bluuebunny/crossref_metadata_2025 huggingface dataset:
Oilwell Cement Durability
Authors: NOIK Ch. , RIVEREAU A.
Published: January 2008

Whatever the reservoir conditions the strict control of cement reactivity and mechanical properties during the life-time of the well are required. These requirements are reinforced under drastic conditions such as temperature above 150°C.

The present paper focuses on cement formulations designed for high temperature and pressure conditions. The chosen selection criteria for the formulations is a specific gravity above 1.9 with an optimized thickening time.

The main objective was to compare the durability performances of several types of cement material and slurry formulations.

Experimental work was based on aging tests at different temperatures over time period between 3 months up to 2 years. Performances such as compressive strength, water permeability were periodically measured and correlated to structural observations by XRD, DRX and SEM. Durability was also tested in different aging solutions : taped water, sea water with or without aggressive gas such as sulfur gas H2S.

Durability of classical weighted formulation adjusted with Portland cement, silica flour and weighting agents is compared with a new type of cement. This new material named RPC - reactive powder cement -is composed of Portland Class G with two silica of different particles sizes. The water adjustment and adaptation of the silica grain size distribution lead to improve the durability and the mechanical properties. Experiments on RPC formulation performed after one year aging indicated that compressive strength increased with time and permeability value remained at the same initial low value.
Seligi Depletion Management
Authors: Selamat S. , Goh S. T. , Lee K. S.
Published: January 2008

The Seligi is a large oil field comprising a multi-closure anticlinal complex with the major reservoirs having relatively thin oil columns with large gas caps and aquifer of varying strength. The field contributes about one third of Esso Production Malaysia Inc.'s (EPMI) operated production and started to decline in 1995. A comprehensive depletion management study was initiated in 1997 to mitigate production decline and maximize ultimate recovery.

This paper describes the challenges faced in managing this large resource, technologies used to address these challenges and some initial results from the studies. Early accomplishments include revised gas injection strategies, an inventory of wellbore opportunities, an optimized well / gathering system capacity, and infill / new development programs. Some of the above opportunities have been successfully implemented in the field; these have helped in mitigating production decline and increasing reserves capture.
Pilot Test of Xanthan Gum Flooding in Shengli Oilfield
Authors: Guo X. H. , Li W. D. , Tian J. , Liu Y. Z.
Published: January 2008

This paper presents a pilot test results of xanthan flooding in Shengli oil field, China. Emphasis is on the polymer flooding solution properties during the field test. The xanthan was considered as a desired polymer because it is shearing resistant and salinity durable. During the injection period, solution property was evaluated after injection pump, at the wellhead and the formation flow back. It is found that under uncontrolled shearing viscosity loss is unacceptable, which was not perceived and somewhat contradictory to early literatures. At first the xanthan was thought to be shearing resistant, therefore, one pump was used to inject the xanthan into four wells. The injection rate for individual well was adjusted by valves. Measurement showed that the solution viscosity behind the values can decrease as much as 40%. So the "one pump for one well" injection was used.
Microbial Core Flooding Experiments Using Indigenous Microbes
Authors: Sugihardjo Sugihardjo , Legowo E. H. , Partomo Partomo , Pratomo S. W.
Published: January 2008

Microbial enhanced oil recovery (MEOR) is well-known as a developing and promising method to improve the oil recovery through microbial's activities. The basic theory behind this is very simple. Specifically selected suitable nutrients are introduced into the producing formation near the wellbore. When the well is shut-in, after nutrients injection, the microbes are encouraged to produce biometabolites and extend colonization outward into the producing formation. Bioproduction of solvent, polymer, and surfactant is done in-situ. when the well is put into production, the fluids flow toward the wellbore, and result in increasing oil recovery.

MEOR had been applied in some old oil fields in Indonesia, such as Prabumulih field (1992), Klamono and Kawengan fields (1993). By that time, a research group was set up to conduct an intensive research on MEOR in LEMIGAS. Samples were collected from Indonesian oil fields, i.e. Rantau, Jambi, Prabumulih, Cirebon, and Cepu fields. Several potential microbes were identified. However, for the first priority microbes from Cepu fields only were further tested in coreflooding. Beside that, variety of medium were formulated to promote bi-osurfactant, biosolvents, and bioacid production.

To simulate the MEOR processes, coreflood experiments were conducted using standard and native cores, and activated microbes from Cepu oil field at reservoir conditions. The mixed cultures were injected into core sample, after completing a waterflood. The core was shut in to let microbes to produce bi-ometabolites. Nutrient or brine was then injected as a post flood. The injection results indicated that the oil recovery increased 10% to 60% of Sor. SEM and X-ray analyses results revealed no damage on the core samples. The permeability test, after the injection of microbes, showed an insignificant decrease on the standard cores. The decrease was significant, however, for the native cores.
A New Effective Method of Maintaining "Hole Gauge" using Synthetic Diamond Enhanced Inserts on Downhole Drilling Tools
Authors: Crowe J. R. W. , Toohey W. G. , Holt Jonathan
Published: January 2008

This paper presents a new concept in the application of synthetically manufactured Shaped Diamond Enhanced Inserts (SDEI), on an innovative range of downhole drilling tools. The main points for discussion will highlight the major advantages in using these materials in the following applications.

