bluuebunny/crossref_metadata_2025 huggingface dataset:
Research Methane Hydrate Meta-stable Property for Application to Natural Gas Storage and Transportation
Authors: Dou Bin , Jiang Guosheng , Wu Xiang , Ning Fulong , Zhang Ling
Published: December 2009

Gas hydrates are group ice-like crystalline compounds, which form through a combination of water and suitably sized guest molecules under low temperature and high pressure conditions. The important properties of hydrate are very high gas to solid ratio, 1m3 of hydrate may contain up to 175m3 of gas (at standard condition). When the conditions change, the methanhydrate can dissociate to methane and water. Hydrate meta-stable (self-preservation) property has been reported by some researchers in recent years. If we can utilize the property economically in addition to its high-density gas containing property, it is possible to store and transport stranded natural gas at higher temperature and lower pressure compared to the conventional liquid natural gas method. The authors conducted laboratory experiments of methane hydrate dissociation in order to examine its potential for application to natural gas storage and transportation. As the result, relatively extremely slow dissociation was confirmed within temperature range between −7.5°C and −3°C. These results seem to be very promising for practical application of self preservation property to natural gas storage and transportation.
Development and Use of Improved Wireline Formation Tester Technologies in Challenging Deltaic Reservoirs
Authors: Orban Nicolas , Ayan Cosan , Ardila Mario
Published: December 2009

Many sedimentary features of gas fields are multilayered, deltaic, thinly laminated shaly sandstones consisting of channel and bar sands with limited lateral and vertical extension. Relying only on conventional openhole log data and performing correlations among nearby wells proved to be inconclusive in identifying gas reservoirs owing to their thin beds, high shale content, and variable formation water resistivity. Missing gas-bearing formations translates into lost productivity, while perforating water zones can have detrimental effects on well performance. Moreover, the limited lateral extent of these relatively tight gas sands leads to extremely depleted reservoirs alternating with layers with virgin zone pressures. As a consequence, the depleted layers face a significant overbalance while drilling with an oil-base mud system.

Given these complexities, fluid identification and pressure measurements have a significant impact in resolving key uncertainties of such reservoirs. The main challenges faced during formation testing in the reservoirs studied have been a) laminated, low mobility and thin formations with varying water salinity, b) high depletion, resulting in extreme overbalance for some layers in new wells, c) possible formation damage while drilling, d) cable creep while station logging.

Several different approaches have been recently launched to increase the success ratio of wireline formation testers (WFT's) in getting reliable pressures and fluid analysis, including real-time monitoring of each survey by reservoir engineers. This paper describes the development path and results from the new techniques: i) extra-large diameter probe, ii) elliptical probe, iii) the openhole driller, iv) cable creep correction and v) extra-extra high displacement pump unit. We will present each project and its impact on the improvement of WFT tester success ratio in such challenging environments.
Optimized Fracturing Design for Buried Hill Reservoirs
Authors: Dan-feng Xiao , Cun-rong Li , Qi Liu , Chang-ming Zhao , Wenming Huang , Ming-hui Zhang
Published: December 2009

The metamorphic rock reservoirs of buried hills in Hailaer oil field have many properties, such as, deeply embedded largely thickness, multifarious rock types, and rock character complexity. There are also widely natural fractured extensive up-growth reservoirs and low stress difference between reservoir and barrier. Therefore, the man-made fractures easily extend along vertical directions during fracturing construction. In this way, it results in low net pressure and narrow man-made fractures. The demanding width and length of these fractures are unavailable. On the basis of stress distribution feature between reservoir and barrier through analyzing factors affecting fracture three-dimensional extension, a new technique was developed and used for definitude controlling factor of man-made fracture extending. According to small volume hydraulic fracture results, utilizing fracture height control technology, optimizing fracturing operation scale and enhancing stimulation, the problem of fracturing lapse for low stress shielding reservoir is solved. This technology was applied to thirty wells. The rate of successful fracturing construction mission reaches to 81% and the effect is marked, the rate of successful of fracturing construction is enhanced and the production improved particularly.
Environmental Risks - Oil & Gas Operations Compliance and Cost Control Using Smart Technology
Authors: Rena S.
Published: December 2009

The objective of the paper is to review the environmental risks facing Oil & Gas industry with the perspective of reducing pollution and environmental compliance costs by using innovative technological tools.

The environmental risks of industry operations are many but are commonly associated with; drilling fluids containing toxic materials (including oil/grease, heavy metals, & naturally occurring radioactive materials); produced waters posing threat of accidental release; potential emissions of hydrogen sulfide in natural gas deposits with its deadly effects on human health; and blowout of exploratory wells (statistically, in 0.5–1% cases) under pressurized contents of a geologic formation resulting in harmful emissions; and other accidents severely impacting environment and the project economics.

