bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Methods for Internal Multiple Attenuation
Authors: Hung Barry , Wang Min 
Published: May 2016

Abstract
Internal multiple attenuation (IMA) has long been regarded as a challenging problem in seismic data processing. The major difficulty stems from the need of identifying the multiple-generating interfaces for IMA. We present and compare two advanced IMA methods that a-priori knowledge about the multiple-generating interfaces is not required in the modeling process. The two approaches are inverse scattering series (ISS) and our methodology based on the convolution-correlation process. We describe our implementation procedure that involves segmenting the input data into different time windows and using a sliding-window approach to ensure that all the top multiple-generating interfaces are included in the modeling process so that internal multiples of all orders can be predicted without any subsurface information. We also discuss and compare the different assumptions made in ISS and our approach for IMA. We show the application of the two methods for handling internal multiples on both the synthetic and field data from the Tupi oilfield in the Santos Basin and on the field data acquired offshore Australia.
An Application of Depth Imaging to Support the Appraisal Phase of a Reservoir Affected by Poor Signal to Noise Ratio
Authors: Ciaccio T. , Andreoletti C. , Fichera R. , Biancone M. , Ellis G. 
Published: May 2016

Abstract
In this paper a workflow that integrates the most advanced tools for seismic data processing and imaging to overcome limits imposed by poor seismic data in the definition of reservoir geometries with the details needed to properly locate the appraisal wells is presented.
The area of study is the north-western coast of Australia. Here the reservoir, Middle Jurassic sandstones, is affected by a very poor signal to noise ratio due to poor energy penetration and illumination associated with reefs, faults and a high level of multiples content that completely masks the target area.
In the following, we will describe our approach to depth imaging with robust velocity analysis, effective attenuation of multiples, choise of most suitable migration algorithm and constant interaction between geological and geophysical expertise. The application of this integrated approach was the added value of the project and the main driver for guiding the interpretation of the reservoir, providing a strong support for well planning.
Design and Application of Expandable Casing Drilling Technology of Deep Sidetrack Horizontal Well in Tahe Oilfield
Authors: Ming Tang 
Published: May 2016

Abstract
The deep sidetrack wells of Tahe oilfield require to meet requirements of avoiding water, and drill to the leakage zone and collapse area of carboniferous system, two pressure systems need to be drilled, which traditional drilling fluids and chemical plugging method can't ensure drilling safety, and if running the conventional casing into the hole, drilling and completion face many difficulties because of following slim hole. All above making the old deeply areas remaining oil can't be liberated.
Expandable casing technology is a new technology, which acts as intermediate casing to block complex formation during drilling. It can optimize the structure of the well bore, block abnormal high pressure layer, collapsed layer and leaking layer, providing a technical plan to drill successfully to the target for complex deep wells.
According to the developing difficulties of F177.8mm casing deep sidetrack horizontal wells in Tahe oilfield, it produces a solution of expandable casing, analysis the operating difficulties of expandable casing, proposes an expandable casing technology solution, adopts unconventional diameter 130mm borehole drilling after expanded. It also describes in detail the drilling block application of expandable casing technology for the first time in the sidetrack horizontal well.
Field application shows that expandable casing drilling technology program designed can solve the drilling problem of the deep sidetrack horizontal well of the Tahe oilfield, and gains good technical practice. The effect of application confirms that the expandable casing implementation can meet the drilling block and follow unconventional slim hole drilling requirements.
In conclusion, the expandable casing drilling technology is the first time for technical casing of sidetrack horizontal wells, which proves the practicability of expandable casing drilling solution, and provides a new way to solve the development problems in Tahe oilfield. Meanwhile we successfully solves the unconventional diameter 130mm borehole drilling problem, using the non-standard small-diameter MWD instrument and non-standard diameter 89mm drill pipes for the first time, perfects slim hole drilling process. Furthermore, this application successfully provides the technical foundation of expandable casing technology in complex stratigraphic drilling.
Enhancing Static Interpretations Using Histogram Equalisation and Edge Detection
Authors: Al Ghamdi Ahmed , Al Garni Khalid 
Published: May 2016

