bluuebunny/crossref_metadata_2025_split huggingface dataset:
World's First Combined Acid Stimulation of Horizontal Openhole Gravel-Pack Application of Coiled Tubing, Dynamically Positioned Vessel, and Floating Production, Storage, and Offloading, Offshore Brazil
Authors: Bogaert Philip , Cavazzoli G. , Perez D. R , Guimaraes C. , Trummer S. , Lungwitz Bernhard 
Published: December 2007

Abstract
Bijupirá is the first offshore field in Brazil to produce oil for an international operator. Since reaching its plateau production in January 2004, Bijupirá has experienced significant production declines. The bulk of the production in the field mainly comes from four sub-sea wells completed with a horizontal open hole gravel pack (HZOHGP). Analysis of the causes of production impairment suggests likely fines migration and possibly BaSO4 scaling.
Scale removal and matrix stimulation treatments were selected as a solution to reestablish productivity. These were performed from a dynamic positioned drillship using CT in the horizontal open hole gravelpacks. The flowbacks were done to the drillship with lift gas supplied from the FPSO. This imposed a very challenging and unique environment for successful implementation.
An extensive laboratory testing program was conducted to determine any negative effects of acid on elastometers and metals used in the wells, subsea system and topsides. Reservoir cores combined with a novel geochemical simulation tool helped to select the acid system and volumes for optimum stimulation treatment whilst limiting possible damage to downhole equipment.
A continuous acid mixing system was designed specifically for this operation to allow handling large volumes of fluids without the need for a stimulation vessel. Fluids were injected via coiled tubing using a special rotating jetting system to ensure mechanical clean-up and diversion. A flow back process was planned, considering the implications of injecting gas from a FPSO to a well, via gas lift valves-recovering hydrocarbons and spent acid to the drillship. This process proved to be effective in eliminating any environmental impact.
This paper describes the whole process including laboratory testing, design, and simulations. Details of the execution phase are given where three scale dissolver and three mud acid treatments were performed with exceptionally outstanding results in terms of execution and production uplift.
The combination of offshore, deepwater, FPSO, drillship and coiled tubing, set a milestone in the industry as first worldwide intervention of this kind.
Fiber-Optic-Enabled Coiled-Tubing Operations on Alaska's North Slope
Authors: Escarra P. D. , Sorman I. , Blount C. G. , Woods N. 
Published: December 2007

Abstract
Fill cleanouts, matrix stimulation, cementing, and downhole milling are some common coiled tubing (CT) operations. The difference between the success and failure of these jobs relies heavily on the knowledge and prediction of the behavior of downhole parameters such as temperature and pressure. Another significant percentage of CT operations depends on highly accurate depth control to ensure the intended result of the operation. These depth-critical operations include setting packers, tubing patches, CT-conveyed perforating, and zonal isolation. And in virtually all CT operations, including fill cleanouts, stimulations, and cementing, the knowledge of an actual tied-in depth is advantageous to operations.
The purpose of this paper is to present a simple and reliable system that allows real-time monitoring of downhole pressure and temperature, and provides depth correlation using a casing collar locator (CCL). In this system, the downhole parameters are recorded in real time without the limitations of conventional wireline-enabled coiled tubing units.
The information presented in this paper summarizes the operations performed during the field-testing of the system at Alaska's North Slope. Twenty-seven CT operations were successfully performed using the system; this demonstrated its reliability and provided the crew with the information needed to improve the efficiency of the operations being performed.
The system comprises three main components: Downhole tools capable of measuring and transmitting bottomhole pressure and temperature as well as identifying casing collars with high accuracy.Fiber optic and fiber optic carrier, which provides real-time transmission of downhole data to surface.Wireless bulkhead and surface interface modules to provide two-way communication between the tools and the monitoring system.
New Tubingless Sucker Rod Pump System in Slimholes
Authors: Yonghui Liu , Yingchuan Li , Zhenzhi Li , Xiyan Fan , Xingfu Zhou 
Published: December 2007

