bluuebunny/crossref_metadata_2025 huggingface dataset:
Cooperation Among Competitors for Better HSE Practices
Authors: Al-Khelaiwi Adil , Berquist Richard
Published: December 2007

Historically the biggest hazard to seismic personnel has been traveling to and from the field operation sites and the ability to get help if an emergency occurs. In the past seismic crews have typically been self sufficient in terms of dealing with emergency situations which significantly limits their ability to provide an adequate response, especially when it involves multiple injury incidents. Improvements in Emergency Response have been achieved through better utilization of existing assets, improved communication and cooperation. Saudi Aramco currently operates eight land seismic crews which are located in various areas of the Eastern Province. Separation between crews is typically 100 - 150 kilometers and individual crews may be as much as 700 kilometers from Saudi Aramco in Dhahran. To facilitate the shortest possible response to an emergency situation a response network was developed whereby each crew will respond to any emergency within their zone of control. Through the cooperation of all the Seismic Contractors and Saudi Aramco's Geophysical Data Acquisition Division, each crew is assigned a 60 kilometer zone around their base camp and any emergency incident inside that radius will be responded to regardless of which Contractor has the emergency. In addition to the seismic crew facilities, local clinics and EMS are also incorporated into the response network when their location falls into an operational area. Ability of each local clinic or EMS unit to respond is determined through direct contact by the Seismic Contractor working in the area of concern. All these emergency response assets are represented on a map which shows the location of each crew and its response zone, all local clinics and what facilities they have and all required emergency contact information.

The second major advancement is in improved waste management for seismic operations. Considerable time and effort has been devoted to assessing current waste disposal practices and how we want to improve for the future. To minimize the Environmental Impact of seismic operations on the environment, Saudi Aramco's Exploration Department has initiated a pilot test for portable Sewage Treatment Plants (STP's) capable of producing recyclable product, which if successful, will be required on all seismic crews. It is the goal of our seismic operations to leave camp sites as clean or cleaner than when first occupied. The elimination of waste pits and sewage bore holes dramatically reduces the chances of contamination to aquifers, reduces insect problems and conserves water by allowing recycling.
Technical and Economic Issues in Transportation of GTL Products from Alaskan North Slope to the Markets
Authors: Khataniar Santanu , Chukwu Godwin A. , Patil Shirish L. , Dandekar Abhijit Y.
Published: December 2007

Gas-to-Liquid (GTL) conversion is an emerging technology that will very likely reach widespread commercialization within the next decade. Given the vast natural gas resources of the Alaskan North Slope (ANS), it will be one of the first areas in the United States to exploit this new technology. Conversion of natural gas to liquid products on a commercial scale will also facilitate potential transportation of such liquids through the existing infrastructure, namely, the Trans Alaska Pipeline System (TAPS). This could very well obviate the need for developing costly alternatives for transportation of the remote ANS gas.

The objective of this study is to evaluate the technical and economic feasibility of transporting GTL products through TAPS. The extreme arctic environment surrounding TAPS creates the unique transportation issue of cold restart of the pipeline following an extended winter shutdown. Fluid property measurements including low temperature gel strength of GTL and GTL-crude oil blends were conducted to assess the feasibility of cold restart for a varying range of throughput types. Several of the GTL samples exhibited rather high gel strengths at temperatures relatively warm by arctic standards. Thus, the results of the study can be used to provide initial guidelines for the type of GTL to be produced at ANS.

There are two possible modes of transporting GTL products through TAPS: (i) batch mode, where GTL and crude oil flow as alternate slugs, and (ii) commingled mode, where GTL and crude oil are mixed to form a single phase. A preliminary economic analysis of the two modes of transportation, including hydraulic modeling of batch and commingled flow modes, indicated that the batch mode would be more economical than the commingled mode.
Management Decision for Mature Steam flood Area with Steam Eruption: An Integrated Approach of Technology and Economics
Authors: Sutadiwiria Gunawan , Luthfi Achmad , Miriawati Ira
Published: December 2007

One of the most challenging problem in reservoir management for mature steam flood Area in determining hydrocarbon potential left in the reservoir is the management decision for go and no go project.

Duri Area 11 is located in Central Sumatera and operated by PT. Caltex Pacific Indonesia. This area is the north from the primary Duri Steam Flood (Area 1, 2, 3, 4, 5, 6, 7, and 8). The Problem in mature steam area was the reservoir is heating up and has indication of smectite clay in Rindu formation, and experience of steam eruption in Surrounding Area (9, 10).

In fact, the oil recovery become lower and the production cost become higher. The Extensive analysis was needed starting from 4D Seismic, geology model interpretation, fault seal analysis, geomechanics, reservoir characterization, steam chest prediction and the economic before the government give approval to develop the field.

Phasing development option will be implemented to reduce the potential of loss money as a possible option. The integrated high grading area was combined with economic analysis to propose reliable decision.