Abstract
In this paper, we introduce a workflow to improve stratigraphic and lithologic interpretations by improving static analyses of seismic data using a histogram equalization technique. In particular, we demonstrate the use of histogram equalization followed by edge detection to enhance geological features such as faults, fractures, and channels. Post-stack and migrated seismic data are often subjected to automatic gain control (AGC) to increase the visibility of low-strength reflections. Unfortunately, AGC can mask stratigraphic details by drastically changing relative amplitude levels and by producing low-amplitude "shadow zones" near strong reflectors and near unconformity terminations.
Histogram equalization (HE) was originally developed for image processing but serves a useful purpose for seismic analysis. Unlike AGC, histogram equalization preserves subtle stratigraphic features and does not create "shadow-zones" beneath strong reflectors. Histogram equalization enhances the sharpness of stratigraphic features, thereby allowing edge detection algorithms to more effectively highlight discontinuities in the amplitude level even if the change is small.
Cold Lake Commercialization of the Liquid Addition to Steam for Enhancing Recovery (LASER) Process
Authors: Stark Shane D. 
Published: May 2016

Abstract
The Cold Lake project, in Alberta, Canada, is one of the world's largest heavy oil in-situ thermal developments with oil production of about 24,000 m3/d (150 kB/d) from more than 4000 wells. The world class Cold Lake hydrocarbon resource is a bitumen deposit, featuring in-situ viscosities in excess of 100,000 cP. The high viscosity of Cold Lake bitumen severely limits steam injectivity below fracture pressure, necessitating the development throughout the 1970s and 1980s of a modified cyclic steam stimulation (CSS) recovery process.
Imperial Oil and ExxonMobil are pursuing a research program to develop the next-generation of bitumen recovery processes that use hydrocarbon solvents as a mobilizing agent, reducing greenhouse gas (GHG) emissions relative to the current commercial recovery processes. Imperial and ExxonMobil are pursuing three processes: a solvent-only process known as Cyclic Solvent Process (CSP), a solvent assisted SAGD process and a solvent assisted CSS process known as Liquid Addition to Steam for Enhancing Recovery (LASER). LASER has the potential to increase oil recovery by more than 5% and reduce direct GHG emissions intensity by approximately 25%.
This paper describes the first commercial application of LASER. The Cold Lake H trunk LASER project is to date the world's largest implementation of a thermal solvent recovery process, with injection of 297 km3 (1.87 million barrels) of solvent into the 240 well project. This paper describes the successful operation of this thermal solvent project over a six year period; including reservoir numerical simulation work to develop bitumen and solvent production forecasts, development of field solvent production measurement methods, and the recovery process learnings from the first cycle of LASER operations. Completion of the first commercial LASER cycle has demonstrated on a large scale the success of solvent addition as a means to increase thermal efficiency and oil production in a heavy oil thermal recovery operation.
Case Studies of Using Far and Ultra-Far Seismic Data in Deep-Water Nigeria Erha North Field: Beauty and the Beast
Authors: Zhang Mei , Lee J.J. , Xu Shiyu , Molyneux Joe , Garfield Tim , Lovell Richard , Jones Stephen , Wildermuth Eric , Lazaratos Spyros , Bauer Steve 
Published: May 2016