Firstly, the ability to offer both gauge protection and hole reaming capability with a single design, while maintaining well bore quality. Secondly, the increased performance and beneficial aspects when compared to existing gauge protection methods. Thirdly, the economic advantages in applying this technology.

A full discussion will be made on the development, concept and the strategic application of Synthetic Diamond Enhanced Inserts. The increased performance capabilities and beneficial opportunities for economic savings will also be highlighted through operational data relating directly to applications of this technology.
Horizontal Drilling Experience in the Panna Field
Authors: Ghosh Kallole , Wali Vinod K. , Brumbaugh Alan J. , Jaggi Anil , Baca Jeff , Murthy R. K.
Published: January 2008

A horizontal drilling program was initiated in the Panna field off the west coast of India during mid 1997 to tap the 20 m thick oil column in the Bassein limestone reservoir. There were formidable challenges – planning trajectories, choosing drilling fluids, steering, preventing the fragile time-dependent shale sections from sloughing in the high angle holes, formation evaluation, completion and the presence of up to 500 ppm H2S. The goal was to execute an accelerated development drilling program by drilling low cost, high quality wells from preinstalled platforms. Earlier directional and limited horizontal drilling experience in the field during the late eighties and early nineties had encountered significant drilling problems. By careful review of data and past practices, and aided by state of art equipment and services, the present drilling campaign has achieved significant improvement in drilling efficiencies and performance.
Drilling the First Ultra Deepwater Wells Offshore Malaysia
Authors: Jenkins R. W. , Schmidt D. A. , Stokes D. , Ong D.
Published: January 2008

This paper will address all of the planning and logistical issues involved with drilling the first ultra deepwater wells off the coast of Malaysia. Murphy Sabah Oil recently contracted the Diamond Offshore Ocean Baroness to drill wells in water depths ranging from 1300 m to 2000 m of water.

Since a moored rig was used for the project long range planning and engineering was required to moor the rig in world record mooring depths without any boats or contractors in the area with ultra deepwater mooring experience.

Well design and strategy required the initial string of conductor casing to be placed at depths exceeding 750 m below the mudline. Due to possible high pore pressures, the riserless section was designed to be drilled with water based mud. The paper will address the logistical and planning issues involved with transporting mud volumes offshore in excess of 15000 bbls in an area without deepwater logistical support. The selection and procurement of proper "deepwater" cement will also be discussed. Synthetic based mud was also a part of the drilling strategy. Since synthetic fluids had never been used before in this area, the planning phase for this fluid requirement will offer several lessons learned for industry.

Well design was further complicated by an abnormally high temperature profile that brought on several well design and strategy issues.

The well was also the initial project for a recently upgraded rig, which added to the complexity of the mobilization along with commissioning requirements. The rig had minimal downtime during the project.
New Shock Resistant Cement Reduces the Required Time for Side-Tracking from KickOff Cement Plugs
Authors: Babasheikh Amjad , Hun Christian , Cunningham Erick , Helou Husam
Published: January 2008

The process of sidetracking an existing borehole with a balanced cement plug has historically been time consuming and problematic for the drilling industry. In many instances long drilling times or even multiple plugs are required to achieve the objective of sidetracking the well. These problems lead to increased drilling time and increased cost for the operator. Traditional cement slurry systems for sidetrack applications have been focused on the development of high compressive strength through reduced water content. Conventional high compressive strength cement systems exhibit low resistance to impact and low resistance to fracture propagation through the set cement. Recent developments in oil well cement system have incorporated a unique micro-ribbon technology with an optimized particle size distribution to increase the durability, load bearing capacity and resistance to fracture propagation of set cement. Field tests with these cement systems have shown substantial improvements over conventional cement slurries in terms of plug success rate and time required to achieve the objective of sidetracking the well. These improvements have resulted in significant reductions in the total cost of the operation of sidetracking wells. This paper will discuss the improved mechanical properties of these new cement systems and the success of the numerous field tests
Foam Cementing on the Eldfisk Field: A Case Study
Authors: Green K. , Johnson P. G. , Hobberstad Rune
Published: January 2008

Data gathered from 15 (5 conventional, 10 foam) production wells on the Eldfisk field in the North Sea indicate that foam cement outperforms conventional cement for zonal isolation and dynamic curing of losses.

Drilling in a highly fractured reservoir presents problems related to losses and providing effective zonal isolation across the producing interval. Nearly all recent wells drilled in the Eldfisk Field have encountered losses in the magnitude of 250 to 300 bbl/hr.