To focus on general environmental risks, statistics of environmental incidences and preventions related to well drilling, pipelines incidents and spills/leaks are described. Guidelines and some economically feasible options based on technological advances to minimize risks to environment & human health are also listed.

However, the paper essentially emphasizes the importance of technological advances to reduce industry's operational and environmental compliance costs during all phases (exploration, drilling, production, transportation, and storage) of oil and gas exploration and production (E&P). An an example, using modern technology, a substantial cost reduction from $8M in 1980 to about $0.1M today is realized for a 50 sq-mile exploration survey. The U.S. Department of Energy (DOE) estimates that by 2020, the lower cost compliance technology programs could decrease cumulative industry environmental compliance costs by over $36 billion. The cost reduction coupled with better survey and monitoring data allows less intrusive methods with least impact on environment. Compliance cost reduction further provides opportunities for investing in continued research & development (R&D) towards achieving environmental protection goals. Therefore, special emphasis is to be given to applications of "smart technological solutions" in achieving essential goals of environmental protection, economic benefits and environmental sustainability.
Non-Explosive Solutions for High Performance and Operational Efficiencies
Authors: Schiavi Victor , Tjoonk Richard , Mahammed Hadj , Waheed Arshad
Published: December 2009

Although it is common to think of health, safety, and environment (HSE) as one focus area, in many countries where internal political stability is of concern, this area also includes security (i.e. HSSE). It is also discernible in such places that a considerable portion of non-productive time (NPT) is associated with waiting for the delivery of explosives to perform routine operations, such as casing perforating or pipe severing, or even setting bridge plugs or packers. The occurrence of NPT can result from many factors, but it primarily arises from the sensitive issue of moving explosives and the security measures it demands. In some cases, this lost time is conservatively estimated to be more than $12 million annually for a land-based operation. It is easily plausible to incur triple these costs for offshore operations, noting that these cost estimates do not account for the revenue losses attributable to a delay in production of hydrocarbons.

Considering the magnitude of the problem, a concerted effort was put forth to determine viable alternatives to the use of explosives. This paper presents a comprehensive range of non-explosive solutions, including field-proven technologies that address a majority of the operations encountered in the field. The solutions come in various forms, such as the use of slickline, electric line, or coiled tubing services with specialty tools, all depending on the well situation.

These technologies provide results and performances comparable to explosive-based methods and, in some cases (such as perforating before a hydraulic fracturing treatment), outperform the traditional solutions. There are also instances, such as in a highly deviated or horizontal wellbore, damaged casing or tubing, or tight restrictions, in which shaped charges will not work effectively but, with the versatility of perforating with coiled tubing using high pressure pumping and abrasive material, can surgically place perforations or sever pipe, as needed, at the preferred location.

The prospects of significantly reducing the NPT and improving performance are substantial. The case histories presented will validate the success of the technologies and their application in the industry.
Cementing Casing Strings across Salt Zones: An Overview of Global Best Practices
Authors: Hunter Bill , Tahmourpour Farzad , Faul Ronnie
Published: December 2009

The global oil and gas industry is being challenged to increase production to meet the rising world energy demand. One of the key areas now being explored and developed to meet this demand are reserves below massive salt formations.

To reach these reserves, it is necessary to drill through and case off the salt. Casing and cementing operations in such salt zones can pose particular challenges, ranging from the effect of salt dissolution on cement-slurry properties, to the potential dangers presented by salt creep to the integrity of the well and the need to plan for contingencies for potential zones of overpressure or lost circulation. This paper examines and explores the challenges inherent with cementing across salt zones in the global arena.

The current best practices for cementing casing strings across salt zones in some of the major subsalt basins of the world, including the North Sea and the Gulf of Mexico, are detailed and discussed.

This work should help assist those tasked with the construction of wells that have to penetrate significant salt formations to achieve their objectives safely and reliably.
Multistage Centrifugal Pumps for Drilling and Production Waste Injection Operations
Authors: Newman K. , Woolsey G. , McCosh K. , Hand E. , Boodhai M.
Published: December 2009

Injecting oilfield waste into suitable receiving formations is an effective and environmentally acceptable method to dispose of drilling and production waste including cuttings, drilling fluids, produced water, emulsions and other produced waste. Traditionally, solid waste is degraded to less than 300 microns and suspended as water-based slurry containing 20% solid matter. Rheological properties are controlled so that the slurry can be injected, typically using triplex pumps, under high pressure (1000 to 5000 psi) through a casing annulus or tubular into hydraulic fractures. At locations, where injection pressures are within limits and the disposal well and domain may cope, or be benefitted with higher rates of injection, increases in the rate of disposal is beneficial to operations due to the increased efficiency allowing faster ROP's or faster evacuation of waste storage devices.