Abstract
This paper highlights the complexity and challenges associated with deep-water exploration and development in Nigeria. The Erha North field Reservoir-300 was discovered using the block-wide 2000 seismic survey. A shallow channel severely attenuated the seismic image at the reservoir level. A new 2005 seismic survey was shot perpendicular to the shallow channel and improved the imagibility of the reservoirs by undershooting the shallow channel. ExxonMobil's Pre-migration Spectral Shaping (EM_PreSS) technique further enhanced the data quality. The EM_PreSS ultra-far 38–48° angle stack provided the best well tie in the Erha North Phase I development area. The significantly improved seismic data quality greatly increased interpretation confidence and impacted the business decision to not drill appraisal well Erha Far-East (EFE) and instead to drill the exploration well Erha North-East (ENE).
The Erha NE prospect is located 7 km away from the center of the Erha North field, with the primary target in Reservoir-300. The seismic response at the up-dip of the prospect is similar to the hydrocarbon response observed at the Erha North field, but lacks conformance to structure - an expected DHI element. The original hole (OH) targeted an up-dip location and encountered multiple gas and oil sands, in both primary and secondary reservoirs. However, the primary target Reservoir-300 was penetrated with two separated thin gas-on-oil sands. No water sand was penetrated. A determination was made that such highly compartmentalized reservoir could not be developed economically.
Down-dip from the Erha NE original hole discovery, a strong low-impedance amplitude anomaly was observed on the ultra-far (38–48°) angle stack. No other angle stack showed a similar strong low-impedance response and no other DHI attributes were observed. This amplitude response was neither similar to other known hydrocarbon responses nor to known water leg responses. Geophysical modeling results could not rule out the possibility of down-dip hydrocarbon presence by using reasonable rock properties assumptions. Given the high resource uncertainty, the operator determined it would be beneficial to test the down-dip location before Phase II development starts. The down-dip side-track (ST) well was drilled and penetrated a thick clean water-bearing sand. Post- drill modeling suggested that abnormally high anisotropy in the sand could be the cause of the ultra-far low impedance amplitude anomaly.
The Application of the Technology of Space Grid Variable Velocity Mapping in the Study of Superdeep Microstructure: A Case in the Tazhong No. 1 Gasfield of Tarim Basin
Authors: Zujun Wang , Dong Lv , Xiongfei Wang , Tianye Wang , Haiqing Lv , Jing Zhao , Xiangzhou Zeng , Zhenzhou Li 
Published: May 2016

Abstract
Block TZ62 of the No. 1 gas field is located in the eastern section of large reef of oil-gas reservoirs in slope break belt of central Tarim Middle-Late Ordovician. Reservoirs (average buried depth?5000 m)on the longitudinal growth developed in a range of 150 meters away from the carbonate rock roof. On the horizontally growth, reservoirs was quasi-layered and contiguous. Currently, the main technical bottleneck of development to increase reserves and production is how to reliably implement microstructures by means of effective variable velocity mapping.
This paper focuses on exploring a method of variable velocity mapping in super deep microstructure and its application on the TZ62 block.
The technology of space grid variable velocity mapping includes quality evaluation of basic data-speed factor analysis-space grid velocity modeling and quality control, etc. At present, due to the collection and processing problems, there are errors, whether from the seismic stacking velocity or logging speed variable velocity mapping. Among the influencing factors, T0-layer and drilling-stratification are more reliable than stacking velocity and logging speed. Based on the analysis on target horizon of block TZ62, by fitting the Three-Dimensional relationship of velocity and T0, we use the variation function of space grid to build the velocity model.
Through the blind Shaft check and application analysis control the quality of velocity model and establish accurate velocity model. According to the time-depth conversion we get reliable fine structure that is suitable for block TZ62. At the same time we get three aspects of the effection:Blind Shaft error is significantly reduced (structure error decreased to within10m from 15~80m),Structural map is more consistent with T0 map in the trend and the microstructure is more accurate,Microstructure and drilling is more matching, structural high place has high gas-oil ratio, oil-gas and water in reservoir distribute whole by the microstructure control.
Innovative Subsurface and Surface Optimisation of Well Placement in Stacked Heavy Oil and Light Oil Pools: A Case Study
Authors: Ruifeng Wang , Qizhi Huang , Xiaoling Yi 
Published: May 2016