Abstract
In this paper, slim hole refers that the nominal diameter of production casing is less than 5 inch. In many problem wells, production casing is destroyed and new casing is reinstalled to continue oil production. And sidetrack drilling in old well is an effective method to find residual oil. Slim-hole drilling is widely used in low productivity, low permeability or low reservoir pressure oilfield for low drilling cost. So the number of slim-hole wells increases quickly. None of artificial lifts turns out to be a good option in slim well. The sucker rod pump system is mainly used. As a result, pump depth and daily fluid production rate are limited by the slim tubing, and oil test isn't available because of the small annulus.
The new tubingless sucker rod pump system can solve some of these problems. It adopts a packer to suspend tail pipe and seal the annulus between tail pipe and the casing, and fixing mechanism and sealing mechanism work together to fix pump system and seal the joint between tail pipe and pump system. Consequently the flow passage of the fluid is built: the mixture from the reservoir flow in tail pipe, then enter pump system to increase the pressure and eventually come into the annulus between rod string and the casing through special screen section. The pump efficiency is high and the production cost is greatly reduced for the tubing string is omitted and most of the conventional equipments are used.
The new system was successfully used in 4 inch and 51/2 inch casing wells in Zhongyuan oilfield, increasing the daily fluid production rate, as compared to the conventional sucker rod pump system. This paper presents description of the new tubingless sucker rod system, and reports the results obtained in two stages of field tests. The design method is also given.
Methods of Using Logs To Quantify Drillability
Authors: Andrews R. , Hareland G. , Nygaard R. , Engler T. , Munro H. , Virginillo B. 
Published: December 2007

Abstract
Correlations between sonic logs and the formation drillability for different lithology types have been developed from data taken from 10 wells in North America. The gamma ray log was used in conjunction with drilling data to calculate the drillability. The drillability from penetration rate models is back calculated from bit design and reported field wear in conjunction with meter by meter operating parameters, formation type and pore pressure. Then this drillability was correlated with sonic logs for different lithologies as defined by the gamma ray log. The different formation types clearly show different correlations for the normalized correlations between drillability and sonic logs. The non-homogeneous lithologies are also correlated and normalized to rock strength from the sonic logs where the percent formation type mixtures are determined from the gamma ray.
Data from multiple wells is presented showing the accuracy of the presented approach where more then 100,000 data points were statistically analyzed and evaluated in the development of the equations presented herein.
The drillability from inverted penetration rate models has been verified to give good representation of rock strength based on comparison with triaxial laboratory data and makes the use of this model more versatile. The correlations provide improved estimations of rock strength which can be used in drilling performance simulation and wellbore stability studies.
Reorientation Refracturing Case Study
Authors: Yao Fei , Weng Dingwei , Li Yang , Yu Yongbo , Hou Feng 
Published: December 2007

Abstract
This paper consideres how the initial hydraulic fractures and the oil and gas wells production/injection impact on initial stress field, and forms the stress field prediction software. Applied the software in Xinzhan Oilfield, 5 layers of 4 wells which might be reorient were selected from 19 layers of 7 wells. In the treatment of these wells, tiltmeter was used to monitor how the fractures propagation. After refracturing, the production histories of the wells were matched. The results show that the reorientation occurred in the refracturing of experiment wells, and so the validation of the software was verified.

Introduction
Reorientation refracturing is that some measures are taken in refracturing process to make the refracturing reorientation. At present, more and more fields and wells need to be refractured. Refracturing has two ways: 1.fractures spreading along original fracture azimuth, 2. fractures spreading along a new azimuth different from original azimuth, reorientation refracturing belongs to the latter. As we know, fractures always spread along the azimuth vertical to the minimum principal stress, so the stress field after the first hydraulic fracturing determines the fractures breakdown and spreading. The research on change trend of stress field could direct the refracturing, predict fractures azimuth and decide the best refracturing opportunity.1–2

