bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimised Stimulation Technology Combined Viscoelastic Acid with Jetting Treatments to Enhance Horizontal Well Productivity in AHDEB Oil Field, Iraq
Authors: Zou Honglan , Wang Xugang , Qi Xiaocheng , Kang Jianli , Chen Yandong 
Published: May 2016

Abstract
This paper describe horizontal well CT acidizing design, valid practices and evaluation with good results. The Ahdeb Oil Field consists of sour, heterogeneous carbonate reservoirs with medium porosity (22 - 26%) and low permeability (5 - 20 mD), buried at depth of 2650 to 3150 meters, containing 0.2 - 3.5 mol% H2S and 3.0 - 4.5 mol% CO2, the degree of mineralization of stratum water being as high as 130,000 - 209,000 ppm, producing heavy oil with 22.5—28.9º API.
With very heterogeneous long section (24000ft-32000ft) open to flow, the acid placement and subsequent wormhole penetration depths are challenges. Integrated completion & stimulation techniques have an increasingly wide utilization in Ahdeb Oil Field. Such as: Using of Oil Swell-able Packer for completion of horizontal wells. The strategies related to the acidizing design included various velocity withdrawing pin-point acid jetting and acid. CT is withdrawn continuously from high to low velocity along the whole horizontal section. Viscoelastic acid treatments help to equalize acid distribution by special acid/rock reaction characteristic for each interval. The jetting action helps to remove deep damaged caused by the drilling fluid and completion fluid and improve acid penetration for relative low permeability section. The acidizing simulator predicts the distribution and penetration of acid during the acid treatment. N2 + CT techniques was used to clear up spend acid quickly.
In the past 3 years, there were over 59 horizontal wells that were stimulated with viscoelastic diversion acidizing using CT conducted achieving an averagely doubled production rate which was great contribute to the Ahdeb Oil Field with 120 mbopd of production capability. Besides, a modified evaluation model for horizontal well performance that can be used for field evaluation of acid treatments is developed based on treatment data. Skin factors performance as functions of position and time were calculated and analyzed for stimulated wells.
A Novel Hydroxylpropyl Sulfobetaine Surfactant for High Temperature and High Salinity Reservoirs
Authors: Zhang Fan , Ma Desheng , Wang Qiang , Zhu Youyi , Luo Wenli 
Published: May 2016

Abstract
Reservoirs with high temperature and high salinity are widely distributed in various countries, which contribute an important percentage of oil output in the world. Pilot tests show that chemical flooding technique is one of effective EOR (Enhanced Oil Recovery) ways to improve the oil recovery for mature oilfields. The key technology of chemical flooding is to develop high efficiency surfactants with low cost. In this paper, the betaine surfactant has been synthesized with cheap raw material of fatty acid, and its functional group of hydroxylpropyl sulfo hydrophilic group can improve the heat resistant and salt tolerant abilities of the surfactant. The surfactant was characterized by Infrared Spectra, Raman Spectra and Element Analyzer. The analytical data show that the surfactant is consistent with the designed molecular structure, hydroxylpropyl sulfobetaine. The interfacial tension between the sulfobetaine solution and crude oils achieve ultra-low values (less than 1.0×10-2 mN/m) with temperature range from 30 °C to 90 °C, or salinity range from 20000 mg/L to 120000 mg/L, when the surfactant concentrations are from 0.05 wt% to 0.3 wt%. The parameters of hydroxypropyl sulfobetaine show that it is a suitable candidate for the oil-displacing agent due to its good long-term stability (within 180 days), low critical micelle concentration (4.74×10-5 mol/L), low dynamic adsorptions (0.44–0.72 mg/g), good injectivity and mobility. Oil recoveries increased 20 % - 24 % (OOIP, Original Oil In Place) after water flooding, with both weak alkali ASP and alkali-free SP formulations combined the sulfobetaine. And the oil displacement efficiencies of weak alkali ASP or alkali-free SP flooding have reached to 73 % - 76 %. Excellent properties of the hydroxypropyl sulfobetaine indicate that it is a promising surfactant, which can be applied in reservoirs with high temperature and high salinity.
Yield Stress Measurement and Thixotropic Behaviour of Waxy Crude Oil from the Malay Basin
Authors: Pannu Jaspreet Kaur , Sariman Mior Zaiga 
Published: May 2016