Abstract
This paper illustrates innovative application of integrated subsurface and surface optimization of well placement in stacked heavy and light oil reservoirs in M field, Sudan. Upper B reservoir is massive bottom water heavy oil reservoir with burial depth of 700 m. Well productivity was low, 200 to 300 BOPD under CHOPS, resulting in denser well spacing and extensive deployment of flowlines, de-sanding equipment etc., often forcing vertical infill wells drilled as directional wells due to footprints limitation. Lower AG reservoir is stratified light oil and gas reservoir with burial depth of 1500–2200 m, overlapped with above B reservoir to some extent. The operator intended to drill infill wells to grow production, whereas two major well placement challenges are confronted:Integration of facilities and subsurface proposed well locations to reduce drilling costs;Integration of lower AG and upper B reservoirs to maximize recovery;
Well placement strategy has been optimized by following approaches:firstly propose infill well locations based on history matching and scenarios screening; secondly input well locations into facilities maps and identify footprint contradiction; thirdly revise well locations to be compatible with facilities and input back into simulation to justify cumulative oil loss within reasonable range;combine best locations in B and AG reservoirs and directionally deepen into AG reservoir to reduce unnecessary vertical wells in AG reservoir.
Altogether 21 optimized well locations were put forward, totally avoiding 5 footprint-limited directional drilling and reducing 3 vertical wells in AG reservoir by directionally deepening into AG reservoir. Drilling costs were greatly saved and speed up field production growth process during 2010–2011.
Conclusions drawn from successful well placement optimization were:subsurface and surface optimization greatly contributed to drilling cost saving;stacked AG and B reservoir optimization contributed to cost-effective development.
Application of U-Shaped Wells Technologies for Efficient Stimulation of CBM
Authors: Zhang Y. , Zhang G.Q. , Sun F.J. , Bao Q.Y. 
Published: May 2016

Abstract
Coal bed methane (CBM) development in China, especially in both Qin-shui Basin and East Ordos Basin has started at a large scale. There are more than 8500 CBM wells drilled in these two basins and most of which are stimulated with induced hydraulic fracturing and multi-lateral horizontal well technology. However, some of the CBM vertical wells are low productions due to the factors of geology, drilling or producing, while some of the horizontal wells have an appreciate production in the early stage but later drop down to a very low level dramatically due to the wall collapse. Thus, a new technology, namely U-shaped well technology, is researched and applied on site in Qinshui basin for enhancing the average gas productions of CBM wells.
An optimum scheme of drilling and completion of the U-shaped well is presented based on the comparison of the price, risk and feasibility of three different schemes in this paper and used as the pilot program. In order to decrease the comprehensive cost and period of the well, such factors as the access to fuel, water and land, the environmental regulations, i.e., water disposal, mud and drilling waste disposal, and so on, should be taken into account while choosing the well site. The reservoir characteristics and physical parameters, the upper formation lithology and the technology requirements of drilling, cementing and completion should be researched in detail before doing the well design which is the basis of the success of the U-shaped well. Besides, drilling along the coal seams and connecting to the vertical well are two key steps in yielding a successful U-shaped well, therefore, it is important to monitor and adjust the well path in time based on the logging response characteristics, measurement parameters of EMWD, and the drilling and mud logging parameters. With the slotted screen completion in the horizontal well, the U-shaped well can still provide a good flow path for the water and gas even though there is a wall collapse in the horizontal well while producing. In addition, the well bores can also be cleaned up by injecting water form the vertical well and circulating out of the horizontal well when the slotted screen is block by the coal dusts. As a result, the U-shaped well technology can solve such problems as production decreasing and cycle shortening of the multilateral horizontal wells due to the wall collapse while producing.
The daily gas production of the pilot well being in production for only 160 days and in control of the casing pressure kept at 0.7–0.8MPa to produce the gas in accordance with the producing rules of CBM wells has exceeded 2000m3/d. It is still rising gradually and would come up to about 8000 to 10000m3/d in a year's production according to the numerical simulation results which exhibits the U-shaped well a promising application prospect.
New Advances in Interwell Seismic and Electromagnetic Imaging
Authors: Nalonnil A. , Zhang P. , Marion B. 
Published: May 2016