The change of development plan scenario will give different investment and producing in which initial POD was full development become phasing development. The changing plan will be affected to government and contractor share. The monitoring, and production analysis respond, steam temp, pressure and referable reserve at each phase development will support in improve production performance and economic field.

Based on the experienced and integrated approvals technology and economic, the real picture of development of Duri Field as a mature steam flood with unpredicted steam eruption has been solved and changed the no prospect development to prospect development.
Experimental Investigation and High Resolution Simulator of in-situ Combustion Processes; 1. Simulator Design and Improved Combustion with Metallic Additives
Authors: Gerritsen M. , Kovscek A. , Castanier L. , Nilsson J. , Younis R. , He B.
Published: December 2007

Proposal

Accurate simulation of in-situ combustion processes is computationally very challenging because the spatial and temporal scales over which the combustion process takes place are very small. We present the design of a new simulation tool based on an efficient Cartesian Adaptive Mesh Refinement technique that allows much higher grid densities to be used near typical fronts than current simulators. The development of the simulation tool will be supported by extensive laboratory experiments conducted to provide validation data, and to study effective variants of the combustion process. In this preliminary report we show how metallic salt additives can promote and sustain combustion by enhancing the oxidation and cracking of hydrocarbons.

Adaptive Mesh Refinement reduces the dependency on grid size and empirically determined subgrid scale models, and allows a more accurate representation of the physics. Preliminary designs for a one-dimensional adaptive simulator which demonstrate the potential of this approach are given. The formulation presented serves as the foundation for the development of a three-dimensional simulator that can handle realistic permeability heterogeneity. Utilizing the multi-scale approach inherent in the simulator, more reliable and scalable subgrid models can be formulated and tested.
Using Empirically Developed Rock Tables to Predict and History Match Fracture Fracture Stimulations
Authors: Leshchyshyn T. H. , Beadall K. K. , Meier P. E. , Hagel M. W. , Meyer B. R.
Published: December 2007

Rock tables giving values for fracture closure gradient, Young's modulus, and Poisson's ratio have been developed by the authors using lithologies determined from well logs, cores and mud logs, and substantiated by numerous mini-fracs. Log curves are layered and analyzed for lithological intervals as thin as one foot. The various rock types are arranged in the table as a function of increasing closure gradient, giving a basic order of sandstone, siltstone, claystone, shale, and the group limestone-calcite-pyrite-anhydrite, dolomite and coal, all below the weight of overburden. Included in the tabulation are mixtures of the various lithologies derived in similar manner from formation logs. An example would be a carbonaceous-limy-sandy-shale having a closure gradient of 0.93 psi/ft (21 kPa/m), a Young's modulus of 2.18x106 psi (1.5x107 kPa), and a Poisson's ratio of 0.33. By comparison, clean sandstone has a closure gradient of 0.66 psi/ft (15 kPa/m), a Young's modulus of 3.33x106 psi (2.3x107 kPa), and a Poisson's ratio of 0.23. Over seventy identifiable lithologies or lithology-mixtures are listed in the table. All values were developed through a combination of rules-of-thumb and interpolation. This empirical data set is analogous to a seven-component, programmed log evaluation. A normal log analysis done manually will yield about fifty layers of rock with distinct compositions per fracture height equivalent to 100-165 ft (30-50 m) of depth. Layer-specific formation characteristics are then assigned to a fracture model for deriving initial shut-in pressure (ISIP) and closure. Next, the calculated results are compared to actual mini-frac data. If corresponding values show little similarity, then there exists some stress difference from normal behavior in the reservoir under study, the most common cause being pressure depletion. Variance is also attributed to such factors as dilation around the wellbore (cracks in the rock), tectonic strain, compressibility changes, density increase from silica diagenesis, and reservoir gas over-pressurization observed in mountainous regions of North America. In-situ stresses can be adjusted to properly model these particular situations. A separate set of rock tables was compiled for southern California siliceous formations where Young's modulus for diagenetically-altered diatomaceous rock ranges from 0.2 × 106 psi (0.14x107 kPa) to 1.0 × 106 psi (0.69 × 107 kPa). Unconverted diatomite, a regional lithology susceptible to depletion-induced compaction, exhibits a Young's modulus as low as 0.04 × 106 psi (0.028 × 107 kPa). Diagenetic sequences such as siliceous shale and porcelanite require special application of the California Rock Tables for depths to 8,000 feet (2,440 m), after which the standard Canadian Rock Tables for post-Precambrian formations can be employed.
Application of Water Based Drilling Fluid - Total Fluid Management
Authors: Jensen B. , Paulsen J. E. , Saasen A. , Prebensen O. I. , Balzer H.
Published: December 2007

North Sea area environmental practice and focus on reduction of drilling costs have limited the discharges of drilling fluid and drilling fluid chemicals to the sea the last years. A method for efficiently recycling water based drilling fluids has been developed. This recycling is conducted in a way beneficial both for the drilling fluid supplier and the operator. Contaminated fluid (slop) is brought back onshore for treatment and reusable fluids from the slop treatment are brought back into the drilling fluids.

