bluuebunny/crossref_metadata_2025_split huggingface dataset:
Avoiding Surface Collision and Drilling a Smooth Well Using Gyro-While-Drilling in Offshore Abu Dhabi/UAE
Authors: Day Tim , Hormozy Behzad , Khaled Al-Awadhi Farhaad , Al-Husseiny Afifi Hassan , Abdul Karim Hassan , Abu Hasira Mohamed , Al-Ameri Fahad 
Published: December 2014

Abstract
Drilling wells from offshore platforms is always a challenge because of the need to eliminate potential collision issues caused by the relatively close spacing of wellheads. On a platform offshore Abu Dhabi, the spacing of the wells is 7.4 ft center-to-center and less than 5 ft wall-to-wall. There are nine slots on the tower, with five slots already used. Based on the required kickoff azimuth, the most logical slot for a high- profile deep and high temperature well was slot 9 (on the corner of the template) to reduce the risk of a well-to-well collision. However, using slot 9 would make it very challenging and risky to use slot 3 in the future.
A detailed risk assessment was conducted, and the following risks were identified: 1. the motor producing an unknown amount of reactive torque while kicking off, could lead to a departure of the well from the plan and a collision with other wells or to block the empty slots. 2. Excessive dogleg at a shallow depth would incur high torque and drag in deeper sections, thus increasing the risk of string washout or twistoff and excessive casing wear. Also putting a higher loading on the top drive to drill the deeper sections. 3. Rig time would be taken for running the single-shot gyro. 4. As the circulation would have to be stopped to take the gyro single shot, there would be risk of hole packoff and stuck pipe. 5. There would be a long distance from the bit to the survey point if the single-shot gyro were run above Measurement-While-Drilling (MWD) tools, causing a "late reaction" to any deviation changes.
After discussion, and a detailed cost / benefit analysis and risk assessment, it was decided to use a Gyro-While-Drilling (GWD) service as this would remove or significantly reduce the identified risks. This was the first usage of this service in the UAE for ADNOC companies (ADMA, ZADCO, ADCO), and the results were excellent. The well was kicked off in the correct direction from the start. There were no violations of the anti-collision rules to offset wells or empty slots. The well was steered away from slot 9, leaving it to be used for future wells. There was no reduction in the drilling parameters used to drill this 26″ hole section. There were no hole packoffs or stuck-pipe incidents, and the service saved at least 8 hours of rig time. Tight communication ensured all personnel involved had timely access to required information, which increased the confidence in decisions to drill ahead.
Global Anisotropic Pre Stack Depth Migration (PSDM) Velocity Modelling to Mitigate Structural Heterogeneity and Eenhance Imaging
Authors: Thakur Ram Kumar , Zhou Fugen , Chakraborty Kalyan , Mike Q Ye , Al-Kandari Abdullah 
Published: December 2014

Abstract
Seismic imaging in time domain is extremely difficult because of the insufficient illumination at the crest of South Fuwaris Humma-ARQ structure with 32 (thirty two) 2D seismic lines which were acquired in two vintages 1978 with 24 fold and 1996 with 80 fold. Due to large near surface lateral velocity variations and severe ray distortion by low velocity layers in surface seismic data, first-arrival turning ray tomography in a 3D sense proved to be useful during the initial time domain processing for deriving statics corrections to minimize these distortions and mitigate different causes of statics problems.
A key element of the reprocessing objectives was to generate an image in depth using prestack migration that takes near-surface velocity model derived from the turning ray tomography into account. For this purpose, the near-surface velocity model was used as the shallow layer of the depth initial velocity model, with the travel time effects calculated directly by ray tracing rather than by statics corrections. The deeper parts of the initial velocity model were derived from 3D smoothed velocity model that was coming from prestack time migration velocities for the re-processed 2D lines.
Two iterations of global isotropic tomographic update for velocity model were computed prior to reach the final anisotropic velocity model in depth domain. Delta and epsilon (anisotropic parameters) were manually picked and then a tomographic update of the anisotropic velocity model and the anisotropic parameter (delta) took place. Special effort was taken to minimize the mistie at well locations at major seismic markers and at the intersection points of the dense intersecting 2D lines with interactive interpretation and processing technique.
This paper presents an innovative Global Anisotropic Pre Stack Depth Migration (PSDM) velocity modelling technique to reduce structural uncertainties which enabled to drill exploratory wells in ARQ field.
Next Generation Broadband Land Acquisition
Authors: Baeten Guido , Hwang Jay , Walk Wim 
Published: December 2014

