bluuebunny/crossref_metadata_2025 huggingface dataset:
Determining Permeability in Coalbed Methane Reservoirs
Authors: Jochen V. A. , Lee W. J. , Semmelbeck M. E.
Published: December 2007

The major objective of this paper is to identify the most generally applicable method to analyze pressure transient tests in coalbed methane reservoirs. The desired methodology should allow us to analyze short term pressure tests and long term performance data consistently and in a way that can lead to an adequate reservoir description. An important part of this work was the evaluation of the methods currently proposed in the literature for estimating properties of coalbed methane reservoirs. The paper identifies the assumptions and data requirements for the conventional (i.e. Perrine-Martin) method and pseudopressure method of Kamal and Six along with their potential range of applicability in coalbed methane reservoirs. The paper compares the results using the analytical solution methods to the results obtained with a 2-phase, 3-dimensional, finite difference simulator. We show that oversimplifying or neglecting desorption of methane from the coalbed methane reservoir matrix as is done in the analytical methods can lead to inaccurate estimates of permeability. Thus, we concluded that the only generally trustworthy method of analysis of transient and longer-term production data is to use a coalbed methane simulator which includes diffusion and desorption.

Another objective of the paper is to validate the method chosen for estimating permeability in a coalbed methane reservoir at a specific geologic location using actual field data. We developed a coalbed methane reservoir description by history matching actual production and pressure data. We compared the permeability values from the simulator to those estimated from the analytical solution methods and found that the analytical methods do not provide accurate estimates of permeability for this field example. The oversimplified assumptions used in the development of the conventional and pseudopressure methods have a significant influence on the permeability estimates and cause inaccurate results.
Fracture Acidizing In High Temperature Limestone
Authors: Smith C.F. , Crowe C.W. , Wieland D.R.
Published: December 2007

During the past few years, concentrated hydrochloric acid has proved to be superior to less concentrated acid in providing improved etch patterns and deeper live acid penetration. In deeper, hotter wells (300 penetration. In deeper, hotter wells (300 degrees F) adequate inhibition of the acid becomes a problem. Various organic acids and HCl-organic acid mixtures have been used effectively, but results are comparable to those expected from 15-per cent HCl.

Recent laboratory studies have been conducted to determine the properties of the commonly used "retarded" acid systems required for treating high-temperature formations. Results indicate the boost in acid concentration from adding an organic acid to HCl is largely offset by a kinetic limitation of reaction whereby carbon dioxide formed by the primary reaction of the acid with limestone prevents complete reaction of the organic acid. Thus, addition of 5 per cent organic acid will result in a reaction of only 2 per cent to 3 per cent of this acid until the carbon dioxide is removed from solution by pressure release.

Concentrated HCl provides the distinct advantage of improved etch pattern and deeper live acid penetration. The world's record producing gas well (Hunton Lime) was acidized producing gas well (Hunton Lime) was acidized with 28 per cent HCl. BHT was in excess of 300 degrees F. The problem with 28 per cent HCl is adequate inhibition. Arsenic inhibitors are ineffective in HCl above 17 per cent concentration. Organic inhibitors give two hours protection so their use with concentrated HCl requires the use of a water pad to cool the pipe. No corrosion pad to cool the pipe. No corrosion problems have been encountered with this problems have been encountered with this technique, but the use of concentrated acid with its limited inhibition leaves small room for error.
Application of Neural Networks in the Prediction of Reservoir Hydrocarbon Mixture Composition From Production Data
Authors: Briones M. F. , Rojas G. A. , Moreno J. A. , Martinez E. R.
Published: December 2007

The objective of this paper is to present some novel applications of the artificial neural network technology in the field of petroleum reservoir engineering. In particular, the paper will be centered in an artificial neural network (ANN) approach to the derivation of nonlinear empirical correlations relating field information, from production tests (GOR, API), with molar composition obtained from validated PVT analysis. As it is well known artificial neural networks are computing devices made of many simple highly interconnected processing units which mimic the information processing that takes place in the neural system of animals. The Radial Basis Function (RBF) neural network architectures have been used successfully in the generation of non-linear correlations between input and output data sets. In this work we use the RBF paradigm to implement a prediction system that relates the gas-oil ratio (GOR) and API gravity with corresponding the molar composition C1 and CO2 and the pseudocomponent composition C2–C6 and C7+. The development of such a prediction system is of great importance since it allows the generation, using the state equation, of synthetic PVT analysis.