The current paper show the total fluid management system operates for offshore drilling. This includes the compensation format being beneficial both for the drilling fluid supplier and for the operator. Furthermore, the paper describes the different actions taken to reuse water based drilling fluids, and how these actions generally reduce total drilling costs. The paper also describes the different systems implemented to minimize loss of drilling fluids and recycling of drilling waste streams. Also addressed are the challenges in establishing sound targets for optimum reuse depending on fluid systems, balancing economy and environment.
Offshore Rig Sharing Improves Exploration Drilling Performance: A Case History
Authors: Bert David R.
Published: December 2007

A jackup-drilling rig drilled seven exploration wells in the U.K. and Norwegian sectors of the North Sea during a two-year drilling program. By using sublet well commitments and assignments, the rig was secured in a very tight rig market. The drilling rig was shared between two Amoco (now a part of BP) business units for four wells and another major operator for three wells. The application of rig and personnel sharing produced over 10% (U.S. $12 million) cost savings to Amoco through shared lessons learned, continuous improvement, and reduced permitting time. An additional savings of over 10% (U.S. $12 million) was achieved through detailed planning and risk assessment that significantly reduced unscheduled-event (trouble) time.

Key factors for success of the program include continuous use of the same rig, crews, and offshore team members; the vision and support of management; adequate well design and pre-planning time; and the commitment of the right people with the right talents to the projects. The same Amoco wellsite supervisors were utilized throughout the program (even as the rig moved from operator to operator). This paper summarizes how the sharing of a rig, people, and best practices can improve exploration drilling performance, even across different teams, business units, operators, and countries. Examples of sharing knowledge between project teams are presented to quantify the value of a long-term drilling rig contract for one-off exploration wells. The paper concludes by providing lessons learned from rig-sharing agreements and future applications of rig sharing.
Correlations and Analysis of Cuttings Transport with Aerated Fluids in Deviated Wells
Authors: Avila R. , Pereira E. , Miska S. , Takach N. , Saasen A.
Published: December 2007

A study of cuttings transport at intermediate inclinations using aerated fluid, to determine the amount of solids that exist in the wellbore and minimum flow requirements for ‘clean-hole’ condition is presented. The experimental program included over 300 tests, performed with a large-scale facility (flow loop 100-ft in length, with 8" OD casing and 4.5" OD drillpipe). The angles of test section inclination were 30°, 45° and 60° from vertical. Four pipe rotational speeds (0, 40, 80, and 110 rpm) were used for different liquid and gas flow rate combinations. New correlations were found to estimate the required critical gas flow rates for hole cleaning at specified liquid flow rate and drill pipe rotation combinations, and to predict volumetric cuttings concentration as a function of air and water flow rate, drill pipe rotational speed and inclination angle.
Well Cleaning Performance
Authors: Saasen A. , Svanes K. , Omland T. H. , Mathiassen E. , Vikane O.
Published: December 2007

The removal of drilling fluids from the cased well prior to installation of critical completion equipment often involves use of special fluids and equipment to ensure a sufficient re moval of both the drilling fluid itself and particles attached to the casing wall. This is a critical operation where failure can lead to excessive complications in the subsequent completion operation with stuck packers or formation damage due to particle invasion into the formation as a consequence. Furthermore, these operations have the highest attention from the environmental authorities because casing cleaning operations are considered as highly polluting operations during drilling and completion of a well. Modern drilling fluids used in the North Sea region are designed to meet occupational hygiene requirements and environmental criteria. These drilling fluids are relatively difficult to remove from the casing surface.

The paper outline in detail an analysis on how the casing cleaning fluids could be evaluated in the laboratory. Thereafter, the effect of wall shear stresses on fluid displacement and well cleaning is described. The paper also outlines how different well cleaning fluids and mechanical cleaning equipment can be applied for different completion solutions. Thereafter, the paper describes displacement methods used to optimize removal of drilling fluid while producing as low as possible amount of drilling fluid slop fluid volumes. This minimization of slop is necessary to fulfil national environmental requirements.
Heavy-Oil Solution Gas Drive in Consolidated and Unconsolidated Rock
Authors: Tang G. Q. , Sahni A. , Gadelle F. , Kumar M. , Kovscek A. R.
Published: December 2007

Solution gas drive is an effective process to recover heavy oil from some reservoirs. However, characterization of the relevant recovery mechanism remains a challenge. In this work, we present an experimental study of solution gas drive of a 9°API crude oil with a composite core (consolidated) and a sandpack (unconsolidated). The composite core is placed in a stainless steel, Hasseler-sleeved type coreholder. A confining pressure is employed during depletion. The sandpack is made up of clean Ottawa sands with a grain size distribution similar to the reservoir cores. This sandpack does not employ a confining pressure and it is transparent to X-rays. Therefore, gas saturation development in the sandpack is monitored through X-ray computed tomography scanning. The live crude oil has a solution gas-oil ratio of 105 SCF/bbl and a viscosity of 258 cp at 178°F.