Abstract
The acquisition of broadband full azimuth surveys in a desert environment requires the application of several new technologies. These technologies can be divided in three main fields: the seismic receiver, the seismic source and the processing algorithms. We will discuss these new technologies, and show that the developments towards high channel counts and low frequencies are intimately related. Hence, an integrated approach is required to make optimum use of new emerging technologies. We also show some applications of the technology, demonstrating the value that these novel acquisition techniques can provide.
Source - Desert surveys almost exclusively use Vibroseis as a source. Over the last two years, the use of low frequencies in onshore seismic acquisition and processing has become more and more a routine practice. However, the emission of low frequencies by seismic vibrators is far from trivial and required a number of new technological developments and field tests. We will discuss the developments in vibrator technology, the limitations that are still in existence today and possible future developments.
Receiver - Current developments in land seismic acquisition show a trend towards higher channel counts and increased bandwidth. In addition, the increase in use of single sensors provides potential for acquiring higher resolution data, and improved signal preservation at the higher frequencies.
For broadband desert surveys, to significantly improve data fidelity, data sampling needs to be much improved by much increasing the channel count and including very low frequencies down to 1Hz. Shell is investing in the development of broad band land sensors that records to very low frequencies (&lt; 1Hz) and are cost-effectively scalable to 1 million channels. Single, light weighted, sensor systems will be much cheaper and faster to deploy, with less staff and lower HSE footprint. We will describe the status and report on recent field trial in the Middle East.
Both the full azimuth aspect of the surveys and the low frequency content require the application of dedicated processing algorithms. These processes vary from a geophone amplitude- and phase correction early in the processing chain, to Full Waveform Inversion and processing techniques that account for azimuthal variations at later stages in the processing. Applications of broadband full azimuth technologies will be shown, demonstrating the benefits that a bandwidth extension can provide to the seismic data in terms of increased resolution and structural definition.
Application of CSS to Develop a Thick Heavy Oil Field in South Oman
Authors: Al-Manhali M. , AL-Rawahi M. , Al-Hinai S. , Alwazeer A. , Al-Shaqsi K. , Brissenden S. J. 
Published: December 2014

Abstract
The "A" East is a heavy oil reservoir in the south of Oman. It was discovered in 1978. The reservoir is sandstone with a 200m thick oil column. Oil sampled from the field showed high oil viscosity and was considered to be problematic for primary production. In 2008, the field development plan proposed to develop the field thermally, starting with cyclic steam stimulation and followed by steamflood. CSS trials (2008 – 2010) were carried out in three wells using temporary facilities to evaluate the injectivity and productivity of the wells. This helped to identify the surface and subsurface challenges in the field and resulted in modifications to the full-field CSS deployment.
During the drilling campaign (2010-2012), a crestal well was cored and oil viscosity data was acquired. The results showed oil viscosity varies from 400 to 400,000 cp (at 55°C) from top to bottom of the reservoir. Production testing, using portable tanks proved the cold production concept. 32 out of 81 wells were selected to be initially cold produced by PCP before converting them later to CSS. On 9th March 2013 cold production from crestal wells started, which provided early production. One of the subsurface concerns identified during the "A" East field development study was the effect of the high initial reservoir pressure (~11,500kPa) on steam injection efficiency. Cold production helped to lower the reservoir pressure. Recently acquired pressure data indicate that the reservoir pressure fell to around 4000 kPa in the crestal area and to 6000 – 10500 kPa on the flanks of the accumulation.
"A" East steam injection started on the 2nd of March 2014. Initial injection data suggest that higher injection rates were achieved due to the lower reservoir pressure from cold production. The current plan is to ramp up steam injection and increase the number of CSS wells through converting more of the cold production wells to CSS. CSS operations will then be followed by pattern type steamflood (inverted 9 spot) once the reservoir pressure is depleted and connectivity is established between the wells.
Heavy Oil and Relative Permeability in Laboratory, Simulations and Production; Is There A Link?
Authors: Berg Eirik Asbjørn , Bjørlykke Ole Petter 
Published: December 2014