This work was made with carefully selected data from two Venezuelan regions with marked differences in fluid properties. On one hand, the new production areas of the North of Monagas and on the other, the traditional old production areas. The neural network training was performed with a data set of 36 examples for the North of Monagas region and 80 examples for the traditional areas. The trained system, was validated with 80 PVT laboratory tests from Eastern Venezuela showing an excellent performance in the prediction of molar composition. In general a prediction error of less than ten per cent was observed.
Field Application of Surfactant-Alcohol Blends for Conformance Control
Authors: Llave F. M. , Dobson R. E.
Published: December 2007

A pilot field test was successfully conducted in Stone Bluff field, Wagoner County, Oklahoma. The test was conducted to evaluate the feasibility of utilizing a surfactant/alcohol-based technology as an effective method for in-depth conformance control. The results from the evaluation of the field performance were indicative of a successful application of the treatment. Field results showed: (1) increased oil production; (2) reduced water production; (3) reduced water injectivity; (4) improved fluid injection profile; (5) shut-off of thief zone; (6) no injectivity problems encountered during treatment; (7) achieved favorable separation of surfactant/alcohol components; and (8) significant delay in post-treatment tracer breakthrough times from injector to producers. From these results, it is concluded that the proposed method can be effectively utilized to treat severe permeability contrast problems.
Injection Rate Controlled Capillary Imbibition Transfer in Fractured Systems
Authors: Babadagli Tayfun
Published: December 2007

In this paper, the effects of injection rate and fracture configuration on capillary imbibition transfer in fractured porous media were studied and analysed. Displacement experiments were conducted on artificially fractured rock samples and the experimental data were evaluated using a numerical simulator. The limiting value of injection rate and fracture capillary number were defined for an efficient capillary imbibition transfer. Some of the core flood experiments were enhanced with the fluid distribution measurements using CT-scan. Also, experiments on 2-D glass bead samples were conducted to scrutinize the influence of the fracture configuration on the matrix saturation distribution at different injection rates. Visualization studies on 2-D glass bead and CT scan of linear core flood experiments revealed that as the injection rate is increased, fracture pattern begins to become an effective parameter on the matrix saturation distribution. As the rate is lowered, however, the system begins to behave like a homogeneous system showing a frontal displacement regardless of the fracture configuration.
An Integrated Study of a Campeche Bay Fractured Carbonate Reservoir
Authors: Hampton D. W. , Hernandez Jesus Garcia , Vasques G. A. Velasco , Aquino Eleazar Vera , Barton Chuck , Laude Larry , Lockhart A. M. E. , Peebles R. G.
Published: December 2007

This paper provides a case study in the reservoir description of a fractured carbonate by a multi-disciplinary team. It illustrates how the synergistic interaction of team members during data analysis and model building resulted in: 1) the identification of previously unrecognized links between several reservoir characteristics; 2) produced a superior reservoir model; and 3) increased the likelihood of successful development.

The significant role fractures played in the connectivity, and hence the productivity of the reservoir, became obvious early in the study. A multi-disciplinary team approach allowed for the study of the fracture system utilizing full range of scales, from microscopic to regional. Team members analyzed cuttings, core, wireline logs, well tests and 3-D seismic. Due to the interaction of team members during data analysis and model building, previously unrecognized links between static and dynamic reservoir characteristics were identified.

It was recognized from the study of cuttings and core that microfractures provide reservoir-quality porosity and permeability in the Cretaceous deepwater carbonates of Yum Field. Further, the fractures are concentrated in dense, siliceous/cherty lime mudstone and wackestone facies. Log analysis supports these findings and shows these reservoir zones to be correlatable, high density-low gamma intervals. Analysis of well test data suggests the presence of discrete reservoir zones within the Cretaceous carbonate succession. Interpretation of 3-D seismic allows for delineation of the structural framework.

In summary, identification, characterization, and delineation of fractured intervals within the deepwater carbonate succession resulted in a preliminary 3-D model of both the static and dynamic properties for the Cretaceous reservoir of the Yum Field which, through reservoir simulation, will provide a predictive tool for development planning.
Experiences with TFL in the Snorre Field
Authors: Gunnarsson B. E. , Christensen O. S. , Brandvoll S. O. , Tonnessen S. H.
Published: December 2007

This paper discusses the development and operational experience of the Snorre Through Flow Line (TFL) system. Included is a review of the TFL system development, installation, qualification and commissioning. Practical experiences, TFL operation and the development of a TFL logging tool are also discussed. Continuity and enthusiasm of personnel have resulted in a high quality, well qualified TFL system, enabling a wide range of operations to be performed.
Improvements in the Schemes of Field Development Offshore Campeche
Authors: Hernandez-Garcia Gustavo , Nieto-Cruz Jorge
Published: December 2007

The extensive use of jackups as well as like-tetrapod slight structures for the offshore field development in the Campeche area is presented in this paper. The field development under this approach is known in Pemex Exploration & Production as the new scheme. Current ways of field development offshore Campeche are revised along with reasons justifying a change; the advantages of using this approach are also discussed. The new scheme offers a different scope on both exploitation and profitability aspects in regard to traditional field development offshore Campeche.