This paper discusses the suitability and application of multistage centrifugal pumps for drilling waste injection and provides some data obtained during real time waste injection operations using multistage centrifugal pumps in parallel installation with traditionally used triplex pumps. Wear data in conjunction with engineering economic evaluation will be discussed. Slurry viscosity and particle size data will be presented to show the effect of pump shear on slurry properties and the implications for waste injection.

A multistage centrifugal pump proved capable of pumping waste slurry continuously at relatively high rates for a limited trial period of time. A multistage centrifugal pump provides a continuous flow without the pulsation normally associated with using a reciprocating plunger-style pump and the need to have such pulsation dampened. Laboratory testing and realtime subsurface injection data at an offshore installation indicates that multistage horizontal centrifugal pumps may offer some benefits compared to traditional reciprocating triplex plunger pumps. Some operations requiring relatively high flow rates with flow media containing solids may benefit from implementation of this style pump providing the net power requirement and equivalent downhole pressure requirement are within the pump design range, and there is available footprint at the location.

Oilfield waste can be disposed of in an environmentally responsible manner under zero-discharge conditions with the performance of the pump ensuring operational reliability and injection assurance. Operations on a global scale may benefit from this new application for multistage pumps. Decreased downtime together with slurry stability and controlled injection assures operational performance and cost effectiveness, enabling oilfield waste to be disposed in a safe, controlled and environmentally responsible manner.
Research on Environmentally Safe Temporary Plugging Drilling Fluid in Water Well Drilling
Authors: Cai Jihua , Wu Xiaoming , Gu Sui
Published: December 2009

In China, the drilling industry has had numerous environmental restrictions on some materials it uses and the methods of the disposal. Both the governors and the drilling engineers welcome the use of environmentally safe drilling fluid. However, there is a contradiction between maintaining borehole stability and protecting the permeability of the reservoir in water well drilling. The mud invades in the porosity in a large radius near the wellbore. With the flushing work, some of the invaded mud is cleaned. However, the majority of the mud remains in the porosity. The residual mud not only plugs the porosity but also is a kind of contamination to the aquifer. It becomes a barrier to recover the permeability of the promising aquifer and greatly decreases the yield of water. The paper proposes the use polymers such as Na-CMC, guar gum and HEC to develop temporarily plugging drilling fluid, combining with the bio-degradation principle in modern biology. This fluid is marked as self-degrading, harmless to the reservoir and can be widely used in oil, gas and water well drilling. Distinguishing from traditional temporarily plugged agents, it does not need additional unplugging technology which elementarily improves the unplugging technology. This paper analyses in detail the action mechanism of temporarily plugging drilling fluid and the enzyme degradation mechanics. Meanwhile, it presents the lab tests of viscosity and permeability recovery and the field trial in Zhangye city of Gansu province of North West China. The results of lab and field trial confirms the performance of temporarily plugging drilling fluid that it can be self-degrading, harmless to the reservoir, effectively maintains the borehole and plugs the leakage while remarkably recovers the permeability of the reservoir. Therefore, it has a promising future.
Fracture Diagnostics and Modeling Help to Understand the Performance of Horizontal Wells in the Jilin Oilfield, China
Authors: Wang Feng , Liu Xinghui , Liu Changyu , Zhang Yingan
Published: December 2009

The Jilin Oilfield is a large complex that consists of more than 20 individual fields. Most of the target zones in these fields are low permeability oil reservoirs. This paper describes fracture treatments in three horizontal wells from three different tight oil reservoirs in the Jilin Oilfield. Fracture diagnostics (microseismic and tilt mapping) and modeling analyses were conducted to understand fracture growth behavior and post-treatment well performance. The fracture orientation and dimension (length and height) for two horizontal wells were obtained from microseismic mapping. The microseismic results indicated that the measured fracture azimuths for both wells differed from expected fracture azimuths and that the fractures in both the wells grew much longer than designed and expected. Surface tilt mapping was performed for the fracture treatments of the third horizontal well. The results revealed that dominant fractures was created during the treatments were vertical in a shallow reservoir at an average payzone depth of 275 m. Fracture models were calibrated using the microseismic results for the first two horizontal wells. Production modeling analyses were also conducted. The mapping and modeling results were used to optimize fracture designs for the remaining stages and future well completions. The mapped fracture azimuths were also used for future horizontal well planning. This paper presents detailed case studies and discusses some lessons learned from these cases.
Start-up of Gelled Waxy Crude Oil Pipelines: A New Analytical Relation to Predict the Restart Pressure
Authors: Vinay Guillaume , Wachs Anthony , Frigaard Ian
Published: December 2009

In this paper, we investigate the problem of the start up of gelled waxy crude oil flows in a pipeline. Waxy crude oils are deemed to be weakly compressible, thixotropic and viscoplastic material. In severe situations, the waxy crude oil is fully gelled in the pipeline and the main issue concerning the restart of waxy crude oils relies on the estimation of the minimum pressure required at the pipe inlet. The objective of this study is to examine the possibility that the flow can restart for a pressure drop below the value predicted by the conservative relation Δp=4τyL/D, where τy denotes the yield stress, L the pipe length and D the pipe diameter, thanks to the combined effects of compressibility and thixotropy.