With the two different porous media, we investigated the effect of depletion rate and overburden pressure on heavy-oil solution gas drive. The results show that the overburden pressure affects heavy oil solution gas drive by offsetting partially the pore pressure decline. As a result, the apparent supersaturation in the sandpack is greater than that in the composite core. In addition, the measured critical gas saturation and oil recovery for the sandpack are greater than that for the composite core at the same depletion rate. The estimated gas relative permeability in the composite core is also greater than that in the sandpack.
Tracking Permeability in a Major Limestone Reservoir: from Rock Observation to 3d Modelling
Authors: Giot Daniel , Dawans Jean Michel , King Raymond , Lehmann Pierre , Shaw Ed , El Wazeer Fathy
Published: December 2007

Full-field static/dynamic models of a major oil and gas bearing limestone reservoir in a giant field onshore Abu Dhabi are being constructed to optimize reservoir management and to evaluate long term development options. An Integrated Reservoir Characterization and Modelling workflow is being developed with the primary objective of understanding and predicting permeability from reservoir to full-field scale.

To build a realistic 3D static model, the initial focus was set on geologically characterizing permeability at all scales by linking reservoir property distribution to reservoir geological characteristics. The ultimate static modelling objective is to derive 3D permeability distribution through the use of geological "filters" represented by Reservoir Rock-type (RRT) classes. In this way we aim to remove the need for global permeability multipliers, often found necessary in past simulation work to achieve satisfactory history matches.

The main steps of the selected Reservoir Characterization and Modelling workflow so far include:

– Definition of RRT and their vertical distribution from core data. – Establishing RRT lateral extension using sets of closely spaced wells, the results of outcrop analogue studies and lateral variography. – Prediction of RRT in uncored wells by use of neural network techniques. – Use of dynamic well data to corroborate permeability distribution and contrasts as derived from core study. – Generation of multiple 3D realizations of RRT distribution. – Investigation of porosity-permeability transform relationships to translate the 3D geological (RRT) model into the 3D property (permeability) model.

The 3D static modelling process uses deterministic and stochastic techniques with repeat testing of the model realizations by flow-simulation. It involves continuous iterative feedback looping between static and dynamic simulations, whilst progressing full-field model building. This method is seen as critical to ensure the timely delivery of a fit-for-purpose model that is in accord with geological, petrophysical and reservoir engineering data.
Technical Challenges Encountered During Coiled Tubing Underbalanced Drilling In Oman
Authors: Hoekstra T , Hopkins Chris , Fleck A , Bell G
Published: December 2007

This paper describes two of the major technical achievements during the first year of operation of a new, purpose built, underbalanced (UB) coiled tubing drilling unit (CTDU).

The unit is designed to drill sidetracks and extensions to existing wells to improve reservoir drainage. The package is fully self-contained, and uses native crude as the primary drilling fluid. Natural gas injection through conventional gas lift mandrels is used to maintain underbalanced conditions. The unit was built during 1998 and mobilised from the USA to Oman. Following final construction work and commissioning, it drilled its first well during February 1999.

This paper focuses mainly on two technical areas. Firstly, the world-record-breaking extended reach wells, including the challenges faced to achieve them. Secondly, the continuing project to minimise high water cut during initial production following workover. Details of operations are included, with an overview of drilling performance for the wells drilled in the first year of operation.

After 6 months of operation it was concluded that the production from slim hole wells drilled by the CTDU and conventional rigs was not as expected (high water cut). During this period a major review of the slim hole campaign took place, concentrating on cement placement around the 2-7/8″ liner and stimulation of the reservoir after perforating. This resulted in a major improvement of production and ultimately the continuation of the slim hole project.

The operator has drilled 21 wells to date with the CTDU and 9 more wells are planned for the year 2000. Technical contributions include:

Improved procedures and techniques for cement placement around a 2 7/8″ liner run on coiled tubing. World Record for longest horizontal section drilled with a coiled tubing (beaten twice – now at 1457m). Underbalanced drilling technology applied safely and successfully.
Underbalanced Drilling with Coiled Tubing
Authors: Matanovi Davorin , Meimurec Nediljka Gaurina , Krištafor Zdenko
Published: December 2007

The conventional overbalanced drilling of production zones generally results in a negative effect on overall productivity and cost, caused primarily by formation damage. As a result, the oil industry is turning more toward methods such as underbalanced drilling (UBD) to increase productivity and reduce overall costs.

UBD, particularly pressure-depleted, mature reservoirs, can minimise or prevent near-wellbore damage, often avoiding the need for stimulation.

A clear and fundamental understanding of drilling technology is required to design and supervise drilling operations on an underbalanced well.

