bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innovative Completion Technology, Preparation, and Contingency Planning Simplifies Baltim Completions While Increasing Reliability and Reducing Remedial Cost
Authors: Aaty Mohamed Gharieb A. , Zuchini Ivano , Giusti F. Duke 
Published: December 2007

Abstract
Enhanced simplicity and reliability are critical in offshore development because of the increased costs of intervention when compared to onshore services. Therefore, many innovative equipment and operational techniques have been introduced to more effectively support these needs in offshore scenarios. For example, cut-to-release production packers provide the reliability of permanent packers but also provide capability to retrieve the entire completion without conducting costly and potentially damaging milling operations. The use of nippleless lock technology keeps the required number of landing nipples to a minimum, while providing the utility to place flow-control devices anywhere in the completion string. In addition to these and other proven completion technologies, the thorough precompletion make-up and testing procedures that are conducted for the assemblies further enhance reliability. When Petrobel began development of their offshore Baltim Field and decided to adopt the above mentioned philosophies, their effectiveness was proven very early in the campaign when leaking tubing necessitated pulling of the completion in the first well of the project.
Because of the overall success experienced in completing the Baltim wells, Petrobel is planning to use the same completion design, though modified to eliminate slickline intervention, in the upcoming Temsah Platform development.
Lower Cretaceous Stratigraphy of Abu Dhabi and the United Arab Emirates - A Reappraisal
Authors: GRANIER Bruno R.C. 
Published: December 2007

Abstract
This paper presents a reappraisal of the published papers on stratigraphic nomenclatures of the Lower Cretaceous rocks. Thought it focuses on the Abu Dhabi offshore areas, it also deals with coeval strata from the neighbouring emirates and countries (Oman, Qatar, etc.). A new stratigraphic classification emerged from the review of the currently used operational units in Abu Dhabi. Accordingly, the Kahmah Allogroup (the best substitute for the Thamama Group) as defined herein comprises 7 alloformations/synthems which are from top to bottom: Shu'aiba, Hawar, Kharaib, Lekhwair, Zakum, Belbazem (new name), and Bu Haseer (new name); Bab and - revised - Habshan are excluded from this allogroup and respectively transferred to Wasi'a and Sahtan allogroups. This new classification which is based on ‘unconformity-bounded units’ is supported by both biostratigraphic and sequence stratigraphic evidence. This revised stratigraphic framework suggests a new interpretation of regional basin history.
Control of Hydrogen Sulphide Scavenger Induced Scale and the Associated Challenge of Sulphide Scale Formation Within a North Sea High Temperature/High Salinity Fields Production Wells. Laboratory Evaluation to Field Application
Authors: Jordan M. M. , Mackin K. , Johnston C. J. , Feasey N. D. 
Published: December 2007

Abstract
Precipitation of mineral scales causes many problems in oil and gas production operations: formation damage, production losses, increased workovers in both producers and injectors, poor injection water quality and equipment failures due to under-deposit corrosion. The most common mineral scales encountered with downhole and topside processes are sulphate and carbonate-based minerals. The development over the past few years of fields where high temperature and high salinity brines are being produced with associated hydrocarbon has presented a more challenging environment for scale management. In such fields hydrogen sulphide gas is quite a common component of the produced fluids. To remove the gas from the process stream hydrogen sulphide scavengers are applied. The introduction of these chemicals can result in a secondary problem arising from their relatively high pH. Changes in localized pH associated with the introduction of such production chemicals has been observed to induce carbonate scale precipitation and in the case of one high salinity brine system unexpected sulphide scales of lead and zinc.
This paper will focus on the mechanism of occurrence of such scale types within a North Sea field and how an inhibitor package was developed that controls both carbonate and sulphide scale formation while it also effectively controls associated hydrogen sulphide. It will outline the field and laboratory testing methods utilized for assessment of the scale challenge, the chemical screening methods used and assess the currently available prediction software so that evaluation of the potential problem within fields during appraisal can be determined prior to production commencing.
Study of Calcium Carbonate Precipitation in the Near-Well Region Using 47Ca2+ as Tracer
Authors: Stamatakis E. , Haugan A. , Chatzichristos C. , Stubos A. , Muller J. , Dugstad Ø. 
Published: December 2007

Abstract
The present study demonstrates radioactive tracer technology as a reliable source of information in scaling experiments in porous media. The critical information obtained from such experiments is the induction time of scaling and the profile of the scale deposition along the deposition medium. In a series of calcite scaling experiments in sandpacks, 47Ca2+ was used as a tracer to monitor CaCO3 precipitation. In these experiments the induction time and the distribution of scale deposition were studied as a function of saturation ratio, temperature, flow velocity, the presence of Mg ions and the type of packing material. The results show that the radiotracer method gives a fast response to scaling events. The technique is applicable for dynamic scaling investigations in any flowing system in porous media and constitutes a valuable tool for further studies of scaling mechanisms involved in processes occurring in a variety of systems (oilfield, geothermal, desalination etc).
Inhibition of Barite Scale in the Presence Of Hydrate Inhibitors
Authors: Tomson Mason B. , Kan Amy T. , Fu Gongmin 
Published: December 2007