Considering the downhole conditions, with pore pressures ranging from 4 to 10 lb/gal in the different productive layers, the importance of zonal isolation, establishing barriers in water productive layers, and achieving overall cement coverage is extremely important.

Because the reservoir section in the Eldfisk Field is mainly chalk, permeability is generally low. If not stimulated, the economics of drilling in this field would be marginal. The overall success of the drilling effort is therefore dependent on the stimulation results, which in turn depend largely on effective zonal isolation/cement coverage across the productive interval.

Foamed cement has been introduced and seems to have fulfilled the requirements of cementing in this challenging field. Since its introduction, the service companies have performed ten jobs successfully. The criteria for success have been measured using each of the following factors: operational performance, fluid diversion during stimulation, and CBL evaluation.

This paper provides details about the following: Design reviewOperational challenges related to strict environmental rulesHandling foam cement returns at surfaceCase review of the stimulation resultPossible conformanceHydraulic fracturingCBL results from one well
Stable Isotope Relations in the Characterization of Giant Complex Reservoirs
Authors: Urbina Rafael , Embid Sonia , Bozo Dorelis , Vasquez Yaneth , de Audemard Nancy
Published: January 2008

Molecular and isotopic compositions of natural gas have been recognized asuseful tools in the evaluation of reservoir continuity and reservoir productionmonitoring. It has been established that similar isotopic compositions reflectreservoir continuity, while differences in these parameters can indicatediscontinuities in the reservoir. Furthermore, stable isotopic composition isless affected by sampling and producing processes than chemical composition.This technique was applied in the Santa Barbara field, one of the largest gascondensate fields in Venezuela.

The isotopic ratio 13C/ 12C, geochemical analyses,pressure tests, conventional fluid analysis and numerical simulation, wereintegrated in a reservoir study to determine areal communication betweendifferent fault blocks.

The isotopes relationship 13C/12C was established forfour components (ethane, propane, n-butane and iso-butane) to define andcompare isotopic profiles of each sample from the selected wells.

The gas formation isotopic analysis provided very useful information on thesealing character of the faults, thus contributing to a better compartmentdefinition, necessary to locate injector wells, and establish exploitationschemes based on gas injection with partial pressure maintenance.
The Utilization of Loss Matrix to Determine the Risks of an Offshore Petroleum Production Unit
Authors: Gonçalves Neto Armando Celestino , Martins Ferreira Filho Virgilio José
Published: January 2008

The main purpose of this paper is to provide a methodology of decision whichwill help the Oil Companies Risk Managers to deal with some specific materialrisks, utilizing insurance coverage, in projects with private partners assumingthe financial support of a new offshore facility construction and operationinstead of Public sources.

To that end, we will discuss a possible Risk Management process, whichencloses the Loss matrix for risk assessment, in order to evaluate the worstloss scenario that can impact the cash flow of the business, which isstructured by Project Finance modeling.
Theoretical Analysis of Turbulent Flow of Power-Law Fluids in Coiled Tubing
Authors: Zhou Y. , Shah S. N.
Published: January 2008

A comprehensive theoretical analysis of turbulent flow of a power-law fluid in coiled tubing is conducted with the approach of boundary layer approximation. Equations of momentum integrals for the boundary layer flow are derived and solved numerically. Based on the results of the numerical analysis, a new friction-factor correlation is developed which is applicable to a wide range of flow behavior index of power-law fluid model. The new correlation is verified by comparing it with the published Ito correlation for the special case of Newtonian fluid. For non-Newtonian fluids, there is also a close agreement between the new correlation and the experimental data from recent full-scale coiled tubing flow experiments.
Minor Modifications Make Major Differences in Remote Deepwater Brine Displacement Operations
Authors: Claiborne Earl "Chip" B. , Shucart John K. , Darring Michael T. , Parks R. D. , Pillow Doug
Published: January 2008

Proposal

Brine displacements were one of several areas of focus in a continuousprocess to optimize completion methodology in Amerada Hess's Ceiba projectwells located in deepwater offshore Equatorial Guinea. The time between whenthe cleaning string is made up and when it is laid down after displacement andfiltration operations are completed can exceed two days and cost $500,000. Itis imperative that wellbore cleaning operations are performed efficiently andcorrectly the first time. Amerada Hess and its brine suppliers working togetherin a joint task force have taken specific steps to minimize the time requiredfor displacement and filtration operations.
Optimizing Fire Protection of pressurized Process Equipment
Authors: Huse Jan Reier , Skulstad Paul , Hekkelstrand Bjørn
Published: January 2008

Protection of pressurized process equipment against fire and thus reducingthe risk of fire escalation is a key concern for all process plants bothoffshore and onshore.