Using a 1.5D numerical model, we evidence that there exists situations where, though the pressure drop is below the theoretical minimum pressure drop 4τyL/D, the flow restarts thanks to the combined effects of thixotropic and compressibility. From a parametric survey, we derived a new analytical relation able to predict more accurately the minimum pressure required to restart pipelines filled with a gelled waxy crude oil. This relation accounts for not only viscoplastic effects but also for compressibility and thixotropic effects.
Performance of Formate Based Drilling Fluids for Gas Hydrates Drilling in Deep Water
Authors: Ning F. L. , Jiang G. S. , Zhang L. , Tu Y. Z. , Zhang H.
Published: December 2009

Marine gas hydrates have now become a hotspot of energy resource researches. Drilling is indispensable when exploring and exploiting gas hydrates existing in deep water. But it will be confronted with more complicated safe problems than that of the conventional marine oil & gas drilling. Drilling fluid is the crux of gas hydrates drilling and its performance is extremely important to the well-off drilling.

The hydrates inhibition and low-temperature stability of formate based drilling fluids as well as effect of hydrates inhibitors on the fluids were evaluated elementarily by the experimental system of gas-hydrate integrative simulation (ESGHIS). The results show that a basic system of formate based drilling fluids, which composed of seawater,3% HCOONa, 3%SK-2, 0.2%KPAM,0.1%LV-PAC, 2%SMP-2 and 0.3% modified starch, has a good performance stability under low temperature environment(−5°C −15°C °C). Adding NaCl and KCl, thermodynamic inhibitors, has little effect on the rheology properties of the basic system, while PVP(K30), a dynamic inhibitor, has a great effect on those. The basic system has a low ability of hydrates inhibition when they are used in deep water over 1400m. Low dosage of PVP(K30) can improve increasingly the hydrate inhibition of the basic system, and the suitable concentration is about 0.5%. Therefore, the formate based drilling fluids which contain high concentration of salts and low dosage of hydrate inhibitors, can meet the needs of gas hydrates drilling in the deep water.
Reservoir Monitoring Using Radar Satellites
Authors: Arnaud Alain , Granda Johanna , Banwell Marie-Josée , Duro Javier
Published: December 2009

Description of the material

InSAR (Interferometry for Synthetic Aperture Radar) technology is a spaceborne measurement method, capable of detecting ground motion with millimetric exactness using radar satellite images. Measurements are taken remotely, from the space.

Application

Ground motion monitoring with radar images can contribute to oil & gas reservoir monitoring in several ways: For oil & gas extraction areas, InSAR ground motion results support site safety since risk areas can be identified at an early stage. In addition for enhanced oil recovery, millimetric ground motion monitoring contributes to production efficiency: By mapping ground motion changes over the production area, InSAR measurements can aid the assessment of whether the pressure of injection is correctly distributed over the area.

Results, observations and conclusions

Ground motion has been detected with high precision and high resolution in several production areas. InSAR technology is particularly successful in EOR production areas. During specific periods, due to its millimetric accuracy, InSAR technology has been able to identify potential risk areas at an early stage which were later confirmed with other data. Therefore, InSAR technology has been proven as an efficient tool for risk prevention and production efficiency enhancement.

Significance of Subject Matter

InSAR technology is very valuable for reservoir monitoring, especially for EOR production. Surface displacement measurements combined with pressure and temperature surveillance in the reservoir deliver important information to understand how the production system is working. In the integration of these three surveillance methods, surface displacement monitoring is extremely relevant, because it provides an accurate measurement of the impact on the surface, and therefore delivers information to aid steam chamber distribution mapping and first alerts for excessive heave. As a summary, surface measurements can contribute to improve production efficiency, safety and reduce environmental impact in EOR production areas.
Is That A Gap In Your Safety Culture – A Discussion Paper on Leading Safety Excellence
Authors: Whitefield D.
Published: December 2009

Safety culture is now recognized as being a significant influencer of safety outcomes within the workplace. However positively changing safety culture has proven to be a bigger challenge than expected in many organisations. If current strategies and initiative have failed to have the impact that was desired, perhaps it is time to discard them and explore other options.