The benefits of UBD technology, the use of CT (coiled tubing) in UBD, UBD fluid systems, control of the well while drilling are presented.
Recent Case Histories of Offshore Dual Multilateral Completion Systems in the Middle East
Authors: DeMong Karl , Rivenbark Mark , Bailey Ernest
Published: December 2007

Multilateral wells in the Middle East Region usually have been completed as non-access, single-selective or limited-access, dual-selective wells. These methods have limited the operator's ability to monitor and enhance a well's production and can lead to total loss of production during large-scale work-over operations. Advances in multilateral (ML) completion technology have developed unique completion systems that have the capability to connect horizontal laterals to parent well-bores and allow segregated production and intervention in new or existing well bores at any time in the life of the well. Recent multilateral wells in Arabian Gulf offshore fields have enhanced productivity using innovative techniques to satisfy the completion, workover, and intervention requirements of dual producing wells.

This paper will discuss case histories in which dual completions with and without pressure-isolated junctions (TAML levels 4 and 5) were developed and used. The completions were run in both new and existing wells, in both preplanned and workover scenarios. The operator's requirements were satisfied in each case. Their success has pushed the envelope for dual-lateral completion and workover in offshore fields of the Middle East.

The techniques discussed are applicable to Level 4 and 5 ML wells. The successes of these installations can be attributed to the dedicated team's pre-planning of contingency methods, drilling operations, wellbore preparations, components of the completion system, and running procedures. The case history data will identify the value gained from each stage of the planning strategy.

Dual multilateral completion technology includes various techniques for maintaining integrity in junction construction, completion configuration, and running techniques that combine to:

Facilitate multilateral technology application when varying production conditions exist in the same well Segregate a dual configuration for isolated or commingled production and dual segregated reentry Reconfigure existing commingled production for segregated production, isolation, reentry, and rig-less intervention Restore hydraulic integrity at failing lateral junctions Enhance effectiveness of production logging, stimulation, and rigless intervention for remedial operations Reduce initial construction cost and risk with a completion that considers the life-long production profile of the well.
Gas Masterplanning: Maximising Value from Integrated Gas and Oil Production Systems
Authors: McEwan Malcolm
Published: December 2007

Complex oil and gas production systems offer major challenges and opportunities for maximising value from the supply chain:

Reserves –> Infrastructure –> Markets.

Gas Masterplanning is a process to maximise long term value of gas resources to enable competitive advantage and to provide the optimum integration of oil, gas, power, chemicals and other hydrocarbon opportunities.

Examples of criteria for developing a Gas Masterplan

Major increase in reserves with implications for infrastructure and marketing strategy. Marketing constraints requiring new outlets to develop reserves. Growing ullage in infrastructure offering opportunities for new deals / alliances / swaps. In a country or region where allocation of reserves to a limited market is required, or for value maximisation in the market place of limited reserves.

Masterplanning is a process as well as a product to ensure ownership by key stakeholders of the results.

The Gas Masterplan will show the envisaged development scenarios for the business, together with the opportunities and threats resulting from those scenarios in the context of changes to the business environment. It will detail the feasible and practicable alternative strategies available, the decision points between conflicting strategies and the recommended course of action.

Many ventures have benefited from masterplanning. A considerable database is now available on hydrocarbon value chain opportunities which enables benchmarking between ventures.
Strategy Formulation and Balanced Scorecard Implementation Adnoc Distribution Case Study
Authors: Guidoum Mohamed
Published: December 2007

Strategy formulation has been the subject of numerous publications. However, smart strategies often fail due to poor implementation. The Balanced Scorecard serves essentially as a strategy implementation methodology and its role has been extended from a mere measurement framework to a strategic management system. The framework lets managers gain consensus on the organistaion's vision and translate it into strategic objectives that are supported by measures, targets and initiatives. The objectives, in turn, are grouped into four main perspectives. This paper describes a case study on the implementation of a major project of strategy formulation and implementation using the Balanced Scorecard in Adnoc Distribution.

The key findings are: 1) the design a good scorecard requires as a pre-requisite the formulation of clear strategies, 2) the involvement of managers is of utmost importance during the discussion of the vision and selection of strategic objectives, measures and initiatives, 3) commitment of management team to use it right away through reporting and linking to budget and planning cycles is necessary and 4) change in behavior of management is the result of a well-designed scorecard. Finally, the paper adds another contribution to the literature of the Balanced Scorecard which lacks publications that report practical implementation.
A Compositional Simulation of Alternative Options of a Gas Injection Project
Authors: Shi Wen , Abdou Medhat
Published: December 2007

Lean gas injection into the oil column has been implemented for two and half years on a portion of a giant gas-capped carbonate reservoir. Intensive monitoring has been performed on a pilot with two frequently logged observers, where gas injection rate is doubled. The major uncertainties in the original development plan were the gas breakthrough time, sweep efficiency and whether miscibility could be achieved.