Abstract
Large volumes of hydrate inhibitors (e.g., methanol, ethanol, monoethylene glycol, and triethylene glycol as cosolvent) are added to control hydrate formation. Such practice has an adverse effect on scale formation since the mineral salts are generally less soluble in the cosolvent. Due to production from reservoirs, oilfield brines are often close to saturation as they enter a well, even a small amount of added methanol, ethanol, etc., is often sufficient to induce various minerals to precipitate, particularly the sparingly soluble minerals, e.g., barite. For example, barite solubility is reduced by as much as 20 folds, with 50% (w/w) methanol.
In this paper, barite nucleation rate were studied over a wide range of concentrations, e.g., Ba (0.5–1.8 mm) SO4 (0.5–1.8 mm) methanol (0–40%), monoethylene glycol (0–40%) or triethylene glycol (40%). Barite nucleation rate is significantly accelerated in as little as 5% (wt/wt) methanol. The barite nucleation rate can be modeled with a modified classical nucleation theory. The inhibition of barite by two phosphonate inhibitors and a polymer inhibitor in the co-solvent/brine solution is more complex. At lower co-solvent concentrations (&lt;30% w/w), the nucleation inhibition can be predicted with a previously derived semi-empirical model that mathematically separates the effect of added inhibitors from that of the uninhibited mineral phase. At high methanol (&gt;30%) concentration, barite nucleation may be difficult to inhibit by scale inhibitors, due to high supersaturation and the tendency of phosphonate to be precipitated as metal salt.
Inhibition of BaSO4 at a Hastelloy Metal Surface and in Solution: The Consequences of Falling Below the Minimum Inhibitor Concentration (MIC)
Authors: Graham A. L. , Vieille E. , Neville A. , Boak L. S. , Sorbie K. S. 
Published: December 2007

Abstract
Scale inhibition efficiency is determined in bulk jar tests in order to determine a minimum inhibitor concentration (MIC) which gives some acceptable level of inhibition (say 95%). However, this test refers principally to the bulk precipitation of barium mineral scale from solution, rather than its deposition on a surface. The complementary tube blocking test gives some insight into scale adhesion at a surface, but this is a very short residence time test. An experimental study has been conducted to examine the interactions between surface and bulk BaSO4 scaling processes in uninhibited and inhibited supersaturated brines. In this study, precipitation both in bulk and onto a Hastelloy metal surface has been studied in longer term bulk jar tests at various temperatures. It has been demonstrated that the use of PPCA at concentrations beneath the MIC level, as determined by bulk jar tests, can promote surface scaling. This comes about as a result of complex interactions between bulk precipitation and surface scaling processes and these are discussed in this paper.
Development of Oil Soluble Precipitation Squeeze Technology for Application in Low and High Water Cut Wells
Authors: Heath S. M. , Wylde J. J. , Archibald M. , Sim M. , Collins I. R. 
Published: December 2007

ABSTRACT
Oilfield scale formation is dependent upon the production of water and as a result most scale inhibitors are water soluble and deployed using an aqueous phase. For treatment of wells that produce only small amounts of water and/or have water sensitive matrices and wells with high water cuts with lifting problems the use of an aqueous inhibitor can cause many problems. Even with the development of oil miscible and emulsified scale inhibitors the same problem can be encountered when the incorrect screening procedure has been used in the laboratory.
This study describes the development of a range of truly oil soluble scale inhibitors for squeeze application. A particular feature of these materials is that they preclude aqueous phases and are soluble in crude oil and diesels. The products have been designed so that is possible to deploy calcium sensitive scale inhibitors in a non-aqueous medium. Upon contact with formation water passing the near wellbore the scale inhibitor will partition into the water phase and undergo a precipitation reaction. This provides a mechanism for potentially increasing treatment lifetime.
In addition, the scale inhibitor precipitation can be further controlled and enhanced through emulsification with a calcium loaded aqueous medium also containing organic additives to aid and enhance the precipitation process. Although this involves incorporating water into the product package the invert emulsion provides an oil continuous matrix and is still considered to be significantly less damaging to water sensitive formations than standard oil dispersible and emulsified scale inhibitor packages.
A detailed investigation into the properties of selected oil soluble and emulsified products has been performed. Experimental data on compatibility with production fluids, thermal ageing, oil/water partitioning, inhibitor performance, extent of precipitation and core flood studies to evaluate formation damage potential and retention and release characteristics will be presented.
This paper will also highlight how the use of the oil soluble precipitation process can increase squeeze lifetimes when compared to traditional aqueous squeeze treatments. In addition, a new core flood procedure for the screening and evaluation of non-aqueous chemical treatments will be described and the implications this has for field application of these products will be discussed.
A Single-Stage Acid Treatment to Remove and Mitigate Calcium Carbonate Scale in Sandstone and Carbonate Reservoirs
Authors: Nasr-El-Din H. A. , Al-Saiari H. A. , Al-Hajji H. H. , Samy M. , Garcia M. , Frenier W. , Samuel M. 
Published: December 2007