Abstract
One important challenge working in heavy oil field development is to present a set of production profiles representing low, base and high production without being overly optimistic or pessimistic. The paper give examples on how various methods of assessing the uncertainty in the relative permeability curve shapes changes the view on project uncertainty. Heavy oil laboratory relative permeability experiments face many well-known challenges. The core data is usually unconsolidated with very high permeability. This combined with high viscosity usually leads to unfavourable laboratory conditions like in example capillary end effects and viscous fingering. Typical core issues are fractures, laminations, loose sand, issues with use of multiple core plugs and very low pressure differential at initiation of the experiment. In addition there is always a discussion about reservoir wettability and core history including impact of drilling operations, drilling mud and core depressurization. The total effect is that the laboratory data is often seen as highly unreliable. The challenges are usually solved by using either light oil or by using steady state together with unsteady state experiments. Weaknesses and strength of the steady state method is addressed. Discussion of the alternative methods that is available is given with examples. Can light oil really be used instead of heavy oil given the large compositional differences? What could the impact of asphaltene content be? Examples are given of some typically laboratory effects. A brief discussion is given regarding possible reasons for differences between light and heavy oil behaviour. A benchmark of relative permeability experience from 50 heavy oil fields is presented. The benchmarking methodology is given and explained. Strength and weaknesses of the method is discussed. Actual field data is shown. Examples of relative permeability data used in simulation models are shown. Impact of grid size and properties on relative permeability is shown. Use of rock curves and alternative curve fit methods is presented with weakness and strengths.
Oil Recovery for Heavy Oil by Displacing Agent/Foam Assisted Steam Flooding: Laboratory Experiments, Numerical Simulations and Field Performances
Authors: Liu Hao , Hou Jian , Wu Guanghuan , Wei Tao , Wang Daigang , Wang Chuanfei 
Published: December 2014

Abstract
Shengli oilfield, the third largest oilfield in China, has abundant ordinary heavy oil resource and steam flooding is one of the most common used recovery methods for it. However, several obstacles have been encountered by conventional steam flooding in those blocks: (1) The significant heterogeneity of formation makes severe steam override and steam channeling. (2) The deposition of reservoir is deep, leading to severe heat-loss. (3) The distribution of remaining oil after water flooding is dispersing.
Laboratory experiments, numerical simulations and field performances of the displacing agent/foam assisted steam flooding pilot are described in this paper. It is an enhanced oil recovery process uses an injectant containing steam and additives consist of oil displacing agent, foam agent and nitrogen gas.
Laboratory experiments indicate that oil recovery factor for displacing agent/foam assisted steam flooding in porous media is much larger than that of steam flooding. Numerical simulation results present that the enriched remaining oil in lower layers caused by steam overlay is effectively produced by using the additives compared with using steam individually.
Displacing agent/foam assisted steam flooding conducted in two well groups at Gudao block is the first field test in Shengli oilfied. The smaller well group consists of one injection well and nine production wells, while the bigger group consists of four injection wells and twenty-one production wells. The total water cut for the smaller well group has decreased from 83.8% to the lowest of 79.4% and daily oil production has been improved from 49.0t to 62.4t. The total water cut for the bigger well group has decreased from 91.0% to 85.7% and daily oil production has been increased from 70.1t to 113.0t. Therefore, displacing agent/foam assisted steam flooding is expected to be a more efficient method than conventional steam flooding to improve oil recovery in Shengli oilfield.
Preparing a Challenging Fractured Carbonate Reservoir with Heavy oil for EOR Application
Authors: Al-Rashdi Y. S. , AL Kindi A. , AL Bulushi S. , Azri N. , te Riele P. M. 
Published: December 2014

