bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seismic Assessment Procedures for Drilling Structures on Offshore Platforms
Authors: Turner J. Ward , Effenberger Michael , Irick Jack 
Published: December 2007

Abstract
The objective of this paper is to provide guidance for the seismic assessment and design of drilling structures on offshore platforms. As a start, recommendations are provided on how to analytically model a drilling structure. Guidance is then given on special mass modeling considerations and how to assess the interaction between setback, mass, and hook loading conditions. Considerable discussion is provided on the aspects of performing a dynamic analysis and how to extract structural reactions. A procedure is provided to rationally develop a consistent set of deck reactions that can be used to assess the integrity of the supporting deck structure. Finally, operational guidance is provided for operating a drilling rig in regions subject to earthquakes.
The guidelines provided are intended to be a supplement to the requirements contained in API Specification 4F. These guidelines are not specification requirements, but do provide a recommended practice for performing seismic assessments and designs of drilling structures on offshore platforms and jackup rigs.
Robotic Controlled Drilling: A New Rotary Steerable Drilling System for the Oil and Gas Industry
Authors: Tetsuo Yonezawa , Cargill Edward J. , Gaynor Tom M. , Hardin J. R. , Hay Richard T. , Akio Ikeda , Kiyosawa Yoshihide 
Published: December 2007

Abstract
The paper reviews the development of a second-generation rotary steerable drilling tool. The principle of operation is a bendable shaft that points the bit in the opposite direction to the shaft bending direction. This tilting action is a departure from other rotary steerable device concepts that push the bit sideways to change the wellbore trajectory. Combining this tilting action with extended gage bit technology provides maximum effectiveness in torque and drag reduction while reducing vibration and further improving hole cleaning. Important to the tool development was basing the design on lessons learned by others thereby improving both performance and reliability. The paper also discusses the application of proven technology from outside the drilling industry. Core elements such as strain wave gearing transmissions and electrically operated clutches were developed initially for use in industrial robots. Other significant elements are examined such as the shaft design, rotary seal systems and anti-rotation devices to limit housing roll rate. The "steering system" was integrated with an existing MWD system to allow automated or manual control from surface using a bi-directional communication system. This is also discussed.
Minimum Air and Water Flow Rates Required for Effective Cuttings Transport in High Angle and Horizontal Wells
Authors: Vieira P. , Miska S. , Reed T. , Kuru E. 
Published: December 2007

Abstract
Many studies have been conducted to determine the optimal hydraulic conditions when conventional fluids are used in drilling operations. However, little information is available for cuttings transport when gasified fluids are used as a drilling fluid. Since deviated and horizontal-well drilling are becoming more common and are frequently combined with the use of non-conventional drilling fluids, such as gasified fluids or aerated muds, a better understanding of the cuttings transport phenomena is needed for these applications.
This study was conducted to help filling this gap and to gain more in-depth understanding of cuttings transport in horizontal and highly-inclined wells when using gasified fluids. Extensive experiments were performed in a unique field-scale low-pressure flow loop (8″ × 4.5″, 90′ long) at horizontal and inclination angle of 80 degrees from vertical. Gravel with 3.29 mm average diameter was used to simulate drill cuttings and water and air were used as the liquid and gas phase. The three phases were injected into the test section of the flow loop, at different volumetric flow rates combinations, for the horizontal and 80 degree inclination angle. Pressure drop, annular pressure, temperature and cuttings accumulation were recorded in each experiment through a data acquisition system. Gas and fluid-interface distribution were visually observed and reported for each experiment. Likewise the solid-liquid distributions were classified into three different patterns and reported for each experiment. The effects of gas and liquid flow rates, drilling rate, inclination angle, pressure drop and flow patterns on cuttings transport were analyzed in this study.
It was observed in the experiments, for the range of volumetric flow rates used during these tests, that cuttings are only transported by the liquid phase. It was also found that it is possible to define a boundary for the minimum air and water velocities required to avoid the formation of a stationary cuttings bed. These minimum requirements exist in the intermittent flow region for the gas and liquid interface distribution. It was observed that the minimum requirements for air and water injection rates are also a function of the solids injection rate. It is postulated in this study that there is a minimum energy required for solids transport, and this is constant for a given solids injection rate. It was observed that the inclination effect for angles close to horizontal is negligible.
Intellectual Property for the Oil Field
Authors: Brewer Peter L. 
Published: December 2007