Finally two field cases are included; the first one present the development plan in a light oil field whereas the second one corresponds to a heavy oil field. In both cases a comparative analysis on the schemes of field development (usual and proposed) is made. The results of this analysis allow the management to share in a better way their budgets prior to initiate the field development in more than one field.
Electrical Submersible Pumps: On and Offshore Problems and Solutions
Authors: Lea J. F. , Wells M. R. , Bearden J. L. , Wilson L. , Shepler R. , Lannom R.
Published: December 2007

The following is an update to an earlier paper compiled and presented in April 1991 at the ESP roundtable held in Houston, Texas.

This paper contains referenced categories of problems that have been encountered in field operations and the solutions that have been found to the problems. The discussion for each problem/solution set is brief, but serves as an index to the particular reference, where more detail can be found. The discussion is restricted to field cases. Many excellent studies such as design techniques and recommended procedures are not covered since they are not in the context of a field study containing problems and solutions. Also, some field operational papers were not included if they presented identical information. This study was originally intended to be review of the field cases and a summary of various failures and their causes as a function of the conditions present. However, when beginning to review the papers in the literature, it became obvious that it is rare for a given paper to list detailed field conditions. In fact out of the fifty or so references examined here, only a few contained sufficient field condition data which would have allowed problems and solutions to be correlated to conditions. In addition to categorized and referenced problems and solutions, new innovations, products and operating techniques are presented.
A New Approach to the Analysis of Deviated Rod-Pumped Wells
Authors: Xu Jun
Published: December 2007

This paper presents the derivation and numerical solutions of a 3D dynamic model for analyzing the behavior of sucker-rod pumping installations in deviated wells. Using differential geometry and variational methods, the rod dynamics in deviated wells is presented by the set of six coupled differential equations with their boundary conditions. The paper describes the fundamental assumptions and simplifications which can be used in the numerical solution. A computer program based on the model is developed and applied to determine the downhole conditions and to predict the rod behavior in the deviated well. A number of wells are examined. Good Agreement is shown by comparing the computed results with the field measurements.
Effect of Fracture Relative Permeabilities on Performance of Naturally Fractured Reservoirs
Authors: Rossen W. R. , Kumar A. T. A.
Published: December 2007

Research into the nature of fracture relative permeabilities and their effect on the performance of naturally fractured reservoirs is described. Flow of wetting phase along the fracture walls provides a means of simultaneous two-phase flow in a single fracture, under conditions where such flow is otherwise prohibited. However, fracture conductivity remains low for simultaneous flow of two phases. Asperities, locations where the fracture walls close, reduce relative permeabilities; the manner of this reduction depends on how aperture is distributed spatially along the fracture.

The effect of fracture relative permeabilities on reservoir performance is illustrated using the waterflood case of the Sixth SPE Comparative Simulation Project (SPE 6) as a basis of comparison. Reduced fracture relative permeabilities impair reservoir performance if they control the attainable flow rate at production wells; such is the case upon a roughly fivefold reduction in relative permeabilities in the SPE 6 project. Reduced fracture relative permeabilities can actually improve reservoir performance in some cases, however, by improving reservoir sweep. The sweep improvement results from an increase in lateral pressure gradient relative to gravity forces driving gravity segregation on a reservoir scale. In both cases, the effect of reduced fracture relative permeabilities is similar to a comparable reduction in absolute permeability of the fracture porespace.
Innovative Additives Can Increase the Drilling Rates of Water-Based Muds
Authors: Growcock F. B. , Sinor L. A. , Reece A. R. , Powers J. R.
Published: December 2007

Several types of organic compounds were tested as rate of penetration (ROP) enhancers for a simple gel/water mud. Experiments conducted in a full-size drilling apparatus with both rollercone and PDC bits at wellbore pressures of 1100 and 2000 psi indicate that a paraffin/ester mixture, several terpenes and a mixture of insoluble poly(proppylene glycols), or PPG's, can all increase the ROP by 5 to 20% when added at levels of 2–4% by volume. Complementary lubricity and shale recovery studies suggest that the paraffin and terpenes function by making the steel surfaces less water-wetting, thereby reducing the tendency of partially hydrated sticky shales to adhere. The PPG mixture, on the other hand, may function primarily by interacting directly with the shales to reduce their tendency to form a sticky mass. In either case, the additives increased ROP to levels comparable to the ROP observed with pure water.
Hydraulic Fracturing in a Naturally Fractured Reservoir
Authors: Britt L. K. , Hager C. J. , Thompson J. W.
Published: December 2007

Hydraulic fracturing of wells in naturally fractured reservoirs can differ dramatically from fracturing wells in conventional isotropic reservoirs. Fluid leakoff is the primary difference. In conventional reservoirs, fluid leakoff is controlled by reservoir matrix and fracture fluid parameters. The fluid leakoff rate in naturally fractured reservoirs is typically excessive and completely dominated by the natural fractures.