Abstract
Combining scale inhibition with matrix stimulation in a single treatment has always been a challenge due to potential formation damage. This concern has been historically prominent in carbonate reservoirs, due to the accelerated precipitation of the scale inhibitor at very low pH values. Earlier experience in combining acid stimulation with scale inhibition in carbonate reservoirs has been reported with limited success.
This paper presents recent development in combining acid stimulation and scale inhibition treatments in sandstone and carbonate reservoirs. The combined treatment utilizes a newly developed scale inhibitor (a polymer-based inhibitor) that offers full compatibility with a wide range of the commercially available acidizing systems, including hydrochloric acid, mud acids and chelating agents.
This treatment minimizes the number of well interventions, significantly reduces well maintenance cost and improves the work-over efficiency. At least one scale inhibitor squeeze treatment is eliminated with every acid stimulation treatment. In addition, there are other inherent advantages including: effective inhibitor placement and better coverage of the target zone.
Injection of Incompatible Water as a Means of Water Shut-Off
Authors: Nasr-El-Din H. A. , Raju K. U. , Hilab V. V. , Esmail O. J. 
Published: December 2007

Abstract
This paper describes laboratory and modeling work to utilize high-sulfate pit brine and calcium chloride solutions as a means to the permeability of water producing zones. The study included compatibility tests, coreflood experiments, and scale prediction to calculate SI and SA at surface and reservoir conditions. The pit brine contains sulfate ions at 120,250 mg/L and its TDS is nearly 400,000 mg/L. Three solutions that contained calcium chloride at 10, 20, and 30 wt% were prepared. Coreflood tests were conducted using carbonate core of 100 to 1,100 md. Tests were conduced at 200°F (reservoir temperature) and overburden pressure of 2,000 psi. Most coreflood tests were conducted at 1 cm3/min. The pressure drop across the cores was monitored during these tests.
Compatibility tests indicated instantaneous precipitation of calcium sulfate when pit water and calcium chloride brines are mixed. Scale predictions are done for 10, 20 and 30 wt% CaCl2 brines with pit brine. The maximum super-saturation at 200°F for CaSO4 occurs at 45, 60 and 70 vol% of pit brine for 10, 20 and 30 wt% of CaCl2, respectively. Predictedmaximum anhydrite is nearly 55, 81 and 97 g/L for the three CaCl2 brines, respectively. Coreflood tests indicated that maximum core plugging occurs when pit brines is injected into cores saturated with CaCl2 brines. The degree of core damage depends on the injection rate. Core flood results were explained in terms of thermodynamics and viscous fingering effects, which occur when a less viscous fluid displaces a more viscous fluid in porous media.
Water production is a serious concern for oil and gas companies. On one hand, there is a cost required to lift this water, and to perform separation, treatment, and then disposal. In addition, water production causes scale, corrosion and emulsion problems. Therefore, every effort should be made to minimize excessive water production.Currenttechniques that rely on chemicals (cross-linked polymers) are expensive and in some cases these chemicals are not environmentally friendly. The technique described in this paper is simple, and utilizes simple and green chemistry. It can be used to plug water-producing zones in carbonate and sandstone reservoirs.
This paper introduces a simple, effective technique that can be used to reduce the flow into high permeability zones. This technique can be used to minimize drill string sticking that occurs during drilling and reduce the amount of produced water during production Coreflood tests indicated that this technique is very effective in reducing the permeability of reservoir cores.
Selection and Deployment of a Scale Inhibitor Squeeze Chemical for the BP Miller Field
Authors: Poynton Neil , Kelly Caroline , Fergusson Alasdair , Ray John , Webb Phil , Strong Allison 
Published: December 2007