"Guideline for Protection of Pressurized Systems Exposed to Fire", referredto as the guideline, was developed by Norsk Hydro, Statoil and Scandpower RiskManagement in 2002. The guideline has been applied in offshore developmentprojects. Based in the experiences gained from users, the guideline is beingrevised December 2003. The procedures set forward in the guideline, has pointedout several areas/topics where further research and testing should beimplemented. One such topic is behavior of flanged connection during realistichydrocarbon fire scenarios. Therefore, large scale experiments on jet fireexposed flange connections under pressurized conditions are carried out duringthe winter 2003/2004.

The guideline is under continuous development and will be updated when newknowledge is gained and available.
Improved Radio-Frequency Silence Guidelines for Wireline Perforating
Authors: Dickes Raymond , Nordquist Mark
Published: January 2008

Transmitters operating in the radio-frequency (RF) spectrum create the potential for accidental detonation of electroexplosive devices (EEDs). This risk is magnified by the potential for an EED to be ballistically connected to other explosives, the widespread use of EEDs in oil- and gas-well perforating services, and the proliferation of radio transmitters.

To prevent accidental detonation, wireline logging operations have relied on radio-silence procedures for the past 50 years. For these procedures to be effective, the well logging crew must identify radio transmitters and then ensure they are disabled when they are within the defined radio-silence zone.The size of the zone varies with the frequency and power of the radiotransmitter, and the size and type of the antenna attached to the EED.

In the past, one or more radio-silence zones were established based on studies performed using antennae and EEDs typical in mining operations. A major oilfield service company has improved this technique through a new study specific to wireline logging-the details of which are presented in this paper.This study has led to smaller radio-silence zones while maintaining perforating safety.
NORM Management and Disposal-Options, Risks, Issues and Decision Making
Authors: Betts S. H. , Wright N. H.
Published: January 2008

The management and disposal of Naturally Occurring Radioactive Material(NORM) scale is oil and gas industry issue which attracts public andinternational interest. NORM, as low activity radioactive waste, presentsspecial handling and disposal challenges due its potential risk to personnel, health, long term effects on food chains, habitats and future generations.Media influence on public perception of radioactivity often eclipses logic andsound technical argument, will be reviewed as part of risk management.

A critique of current NORM decontamination techniques offshore and onshorewill be presented in terms of HSE and other risks, together with insights intothe future. Estimates of NORM scale generation in oil and gas and plannedfuture decommissioning demand an acceptable NORM management strategy for thefuture.

NORM disposal is an issue where the industry must "walk the talk" onsustainable development and not leave an accumulating problem which may impairfuture generations. A comparison will be made between the acceptable dischargeof NORM and radionuclides in production water offshore and the accepteddisposal options available from onshore decontamination (inshore discharge, storage or onshore re-injection). A summary of approaches to NORM managementand disposal in North Sea and other counties facing this issue will bepresented. The case for NORM reinjection offshore (in an isolated reservoir)will be addressed, although it has not been accepted as a disposal route todate in the UK. Re-injection is widely practiced in the USA.

NORM management and disposal options will be considered in terms of riskmanagement (safety, health environment, sustainable development, financial/reputation) together with a formula for risk ranking geared todecision making. This can be used by the industry to enhance publicunderstanding of radioactivity, and promote convergence in decision making byindustry and stakeholders on the risks and benefits of NORM disposaloptions.
Chad Export Project: Environmental Protection Measures
Authors: Moynihan Kelly J. , Caldwell Ed R. , Sellier Ulrich L. , Kaul Clayton F. , Daetwyler Neil A. , Hayward Gary L. , Batterhame Grant
Published: January 2008

The Chad Export Project has developed and implemented an array of measuresto mitigate a wide variety of environmental impacts, issues, and challenges. Extensive integrated analyses, supported by on-the-ground surveys and publicconsultation, were undertaken during the Project’s multi-year planning anddesign period so as to avoid issues/impacts to the extent practical. Selectionof a route for the 1070 kilometer onshore export pipeline and locations for theProject’s various permanent facilities required a complex balancing of anassortment of technical, environmental, social, and economic considerations. The width of the pipeline construction right-of-way was restricted to limitenvironmental and socioeconomic impacts, and an extensive program wasimplemented to reclaim the easement. An induced access management plan wasprepared to protect the flora and fauna in three identified ecologicallysensitive areas traversed by the pipeline in Cameroon. In addition, the Projectestablished a strict anti-bushmeat policy to prevent workers from hunting, poaching, purchasing, or consuming game while working. Special programs weredeveloped to safeguard rare/threatened/endangered (RTE) species (e.g., primates, marine turtles) known to inhabit certain Project-pertinent locales. Amulti-component water monitoring program has been implemented by the Project toprotect groundwater and surface water resources relied upon by localinhabitants, and several high quality waste management facilities have been putin place, including waste storage structures, engineered hazardous andnon-hazardous solid waste landfills, and a hazardous waste-capableincinerator.
Preparing for Improved Near Shore and Arctic Oil Spill Response. Full Scale Testing of Equipment Developed in the NOFO R&D Programme
Authors: Brekne Tharald M. , Holmemo Sigmund , Skeie Geir Morten
Published: January 2008

The Norwegian Continental Shelf may be considered to be in a mature stage of development. Offshore oil and gas production are primarily located in areas far from the shore, allowing a significant time interval for near shore response in the case of an oil spill.