Abstract
Crosswell imaging as a concept and measurement technique for the oilfield has been maturing over the past two decades. As part of this development, both the seismic and electromagnetic versions of the measurement have seen recent advances that have allowed the technologies to answer more complex imaging requirements in the industry today. This paper features case studies which focus on the areas in which the methods have advanced, specifically; downhole seismic source, frequency attenuation tomography and indicator probability imaging.

Introduction

Crosswell Seismic Imaging
Crosswell seismic images the interwell space with an improved vertical resolution of up to 5–10 times higher than surface seismic data. Both direct and reflected wavefields are processed to provide a detailed image of the reservoir. By using higher frequency sources that are deployed alongside the reservoir interval, crosswell seismic surveying generates high vertical resolution reflection images with resolution on the order of 1–3 m. This is due to the high bandwidth of the transmitters used during acquisition with upper frequencies ranging from 800Hz to 2 kHz (depending on the transmitter used and imaging objective).
Since seismic velocity is very sensitive to pressure, temperature and saturation changes caused by the injection of CO2, gas, and steam, crosswell seismic provides valuable information for monitoring injection performance and efficiency as well as reservoir characterization. Crosswell seismic can reliably detect compressional wave velocity changes as small as 1–3%. (Lazaratos et al., 1997) Additionally, since the migrated reflection section provides a high-resolution image of the structure between wells, it helps in answering key questions about the geologic causes of the observed injection performance and fluid flow.
By-Pass Pigging - A 'Simple' Technology with Significant Business Impact
Authors: Entaban Asun , Ismail Ajemi , Jambari Mahmud , Ting Peter , Amin Khalid Mohamad , Ping Chow Chee , Zou Sean , van Spronsen Gert 
Published: May 2016

Abstract
Bypass pigs are similar to normal pigs but have bypass ports to allow for a certain amount of fluid flow through. The bypass flow can "smooth out" the liquid surge. As for non-bypass pigging, all materials present in the pipeline before pig launch will be "pigged" out during the pig passage and nothing will "leak" backward through the bypass ports. Compared to non-bypass pigging, the use of bypass pigging can significantly reduce the production deferment as a result of pigging, capacity requirements for the slug catcher or separator, and the cost of wax inhibitors and risk of wax maintanence pigging. Bypass pigging has been around for many years but simply not been used enough, particularly its potential in handling the pigging slug and reducing production defermerment. This paper presents a case history of a recent successful application in Malaysia. Application of bypass pigging in the trunkline system of Malaysia LNG (MLNG) resulted in very significant production benefits, at virtually zero cost.

Background
Over the years, regular pigging (non-bypass) has been widely used in the industry to clean up pipelines (removal of debris and liquid holdup/slug), and sometimes to apply corrosion inhibitors. However, the liquid and debris volumes generated from the regular pigging operations, under normal production rates, will arrive at the receiving facilities within a short time period and may overwhelm the liquid/solid handling capabilities of the receiving facilities (slug catcher, separator, …), and bring gas starvation risks and even tripping risks in downstream facilities. To mitigate these risks, production levels are reduced during pigging operation.
Applying bypass ports will slow down the pig travel speed and allow debris or liquid surge to travel faster than the pig. Just as with non-bypass pigging, all material present in the line before pig launch will be "pigged" out and nothing will "leak" backwards through the bypass ports because pressure behind the pig is always higher than pressure in front of the pig. The bypass flow can "smooth out" the liquid surge (Figure 1) and transport the solid debris as slurry, and wet the top of the line with the liquid (corrosion inhibitor). By applying bypass pigging, production deferment is reduced or avoided.