The theory of the stress field prediction
No matter what refracturing reorientation induced by principal stress reorientation or that induced by shear stress change making fractures spread along shear plane, the original stress field change is the basic dominating factor.
The existence of the first hydraulic fractures and the production of wells, the anisotropy of reservoir, the fractures and injection or production of neighboring wells cause the change of original stress field, and may make the stress reorientation. In these factors, the existence of the first hydraulic fracture and the production of wells are the most important ones.3 The physical models (Fig. 1) are used to describe stress induced by the existence of the first hydraulic fracturing:4 a plate with a 2 a long linear fracture, the fracture has the same thickness with the plate, and the tension on the fracture is - P. The principal stress and shear stress in x, y, z direction induced by the first hydraulic fractures can be described by the following formulas:
Detection of Impacts in a Changing and Highly Variable World: The Case of a Floating Storage and Offloading (FSO) Unit in the Gulf of Paria (Venezuela)
Authors: Cruz-Motta J. J. , Petkoff Irene , Klein Eduardo , Alvarez Haymara 
Published: December 2007

Abstract
Studies of environmental impact assessment (EIA) base their final conclusions and/or decisions, typically, on available information that has been extracted from existing environmental studies. To solve this, conclusions and desicisons taken after an EIA can be re-stated in the form of hypothyeses, and the appropriate monitoring programs are put in place to test them. These monitoring programs should be designed to detect the potential impacts that a given development might cause. An important aspect to be developed to reliably detect an anthropogenic impact is the development of an effective and precise analytical framework able to differentiate between human induced changes and the natural spatio-temporal variability shown by most populations. Among all the possibilities, "Beyond-BACI designs" allow addressing unequivocally these issues, but until the beginning of the millennium their use was limited to the analysis of single variables (e.g. abundance of a single species or any measure of biodiversity). In this paper we describe an asymmetrical sampling design that will allow the use of an analytical procedure able to unambiguously detect if there is any effect of a FSO on the natural conditions of the surrounding marine areas and assemblages living in it, more specifically, pelagic and soft-bottom benthic assemblages. The FSO will be located in the Gulf of Paria, Venezuela.
The proposed sampling design consists of one potentially impacted location (1 km radius area around the exact location of the FSO) and three reference locations (same area as the impacted one) sampled at two spatial scales: three sites within each location (separated by 2 −3 km) and replicate units within each site (separated by 100´s of meters). This spatial layout of sampling sites will be sampled three times before and three after the placement of the FSO.
In this study, the comparison of the different variance components for the assessment of potential impacts will be done using a recently developed multivariate method: dissimilarity-based permutational MANOVA, for the analysis of multi-species data matrices in response to complex sampling designs such as the one described above.
This type of experimental design and associated analyses are complicated and require a considerable increment of replication effort beyond to what we are accustomed to, involving costs above what has traditionally been the case. This expenditure, however, is warranted because, among other reasons that will be discussed in the paper, it does protect against unfounded claims of impacts, and realistically determines the level of a predicted impact so that corrective or mitigating options can be developed and implemented.
16Cr Coiled-Tubing Field Trial at Prudhoe Bay, Alaska
Authors: Julian J. Y. , McLellan B. J. , McNerlin B. J. , Martin J. R. , Van Arnam W. D. , Normoyle B. K. , Tipton S. M. , Burke K. W. 
Published: December 2007

