity the method mainly is to inject a mineral dispersion system(SMD) to improve the sweep effciency and recover the residual oil by emulsification-entrainment. This system is a pseudoplastic fluid with temperature tolerance,shearing resistence and good stability. Core flooding tests show the oil recovery is increased by 10%. The displacement nechanisms have been studied by microscopic modeling technique. After a successful pilot test,The commercial field test are conducted and the initial results are obtained.
Solids-Free H2S Scavenger Improves Performance and Operational Flexibility
Authors: Schieman Susan R. 
Published: December 2007

Abstract
HCI Travis has developed an H2S scavenger that offers the advantages of enhanced performance and a reacted material (scavenger + H2S) that is completely free of solids. Consequently, this product is suitable for use in a wider range of applications than many of the liquid scavengers currently available to the industry. The fact that the spent material consists of two liquid phases is of special interest to producers who want to scavenge H2S by using packed contact towers or continuous injection either directly into the flowline or into the annulus of a well. These application techniques generally allow for increased contact time and therefore optimize the use of the scavenger. However, it is imperative that solid formation does not occur in these scavenging systems as solids could lead to potentially serious operational problems.
This new material, SULFAGUARD™ 4531, was developed in 1995 and has been extensively field tested. Several case histories where SULFAGUARD™ 4531 was used to overcome operational limitations and where improved effectiveness over traditional triazine scavengers was demonstrated will be discussed.
Chemical Treatment vs. Mechanical Operations in Tank Cleaning: Who Won?
Authors: Shaheen S. E. , Ibrahim H. M. , Raoul P. G. 
Published: December 2007

Abstract
Sludge removal from a storage tank is an easy task if the objective is just to increase the storage capacity. However, sludge transformer in crude oil is much desirable in order to benefit from the value of the recovered crude. Desludging approaches used could be chemical or mechanical. The objective of this paper is to evaluate both these approaches and propose the most cost effective methodology in tank cleaning operations.
No doubt that performing the cleaning task without opening the tank is of advantage. Also working without adding chemical products, heating or applying steam is safer for the facilities and the workers.
Other aspects that are discussed in the paper include the need to eliminate pollution of air and soil, in addition to changing the sludge into crude which can be sold in the international market. Furthermore, real examples are discussed in the paper where the sludge in the tank was about 30.7 ft and the cleaning process is explained in detail. One of the examples shows how 74 676 barrels of sludge changed to crude in only 37 days by optimizing the applied technique.
The Advancement of the Petroleum Engineering Professional: Establishment of Professional Competency Guidelines
Authors: Bobo James E. , Reece Cindy 
Published: December 2007

Abstract
An SPE Task Force (Task Force) was established to define the criteria for minimum competency for petroleum engineers. The original scope of the task force was to apply minimum competency requirements to the U.S. Principles and Practice Examination for Petroleum Engineers (Exam). However, the resulting criteria can be used in more global endeavors. This includes the establishment of professional guidelines for continued professional development for petroleum engineers as well as integration with petroleum engineering degree curricula. This systematic approach will help foster efforts to elevate engineering to a recognized profession such as law or medicine.
Identification and Distribution of Natural Fractures
Authors: Song Xinmin , Zhu Yixiang , Liu Qinghuai , Chen Jun , Ren Dianxing , Li Yanlan , Wang Bo , Liao Mingshu 
Published: December 2007

Abstract
Identification and distribution of natural fractures are important in development of oil and gas fields. On the basis of detailed observation and description of core fractures and their comparison with advanced imaging well-logging fractures, natural fractures can be distinguished from induced fractures. Due to conventional well-logging responses to the high conductivity of fractures, all kinds of fractures may be recognized. Lithology and lithologic association control on the distribution and behavior of natural fractures under concurrent structural settings, natural fracture distribution is indirectly predicted by searching for lithologic combination, which is implemented by seismic inversion under the control of well- logging quality. In addition, fracture distribution is forecasted by extracting fracture information from compressional wave data after excluding lithologic factor.
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