Abstract
Heavy oil fields with complex geology present a great challenge for a commercial development. The field described in the paper is a heterogeneous, sparsely fractured carbonate field with oil viscosity of 5,000–10,000 cP. Initial production test proved that the field cannot be commercially developed using conventional development primary and secondary recovery technologies.
A number of EOR recovery processes have been reviewed for applicability to this field. A fit for purpose uncertainty analysis on key parameters lead to the conclusion that thermal recovery methods are not technically feasible mainly due to steam confimenent issues. A solvent based EOR development scheme was identified as a potential recovery route for such reservoir environment. A feasibility study was conducted to determine whether solvent injection is attractive under a number of realistic subsurface realizations and completion strategies. This study resulted in a number of activities to derisk uncertainties and come to quality decisions towards a solvent development.
Series of field tests have been conducted to mitigate some of the risks associated with the solvent development. Firstly, given the low permeability and low oil mobility, the presence of mobile water is essential in order to inject the solvent and contact the oil with the solvent. Water injection tests were carried out to demonstrate the presence of mobile water in all different reservoir zones and confirmed matrix injectivity is possible. A next step is to utilize the mobile water to inject a solvent into the reservoir and contact the oil accordingly for which a solvent test is planned using a mixture of xylene and diesel. A xylene-diesel mixture was selected as this showed in laboratory tests first contact miscibile with the field crude oil and is readily available for field application. The objectives of this single well injection test are to 1) confirm and quantify solvent injectivity, 2) prove heavy oil mobilization through solvent EOR methods from carbonate reservoir settings and 3) to determine near wellbore sweep efficiency of solvents injected into long horizontal wells. If successful a multi well continuous injection trial will be designed and executed.
This paper describes the design and analysis of the single well solvent injection test for this heavy oil carbonate field. It also describes the experimental lab work conducted to confirm xylene-diesel compatibility with the field crude oil and its suitability for application in a solvent EOR development derisking.
Fast Yet Clean Downhole Heavy Oil Samples From Wireline Formation Tester Using Selective Slug Sampling Technique
Authors: Tran Huy N. , Tran Lam V. , Nguyen Thang V. , Tran Ninh D. , Tran Dinh V. , Hardikar Nikhil P. , Coskun Sefer B. 
Published: December 2014

Abstract
This paper discusses the application of selective slug sampling using the wireline formation tester – RCX* (Reservoir Characterization eXplorer), in a clastic heavy oil reservoir and its significance to fluid characterization. The low mobility ratio between the reservoir fluid and water-based mud filtrate results in a long cleanup time to obtain samples with an acceptable level of contamination. Tool sticking and wellbore stability issues add to the challenges in open-hole fluid characterization and testing. Increasing the flow rate to reduce cleanup time does not help mostly due to formation of an emulsion between the viscous oil and the mud filtrate. The emulsion is hard to disperse, leading to a contaminated sample. A higher flow rate results in sanding and loss of seal.
In selective slug sampling, phase segregation is achieved by lowering and optimizing the flow rate, reducing the pressure drawdown that curtails emulsion formation and movement of grains thus increasing the sealing efficiency. The segregated oil slugs can be selectively collected in sample tanks multiple times downhole. Even a water cut of 60 to 70% is sufficient to collect high-quality samples, which is a significant improvement in sampling time compared to conventional fluid sampling, where 10% or less water cut is required.
The technique was applied in an unconsolidated clastic heavy oil reservoir in Vietnam. Four 14- to 22-°API single-phase oil samples were collected in two hours each. Laboratory results indicate less than 10% contamination; water cut being 50 to 75% at the time of the sampling. It was the first time that successful heavy oil samples were collected from these layers.
Fluid sampling is critical to identifying compositional variation of reservoir fluids along the depth, resulting in appropriate sampling strategy and eventually correct fluid characterization. Sampling in unconsolidated heavy oil reservoirs is improved using the selective slug sampling technique, making it possible to secure fast, yet high-quality samples, aiding fluid property characterization.
Development Of The Mexican Field - Samaria Neogene
Authors: Flores de Dios Mosqueda Tania , Isidro Torres Ezequiel Arturo , Arteaga Cardona Marcela , Tapia Garcia Carlos Fernando , Silva Lopez Pedro 
Published: December 2014