Abstract
This paper presents a general overview of intellectual property. Various types of intellectual property rights are identified and discussed, including patents, copyrights, trademarks, and trade secrets. The United States legal system provides enforceable property rights incident to each of these types of intellectual property. However, the corresponding property rights are distinct, and the process for protecting each type of intellectual property is very different. These differences are discussed in general terms in the paper so as to afford a foundation of knowledge for the layperson. In addition, the role of each type of intellectual property in the oil field is outlined.
This paper presents a general overview of intellectual property. The purpose is to identify different types of intellectual property recognized within the United States legal system, and to discuss intellectual property issues which oil companies and oil service companies currently face.1
Because of the complexity and sheer volume of laws and regulations which apply in intellectual property, it is not possible to provide more than a thumbnail sketch of the subject. This paper will serve as a useful reference tool for laypersons, enabling them to identify general issues as they might arise.
Offsetting Kill and Choke Lines Friction Losses for Deepwater Well Control: The Field Test
Authors: Isambourg Patrick , Simondin Armel , Studer Regis 
Published: December 2007

Abstract
Deepwater well control with a subsea BOP is often difficult and in many circumstances impossible with the usual methods and procedures. This is mainly due to the difficulty to maintain the circulating pressure below the low formation fracture pressure, because of high friction losses in kill and choke lines. Such a situation often leads to losing the drilled section. To cope with this situation, a new method was developed and presented in a previous paper. It consists in lightening the mud column inside the choke line by injecting base oil or water at the BOP level. Simulations using a dedicated software demonstrated the possibility to compensate lines friction losses.(essai labo ?) To validate simulations and to confirm the operational feasibility of this method, a field test was conducted on a Deepwater well in Angola. Pressures were recorded at surface, at the BOP level and downhole, and confirmed predicted values. The test was performed without any modification of the drilling rig, and no operational problems were encountered. The test fully confirmed that the method allows the physical removal of friction losses in the choke lines. The obtained downhole pressure during a well control is then lowered compared to a conventional method in all cases where the choke line friction losses cannot be removed artificially at the choke. (such as swak kick in an horizontal section). Test procedure, simulated pressures and field measurements, are detailed in this paper, and complemented by their analysis and resulting operational guide lines.
Unique Offshore Recovery System Dramatically Reduces Environmental Impact by Recycling Stimulation Proppant
Authors: Slater Martin , Perez Daniel , Teesdale Chris , Hilbig Nicholas 
Published: December 2007

Abstract
Over the past four years, the use of multiple-zone proppant fractures has significantly improved production and the ultimate productive life of horizontal wells in the Valhall chalk field. A typical well is designed with up to 10 proppant-fractured zones. The stimulation technique involves the pumping of as much as 300,000 lb of proppant into each zone and during this process up to 70,000 lb of excess proppant may remain in the wellbore, which is cleaned out using coiled tubing. Since the material contains a resin coating to facilitate adhesion in the reservoir, disposal is restricted.
Previously, this waste had to be collected offshore, placed in large bags, containerized and shipped to shore for incineration - a practice that was costly, wasteful and environmentally suspect. In 1997, engineering studies revealed that the properties of the waste material made it suitable for re-cycling and use in future operations with minimal impact on fracture performance. While re-using proppant has become an accepted practice with no noticeable effect on well productivity, logistically it had some limitations. The material still had to be collected offshore and transported onshore where it was stored for several months before being reloaded into the stimulation vessel for reuse in the next fracture treatment. This represents storage problems and environmental exposure of these materials. Furthermore, with no unforeseen delays, this was a 24-hour two-way trip.
This paper describes the development and successful application of a unique system that allows the excess proppant to be collected, treated and recycled on location. The authors will discuss the evolution of the recycling technique and discuss the step-change improvement that allows the material to be reused immediately offshore utilizing specialized vacuum equipment.
Some 150,000 lb of proppant was successfully recovered and recycled on the first well. The technique is still evolving and is likely to become a standard operation on Valhall wells. The offshore collection and recycling technique has eliminated the logistical problems associated with the previous method and will in time reduce the total proppant costs, along with minimizing the associated HSE impact.
Innovative Technology Improves Penetration Rates of PDC Bits in Shales Drilled at Great Depth with Weighted Water Based Mud Systems
Authors: Mensa-Wilmot Graham , Fear Martyn 
Published: December 2007

Abstract
Shales present lower mechanical and drillability challenges, when compared to other common lithology types such as sandstones and carbonates1,2. However the penetration rates (ROP) of drill bits, especially that of PDC bits, do not always reflect this characterization. Research efforts, focusing on shale drillability, have now revealed that bit performance in shales is much more dependent on factors such as depositional depths, mud types and mud weights than it is on hardness and/or abrasiveness3,4. The characteristics and/or magnitudes of these factors, that have adverse effects on bit performance, will be referred to as "negative performance factors" (NPF) in this paper. PDC bits usually drill twice as fast as roller cone (RC) bits in Shales. However, this ROP trend reverses when both bit types are exposed to NPF environments.
This paper will identify the causes of poor PDC bit performance when exposed to the influences of NPF environments. It will discuss an innovative technology which has specifically been developed to improve the ROPs of PDC bits in shales, especially when drilled at great depths with weighted water based mud systems. Laboratory and field data, showing the technology's positive effects on PDC bit performance will be presented. Specific laboratory tests, designed to identify operational conditions that enhance PDC bit performance in such applications, will also be discussed.
The Drilling Fluid Inhibition Properties Effect on Hole Quality - A Well Survey
Authors: Løklingholm G. 
Published: December 2007