Historically, attempts to fracture-stimulate wells in naturally fractured reservoirs have been unsuccessful due to high leakoff rates and gel damage. The typical approach is to attempt to control the leakoff with larger pad volumes and solid fluid loss additives. This approach is not universally effective and can do more harm than good.

This paper presents several field examples of a fracture stimulation program performed on the naturally fractured Devonian carbonate of West Texas. Qualitative pressure decline analysis and net treating pressure interpretation techniques were utilized to evaluate the existence of natural fractures in the Devonian Formation. Quantitative techniques were utilized to assess the importance of the natural fractures to the fracturing process. This paper demonstrates that bottomhole pressure monitoring of fracture stimulations has benefits over conducting minifrac treatments in naturally fractured reservoirs. Finally, the results of this evaluation were used to redesign fracture treatments to ensure maximum productivity and minimize costs.
Environmental Impact of Offshore Operation Reduced Using Innovative Engineering Solutions
Authors: Ritchie C. J. , Wensel E. A. , Edelblum L. S. , Beal Dan
Published: December 2007

The North Dauphin Island Tract 73 platform is located in eleven feet (3.4 m) of water and one mile (1.6 km) from shore in Mobile Bay, Alabama. The platform is designed to dehydrate and compress up to 70 MMSCFD (1.98 × 106 SM3) from five remote gas production wells. Located near the city of Mobile, Alabama, the surrounding metropolitan and coastal area has multiple uses including manufacturing, tourism, commercial and sport fishing, and wetlands and wildlife conservation. The multiple and interdependent economic uses of the area required that the platform be designed to minimize any adverse environmental impact. A cost-effective environmental engineering solution was desired at the design phase of the project. A water catchment, containment and disposal system was designed to meet the zero discharge requirement. Pollution from air emissions was reduced by the installation of lean burning engines. A floatover installation process was used to prevent dredging of the bay, thus protecting the bay water quality. An aesthetically concealing paint and lighting scheme was chosen and applied to the entire structure. These cost-effective engineering solutions during the design phase of the project saved time and money over the life of the project. Costly changes or modifications to the design during the construction, startup and operations phases of the project were unnecessary. All regulatory permits were obtained in a timely manner, with little or no opposition. The operator of the North Dauphin Island Development won several environmental awards due to the implementation of innovative solutions and their commitment to conservation of the natural environment.
Exploration and Production Operations in an Environmentally Sensitive Area
Authors: Barker G. W. , Steele E. J. , Robalino José , Baldwin S. J.
Published: December 2007

The Ecuadorian portion of the Amazon Basin, known locally as the Oriente, is the major oil producing region in Ecuador. The tropical rain forests of the Oriente contain some of the Earth's most biologically diverse and ecologically sensitive areas. In addition, the rain forest is home to several groups of indigenous peoples. When formulating an exploration plan and prior to beginning E&P activities in the Oriente, operators must understand the environmental and sociocultural issues in the region. These concerns are considered throughout the planning process, from project conception to project closure. An environmental management plan is adopted which addresses environmental and sociocultural concerns, minimizes environmental impact, prevents delays, and limits environmental liability.
Variance in Environmental Legislation. Cause and Effect on Drilling Fluid Research and Use
Authors: Jachnik R. P.
Published: December 2007

Drilling Fluids are presently undergoing a period of pronounced change. A significant proportion of new developments are due to legislation adopted within the last ten to fifteen years by the Paris Commission (Parcom) – involving the North Sea countries, and the United States Environmental Protection Agency (EPA). The environmental rules and laws passed by countries that are members of these respective organisations specify what is acceptable or not in environmental terms. Data will be presented to show that a uniform or consensus approach to the selection of environmental criteria for the offshore oil industry appears to be lacking, with an ensuing effect on product research, mud system development and focus.
Use of the Decision Quality Process for Strategic Planning in the Duri Field, Indonesia
Authors: Neal Larry
Published: December 2007

Strategic planning and rigorous decision analysis applications will be primary management tools for upstream companies in the 1990's. Merging the long term focus of a strategic planning process with the probabilistic output of decision analysis techniques can yield insightful views of the potential successes and failures of a business plan.