Looking towards future activities, the trend seems to be that the most interesting areas for exploration activities are located closer to the shore, as well as further to the north than present oil producing installation.

Another trend is an increasing diversity of oil types produced over existing installations, as satellite fields are developed. This requires increased flexibility of oil spill response measures and strategies.

Anticipating these developments, the Norwegian Clean Seas Association for Operating Companies in 2002 initiated an R & D program for development of more flexible and robust equipment. This program includes redesign of skimmers, development of new booms and boom concepts, allowing higher towing speeds, as well as redesign and improvement of helicopter based dispersant systems.

In June 2003, prototypes of this equipment were tested in NOFO's large scaleoil – on – water exercise.

In this paper, highlights from these tests are presented. Further, the application of such equipment in near shore oil spill response operations along the Norwegian coast is discussed.
Transportation of High Pour Point Oil through Long Hilly Terrain Pipe Line, A Case Study in Kalimantan Indonesia
Authors: Putra Satya A.
Published: January 2008

Characteristic of high pour point oil may cause problems in pipeline transportation if it is not handled carefully, especially in long and hilly terrain pipeline. It may form solid in ambient temperature, and further may cause pipe plugging along the line, especially in sloping pipe area. The pipeline is 20 inch diameter stretch 250 km from Tanjung oil field to oil refinery in Balikpapan, East Kalimantan Province of Indonesia.

Alternatives of transportation had been considered, such as insulation line, heating, chemical, etc. Alternative chosen was transportation of mix fluid of the high pour point oil and water. Transportation of mix liquid may prevent accumulation of solid oil particle at places along the line and avoid pipe plugging, and the method was also considered low cost of investment and operation. Such method of transportation has been conducted since 1963 and reached peak pumping of 44.000 BOPD oil production. At present time total oil production has declined to only 7800 BOPD, and transportation of the oil production is conducted periodically 12 times a year in oil-water mixture of 65% oil and 35% water, with total oil transported 250.000 Barrel per-pumping period.

On year 2002 it was experienced an operational failure, when the pipeline was plugged caused by solid oil particle accumulation, causing interruption of pumping. An effort to remove the plugging has succeeded by conducting "rocking" method and injection of light oil, and such method was able to bring transportation to normal operation in considerably short time.

A simple modelling approach of the high pour point crude oil transportation has been obtained using Multi Phase Flow Dynamic Model OLGA to study characteristic of the flow in pipeline through a hill, and predict critical operation conditions to avoid unexpected transportation failure in the future.
Rock Mechanics Lab Testing and Computerized Simulation of Bit Dynamics Improves Drilling Performance in Horizontal Chalk Reservoirs
Authors: Gillick S. , Hamilton R. , Singh A. , Kraan A. van der Pouw
Published: January 2008

Maersk Oil and Gas AS are typically drilling the carbonate reservoirs in the Danish Sector of the North Sea in 8½" horizontal hole sections, with section lengths regularly over 15,000 ft. The two lithological components of the formation show a large variation in geo-mechanical properties: a soft, plastic chalk matrix and large, hard, brittle, chert nodules. Impact loading on cutting structures and penetration difficulties in the hard, microcrystalline chert are generally the limiting factors on bit longevity and performance. These long horizontal sections highlighted the opportunity for optimising the durability of single bit runs. In June 2001 Maersk Oil implemented a bit development priority that was to produce significant, beneficial results.
Optimization of Big-Bore HTHP Wells to Exploit a Low Pressure Reservoir in Indonesia
Authors: Benesch J. M. , Nor Nazri
Published: January 2008

A Big-Bore HTHP drilling and completion program of seven wells was undertaken under challenging conditions in a low pressure carbonate reef in Indonesia. Significant enhancements made during the program substantially reduced well times and cost. These wells incorporated the largest tubingless gas completions in the world. Higher than anticipated initial flow rates were achieved through an innovative strategy to decrease formation damage. The wells were completed open-hole without pumping kill weight fluids at the end of underbalanced drilling operations. These wells are the first to combine Big-Bore completions, drill-in liners and underbalanced drilling in individual wellbores.
3D Geological Model to Reservoir Simulation of the Lower Arab Formation – Abu Al Bukhoosh (ABK) Field, Offshore Abu Dhabi
Authors: Javaux C. , Cochet F. , Gauthier B. , Prinet C. , Ten haven L. , Herriou M.
Published: January 2008