Abstract
Shale inhibition is considered to be the most important factor to prevent hole problems when drilling with water based drilling fluid (WBM). Some components are believed to be vital for well bore inhibition like KCl, glycols and designed polymers. The effect of the products is largely based on the cuttings quality seen in the return flow at the rig. When new systems are introduced they are often tested in relatively simple wells and performance are evaluated based on results form that well.
Some incidental observations where systems not regarded as inhibitive outperformed the state of the art water based drilling fluid systems. This observation trigged of a larger survey on drilling efficiency with respect to water based drilling fluid system. Water based drilling fluid systems used in Statoil's operations over the last 15 years in the North Sea were compared with respect to hole quality. Data from the survey shows that today's highly inhibitive systems do not perform any better than systems used for 15 years ago. The survey raises a question around the way drilling fluid systems are designed today. Are we using the right methods for designing the drilling fluids?
The paper describes the result from the survey. In the paper a method using different "indicators" to measure the hole quality is used. Such indicators include: stuck pipe frequency, tripping time, drilling progress, caliper data and cuttings quality. As a result of the first part of the survey, the drilling fluid chemical composition was altered both when drilling through non-reactive and reactive formations in a series of wells. An increased drilling efficiency was observed. The paper describes how the drilling fluid composition could be optimized dependent on the smectite content of the formation.
Innovative Concept to Reduce the Total Cost of Scale Management through the Capture and Re-Use of Chemical Inhibitors
Authors: Feasey N. D. , Graham G. C. , Seland G. , Stalker R. 
Published: December 2007

Abstract
Conventional scale inhibitor squeezes are widely used to prevent or delay scale formation. Although long established the process can be wasteful of chemical used. In common with the use of most production chemicals such treatments are ‘once through’ and non-recoverable with high operating costs. In addition in offshore operations such production chemicals are discharged into the sea. Such discharges are also subject to environmental legislation with associated costs. Increasingly there is a need to avoid such discharges. Modifications of the squeeze procedure have been introduced to extend squeeze lifetime but further improvements are still sought. This paper describes the results of a study to investigate the potential for membrane separation to capture a representative scale inhibitor from brine. Over a range of temperatures, scale inhibitor concentrations and brine chemistries more than 96% of the scale inhibitor was captured. This was obtained without any attempt to optimise operating conditions. The resulting captured material was compared to the original product using dynamic tube blocking tests and static barium sulphate tests. The static tests showed similar performance for recovered and initial material, while the dynamic tests showed a marginal increase in performance for the recovered material in some cases. This increase in performance correlates with the retention factor for each given test run. It is believed that this is due to a slight purification of the inhibitor during the separation process, as shown by Dionex Ion Chromatography. The effective performance of the recovered inhibitor suggests that it could be re-used in a similar manner to the original product.
Meeting the Challenges of Downhole Scale Inhibitor Selection for an Environmentally Sensitive Part of the Norwegian North Sea
Authors: Chen Ping , Hagen Thomas , MacLean Alan , Selle Olav Martin , Stene Karin , Wat Rex 
Published: December 2007

Abstract
The Haltenbanken area is environmentally sensitive due to its plentiful fish reserves and licensees are therefore faced with stringent guidelines for the use of chemicals. The Heidrun Field is located within the Haltenbanken group consisting of Heidrun, Asgard and Norne. All are relatively new developments. The reservoir has a bottom hole temperature of 85°C and a relatively low reservoir pressure of 250 bar, hence seawater injection for pressure support has been utilized. With Ba2+ levels in the range from 100 to 300ppm, downhole sulphate scale deposition was identified within the formation and the gravel pack. This has been highlighted by the active squeeze campaign since spring 2000 when seawater first broke through. Different generic scale inhibitors, including one biodegradable scale inhibitor, have been deployed in the field so far.
Due to the environmental sensitivity of the area, the scale control strategy has focused on the selection of environmentally friendly, or green, scale inhibitors. Moreover, the selected green inhibitors as well as exhibiting good performance and a long squeeze life, must overcome the severe emulsion formation experienced topside during initial flowback.
In this paper, the laboratory evaluation of potential green scale inhibitors is presented and some novel inhibitor test methodology is discussed. For example, the effect of temperature on inhibitor efficiency was found to vary when the cooling method was compared with the standard method where the test sample was pre-set to a target temperature. The cooling method was therefore found to better simulate field conditions where the fluid experiences temperature drops as it travels from the formation to surface. Also, in the inhibitor adsorption/desorption study, the static beaker tests were found to be an effective method of testing inhibitor adsorption properties for quick screening. While traditional beaker tests focus on the inhibitor adsorption, the inhibitor desorption property is usually studied using core floods. In this paper we shall present a new methodology based on bulk desorption tests. This has been used, in addition to the conventional core test, for our chemical selection. The field inhibitor squeeze return data demonstrated that the newly selected inhibitor offered an improved squeeze life than that previously experienced on Heidrun.
How is Scale Prevention Affected by the Late Field Depressurisation of Waterflooded Reservoirs?
Authors: Mackay E. J. , Agiddi D. , Graham G. M. 
Published: December 2007