Abstract
Sixteen chrome coiled tubing (16Cr CT) was introduced in the spring of 2003 and over 200 strings have been put into field use as velocity strings. Following preliminary testing, two 16Cr CT reels were deployed at Prudhoe Bay, Alaska to evaluate feasibility as an intervention workstring. The two reels performed a variety of standard CT applications on a daily basis. Observations and data were gathered to determine operating guidelines, applicability, and limitations. The field trial indicated that 16Cr CT can be deployed in the field with only minor operational modifications.
16Cr has superior abrasion resistance in 13Cr production tubulars and little CT surface (external) wear was seen during the field trial. The second reel developed a pinhole failure earlier than expected; however, analysis of the adjacent material indicates that 16Cr has increased low cycle fatigue life when compared to standard carbon steel CT. Additional testing is ongoing, and it is felt that the conditions resulting in the failure can be mitigated to avoid future premature failure.
This paper documents the lab and field trial results. Standard operating procedures for 16Cr CT are described that provide easily implemented guidelines. 16Cr has applicability as an intervention workstring, particularly in corrosive environments and in areas where abrasive 13Cr production tubulars must be endured.
Coiled Tubing Cement Packer Repair at Prudhoe Bay, History and Current Techniques
Authors: Julian J. Y. , Sack J. K. , Johns J. E. 
Published: December 2007

Abstract
Packer repair utilizing CT is an important non-rig remediation in the greater Prudhoe Bay Area, Alaska where rig workover costs are significant. To date, approximately 22 CT packer repairs have been performed with a 100% success rate. This high success rate has resulted in investigating possible improvements in efficiency. These are primarily associated with reducing cement and plug milling operations.
This paper presents the history of packer leak detection and repair at Prudhoe Bay. Diagnostics are detailed, including conventional logging methods with temperature, spinner, and waterflow logs. Additionally, the newly developed ultrasonic leak detection log is described. This tool has the ability to detect ultra small leaks and has led to an increase in number of candidates.
Cement packer repair design is discussed, as well as detailed CT operation guidelines. Recent improvements and optimizations to techniques are presented along with areas for future investigations.
The Successful Application of Underbalanced Drilling Technology for Reservoir Evaluation and Drilling Performance Improvement in Kuwait
Authors: Vieira P. , Larroque F. , Al-Saleh A. M. , Ismael H. , Qutob H. H. , Chopty J. R. 
Published: December 2007

Abstract
The Shuaiba formation in the Raudhatain field is a highly fractured limestone reservoir. Conventional drilling technology in this formation usually results in a complete loss of drilling fluids to the formation. These losses cause severe formation damage which results in masking the evaluation of the potential for hydrocarbon production.
Underbalanced Drilling Technology was proposed as an alternative drilling method. The main objective of the UBD drilling application was to evaluate the potential of hydrocarbon in the Shuaiba formation while simultaneously eliminating fluid loss to the formation and improving drilling performance.
This well was the first well drilled underbalanced by KOC, a training program was prepared in order to familiarize the rig personal involved with the operation of the UBD equipment and procedures. The openhole section was drilled out of a 10 ¾" casing with an 8 ½" bit. A conventional mud pulse MWD/PWD/LWD tool with real-time annular pressure, temperature and gamma ray sensors were incorporated in the BHA. The use of MWD/PWD/LWD provided a means of monitoring the downhole underbalanced conditions and formation properties while drilling. The Shuaiba formation was successfully drilled underbalanced without any fluid loss during the drilling phase. The openhole section was drilled to a total depth (TD) of 8942 ft MD, with an openhole length of 242 ft.
Integrated efforts of KOC and service companies of various disciplines during planning and operation stages of the well led to the success of the project. No QHSE incidents were reported.
This paper highlights the key factors in the underbalanced drilling design phase, the operational challenges faced, and the results of the first well drilled in Kuwait using underbalanced drilling technology.
Pipeline Flow Capability Restoration Using Coiled-Tubing and Rotating-Jetting Technology
Authors: Acosta Marco , Santamaría Juan , Moss Paul , Rivera Herman , Mosquera Julio , Robles Mario , Barragán Fernando 
Published: December 2007