Even with these insights, comparing and deciding among a group of alternatives will remain a difficult task. In addition to uncertainties, business partners do not always share common value measures. Marketers want more barrels to sell, field supervisors like low operating cost strategies, and stockholders like cashflow. This environment complicates the managers' ability to choose between available options.

The Decision Quality Process, a combination of classical decision analysis techniques coupled with Quality Improvement (QI) principles, bridges this gap. The process allows managers to develop and decide between different long term strategic plans, explicitly accounting for uncertainties, unknowns, and differing value measures.

Three teams consisting of engineers, geologists, front line managers, and the highest levels of management within Caltex Pacific Indonesia, Texaco, and Chevron, spent 18 months developing and evaluating a multitude of development scenarios for the Duri Field. More than 200,000 cases of economics were run to support the evaluation. The result was a significant increase in expected value for the field regardless of the value measure used.
Towards a High Performance Organisation (An E&P Company's Experience)
Authors: Steel David , Mallon L. M.
Published: December 2007

This paper discusses the way in which an Affiliate of a major oil corporation is meeting the challenges and economic realities facing our industry in the current increasingly competitive and unstable environment

The cultural change programme, which began in 1988, and is ongoing, is described in some detail. There have been three distinct phases in this programme and each is discussed, with most attention being focused on the current phase of development towards a High Performance Organisation.

The results of each phase of the programme, and some of the lessons learnt, are presented in the hope that they might provide some direction for others.
Life Cycle Planning: An Evolving Concept
Authors: Moore P. J. R. , Gorman I. G.
Published: December 2007

Life-cycle planning is an evolving concept in the management of oil and gas projects. BHP Petroleum now interprets this idea to include all development planning from discovery and field appraisal to final abandonment and includes safety, environmental, technical, plant, regulatory, and staffing issues.

This article describes in the context of the Timor Sea, how despite initial successes and continuing facilities upgrades, BHPP came to perceive that current operations could be the victim of early development successes, particularly in the areas of corrosion and maintenance.

The search for analogies elsewhere lead to the UK North Sea, including the experiences of Britoil1 and BP, both of which performed detailed "Life of Field" studies in the later eighties. These materials have been used to construct a format and content for total Life-cycle plans in general and the social changes required to ensure their successful application in Timor Sea operations and deployment throughout Australasia.
Reservoir Management in a Hydrodynamic Environment, Iagifu-Hedinia Area, Southern Highlands, Papua New Guinea
Authors: Eisenberg L. I. , Langston M. V. , Fitzmorris R. E.
Published: December 2007

Northwest to southeast regional scale flow in the Toro Sandstone parallels the Papuan Fold and Thrust Belt for a distance of 115km, passing through Iagifu/Hedinia oil field along the way. This has had a profound effect on oil distribution in the Toro there, having swept the northwest side flee of moveable oil. A structurally controlled flow restriction causes a local, rapid drop in hydraulic potential, tilting local oil/water contacts up to six degrees and causing the three sandstone members of the Toro to locally behave as separate reservoirs, each with its own hydrocarbon/water contact.

Reservoir simulations of Iagifu/Hedinia which include a flowing aquifer are able to match observed production history. Without a flowing aquifer, simulation predicts greater and earlier water production, and a greater pres-sure drop in the oil leg than has been observed. Reservoir modeling using a flowing aquifer has allowed downhole, structural targeting of later infill wells to be much closer to die OWC than would otherwise have been thought prudent, and has raised questions as to the potential effectiveness of a downdip water injection scheme.

Production results from a small satellite field "upstream" of the main Iagifu/Hedinia field have shown a sudden increase in water production and reservoir pressure after a long period of pressure decline and no water production. This behavior appears to be due to an influx of higher hydraulic potential from a separate reservoir sand, the influx being brought about by pressure draw down during production and consequent breakdown of fault seal.
Length-Dependent Pseudofunction: An Improved Up-scaling Method in Black Oil Simulation
Authors: Soedarmo E. , Taggart I. J. , Paterson L.
Published: December 2007

The up-scaling of multiphase flow from fine-scale grid data to coarse-scale grid blocks is an important step in the development of numerical models to predict full field behaviour. To perform the up-scaling, use is made of pseudofunctions for fractional flow, relative permeability and capillary pressure. While the use of pseudofunction techniques, such as those proposed by Kyte and Berry, is widespread, the general application of such up-scaled properties generates inconsistent results. This paper proposes that the underlying cause of this discrepancy is the non-constant behaviour of saturation velocities in the original fine-scale simulation.