Abstract
Predicting the restart pressure for gelled waxy crude has always been a challenge due to the thixotropic nature of the crude apart from the thermal shrinkage and presence of gas voids within the gelled crude. Thixotropy is a phenomenon where the viscosity decreases under constant shear rate followed by a gradual recovery over time when the shear rate is removed. In pipeline transportation of crude oil, for instance, it is important to characterize the thixotropic behaviour of the crude oil in order for the flow characteristics to be well predicted and understood. Various methods have been proposed to quantify thixotropy, including the well-known "thixotropic-loop" tests. Yield stress is the stress corresponding to the transition from elastic to plastic deformation, the value of shear stress above which the material flows. Existing method defines two yield stresses, one static and one dynamic. While static yield stress is more difficult to measure since most occur at very low stresses and that the measuring methods is still subjected to many debates whereas the dynamic yield stress is relatively easier to be obtained and requires linear extrapolation of viscosity data at high shear rates. Therefore, the measurement for static yield stress was done with oscillatory testing and dynamic yield stress with steady state peak hold testing. All measurement was done under the rheometer with minimized wall slip effect for both statically and dynamically cooled sample. In this paper, the thixotropic behaviour of a waxy crude oil from the Malay basin is explored together with the effects of temperature. Data showed that the extent of thixotropy increases with the reduction in temperature below the Wax Appearance Temperature of the crude oil. For the yield stress measurement, it also exhibited some interesting features of the waxy crude oil. The outcome of the study could then be used to fully understand the nature of the gelled crude.
High Resolution Full Wavefield Inversion: Impact on Imaging and Reservoir Characterisation
Authors: McAdow David , Lazartos Spyros , Routh Partha Routh 
Published: May 2016

Abstract
Seismic imaging has been advancing rapidly over the last two decades, transitioning from post-stack time migration to pre-stack depth migration and from ray-theoretic algorithms (Kirchhoff migration) to one-way wave equation solvers (wave equation migration) and recently to two-way wave equation methods like Reverse Time Migration (RTM). The most recent step in this evolving sequence is Full Wavefield Inversion (FWI), which has rapidly become a focal area of research, development, and application within the geophysical community and industry.
FWI products, unlike migration results, are not depictions of seismic reflectivity, but rather high resolution images of subsurface properties such as compressional and shear velocities and density. The high resolution velocity models generated with FWI can be used to address challenging imaging problems that are difficult to solve using conventional processing tools. High fidelity velocity models will assist in imaging below fault shadows and shallow channels and may also better identify and quantify overpressured drilling hazards. FWI estimates of other elastic paramters, in particular the Vp/Vs ratio, are promising lithology indicators useful in reservoir characterization applications. In addition to imaging challenges, the broadband nature of FWI is ideally suited to address reservoir monitoring problems with the ability to provide high resolution updates of property changes in the subsurface due to production. FWI products, appropriately integrated into an interpretation strategy, will allow us to better understand subtler subsurface features such as stratigraphic traps or non-DHI plays. In our presentation, we will use FWI examples from several real data studies to explain the nature of the process and illustrate some of the potential applications.

Introduction
Full Wavefield Inversion (FWI) is the most advanced and ambitious seismic imaging technology ever conceived. This technology produces the dream of every geoscientist: broadband images of sub-surface rock properties ahead of the drill bit. Seismic imaging has advanced rapidly over the last two decades in lockstep with advances in High Performance Computing (HPC). Traditional seismic imaging methods, such as Beam Migration or Reverse Time Migration (RTM), focus seismic reflections from layer interfaces that the geoscientist can use to map structure and amplitudes that relate to the change in rock properties across layer boundaries. By contrast, FWI simultaneously focuses the image of the subsurface and produces amplitudes that represent actual elastic rock properties within the layers (velocity, density, etc).
XuJiahe Formation Petroleum System in Central Sichuan basin, China
Authors: Liao Xi , Cortis Anthony , Xu Long , Rolph Alan , Ha Kwong Tak , Hua Zhu , Zhang Andy , Zhao Da Hua , Carl Brian S. 
Published: May 2016