The Abu Al Bukhoosh (ABK) field is already in production since 1974. At this stage, the distribution of the remaining reserves and further development programme, including gas injection, become highly sensitive to a better understanding of the reservoir. The present paper focuses on the detailed 3D geological model of the ABK Lower Arab Formation conducted through an integrated study. In particular, it incorporates an original methodology to determine rock types from cores and extend them to wireline logs, build a sequence stratigraphy-related reservoir layering, populate the 3D model for rock types and introduce the effects of fracturing. Emphasis is also placed upon the input of the 3D geological model in the reservoir simulation model.
Utilizing Perforation Performance Module (PPM) and Extreme Under-Balance (EUB) Perforating to Maximize Asset Value in Deep Low Porosity - Low Permeability Gas Reservoirs – A case study from VICO Indonesia
Authors: Irvana Sonny , Sumaryanto Sumaryanto , Hari Kontha I Nyoman , Joenoes Krisjahbana , Nieuwland Bastiaan , Kaura Jiten D
Published: January 2008

Proposal

VICO Indonesia is an Oil and Gas Company operating the Sanga-Sanga PSC in East Kalimantan. This PSC comprises of four operating assets: Nilam, Mutiara, Semberah and Badak. The depositional environment consists of fluvial-deltaic sands with oil and gas bearing sandstone formations stacked on top of each other, there are on average ten to twenty zones per well. Exploiting these reservoirs to their maximum potential to meet the gas delivery to Bontang LNG plant is the object of the asset teams. Maximizing asset value by increasing production with lower investment is very important within the VICO organization.

In order to achieve the above objective at optimal costs, a lot of emphasis is being given to rigless activities. The main activity is to open these stacked gas bearing sandstone formations by adding perforations either by wireline or by utilizing extreme under balanced perforating techniques.

This paper focuses on the utilization of state-of-the-art software, perforation performance module (PPM) in conjunction with extreme under balanced (EUB) perforating technique for maximizing gas production from the deep low permeability and low porosity gas bearing reservoirs. This paper presents various cases showing how effectively and economically these deep sandstone formations can be completed to maximize the return on investment (ROI). The PPM was utilized to predict the performance from these reservoirs. The actual post-job results were then used to verify the predictions. This was essentially to assist VICO in making the decisions in line with the economic benefits for various perforating techniques.
Interactive Visualization of Uncertainty in Well Test Interpretation
Authors: Khasanov Mars , Khabibullin Rinat , Krasnov Vitaly
Published: January 2008

Proposal

A way to represent the uncertainty in well test interpretation software isproposed. An uncertainty guided, interactive method of model parametersidentification is introduced. Examples of method application are given.

Well test interpretation problem is usually posed as model parametersidentification based on the criterion of matching synthetic and actual pressuretransient response. It is an ill-posed inverse problem. It means that thesolution of this problem is very sensitive to the errors in input data and evenfor the small variations of input data there can exist the large set ofallowable solutions.

Though the problem of uncertainty is discussed in literature, most ofcommercial software for well test interpretation automatically offers only thesingle result that yields the best match of the model and actual data. Thissingle outcome is often mistaken for reality. Also sometimes engineer hasadditional information, which indicates that other value of parameter is moreprobable than what is automatically identified. But using the standard welltest interpretation software it's pretty difficult to realize how close is thisvalue to the allowable set of values.

So when creating software for well test interpretation it is important toprovide the engineer with the means to vary values of model parameters withinteractive feedback about how good this value fits the data.

In presenting work the new approach to visualization of uncertainty in welltest interpretation is proposed. The approach is based on mapping of theresidual between the synthetic and actual pressure response as a function ofidentified values.

Residual maps guide the interpreter when making decision about values ofmodel parameters and allow having a more direct sense of exploring the space ofuncertainty. The interactivity is added by enabling the engineer to visuallypick up the solution, which he thinks is the most appropriate for theparticular case. Interactive visualization improves decision-making byconfronting engineer with the clear representation of uncertainty.
Enhanced Reliability with Unique Tubing-Retrievable Safety Valve Design
Authors: Vinzant Mike , Vick James , Parakka Anthony
Published: January 2008

Tubing-retrievable safety valve (TRSV) performance has been improveddrastically over the last decade as a result of simplified design concepts,increased use of non-elastomeric and metal-to-metal (M-t-M) sealing materials,and enhanced validation testing. At the same time, the demands imposed bydeep-water, high-pressure/high-temperature (HPHT) environments, high-flow-rategas reservoirs and remote subsea applications have also increased, and in spiteof continuing improvement in safety-valve technology, equipment has continuedto be pushed to its limits. As a result, higher valve-opening pressuresassociated with deep-set applications have emerged, and to address these needs,conventional solutions have focused on balancing the wellbore and its reactionto the hydraulic piston area using mechanisms that require additional sealsand/or gas-charged chambers. These solutions are heavily dependent onelastomeric seals and/or the permanent, long-term containment of a dome (gas)charge or pressure counterbalance, to maintain reliability. Unfortunately,dynamic elastomeric seals have posed a major limitation when design intentfocuses on equipment that will provide enhanced life-of-the-wellreliability.