Using a traditional safety model where the physical environment, systems of work, and personal behavior all interact to impact on safety outcomes, this paper takes a a unique approach to revamp and reorganize this model in a pway which identifies the key drivers and outputs required. What emerges is a very practical and logical model that clearly shows the various strategies that should be focused on in the areas of safety control (safe environment), safety management (systems of work) and safety leadership (safe behaviours). With reference then to safety culture being an influencer of safety in general, and safety culture being directly affected by the safety attitudes of personnel, then safety leadership becomes the key driver for change.

Safety leadership is something that everyone already does. Effective and positive safety leadership on the other hand requires a safety thinking mindset, and then the application of leadership skills such as leading safe behaviours, coaching safety thinking and rewarding positive safety behaviors. In addition, some strategies that appear to be safety focused may in fact be harming safety culture. These include the recording and measurement of incident data, the use of safety slogans, and in particular the use of "zero harm" terminology. Organisation should consider discarding these strategies.
Permanent Downhole Gauge: A Need or A Luxury?
Authors: Chris Chen Jiun Horng @ , Nordin Norbashinatun Salmi , Nuriyadi M Azrul , Samsudin Noren , Kasim Abdullah , Hoe Chum Wai , Rahman Roziman Abdul
Published: December 2009

Moving into electronic age, completion tool and accessories are getting advanced. For the past 10 years, permanent downhole gauge (PDG) technology has been supported with tremendous investment in its research and development. This pacing technology is no longer new to the industry oil and gas operators. Some operators have made it as standard practice but however, some operators are still performing financial model analysis to justify for PDG installation. Is it a real need to install PDG or it is just another fancy luxury that give limited financial returns to the project? How much data is required by petroleum and reservoir engineer to understand the reservoir? This paper presents in detailed about the financial model analysis and demonstrates the tangible and intangible benefit of the PDG and the added value to full field life cycle.
Hearing Conservation Program in Oil and Gas Company
Authors: Hadad Ashif , Cahyono Dwi , Putra I. B. Ardhana , Susanto J. , Rianto Bambang Udji Djoko , Tjahjono E. W
Published: December 2009

Noise is one of hazards in Oil and Gas Company. It is managed thru Hearing Conservation Program (HCP) which mainly consists of workplace noise measurement, noise dose calculation for HCP member (personnel intentionally exposed to noise hazard) or noise exposure, Noise control (Engineering Control, Administrative Control, and Hearing Protection Device), Training and socialization, Audiometric testing and evaluation program. Letter assigning HCP Committee and issuance of procedure for HCP have been issued as a proove of support from Management.

It is recently developed INASyst® software (Integrated Noise Assessment System) to support the program which provides some essential noise features such as, Noise Mapping, Noise Source measurement analysis, Noise Dose Calculation, HPD (Hearing Protection Device) Selection, Noise Criteria Calculation. The noise simulation program, on the other hand, will also allow prior analysis to the planned alteration on noise source hence noise levels at the working places. Therefore early precaution and action plan concerning the HCP can be appropriately prepared

In health surveillance aspect, Audiometric test is performed regularly refers to the procedure and evaluated together with ENT (Ear, Nose & Throat) specialist for early detection of the Noise Induced Hearing Loss. All Audiometric test result is entried into database. For improving employees awareness related to Noise, Similar Exposure Group health talk is performed using variety tools (Playing games/animation) by Medical Staff and regularly by ENT Specialist with the topic Noise effect, Noise control and the appropriateness useful of ear protector. The program evaluation was performed by elements program inspection and also presented to the management for continuous improvement

Hearing Conservation Program in Oil and Gas Company.
Managed Pressure Drilling Proves its Value in Offshore East Java Field Development
Authors: Lang Clifford , Attema Huib , Toralde Julmar Shaun , Nas Steve , Fisher Kevin
Published: December 2009

The development drilling campaign for the Ujung Pangkah field in offshore East Java, Indonesia, began in the first quarter of 2007. To prepare for circulation losses, the field operator tendered for managed pressure drilling (MPD) services as a contingency. The first gas well was successfully drilled by relying on conventional lost circulation material (LCM) to minimize the losses encountered. However, after drilling a pilot hole, plugging back and sidetracking the second gas well, total losses were encountered, followed by the persistent migration of gas up the annulus despite seawater bullheading. After stabilizing the well, MPD equipment and personnel were then mobilized and the system was rigged up to allow for clean-out and completion operations. Total losses were again experienced, but MPD made washing and reaming down to the previous depth possible. MPD techniques also kept gas migration in check, allowing for safer tripping operations in and out of the hole. An additional 55 ft of new formation was drilled and completion was run using MPD methods. This gas well has proved to be the most productive well drilled in the field to date.

In subsequent wells, MPD equipment was rigged up before drilling the hole sections where severe circulation losses are anticipated. This practice paid dividends when severe losses were again experienced while drilling the first oil well. With the MPD system already installed, drilling was able to resume immediately in MPD mode up to the target depth for the section, despite total losses. Liner running and cementing was then successfully done in MPD mode, allowing for the successful isolation of the zone where the losses were and for drilling operations for the next hole section to proceed immediately.