Abstract
The Golden Autumn Tight Gas Block is located in the northwest of the Central Sichuan Basin and covers an area of 4,067 km2. Shell, in partnership with PetroChina, has been appraising the gas potential of the area since 2010. The primary target interval, the Late Triassic Xujiahe Formation, is about 1000m thick, and thickens towards the northwest. It is dominated by alternating sand and shale rich members. From bottom to top, the Xujiahe Formation is separated into six, thick members labeled the Xu1 (T3×1) to Xu5-6 (T3×5-6) respectively. The Xu1, Xu3(T3×3) and Xu5-6 members dominantly comprise coaly and calcareous shales versus the sand dominated Xu2 (T3×2) and Xu4 (T3×4) members.
The Xujiahe Formation is considered a self-charged, over-pressured petroleum system with complicated migration history and complex play types. The major source rocks are dark shales and coals within the Xu1, Xu3 and Xu5-6 members. Reservoirs are tight, discontinuous channelized calcarenite sands in shaley formations (e.g. Xu5-6) and regionally amalgamated, largely continuous, litharenite sands in the Xu2 and Xu4 members.
The Jurassic overburden is about 3000m thick and mainly comprised of red lacustrian mudstones and siltstones. Gas and condensate are present and productive from the Xujiahe formation across the entire block. However, zones with higher WGR and even water satured zones occur in the Xu2 and Xu4 members and are interspersed with drier gas zones. In contrast, minimal water production is observed from reservoir sands in the Xu3 and Xu5-6. This indicates various play types within different zones.

Introduction

Exploration and Production History:
The Golden Autumn Block covers an area of 4,067 km2 and is located in the northwest of the Sichuan Basin, in the southwest part of the People's Republic of China. Shell and partner PetroChina have been appraising the gas potential of the block under terms of a PSC (production sharing contract) since May 2010. The block itself has been explored and developed since the 1970s. There are twelve PetroChina/Foreign Cooperation wells and sixteen Shell wells drilled into Xujiahe Formation as of November 2012. Prior to commencement of the PSC, the only extensive production history from the Xujiahe Formation was derived from two older PetroChina wells. One well tested the Xu2 and Xu4 members and has produced economic gas (unstimulated) since 1983. The other one tested the Xu4 and Xu5-6 members with higher gas rates plus some condensate (unstimulated) since 2002. As of end November 2012, four Shell wells demonstrated good initial gas production from the Xu5-6 member, two wells have produced at high rates from the Xu3 member, and one well has produced at high rates from the Xu2 member. With the exception of a single test in the ZZ2 well, all wells show poor Xu4 performance, even after fracture stimulation.
The Historical Statistical Analysis of Spill Incidents in Federal Outer Continental Shelf of U.S
Authors: Tian Hongliang , Lv Jianzhong , Li Wanping 
Published: May 2016

Abstract
Nearly 800 offshore spill accidents in total in the U.S. Gulf of Mexico occurred over the past 50 years. Of these, 80% took place in the oilfield development period, a quarter during drilling and mining operations, and 72% on the platform or rig.
Since 2000, the offshore oil and gas exploration and development has been booming with significantly increased number of oil spills. In 2005, most of leak accidents, including 49 cases with results of leakage of more than 50 barrels and 39 cases of 1~49 barrels, appeared in the history, resulting in total leakage of 16,155 barrels.
There is no obviously direct relations among operating water depth, distance from the shore and accident frequency. Most of accidents involved oil spills, followed by diesel and mud spills. The statistics of spill incidents show oil spills accounted for 48% to 63% and the diesel spills for 15% to 21%. There are less accidents resulting in casualties and the deepwater horizon accidents is the biggest accidents in the history.
Equipment, weather, human factors and external forces (waves, tides and currents, etc.) are the four major factors behind oil spills at sea. Among them, equipment failure is the primary cause for 43% of the total accidents; weather is the second killer, triggering 29%; and human errors involve 18%. In addition, 36% of the total accidents are caused by a single factor, 45% by two concurrent factors, and most of them by the two concurrent factors, bad weather and equipment failure.
Development of offshore oil mining must be corresponding with four conditions: advanced technology and equipment, strong capability of early climate warning, high-quality professional teams, better ability to cope with marine external forces.