Abstract
Problems associated with Pipeline flow capacity reduction due to the presence of Scales, Asphaltenes and Parrafins have always been present and are well documented. Solutions to these problems are not however as well understood or discussed and, more often than not, complete replacement of the affected section is imminent because of the limited solutions available to the operator. Completely changing a section of Pipeline can have significant costs associated with it. Indeed, material & labor costs, environmental impact due to Pipeline construction and loss of flowing capacity represent the key reasons to avoid this type of operation if at all possible and give reason for ongoing investigations into possible alternatives.
This paper outlines a solution that was implemented several times in Ecuador whereby Coiled Tubing employing rotating & jetting technology was used to completely restore Pipeline flow capability without the need to replace any section of the affected tubular.
This solution involved the use of proprietary rotating/jetting technology introduced into the Pipeline at strategic locations, defined by computer simulations, to affect a successful cleanout operation. Selecting an efficient cleaning fluid was also very important for the success of these operations as there were significant economical and environmental limitations that had to be overcome.
Details about this solution, including defining the operational limitations of the Coiled Tubing material due to restrictions, orientation and curvature as well as fluid selection and other design limitations and considerations are included in this paper.
A New Approach for Phase Behavior and Well Productivity Studies in the Deep Gas-Condensate Reservoir With Low Permeability
Authors: Zhilin Q. , Wang Shouping , Du Zhimin , Liang Baosheng , Deng Ruijian , Zhao Wei 
Published: December 2007

Abstract
Deep gas-condensate reservoirs, with high temperature, high pressure, and low permeability, account for a high proportion in the recent years. Quite different with conventional gas-condensate reservoir, this type of reservoir has smaller rock grains, prominent interfacial phenomena, and appreciable reservoir deformation. Consequently, it is necessary to study phase behavior and well productivity to model these deep gas-condensate reservoirs more accurately.
This paper considered both interfacial effect and reservoir deformation, and proposed a new method for calculating oil-gas phase equilibrium in deep gas-condensate reservoirs. We introduced phase equilibrium calculation into fluid flow theory for condensate oil and gas system and then mathematically developed a physical-chemical flow model with consideration of interfacial effect and reservoir deformation. Gas well productivity was also studied and the corresponding equation was derived. Because flow behavior near wellbore is essentially important for a gas-condensate reservoir, we investigated fluid flow near wellbore and provided methods to determine retrograde condensate saturation, gas relative permeability, and pressure distribution.
We applied to a real gas condensate reservoir and calculated well productivity, retrograde condensate saturation distribution, and gas relative permeability, particularly near wellbore. The results illustrated that interfacial phenomena and reservoir deformation made retrograde condensation appear much earlier and consequently aggravate formation damage. Therefore, the decrease of gas relative permeability and the drop of well production are faster than usual.
A New Darcy-Stokes Flow Model for Cavity-Fractured Reservoir
Authors: Peng Xiaolong , Qi Zhilin , Liang Baosheng , Liu Xueli 
Published: December 2007

Abstract
Conventional cavity-fractured reservoir has small sizes of cavity and the corresponding flow behavior is presented by the equivalent model for fluid flow in porous media. However, in Tarim Basin, the biggest land oil/gas-baring basin in China, many unconventional fractured reservoirs are found that cavities are the main storage space while both fractures and cavities offer flow paths. Current porous flow model are not applicable due to the large cavities even with the scale of meter. A new flow model is needed to describe the flow behavior in order to successfully develop these cavity-fractured reservoirs.
In this paper, fluid flow in Tarim cavity-fractured reservoirs is firstly studied by integrating geology and reservoir engineering. As an example, Tahe Ordovician carbonate reservoir is analyzed in detail. Then, a new Darcy-Stokes model for slightly compressible two-phase flow is built. In our model, flow area is divided into porous flow region and free flow region according to flow characteristics. Porous flow region obeys Darcy's law and is described by the flow in porous media with multiple porosities. On the other hand, free flow region satisfies Navier-Stokes flow and the equation describing slightly compressible two-phase flow is developed. The connection at the interfaces of these two flow regions is derived by the extension of Beavers-Joseph-Saffman boundary condition to two-phase flow.
The application of Darcy-Stokes flow model to Tahe reservoir demonstrates that this model gets better prediction on oil production performance than the fractured model with dual porosity.