Abstract
Due to the success and experience obtained in the Samaria Neogene field pilot test, it was decided to exploit the field by cycling steam stimulation.
The development of the field has been carried out in three phases. The first phase, 48 wells were drilled with 400 meters spacing. The positive results of the first phase encouragement the development of the second and third phases, they consisted in 43 and 33 infill wells, with 200 and 150 meters spacing respectively.
In the first cycles, the injection pressure was very high, even in the wells that were produced for 6 months with Sucker Rod Pump (up to 2,400 psi in the deepest wells). In the second cycles there were no high injection pressures since the well surroundings were depressurized by the first cycle. In the second cycles the injection pressure drop between 50 to 400 psi, achieving a very good steam admission by the wells in the second and third cycles.
As a result of the decrease in the well spacing, the wells close to the injection wells began to show a heat increase in the produced fluids, for example, in two wells with less than 50 meters of spacing between them, during the injection of one, the other rase the temperature from 60°C to 110°C. This behavior has been very benefical for the project because reduces the viscosity not only in the injection well if not also in some of the nearby wells, resulting in an increased production in both wells. In most cases, when one of the neighboring wells is producing from the same sands, also there is steam channeling. If this channeling will be controlled, it would exist the possibility of moving to a continuous steam injection.
This paper will present how the steam injection has been successful despite different conditions taken in the pilot test.
On Thermodynamics of Undrained Zone in SAGD Process
Authors: Irani Mazda , Ghannadi Sahar 
Published: December 2014

Abstract
In Part 1 of this study (SPE 165457-MS) a permeability enhancement at the edge of steam chamber where the oil sand has been sheared under thermal stimulation was described and an increase in oil drainage rates was calculated for different conditions. Finally, a modified Butler's Theory that includes geomechanical effects was described.
Since heat transfer mechanisms are pivotal to the SAGD process and there are some doubts on the behaviour of the undrained zone at the edge of SAGD steam chamber in this study thermodynamics of undrained zone is discussed and new mechano-thermal equations are described. At the edge of steam chamber heat energy is transferred from steam to reservoir, reducing the viscosity of the bitumen, which flows under gravity toward a horizontal production well. Some of the heat transferred into the reservoir is used to increase the temperature of the reservoir, and some is stored as strain energy associated with the thermal stress field. The classical approach to exploring heat transfer studies in the SAGD industry is designed to satisfy only the "conservation of energy". Therefore, there is a lack of understanding of strain energy absorbed within the reservoir, and its effect on temperature variation inside the reservoir. The aim of the present work is to introduce a thermodynamic model to explore the effects of strain energy on temperature within the reservoir. This study explores the negative effect of developed stress field on heat transfer normal to the steam chamber interface. The novelty of this approach is the fact that it fully honours the energy equation. This study suggests the strain-energy number (NΔ) as a new dimensionless number representing an importance of the strain energy effect on the temperature profile within the reservoir. The results obtained from this study reveal that it is suitable to use Butler's theory and to exclude the strain energy effects in heat transfer in the SAGD process. This study uses both thermodynamic approach and pressure front evaluation to argue the current practice of suggesting no permeability enhancement occurrence beyond the 12 m from the steam interface suggested by Li et al. (2004) based on the bitumen viscosity greater than 20,000 cP. This study proposes using one tenth-length of pressure front for drained zone which is beyond the temperature front advancement. Knowing that the shear is mostly induced within temperature front, geomechanical effects within the reservoir can be studied suggesting drained condition.