Abstract
A number of mature waterflooded fields, such as Brent in the North Sea and others elsewhere are undergoing tertiary recovery by depressurisation Pressure depletion is achieved by stopping water injection and by producing from the aquifer as well as the hydrocarbon bearing strata. Previously bypassed oil rims and trapped oil and gas are then released. This paper discusses how mineral scale deposition is affected by the change in reservoir conditions that occur during blow down.
Pressure maintenance by waterflooding may prevent reservoir fluids from dropping below the CO2 bubble point until they are in the production string. However, as a result of depressurisation, the CO2 bubble point will move down the tubing and into the formation. Calcite scales form as a result of the increase in pH that occurs when CO2 is evolved, and thus the calcite scaling problem will migrate into the near production well formation during depressurisation. The balance of oil-water and gas-oil capillary pressures changes with pressure depletion, resulting in the mobilisation of previously trapped formation brines. Waterflooding also results in large volumes of seawater being injected into the oil bearing strata. During depressurisation, this seawater is back produced through the former injectors. Depending on the strength of the aquifer, formation brine may also be produced. If these brines are incompatible, then mixing in the wellbore or near well formation will result in sulphate scale damage. Calculations demonstrate that co-production of aquifer and injected brines may occur for more extensive periods at the critical mixing ratios than would be typical of conventional production scenarios. Former injection wells will produce at near 100% watercuts, with the result that large volumes of water need to be protected. Calculations of reservoir temp eratures and the scaling potentials show that the problem is exacerbated by the fact that during water injection these zones will have been cooled.
Real-Time Method for the Detection and Characterization of Scale
Authors: Poyet Jean-Pierre , Segeral Gerard , Toskey Eric 
Published: December 2007

Abstract
A new technique is presented to detect scale deposition and to determine its composition and thickness in real-time in oilfield tubing and pipe. The method is based on continuous triple energy gamma-ray attenuation measurements made at a dedicated, instrumented mandrel or spool piece. Detection and identification of extremely thin scale deposits are possible without disrupting the flow. Simulations of scale deposits in a three-phase pipe are given to demonstrate the method’s practical application. The feasibility of the method has been verified with field measurements. The instrumentation required is based on existing technology with a proven track record in field conditions. Surface installations are safe to operating personnel and the environment.
This new method enables a simple monitoring device to detect and characterize scale in its earliest stages of formation. The technique may be used to determine the appropriate type of inhibition or removal treatment according to the type of scale present, to evaluate the effectiveness of scale treatments in-situ in the pipe in real-time, and can help to optimize chemical consumption for continuous treatment.
Role of Impermeable Layers in Barium Sulphate Oilfield Scaling: Modelling & Field Study
Authors: Bedrikovetsky P. , Rosario F. , Bezerra M. , Silva M. , Junior R. 
Published: December 2007

Abstract
Several different scenario of injected and reservoir water mixing have been proposed: mixing at high velocity near to injectors, mixing at low velocity inside reservoirs, mixing by diffusion via boundaries of layers with different permeabilities, mixing of injected, connate and aquifer waters at high velocity near to producers. Just the latter mechanism results in the accumulation of formation damage, while other mechanisms cause precipitation near to moving concentration front. In the current paper a new mechanism of oilfield scaling by diffusion of Barium from impermeable layer into the reservoir is proposed. The mechanism results in accumulation of precipitant and of formation damage.
Viscous dominant regime of waterflooding takes place in the majority of oil fields. The Welge´s method allows calculating the permeability distribution from water cut history. The proposed extension to Welge´s method determines the partition of permeable layers in a reservoir from tracer concentration in production wells. Knowledge of this partition is important for modelling of oilfield scaling accounting for Barium supply from impermeable layers.