The MPD system in the Ujung Pangkah field has proven its value as a contingency measure by allowing drilling operations to continue despite total loss of circulation and by minimizing the non-performance time involved when the eventuality occurs.
Challenges for Coiled Tubing in Slim Hole Horizontal Well Intervention
Authors: Al-Sharji Hamed , Kumar Santhana , Ferdiansyah Erik , Neyaei Fardin Ali
Published: December 2009

This paper addresses challenges faced in Coiled Tubing (CT) intervention in slimhole horizontal wells in one of the most mature fields in Oman. An intensive production optimization program has been set by the reservoir management team. The optimization activity consisted of clean-out, saturation logging, perforation and stimulation. CT units utilization played the main role in this program. Large number of these wells were completed with 2 7/8" cemented horizontal liner and 4½" tubing equipped with gas lift system. These wells were sidetracked using CT drilling. The length of the horizontal 2 7/8" section ranges between 1000 m and 1600 m, having the kick-off depth at about 1300 m.

CT intervention was very challenging in these well, as CT reach was limited in most of the cases. This is mainly due to the following factors: Complex well trajectory path or "snake-like" wells.Limited tools and CT pipe size due to small cross sectional area.Scale build up on completion.High production rate resulting in resisting CT passage.Corroded liner and poor cement bond resulting in preventing scale cleanout with reactive fluids.Bad liner and/or tubing conditions resulting in mechanically obstructing CT passage.

Therefore some unsuccessful cleanouts or dummy runs were held. Hence, no logging and or optimization activities could be done.

A total of 22 wells were intervened in this project. At project midway success rate was 40% and at the end success rate was increased to 60%.This paper addresses the lesson learnt throughout this project and techniques used to enhance CT reach. The technique involved the use of CT force models and reach simulator to sensitize different factors. As more jobs were performed, models were compared with actual data and some learning could be gained. The main learning was that well flow rate was the highest contributor preventing a deep reach. Hence, the improvement techniques involved manipulating gas lifting flow rate to reduce well flow rate while CT runs in hole.
Silicon Containing Scale Forming Characteristics and How Scaling Impacts Sucker Rod Pump in ASP Flooding
Authors: Jinling Li , Tiande Li , Jidong Yan , Xiwen Zuo , Yan Zheng , Feng Yang
Published: December 2009

ASP (alkali-surfactant-polymer) flooding improves recovery rate dramatically. However, scaling problem happens in artificial lift systems and causes pump sticking in sucker rod pumps and the average pump running time decrease from 500 days to 37 days. By analyzing the constituents and characteristics of scales from ASP production wells and experimenting with simulating produced liquid, characteristics and mechanism of silicon containing scale forming are researched. The results show that Ca2+, Mg2+, Al3+, polyacrylamide, surfactant and silicon influence the ASP scales structures and forming processes. The ASP scales have the characteristics of absorbing and sticking. Basing on describing of scaling characteristics, mechanisms and the pump structures, the reasons for pump sticking are analyzed. Pump sticking which caused by scaling between the plunger and barrel occurs when the sucker rod pump is sucking, hot water is circulating or the pump is stopping. When the well is shut down, one major reason of pump sticking is scale particles set down, stick and pack in the anti-sand groove. When a great deal of hot water is circulating in the well bore, liquid viscosity lowers and scale particles set down speed increases also. The slow-dissolved solid scale-inhibitor SY-2 and anti-scale pump with long plunger-short barrel are developed and applied in field. Through these methods applications, the pump running time have been prolonged and good results have been achieved.
Novel Injecting Concentration Design Method for Polymer Flooding in Heterogeneous Reservoirs
Authors: Zhang Xiaoqin , Guan Wenting , Li Xia , Liu Zhen , Meng Jing , Jiang Dongyang
Published: December 2009

Daqing oilfield is a multilayer heterogeneous oilfield. Recently, as the development target is more complex and reservoir heterogeneity is more serious, simple injection concentration can not meet the requirement of polymer flooding in Daqing oilfield. Therefore, based on different reservoir geologic characteristics, individualized design of injection concentration for single well is needed to relieve the areal contradictory. Numerical simulation study shows that under the same pressure difference, reservoirs with different permeability are compatible with polymer solutions of diverse concentrations. In the field site, individualized design for single well is based on actual permeability and injection pressure scope, injection concentration ranges from 400mg/L to 2500mg/L. After implement, breakthrough rate of polymer along high permeability zone is effectively controlled; meanwhile, development degree of low permeability reservoir is increased, areal contradictory is relieved as well as polymer flooding effect is improved.
Safety Cultures – Pushing the Boundaries of Risk Assessment
Authors: Lee Nai Ming
Published: December 2009

With an ever growing interest in the safety, health and environmental performances of organisations across the industries, today's responsible businesses are committed to the conservation of workplace safety and health, as well as the environment.