The concept of length-dependency, or the length-dependent pseudofunction (LDP) method, is introduced in this work to allow coarse grid block models to more closely match the average behaviour of fine-scale models. Using predictions of two-dimensional reservoir displacement with varying amounts of viscous, gravity and capillary interaction, a length-dependent pseudofunction method based upon pseudo fractional flow concepts is compared to results generated through the use of the standard Kyte and Berry method. Results show that in communicating and non-communicating layered models, the proposed length-dependent pseudofunction method provides more accurate estimates of fluid flow behaviour.
Enhanced Carbon-Oxygen Log Interpretation Using Supplemental Log Curves
Authors: Wyatt D. F. , Jacobson L. A. , Fox P.
Published: December 2007

Supplemental measurements from induced nuclear spectrometry tools are examined to demonstrate what additional information they provide about the well and reservoir conditions. Logs in shut-in wells from Indonesia provide examples of oxygen activation measurements showing cross-flow from one reservoir to another via open perforations. Leaking squeezed perforations were also observed. An example from Alaska shows radioactive scale build-up in the casing which spectral analysis identifies as a mixture of uranium and thorium salts. Another log, where the casing fluid was replaced with crude oil, demonstrates a technique for identifying cement channels. Logs from Nigeria comparing oil saturation estimates before and after a squeeze operation illustrate the effect of casing fluid flushing of the formation through open perforations. Understanding the diagnostic character of these curves leads to higher confidence in the overall log interpretation process.
Gaslift Operations in Bass Strait
Authors: Walsh P. W.
Published: December 2007

Gaslift is of high importance to Esso Australia's Bass Strait operation, with 65% of oil production being gaslifted, an average of 198 kbd for 1993. As water cut increased in recent years, the importance of gaslift to crude production was recognised, hence a co-ordinated effort to improve the gaslift operation was embarked upon, including the following elements: A quality assurance program was commenced which has resulted in more reliable downhole gaslift installations.Inventory, valve testing and setting, and tracking valve histories have been established - all important in achieving quality gaslift installations.Improvements were made in gaslift optimisation through computer modelling, gaslift metering, well control and problem diagnosis to increase production within platform facility limitations.Development of a gaslift design method which is easy to understand and has provided reliable and efficient gaslift designs, including optimal injection depths and successful dual gaslift wells.Comprehensive operator training.

The combination of these elements into a co-ordinated gaslift improvement program has been successful at EAL and can serve as a model for other operations to achieve a high level of gaslift performance.
Sucker-Rod Pumping Wells Optimisation Using a Spreadsheet Database on Barrow Island, Western Australia
Authors: Lee Wilson , Mantecon J. C.
Published: December 2007

This paper demonstrates how a carefully designed spreadsheet database can be used as an innovative tool by production engineers and field operators to optimise the performance of sucker rod pumping (SRP) wells. The spreadsheet will be available on SPE EXCHANGE DISKS for potential users.

An extensive Artificial Lift Optimisation Program (ALOP) was implemented by West Australian Petroleum Pty. Limited (WAPET) in 1991 on its Barrow Island field (BWI). Any ALOP requires extensive data collection, screening, validation and continuous monitoring. BWI has over 420 active oil producers, and 350 of them are SRP wells.

As part of the ALOP, WAPET decided to compile a Microsoft Excel spreadsheet database. The spreadsheet database contains all relevant individual well’s information and a comprehensive dynamometer card analysis module.

Apart from individual well optimisation, the database was designed to: a)identify inefficient / low profit wells,b)rank wells according to profit generation,c)establish priorities to maximise revenue during production system upsets,d)spot and fix problems early before large production losses occur,e)evaluate and plan for long term production goals.

The database provides the engineers with valuable clues indicating which wells should receive attention and where the potential for improved behaviour or increased production lies. In addition, the database provides more accurate records and better retention of the information for designing or redesigning artificial lift equipment. Without the database, engineering analysis is very time consuming.

The database has greatly enhanced communication between field and central office staff. When information is required, either in the field or in the central office, the database makes it easily available. Total revenue is also increased by communicating information on production priorities in a useful format.
Kikori River Basin Project To Sustain Environment Alongside Development
Authors: Price J. B. , Power A. P. , Henry Don
Published: December 2007

Protecting people and the environment is an essential design and operational criteria for the Kutubu Petroleum Development Project to minimise the physical, social and economic impacts on the local people and their environment in Papua New Guinea. This paper describes how Kutubu was implemented, and how World Wildlife Fund is assisting the neighbouring communities to utilise their natural resources for long term benefit. The objectives and first year expectations of a three year integrated conservation and development project are identified, and the progress is summarised.
The Testing, Assessment, and Use of Dispersants: A Systematic Approach
Authors: Wardrop J. A. , Smith J. P. , Palmer Don , Seignior Michael , Fucik Ken , Giroletti Mark , Leeder John
Published: December 2007

Dispersants are a valuable tool in oil spill management but also one that causes considerable concern amongst environmental groups. Some of these concerns are based on observations dating back to the Torrey Canyon oil spill of 1967 and are consequently dismissed on the basis that the dispersant and the manner in which they are used have changed considerably since then.