Introduction
The U.S. Gulf of Mexico is the earliest developed area among the world's four major offshore oil and gas gathering areas in the past half century and frequent leakage accidents have occurred there due to various reasons. Some laws or clues related to marine spills could be found and key elements in the safety of offshore oilfield development could be deeply understood, through the analysis of the data of these accidents.
There occurred a total of 337 accidents involving more than 50 barrels of leakage in the Gulf of Mexico in the period from 1964 to 2010, with more than seven cases a year; a total of 459 accidents involving 1 to 49 barrels of leakage took place in the period 1970 to 2010, with more than 11 cases a year. These accidents appear during multiple operations period including exploration drilling, production, pipeline laying, transportation, processing, and chemical additives injection. Such accidents are generally results of a variety of factors involving technical equipment, human management and inclement weather.
New HTHP Cutter Technology Coupled with FEA-Based Bit Selection System Improves ROP by 60% in Abrasive Zubair Formation
Authors: Al-Muhailan Mohannad , Hussain Iqbal , Maliekkal Harish , Ghoneim Osama , Nair Prakash , Fayed Mustafa 
Published: May 2016

Abstract
Efficiently drilling the abrasive Zubair sandstone is one of the Middle East's most daunting challenges. Adding to application complexity, the pyritic formation is also interbedded with hard shale streaks and has a compressive strength that ranges between 3–10kpsi. In Kuwait, the formation is first encountered at a depth of approximately 9000ft and been drilled with mixed performance results based on bit diameter. Generally, the large diameter PDC bits are still struggling to achieve the durability objective with some wells requiring more than two PDCs to complete the short 1400ft hole section. In the smaller hole sections, technological advances have overcome the cutter/bit durability issue but with no significant improvement in ROP. The objective of an intensive bit optimization effort has focused on increasing penetration rates while striving to improve overall bit life/cutter durability.
To accomplish the operator driven objectives without time-consuming field trails, the drilling team used a software system to calibrate rock strength. This data was used in conjunction with an advanced FEA-based modeling system to analyze different PDC cutting structures to select a PDC bit with the blade count and shearing configuration that would produce dynamically stable drilling. The bit body would be equipped with a new O2 cutter to increase abrasion resistance and maintain temperature at the cutter tip by using:enhanced HTHP sintering process;refined post-pressing process to improve thermal stabilityoptimized hydraulics to maximizing cutter cooling.
The authors will discuss the bit selection process and modeling system which eliminated costly field trials and the new manufacturing processes that produced the HTHP cutter technology that increased ROP by 60% in the 8-1/2" hole section. The new PDC bit achieved the operator's objective of drilling shoe to TD eliminating several trips for new bits while delivering a significant reduction in drilling costs.

Introduction
This paper is discussing the modern reliable bit selection process and modeling system which can eliminate traditional field trial and error product development system, which is very costly especially when the formation to be drilled is highly abrasive and Pyritic sand formations, where cutting structure durability is very crucial.
Thermal stability of the PDC cutters are of great importance, as quick cutter wear or diamond table loss are caused by high temperatures at the cutter tips while drilling through such highly abrasive fromations. This paper will be looking into the new generation thermaly stable PDC cutter developments that helped to double the PDC cutter durability and further rate of penetration improvements, through a case study of drilling through highly abrasive Zubair formation in Kuwait which quite often Pyritic.
Acquiring and Maintaining Social License to Operate for a Major LNG Project in Papua New Guinea
Authors: Canning James W. , Marru Ian , Walters Kenneth W. 
Published: May 2016