This paper will review a unique TRSV design that is a revolutionary newconcept. This design incorporates a floating magnetic coupler that allows thehydraulic actuator to be positioned in a dedicated chamber isolated fromcontact with well fluids and pressure. Since the hydraulic actuator has beenseparated from the tubing wellbore, this new valve is the first in the industryto have 100% M-t-M sealing with no moving seals within the tubing wellbore.

The new intrinsically simple design: Increases environmental and personnel safetyReduces system costsReduces sealing requirementsProvides an extremely reliable tubing retrievable safety valveEnhances life-of-the-well.
Disproportionate Permeability Reduction by Soft Preformed Microgels
Authors: Chauveteau Guy , Tabary René , Blin Nicolas , Renard Michel , Rousseau David , Faber Rien
Published: January 2008

Injecting soft, stable and size-controlled microgels to reduce water production is a new concept, introduced some years ago, we refer to as STARPOL process. Microgels specifically designed for water shutoff (WSO) treatments do not contain toxic products and can be produced to be fully self-repulsive. They adsorb onto rock pore surface by forming soft monolayers with a thickness equal to their size. This size can be adjusted as desired during the manufacturing process. As a consequence, water permeability can be reduced as desired. Microgel chemistry is chosen to be insensitive to pH and salinity variations.

This paper reports laboratory results obtained with a new type of microgel expected to be available at industrial scale in a near future, under both powder and liquid form. The results include their characteristics in solution (size, intrinsic viscosity, mutual interactions and rheology), as well as their performances in porous media (model granular packs and Berea sandstones). These microgels were found to reduce water permeability strongly by forming thick adsorbed layers which are so soft that oil permeability is not affected. As expected from their crosslinked structure, their mechanical and thermal stability is excellent: shear rates as high as 1.5×104 s−1 or one month aging at 150°C do not reduce their viscosity. Another very significant advantage of microgels over gelling systems is that they can be quasi-ideally placed without need of zonal isolation when properly designed according to reservoir conditions: in this case, they penetrate almost exclusively into the highest permeability layers.
Small outer Diameter, Big Bore Permanent Straddle System
Authors: Halvorsen Helge , Enerstvedt Eirik
Published: January 2008

This paper describes a case history of a "Small Outer Diameter -Big Bore Permanent Straddle System" installed in a well offshore in the North Sea December 2002.

The purpose of the platform well as an injector was WAG injection in the lower zones. To obtain this, the upper zones had to be isolated due to corrosion in the tubing. This was successfully achieved with Weatherford Seal Bore Packer system, leaving access to the lower zones with 2 3/8″ CT through the Straddle.

Economically it is cheaper to use a solution like this instead of changing the whole tubing with a full workover of the well.
The Keys to Successfully Acidizing Horizontal Injection Wells in the Marlim Sul Field
Authors: Da Silva Mario Germino Ferreira , Calderon Agostinho , Motta Eduardo Ponce da
Published: January 2008

This paper presents field data from the acidizing of several horizontal, gravel-packed, water injection wells in the deepwater field of Marlim Sul, Campos Basin, Brazil. We describe the keys to the strategy that led us to achieve highly successful results, which involved changes in the composition of the drill-in fluids (DIF), the use controlled acidizing parameters and special acidizing tools that provide mechanical diversion, and modifications in the conventional acidizing program, that made fluids compatible with the acidizing tools. Since the main type of damage present in the wells is the mudcake from the DIF, small acid volumes are able to remove all damage. The small damage penetration also recommends low injection rates, instead of the traditional high rates that would not provide enough contact time to dissolve the damage and would create preferential paths for the acid.

Before the use of the new strategy, the injections wells in Marlim Sul were treated with regular wash pipes, with no guarantee of mechanical diversion, and poor results. After starting to use specially designed acidizing tools (one-trip or straddle packer), and to minimize solids and filtrate in the DIF, the average completion efficiency (CE) after the treatments became 77%, what delivered injectivity indexes far above the injection quotas defined by reservoir engineering. A subsequent improvement was to start acidizing the whole horizontal section, instead of only the points of higher damage, as shown by the flowmeter logs. This has made the final completion efficiencies come very close to 100% for all treatments. As a consequence of that, and of the good results also obtained in the producer wells, the production platform P-40 became overloaded with oil and a new production facility, FPSO-Marlim Sul, had to be added to the project to accommodate the extra oil. Due to the good results obtained, all the other deepwater fields at the Campos basin adopted the same strategy for acidizing their horizontal injectors.