The current gas injection and alternative recovery options, including enriched gas injection, double gas injection rate, conversion to water injection and WAG are evaluated by a compositional sector model. A 10-component Equation-of-State was first generated for the whole reservoir with laterally diverse phase properties by matching 48 ordinary and advance PVT tests and 4 slim-tube tests. Three nested refined local grids were utilized to focus on the key area. A realistic boundary condition adopted from the black oil full field model is utilized in history match and all prediction cases.

Production history and the latest time-lapse logging results (gas breakthrough time and saturation profiles) of the observers were matched. The simulation results reveal the severity of the vertical sweep efficiency problem of the current gas injection. No significant improvement will be made by WAG. The lean gas being injected can only reach a near miscible state with the reservoir oil. The ultimate recovery of current gas injection will not be high because of the poor vertical sweep efficiency and the strict GOR constraint.
A Unique Method for Predicting Long-Term Performance of a Mature Supergiant Kuwait Oil Field using Complex Simulation Modeling, Simple Analogies, and Classical Analyses
Authors: Carr Brian , Kumar Pradeep S. , Dashti Qasem
Published: December 2007

This paper describes a unique approach for estimating reservoir performance of the Burgan formation of Greater Burgan field in Kuwait, by integrating results of complex simulation modeling with simple analogies and classical analyses. The method involved first running short-term predictions with a full-field multi-reservoir simulation model, with each case focused on an individual reservoir. Simulation results were then extracted and analyzed; average well oil decline rates were developed from the extracted simulation results for each reservoir and for each area of the field. These simulator declines were used as initial declines in long-term profiling, with additional subsequent decline periods considered for long-term performance. Water production was estimated based on extrapolation of predicted oil/water ratios from the simulator, and by incorporating adjustments based on analogies. Ultimate recoveries were estimated based on analogies. Performance profiles were then generated by integrating the oil rates, water rates, and recoveries.

This paper illustrates an alternative to the over-reliance on reservoir simulation that seems prevalent in our industry. The unusual approach of combining complex reservoir simulation with simplistic analyses is demonstrated as a viable method for generating profiles of long-term reservoir performance.
Leakage is Management by a New Sealing System for Twin-Screw Multiphase Pumps
Authors: Brandt Jens-Uwe , Müeller-link Dietrich , Rohlfing Gerhard
Published: December 2007

Multiphase Pumping is recognised as state-of-the-art technology. But still operators and manufacturers see themselves confronted by two major challenges which are first the set of operating parameters, and second the Mean Time Between Failure.

The mechanical seal system strongly contributes to the MTBF, hence this has been subject to various brainstorming with all parties involved.

Modern "Multiphase Boosters" have little in common with standard pumps or compressors as far as operating parameters are concerned. All parameters especially effecting the seals are of a transient character while those in pumps or compressors are quasi-static.

This paper presents a new sealing technology, which keeps any process liquid inside the pump, with emphasis on experience gained in test-bed runs and field operations.
Electrification of Gas Well Production System Reduces Operational Costs in Saudi Aramco Gas Field
Authors: Rivenbark Mark , Khater Sami , Barnes Steven , MacKenzie Roy
Published: December 2007

A major Middle East operator has been producing gas from the same formation for approximately 20 years, using conventional hydraulic actuators to control wellhead gate valves. These actuators have been operated from a hydraulic control panel that is pneumatically powered, and the compressors used to generate the instrument air have been electrically driven. Although the actuators have been able to perform satisfactorily in controlling the wellhead gate valves, the operations have not been cost efficient for several reasons. First, the pneumatic/hydraulic control systems have been maintenance intensive. Secondly, electricity has been required to run air compressors to power the hydraulic actuators.

Recently, the operator began a five-year drilling program to develop additional gas reserves, and as part of this process, decided to investigate alternatives to existing well-site equipment. One of the primary requirements of the new equipment was that it reduce operating costs. Areas targeted to provide the savings would be:

The current levels of equipment maintenance and related manpower needs Equipment integrity against the environmental conditions inherent to the area (blowing sand, heat, rain, etc.) Environmental safety.

This paper will discuss a first-of-its-kind all electric system using electric gate-valve actuators, an electric control panel with PLC logic controller as well as electric pressure pilots, electric fusible plugs, electric emergency shut-down (ESD) switches, and a battery back-up system that was developed for this installation.

An existing well was converted to the system, and a rigorous one year testing program was carried out by the operator. In addition to normal exposure to the elements and routine opening and closing of the well to meet production demands, the test also included over 300 additional open and close cycles on each of the 3 electric actuators on the tree. After conducting the test program, the operator estimates that capital cost savings for the all electric system could be in excess of $200,000 per well over the present pneumatic/hydraulic systems. Additional savings in manpower and maintenance are also anticipated.
Twister Supersonic Gas Conditioning Process
Authors: Okimoto Fred T. , Sibani Salim , Lander Michael
Published: December 2007

Twister Supersonic Separator is an innovative and revolutionary gas processing system. The Twister technology was developed by Shell. Twister B.V. was launched as a separate company in April 2000 by Shell Technology Investments Partnership, a 50/50 venture between Shell and the Beacon Group. Twister Supersonic Separator is the resulting synergy from combining aero-dynamics with the traditional gas processing concepts of thermodynamics and fluid dynamics. Twister is based on the following concepts (Figure 1):

– Gas is expanded in a Laval nozzle to supersonic velocities with resulting lower temperatures. – Nucleation of water and hydrocarbon occur, followed by growth of liquid droplets. – The gas and liquid droplets enter the wing section, where a very high swirl is created and the liquid droplets are centrifuged onto the walls, creating a liquid film. – The gas and liquids are separated in the drainage section. – Pressure is recovered in the diffuser section, to about 7080% of the initial pressure.