Abstract
Legal license to design, construct, and operate a major project in any country is granted by the government and regulatory bodies of the respective country. Such is the case with the PNG LNG Project currently being built by ExxonMobil and its co-venturers in Papua New Guinea (PNG). The Project, which includes gas wells, a 960 MSCFD gas conditioning facility, a 300 kilometer onshore pipeline, a 400 kilometer offshore pipeline, and a 6.9 Mta LNG plant, would be a major challenge in any country in the world. Government and regulatory approvals were granted in 2009 in order for design and construction to begin, and the project is on track to start up in 2014.
However, a significant hurdle to building the project and operating it for 30+ years is acquiring and maintaining the social license that is "granted" by the indigenous people of PNG who live in the project impacted areas. In a country of almost 7 million people speaking over 800 different languages and living a largely subsistence lifestyle, the Project represents an opportunity to improve their lifestyle and and allow government to fulfill promises and commitments that have been made by governments over many years. The indigenous people use a variety of techniques to negotiate and frequently stop work and hinder progress in order to have their voices heard and their demands addressed. In order for the PNG LNG Project to be a long term success in Papua New Guinea, a comprehensive strategy for acquiring and maintaining social license to operate had to be developed and implemented.
This paper will define what is meant by social license to operate (SLO), discuss the business drivers of SLO and why it is important to manage it with the appropriate people, skills, and strategies, describe ExxonMobil's approach to acquiring and maintaining SLO in PNG, and offer some lessons learned.
Unlocking Reserves, Fracturing Tight Gas-Condensate Bearing Sandstone: The Case History of a North African Field (Algeria)
Authors: Bertoldi Lucio , Perfetto Raffaele , Rinaldi Francesca , Carpineta Gabriele , Granado Luis , Farina Lisa , Secco Giovanni 
Published: May 2016

Abstract
Hydraulic fracturing technique is worldwide used to unlock reserves in tight formations. The Devonian layer, present in this field in the Berkine Basin (Algeria), is gas condensate bearing with a permeability range of 1 to 0.1 md; the zone shows also an highly tectonic stresses, and the frac gradient can rise easily values above 1.0 psi/ft. 3 previous fracturing treatments performed in 2005 and 2006 in 3 vertical wells were without success, due to the high stresses encountered, the wrong frac designs and completion limitation. Aim of this paper is describing the successful multiple propped hydraulic fracturing treatments, placed in a subhorizontal well in March 2012, listing all the actions done in terms of Completion design Materials choice and Frac schedule optimization.
This paper describes also the multiple lessons learned experienced in the execution phase of the multifrac job about frac placement, frac design and completion choice, that have to be considered for the fracturing jobs already planned, in fact the good results of this treatment allowed the Operator to plan a future appraisal/development phase for the Devonian layer.
Development and Application of Pressure Control Drilling System (PCDS) for Drilling Complex Problem
Authors: Liu Wei , Shi Lin , Zhou Yingcao , Wang Ying , Jiang Hongwei 
Published: May 2016

Abstract
In the complex geological condition, drilling operation often encounters the stratum whose fracturing pressure and formation pressure is very near. It is easy to cause drilling complex problems such as well kick and well loss. In order to solve the problems, a pressure control drilling system (PCDS) was developed, including automatic manifold system, back-pump system and auto-control system, which can control the pressure distribution in the entire borehole annular precisely through closed-loop automatic control system. The kernel of PCDS is auto-control system which has three significant characteristic, including an advanced real-time hydraulic method, simple and effective control system, self-adaptive control strategies. The auto-control system configuration composes of field-bus device, controller and workstation which form three levels. Level? is measure and on-site diagnosis level. Level? is monitor and control level. Level ? is optimized control level.
From 2011 to now, the PCDS has successfully finished six field services in China which can provides additional flow-rate and back pressure to compensate for the reduction or increment of bottom hole pressure while making a connection, reduction in rig pump rate, change in mud weight or drill pipe movement and so on. The underbalanced-pressure control technology is also developed which is different from the conventional PCDS technology because the controlled bottom-hole pressure is lower than pore pressure of formation and the gas or fluid can be allowed to come out from formation at a controlled rate which is benefit to protect reservoir and improve ROP.
The applications prove that the PCDS equipment can control the bottom-hole pressure in an exact range and the precise pressure control technology of underbalanced drilling is feasible. So the PCDS equipment can easily adapt to do over-balanced, near-balanced and under-balanced drilling operation and will be more successful in the oil or gas well with safety and fast drilling in the future.