The outline of the strategy presented in this paper may be helpful for improving the results of acidizing jobs of horizontal water injectors in similar offshore fields around the world. The pioneer application of special acidizing tools, the modifications in the DIF composition, and the use of controlled acidizing parameters constitute very important advances for the complex task of acidizing horizontal wells.
Optimization of Rotary Steerable System Bottomhole Assemblies Minimizes Wellbore Tortuosity and Increases Directional Drilling Efficiency
Authors: Stroud D. , Peach S. , Johnston I.
Published: January 2008

Maintaining wellbore quality, and in particular hole gauge, is crucial to the steering performance of point-the-bit rotary steerable systems (RSS).4

This paper describes how computer-based predictive modeling and full-scale laboratory drilling tests (conducted in horizontal concrete blocks) have been successful in optimizing bottomhole assembly (BHA) design in terms of directional steerability and hole quality. The modeled predictions were proven in the field as well as the laboratory.

The precise control of drilling parameters and formation characteristics achieved in these laboratory tests has also been important in comparing laboratory drilling results with BHA software modeling predictions. Excellent correlation between BHA modeling and practical (laboratory and field) tests are obtained, resulting in data that is believed unique in the literature.4

Two distinct areas of BHA optimization related to the steering performance of an RSS in 6 1/8-in. hole were investigated.
Crosslinked Cements Solve Lost Circulation Problems
Authors: Mata Freddy , Veiga Manuel
Published: January 2008

A novel alternative has been developed to solve severe lost circulation problems. Cross linked cements (CC) can help to seal temporarily or indefinitely critical intervals where drilling and cementing operations are very difficult to be successfully accomplished due to severe lost circulation. The system can be designed in two versions, the first is a Magnesia cross linked cement (MCC), up to 98% soluble, especially designed to be used in pay zones, the second, a low cost alternative, is a regular cross linked cement(RCC) which is 73% soluble and is appropriate for sealing non- productive intervals. Positive results have been observed in field applications of both systems.
Gravel Packing Deep Water Long Horizontal Wells Under Low Fracture Gradient
Authors: Chen Zhongming , Novotny Rudolf J. , Farias Rodrigo , Mendez Alfredo , Pedroso Carlos A. , Fernandes Lucia Helena C.
Published: January 2008

The economics of the oil and gas production requirements and advanceddrilling technologies are often pushing the length of horizontal well to newrecords. Gravel packing these very long horizontal wells present new challengesto completion operations. The combination of long horizontal sections ofunconsolidated formations, low fracture gradients and costly rig time are theother constraints that must be faced in the design and execution of asuccessful gravel packing completion offshore. Innovative technologies, optimized job design and planning are the keys for the success of packingjobs.

This paper addresses several key factors that must be considered carefullyin installing a successful gravel pack completion. Pack completion requiresthat these low fracture gradient wells not be fractured during gravel placementto avoid excess leakoff and premature screenouts. The discussion includesvarious measures such as optimized screen wash pipe annulus and appropriateusing the differential valves, to effectively reduce frictional pressure duringBeta wave buildup. Fluid leakoff and leakoff control, in-situ gravelconcentration, and their relationship are also discussed. The gravelconcentration is dynamically changing through out the treatment based on theflow conditions in the wellbore, especially when the gravel starts to packaround screen. While most of the fluid travels down the screen-casing annulus, portion of the fluid leaks into formation, portion of the fluid diverges intothe screen-wash pipe annulus. The results may be an effective in-situ gravelconcentration higher than critical concentration, forcing gravel particledeposition to occur too soon and building up a premature bridge.

Several job designs and application histories are also presented in thepaper to demonstrate the design considerations and valuable lessons learnt. Agroup of type curves are generated for a quick and easy check during joboperation, if any undesired condition is present, the operator can adjust theoperation and thus to avoid a job failure. The overall system of fluid dynamicsare discussed and treatment guidelines are presented to provide the CompletionEngineers the necessary information for designing successful treatments.
Reservoir Management Optimization Using Permanent Downhole Gauge Data
Authors: de Oliveira Silva Márcia Ida , Kato Edson Tsuneo
Published: January 2008

Petroleum field exploitation on deep-water environment requires well completion strategy that minimizes the number of workover operations and provides an efficient reservoir data acquisition system to support field management decisions. This paper presents a Petrobras field experience in integrating monitoring data into reservoir management optimization on Campos Basin, Brazil.

The field development plan comprised satellite wells completed with wet-Xmas tree and producing with independent flowlines to a FPSO. To ensure an adequate monitoring data program1, all wells were equipped with permanent temperature and pressure sensors at downhole (PDG), wet-Xmas tree and production header.

The anticipated production program generated a huge high-frequency database during the initial field development plan implementation. Additional time-lapse data obtained from new drilled wells during field development increased reservoir knowledge about reservoir depletion, compartmentalization, barriers, waterflood efficiency, etc. Until nowadays data from PDG and time-lapse data allow frequent updates of the geological and reservoir flow model, reducing the project uncertainties.

The challenge is to incorporate these data into reservoir management optimization at the right time without loosing the economic opportunity window.

The strategy adopted has been considered efficient to face the preeminent decision making required by this type of reservoir in a deep-water field under anticipated production.