In Oil Spill Response, risk assessment (RA) is an integral part of the Safety Management System and pivotal to operational safety. RA is used to address hazards and risks to our staff, contractors, and the large number of industry delegates subscribing to our training courses annually.

Over the years, the approach to RA has constantly evolved. While the concept is not foreign, a lack of common understanding on how risk assessment should be applied has limited the purpose for which it is meant. Following a recent in-depth review of the existing process, the methodology for risk assessment underwent a major revamp. Central to this review is the need for a coherent approach to the conduct of RA across all levels of the organisation.

The outcome of the study signifies a step change in the approach to risk assessment, with an ensuing framework that is more rigorous and comprehensive. Aligned to approach taken by leading organisations in the Oil and Gas industry, hazards and risks to people, environment, assets and reputation are addressed using defined sets of criteria.

This paper will outline key challenges in the conduct of RA, and the different considerations when reviewing the approach to managing operational hazards and risks. The corresponding build-up of a framework to administer the process, and to support the communication of risks, coupled with the implementation of risk control measures and post-activity review, will also be discussed, with an intention to highlight how management commitment and visibility is demonstrated through its application.

Lastly, the paper will explain the practical application of the revised methodology, taking in view the diverse environments that spill responders would be required to work in.
Bringing the 1st BP Operated Subsea to Shore Gas Field into Production: Flow Assurance Lessons Learned
Authors: Harun A. F. , Watt N.
Published: December 2009

Taurt field located in the Mediterranean Sea in 108 m water depth is the 1st BP operated subsea to shore gas development. Phase 1 of the project consists of two subsea wells producing directly from the subsea manifold to the onshore gas processing plant via a 68 km, 20-in pipeline. The field has been brought into production and ramped up to 230 MMscfd successfully despite facilities constraints during initial start-up. The main flow assurance issues experienced during the initial start-up are hydrate risks due to J-T cooling and liquid production handling onshore particularly due to potential completion brine return.

The experience during initial start-up highlights the importance of collecting good fluid samples during exploration and appraisal, and also the down hole and wellhead pressures and temperatures during flow back. Confirming the condensate yield helps prediction of liquid holdup in the pipeline which in turn will affect the prediction of liquid production coming to onshore during ramp-up. More accurate prediction of the wellhead temperature affects the requirement for hydrate inhibitor which in turn also affects the liquid holdup in the pipeline and liquid production coming onshore.

Transient simulations help in selecting the dewatering strategy to be either pigged or pig less operation by predicting the amount of remaining water and how it impacts the production ramp up. Simulations also help prediction of the liquid production for setting up temporary liquid handling facilities to prevent the possibility of completion brine return upsetting the processing plant.

Comparison with the actual liquid production data suggests that simulations should have been performed with less conservative condensate yield, although predicting the completion brine return onshore is still difficult. After obtaining the latest fluid composition and the actual operating conditions, the hydrate management strategy has been re-visited and resulted in operations cost saving and simpler operating procedures.
Reusing Recovered Base Oil from OBM Cuttings
Authors: Kleppe Stein
Published: December 2009

Millions of tones of oil contaminated drill cuttings are produced every year. By nature the cuttings are contaminated by drilling mud. The level of contamination depends on the efficiency of the mud return system carried out by means of shell shakers. The cuttings may origin from drilling with water based mud (WBM) or oil based mud (OBM). Many different composition of mud and many different properties in the well result in a vast variety of cuttings properties. Defining caracteristics of the cuttings is difficult and it is often not made easier by the drillers and mud suppliers who tend to protect details about their mud.

Drill cuttings have different destinys in different areas. Some is dumped, some is reinjected, sometimes the material is cleaned and parts of the waste are reused in new mud. It appears as if the destiny of drilling wastes often is decided based upon limited input and without overall conciderations. In some cases the decision seems based on unproportional focus in only a few areas like ease of operation, emissions to sea/air, cost, storage, etc. Often the value of oil in the cuttings is not given appropriate attention.

The purpose of this document is to touch upon the different routes OBM cuttings may take and treatment methods in general, then to discuss available thermal separation techniques and finally to describe studies made of oil quality from thermal separation by means of friction based hammermill driers.

Often the oil recovery acceptance criteria are based on a maximum flash point reduction caused by the thermal process, but comparison is made to virgin base oil which not necessarily represents the actual oil in the feed. Tests have shown a measurable shift in distillation curve and flash point from virgin base oil to oil in drill cuttings. This study does not include identification of the scources of degradation of oil before separation, but it is likely that aging and pollution from mud additives or from well formation are factors of significance.