Abstract
The BP operated Miller field arguably produces the most severe barium sulphate scaling waters in the world. There is an operational need to carry out scale squeeze operations almost continually in order to maintain the oil and gas production.
In this paper, we will present the challenges overcome proposing and in applying a new downhole product in this challenging environment. The paper will describe the selection process and test protocols needed to identify suitable squeeze inhibitor chemistry and review the laboratory data generated for a specific chemistry.
A pre-requisite in assuring the performance of a squeeze chemical on the Miller asset is the ability, for the supplier, to guarantee a 24 hour turn around time for residual inhibitor analysis. The conventional detection method for the type of chemistry selected is the hyamine test, which is time consuming and can be inaccurate. This paper will also include results from the Baker Petrolite High Performance Liquid Chromatography (HPLC) method for residual analysis, developed for detection of polymeric scale inhibitors in produced water. This method has the advantage of producing accurate results in a very short time frame.
The paper will also review the actual deployment of this chemical in the field, and demonstrate how the implementation of the selected chemistry resulted in immediate annualized operational savings to BP of an estimated $2.9MM on a single well.
The results of Squeeze V modeling are also reported, demonstrating how the squeeze applications are being optimized to bring even larger operational savings to BP by improving the squeeze lives on selected wells.
How Scale Inhibitors Work: Mechanisms of Selected Barium Sulphate Scale inhibitors Across a Wide Temperature Range
Authors: Sorbie K. S. , Laing N. 
Published: December 2007

Abstract
Scale inhibitors (SI) have been applied very successfully over many years in oilfields to prevent the formation of mineral scale. Both barium sulphate and calcium carbonate scales may be prevented using inhibitors, although in this work we will focus on the more difficult barite inhibition problem. A number of publications have appeared discussing the mechanisms by which barium sulphate scale inhibitors operate to prevent or retard scale formation. The mechanisms are discussed here in terms of (a) nucleation inhibition where the scale proto-crystals forms but are then disrupted or redissolved by the action of the inhibitor molecules, and (b) crystal growth inhibition where the inhibitor is thought to adsorb or interact with the active crystal growth sites (growing edges or spirals) hence retarding or stopping the crystal growth process. Both of these mechanisms are consistent with the inhibition of mineral scale at "threshold" levels, typically for MIC = 0.5 – 20 ppm (MIC = minimum inhibitor concentration for a defined level of inhibition for a given test procedure). The MIC is always considerably below stoichiometric values in terms of the scale inhibitor to mineral scale molar ratios. It is known that most inhibitor types from the small molecular phosphonates (e.g. DETPMP) to polymeric species (e.g. PAA, PVS, PPCA) actually operate through both of the above mechanisms although one of these may predominate for specific species. Previous work has established that, broadly speaking, smaller phosphonates operate principally as crystal growth inhibitors and polymeric species work mainly as nucleation inhibitors.
A number of factors are known to affect the inhibition efficiency (IE) of scale inhibitors against barite formation, the main ones of concern here being pH, temperature and the calcium and magnesium levels in the scaling brine mixture. The general observed effects of these factors have been described in the literature and will be discussed in detail in this paper. However, no complete description of the mechanism of barite inhibition has appeared which clearly and consistently explains all of the observed effects of these parameters for different scale inhibitor types. It is the central aim of this paper to present a complete and consistent set of mechanisms for barite inhibition which may vary in degree for different inhibitor types. Our proposed mechanisms are based on a wide range of observations from the open literature analysed with our own experimental and modelling results.
Avoiding Drilling Equipment Downtime – Four Case Studies
Authors: Sattler Jeff , Reed Bob 
Published: December 2007

Abstract
Occasionally, equipment issues drift out of focus as long as the drill bit keeps turning to the right and no "incidents" are recorded, particularly when activity levels and utilization rates are high. Unfortunately, it sometime takes a significant event to regain compliance with established operating and maintenance policies and procedures.
Investigations were undertaken as a result of events that occurred on four rigs. This paper will outline these incidents, describe the root causes determined, and delineate recommended steps that might be taken to prevent similar events.
Applications and Case Histories of Geared Turbodrilling in the North Sea
Authors: Beaton T. , Seale R. , Van Den Bos M. , Salomons G. , Strang G. 
Published: December 2007

Abstract
Over the years, drilling technology in the Dutch sector of the North Sea has evolved in an attempt to overcome many drilling challenges. Gaz de France’s 12-1/4" hole section, in the K12 field, has been a very active arena for technological advancement and new product development. Many new drilling systems and new drill bit designs have been tested and developed through this complex drilling interval. However, even with all of the advanced technology utilized in drilling this section, many operational difficulties remain, due to the variety of formations, the directional requirements, and the length of this interval. Until recently, this section was drilled using a variety of different products, including roller cone and PDC drill bits, on both downhole motors and rotary drive systems.
In an effort to improve the performance through this interval, another new technology was introduced to this drilling program, the geared Turbodrill. This new downhole drive system is capable of producing very high mechanical power at the bit, both high torque and relatively high RPM. The high power of this new tool, in conjunction with aggressive PDC drill bits, has proven to provide excellent performance in this challenging environment. This paper will detail the development and characteristics of this new geared Turbodrill, and also analyze recent North Sea case histories that included the 12-1/4" hole section through the upper Cretaceous chalk down to the upper Permian Zechstein formation.