However, it must be stated that chemically dispersed oil is generally toxic, even if the dispersant themselves have a low toxicity. Consequently environmental damage may result from their use. The decision on whether to use dispersant or not depends then on the relative damage that can be expected from dispersed oil compared to undispersed oil.

In order to evaluate this potential, it is necessary to determine the efficiency of dispersant on an oil and the influence of chemical dispersant on the behaviour and toxicity of oil, both at sea and on shorelines.

The paper discusses a systematic approach to the testing of dispersant and oils in order to better predict and assess possible environmental and operational benefits. The use of the procedures in the testing of two paraffinic Indonesian crude oils is discussed. The broader scientific information currently available suggests a number of areas in which additional data is required.
A New Approach to Selecting Optimum Bottomhole Assembly Configuration for Any Given Well Trajectory
Authors: Agawani Mamdouh , Rahman S. S. , Maidla E. E.
Published: December 2007

In recent years the application of steerable bottomhole assembly (BHA) systems in drilling directional and horizontal wells is quite common. The quality of their performance and the amount of time spent in the hole often determines the successful execution of the planned trajectory and cost effectiveness of the well. This paper presents an analytical model for predicting performance of steerable BHA systems containing bent housing motors, stabilisers, wear pads etc.. Based on field data a design criterion is proposed which allows selection and optimisation of BHAs for a given well trajectory. This will reduce undesired dog legs and increase cost effectiveness of the wells by reducing drilling time.
Extended Reach Drilling Advancements Dramatically Improve Performance on Bass Strait Wells
Authors: Santostefano Vince , Krepp A. N.
Published: December 2007

Esso Australia Ltd. (EAL) has been drilling deviated wells in Bass Strait (see Figure (i)) since 1968. Recent technological developments have been employed on the Mackerel Infill Drilling Project, that have significantly improved EAL's ability to drill Long Reach (LR1) / Extended Reach (ER2) wells more economically and consistently. The more notable achievements have been: Advancements in hole condition reporting, utilising torque and drag monitoring;The successful use of non-rotating drillpipe rubbers to reduce surface torque to acceptable levels;Deeper casing setting depths, to minimise torque and drag, and to reduce time-dependent hole problems;The use of inhibitive / encapsulating mud systems for control of reactive clays / shales; andUse of wellbore stability modelling.Figure (i)Map of Bass Strait field, and (inset) Bass Strait field position relative to Australia.

These advancements have helped EAL to drill 50% greater metreage than was expected in 1993, at 16% lower cost per metre. This paper chronicles the engineering decisions behind these advancements, their applications in the field, the success / failure story on Mackerel to date, and how these developments have been incorporated in EAL's future well planning.
SE Gobe: Papua New Guinea's Second Oil Development
Authors: Langston M. V. , McCaul T. R. , Fitzmorris R. E.
Published: December 2007

A reservoir development plan was developed from a detailed geological model of the SE Gobe Iagifu reservoir. This model incorporated sequence stratigraphy and extensive core and log analysis to provide the detailed layering framework for reservoir simulation. Cross-sectional balancing techniques were applied to field derived dip and strike, dipmeter log, and RFT data to obtain a structural model for the reservoir. Cross-sectional, sector and, finally, full field reservoir simulation models were constructed and used by the team to generate a reservoir development and management plan.

The simulation models were used to examine the relative merits of vertical, deviated and horizontal wells, well placement, offtake rates, gas compression requirements and pressure maintenance strategies. Due to the uncertainty in the size and shape of the field, development options were considered at each of three reserve levels: proven, probable and possible.

The simulation results showed that well rates should be held to less than 8000 stb/d and that horizontal wells, with a length of at least 700 m, generally out-performed vertical wells. Oil recovery ranged between 34 and 45% of OOIP. The cases offering the best recoveries included both water injection and horizontal wells.
Technology and Economics of Gas Utilisation: Methanol
Authors: Seddon Duncan
Published: December 2007

The paper reviews the current and emerging technology for the conversion of natural gas into methanol and assesses its impact on the production economics. Technologies of potential use for offshore developments of large gas reserves or associated gas are discussed. New technologies for the production of methanol synthesis - gas, such as autothermal reforming and GHR technology, are described and the economic advantages over conventional steam reforming are quantified. New methanol synthesis technology, such as slurry phase reactors, are outlined but appear to offer little advantage over conventional technology for offshore gas utilization.