This is done without chemicals or rotating equipment, and requiring minimum space and weight, thus saving significant capital and operating costs.
Managing Onshore Drilling Wastes – Abu Dhabi Experience
Authors: Mokhalalati Talal , Al-Suwaidi Abdullah , El-Fatah Hendi Abdul
Published: December 2007

When drilling fluids and cuttings are discharged into the ground, the liquid fraction including any dissolved chemicals begins to enter and travel through the soil bore. Contaminants can reach groundwater, dissolve into it and be transported to other horizons. Very small solids, heavy metal can also be transported to the ground water although the porous media will filter large particles.

Spilled or improperly disposed drilling wastes have the potential to harm plants and animals, it should be managed to minimize risk to human health and the environment.

The paper describes how Abu Dhabi Company for Onshore Oil Operations (ADCO) handled the various drilling-related wastes. It provides information on some of the cost-effective techniques utilized to tackle the major drilling wastes, these include:-

Drilling fluid system and related rig equipment have been modified with waste minimization in mind. Mud chemical products have been substituted with less toxic substances. Oil based drilling fluid has been used in multi-wells prior to being permanently injected downhole. Oily drilled cuttings are treated by thermal desorption technique, slurrification and injection downhole, or transported to central waste plant. High salinity water based drilling fluid is injected downhole Acid used during well testing is neutralized prior to disposing. Flaring oil during well testing is eliminated either by flowing to station or trucking. Free gas is flowed to production facilities and flared only when operations dictate. Other options such as biological treatment are in the study phase.

The paper summarize the experience ADCO gained to date during the operations of minimizing environmental impacts on five major onshore fields operated by the company.
Environment Protection in Oil and Gas Industry: A Gateway to Sustainable Development
Authors: Drapier Maurice , Sutton Catherine , Morillon Anne
Published: December 2007

During the last two decades, people began to realise that we cannot have a healthy society in a world with environment degradation. The development that human kind achieves nowadays makes more and more urgent the need to implement sound and appropriate environment protection measures and to plan a concerted and controlled use of raw materials.

On it's part, the United Arab Emirates, aware of its very sensitive natural areas and singular environment, has organised since 1998 numerous symposiums aimed at sharing experience in the field of wildlife protection. Abu Dhabi Oil Operating Companies, each one in its own way, have been active partners in a progressive effort that highlights the role of environment conservation in their operations.

Among them, Total Abu Al Bukhoosh, like most of the Group subsidiaries (TotalFinaElf is the new name of Total Group after the mergers with Petrofina and Elf), has developed since 1992 an environment management plan whose goal is to identify, control and decrease polluting emissions to the environment resulting from exploration and production activities. In this way, the environment protection is a key point in our practice, an obliged gateway where shareholders, employees and customers must feel our strong concern for conserving our environment.
Corrosion Monitoring in Mauddud Pilot Wells in North Kuwait Oil Fields: Data Analysis, LPR/pH and Downhole ESP Relationships, Problems and Solutions
Authors: Al-Aqeel Zaid A. , El-Shourbagi Said M. , Mousawi Ahmed Z.
Published: December 2007

Water Flood Pilot (WFP) Projects were started during June 1997 in two of North Kuwait's major oil fields to determine the feasibility of waterflooding the Mauddud Carbonate Reservoir.

In each of the two pilots, the injection water supply comprised source water well, completed with a downhole electrical submersible pump (ESP) across the underlying Lower Burgan aquifer. Source water rates of up to 10,000BWPD were pumped from the well to a surface booster pump, designed to deliver an injection pressure of 2000 psi at the injection well.

A significant part of the feasibility study was monitoring system corrosion. Specific surface measurements included pH, total suspended solids (TSS), corrosion rate derived from Linear Polarization Resistance (LPR) and concentration of injected corrosion inhibitor. This suite of data and associated interpretations are presented and discussed. The data recorded also documents radical fluctuations in LPR and pH measurements several days before ESP failures.

Downhole corrosion in producers experiencing breakthrough of injection water is also examined through a sequence of Wireline Micro Vertilog (MVRT) interpretations. Corrosion rate variations relative to produced watercut are presented.