The findings are that the hammermill works for recovery of high quality oil from OBM drill cuttings without degrading oil qualit ard. In fact the thermal separation process can be used to raise the quality of oil compared to the actual feed to the unit by removing oil fractions outside of the virgin base oil specification. Recovery and reconditioning of the valuable base oil justifies the cost of the cleaning process, providing a win/win situation for the drillers, mud companies and for the environment.
Verification of Microbial Activities for Microbial Restoration of Methane Deposit With Subsurface CO2 Sequestration into the Depleted Oil Fields
Authors: Otagaki H. , Fujiwara K. , Hattori Y. , Sugai Y. , Okatsu K.
Published: December 2009

The objective of this research is to estimate the possibility of microbial restoration of methane deposits using subsurface sequestered CO2 and indigenous anaerobes in depleted oil fields. The most important factors are the efficiency and velocity of methane conversion by indigenous anaerobes inhabiting a reservoir. Field samples (producing oil and water) from oil field in Japan were collected and analyzed in order to clarify the existence and survivability of indigenous methane-producing anaerobes under reservoir conditions. The hydrogenotrophic methanogen consortium MYH-4 consortium was separated from the enrichment culture added oil reservoir water. By using MYH-4 consortium, two experiments were conducted. ( i )Direct calculation of the CO2 to methane conversion rate for economic assessment. ( ii )As the main objective of the field operation test, it is necessary to identify the state of the subsurface injection environment and the limitations that it poses to methane production. To clarify this, the experiment was carried out by using stable isotope probing. At the result of these studies, it has been understood that the methane conversion efficiency from CO2 was approximately 50%.
Re-Evaluation of a Complex Mature Field (Dunbar, UKCS): A Geosciences Integrated Work
Authors: Ben Brahim L. , Coombes T. , Cooper R. , Fredonnet J. , Taylor D. , Varley S.
Published: December 2009

Dunbar Field (3/14 block) is operated by Total E&P UK. Situated on an intermediate terrace between the East Shetland Platform and the Viking Graben, the field is characterised by a series of pre-Cretaceous and structurally aligned tilted fault blocks. The principal hydrocarbon accumulations are contained in the Middle Jurassic Brent Group and younger Upper Jurassic Heather Sands with additional volumes in the Lower Jurassic Statfjord and Triassic.

Internally, the field is compartmentalised by a number of N-S faults and a secondary alignment of NE-SW faults which cross cut and often offset the main N-S faults. The larger scale faults down throw to the east and subdivide the field into four main areas; the West Flank, Central Panel and Frontal Panel with an uplifted Horst (Triassic) Panel in the south. Each of these panels has specific reservoir and fluid characteristics.

Discovered in 1973 the field did not start production until 1994 owing to the high levels of complexity and geophysical uncertainty. Compartmentalisation, with limited or no interaction between panels, was a major obstacle in assessing the potential of the field. (Coombes et al, 1996)

The field has so far produced more than 280 MMBoe.

Better understanding of the reservoir behaviour relies on our ability to better define the size of the connected volumes through a combination of seismic horizon and fault picking followed by refined geological and reservoir models. A full re-evaluation of the field was launched in 2007. It includes a PSDM3D reprocessing of the third 3D seismic survey on the field, shot in 2001. Use of the latest time processing and depth imaging techniques has enabled us to better understand the results of Phase III drilling (2005 – 2007) and improve our understanding of compartmentalisation to better define new targets, including the undeveloped volumes in the Triassic southern horst.
An Integrated Computer Based Method to Maximize Infill Drilling, Sidetracking, and Workover Potential in Multiple Stacked Hydrocarbon Reservoirs
Authors: Friedel Torsten , Trebolle Ramiro , Flew Stephen , Belfield William , Meyer Juergen , Curteis Charles , Syaifullah Nalom , Caretta Fausto
Published: December 2009

A novel workflow methodology that covers the entire cycle of field development maximizes the production potential and can increase reserves in stacked reservoirs. The approach will potentially reduce associated costs, risks, and uncertainties, in spite of complex geological structures and drainage patterns.

The new workflow encompasses planning from concept selection to preparation of well proposals during the implementation work. Scalable to any given size of hydrocarbon prospect and number of infill wells, the computational method incorporates cross-disciplinary software (geomodeling and seismic packages) as well as reservoir, production, completion, and drilling software. Linkage between the disciplines is close and conducted iteratively, operating in parallel instead of the common sequential and decoupled approach.

The method has been successfully tested in a brown field with 165 stacked reservoirs. Reserves increased significantly compared to the offset field development plan (FDP), while water production was significantly reduced. The optimized drainage pattern for the whole field also revealed significant future workover potential in shallower reservoirs, maximizing contingency and lifetime value of infill wells.