In addition, the application of chemical inhibitors and plastic coated surface and downhole tubular are discussed relative to managing the conditions experienced. Finally, the collation of this daily data over a two-year period enables conclusions to be drawn regarding optimum sampling procedures and the advantages and disadvantages of the water system used.

The collection of data during this project has resulted in significant learning, some of which is transferable to other waterflood operations. Significant technical contributions are made on corrosion monitoring and inhibition, MVRT interpretation and surface sampling.
High Oil Recoveries from Transition Zones
Authors: Masalmeh Shehadeh K.
Published: December 2007

Oil-water transition zones may contain a sizable part of a field's STOIIP, specifically in low permeable sandstone and carbonate reservoirs. The amount of recoverable oil in a transition zone depends–among other things- on the distribution of initial oil saturation (Soi) as a function of depth and the dependency of the oil's mobility, i.e., the residual oil saturation (Sor) and relative permeability, on initial oil saturation.

In this paper we present laboratory measurements of residual oil saturation and oil relative permeability as a function of initial oil saturation to properly characterize oil mobility in transition zone. We found that the residual oil saturation after water flooding showed, for the example studied here, no dependence on initial oil saturation. On the other hand we found that there is a clear trend in the imbibition oil relative permeability for decreasing Soi, i.e., for a given oil saturation oil mobility increases as initial oil saturation decreases. In other words, laboratory measurements show that the mobility of oil in the transition zone is much higher than conventional analysis would suggest. Consequently, in a given time span more oil can be produced from the transition zone than generally assumed and potentially large volumes of reserves can be added to reservoirs with large transition zones.

The impact of the measured relative permeabilities and residual oil saturations on oil recovery has been quantified for a generic field example by numerical modeling using MoReS, the Shell group reservoir simulator. The recovery factor was found to increase from 32% using a single set of relative permeability curves for the whole field independent of initial oil saturation to 56% using the measured Soi dependent relative permeability curves. The water cut at abandonment was for both cases taken at 95%.
Analysis of a Fractured Carbonate Reservoir (Thamama Group) Using Borehole Images From an Horizontal Well, Offshore UAE
Authors: Williams P. D. , Maddock R. H. , Sapru A. K. , Lawrence M. J. F.
Published: December 2007

Structural analysis has been performed on borehole resistivity images from a horizontal well through the Lower Cretaceous Thamama Group carbonates, offshore UAE, in order to investigate structural compartmentalisation within a complex faulted reservoir.

The study interval has been divided into four major Borehole Image Units on the basis of borehole image and openhole log response. The contacts between these units include bed boundaries and faults. Within these units, both electrically conductive and resistive stylolitic bed boundaries were identified.

Faults and fractures with varying appearance and extent along the wellbore are identified from the borehole image log. These features were classified by their electrical response and image appearance. Faults were discriminated from fractures by evidence of offset, interpreted lithological juxtaposition and greater thickness. Resistive fractures, interpreted as cemented, may act as baffles to fluid movement. Conductive fractures, interpreted as having aperture filled by (electrically conductive) drilling fluid, may act as fluid pathways. Fractures with a mixed electrical response on the images may be vuggy.

Fractures occur as clusters along the wellbore, with increased fracture intensity within damage zones associated with some faults. Clustering of conductive fractures is due to both tectonic and litho-stratigraphic factors. Resistive fractures show a dominant NW-SE strike, and conductive fractures show a dominant NE-SW strike. NE-SW to ENE-WSW striking fractures are under-sampled because of the borehole orientation (SW). The strike of conductive fractures is broadly similar to the regional direction of the maximum horizontal stress.

Reservoir pressure data correlate with the Borehole Image Units and the distribution of resistive faults. Resistive fault boundaries support modest static fluid pressure differences and are interpreted to isolate three reservoir pressure compartments.
Effective Mineral Scale Control in Canyon Express, Gulf of Mexico
Authors: Yuan M. , Smith J. K. , Cooley C. , Williamson D. A.
Published: December 2007

In deepwater subsea oil and gas production, methanol is commonly used for preventing gas hydrate formation. Other than some recent laboratory experiments on the effect of methanol on mineral scale precipitation,1&2 there however have been no field reports of methanol-induced or aggravated mineral scale deposition in the oilfield produced fluids. This paper presents a unique and severe calcium sulfate (gypsum) scale deposition problem in the Canyon Express field system, a deepwater subsea tieback in the Gulf of Mexico, and its successful inhibition by using methanol soluble scale control products. In this case, the gypsum scaling was found to be directly caused by continuous injection of large volumes of methanol into the produced fluids for hydrate inhibition. This paper describes and discusses this particular scale problem, its diagnosis, computer prediction of methanol effect on scale formation, qualification of a methanol soluble combination scale/corrosion inhibitor, and the subsequent successful inhibition treatment of the gypsum scale. This paper highlights the drastically detrimental impact of methanol on scale formation and demonstrates the benefits of using methanol soluble scale control products that reduce the need for additional subsea injection lines and eliminate the potential for chemical incompatibility.