The purification of methanol for fuel and chemical grade product is outlined and the cost of transport presented.

The data presented gives an overview of the production costs for production of methanol from large gas reserves (> ITcf, 25 - 35PJ/a) and smaller scale reserves (10 - 20MMscfd, 4-10PJ/a). The variation of the production cost of methanol with gas price indicates that the gas price is the principal economic consideration. However, adoption of new technology will improve production economics by an amount equivalent to an incremental gas cost of about $0.5/GJ. For gas reserves of low development cost, the adoption of new technology is not a prerequisite to economic viability.
Maximizing the Value of Multi-Field Developments
Authors: Barker Geoff , Brinschwitz Kurt , Krishnamoorthy Mohan , Mills Graham
Published: December 2007

When a gas or oil field development project consists of a large number of fields using common infrastructure, it becomes difficult to ensure that the development plan chosen for each field will max-imise the value of the total project. The large number of alternative schedules make it impractical to manually evaluate each plan explicitly.

A method based on mixed integer linear programming is presented for maximising the net present value of a gas project consisting of more than 20 fields and prospects over a 40 year time frame. The method estimates the optimum order, timing, installed capacity and offtake profile of each development. The constraints imposed by facilities and sales contracts are incorporated. Phase behaviour and reservoir depletion can also modelled. The paper will present the problem formulation, results of example cases and suggestions for further application and enhancements.
Determination From Well Logs of Porosity and Permeability in a Heterogeneous Reservoir
Authors: Lin Jing Long , Salisch H. A.
Published: December 2007

A technique has been developed for the petrophysical evaluation of well logs from lithologically complex sandstone reservoirs located in the Barrow Sub-basin in Western Australia. The reservoirs are sands of fairly high porosity and low permeability with a significant amount of clay minerals, among them glauconite.

Principal component and cluster analysis were applied to classify the electric fades associated with lithofacies. Bayes discriminant analysis was used to identify several lithofacies in the reservoirs. The different lithofacies are characterised by distinct relationships between porosity and acoustic interval transit times as well as between porosity and permeability. This paper presents mathematical models for each lithofacies for the determination of porosity and permeability from well logs.
Statistical Method To Determine Whether a Wireline Water Sample Is 100% Mud Filtrate
Authors: Remeljej C. W.
Published: December 2007

Formation fluid samples are frequently obtained by twin chamber wireline sampling or less commonly by pump out sampling tools. If a retrieved sample is found to be practicably 100% water (negligible hydrocarbons) the immediate question is whether the sample is filtrate (water based mud used) or contains a significant proportion of formation water.

This paper details a novel statistical approach which applies ANOVA (One Way Analysis of Variance) to assess whether a water sample is pure filtrate or has been diluted with formation water. This qualitative information assists in the decision to further evaluate the formation with the wireline sampling tool. This method requires only the analysis of some non-reactive or marginally reactive ions in the mud system.

No specific tracer, such as tritium, is required for this method.
Quantifying HIRES Nuclear Tool Resolution in Thinly Bedded Reservoirs Using Time Series Analysis
Authors: Dodge W. S.
Published: December 2007

To assess the benefits of high resolution nuclear logs run in the Gippsland Basin, time series analysis has been used to quantify vertical resolution and random noise. Time series analysis involved taking the Fourier transform of the measurement signal which was then analysed in the frequency domain. The frequency response characteristics of the signal were used to compute the vertical resolution of the measurement based upon signal and noise coherence. The signal to noise ratio of the measurements yielded information about the random broadband noise inherent in nuclear measurements.

HIRES data provided by service companies showed a significant vertical resolution enhancement relative to standard acquisition data but at the expense of greater random noise. The enhanced resolution processing algorithms used by one service company improved the intrinsic resolution of HIRES bulk density and thermal neutron porosity data, while the other company's processing showed enhancement for the bulk density measurement but not the thermal neutron porosity. Broadband noise is a significant tradeoff to using data with enhanced resolution processing for both the bulk density and neutron porosity measurements.
The Influence of Fluid Properties on the Success of Hydraulic Fracturing Operations
Authors: Power D. J. , Paterson Lincoln , Boger D. V.
Published: December 2007

HydroxyprOpylguar based fluids are the most commonly used fluids for hydraulic fracturing. Through the addition of borate ions the polymer present in the fluid can crosslink to form a high viscosity gel. Prior to placement in the fracture the fluid is required to have a low viscosity to minimise friction losses in the tubular goods. A high viscosity fluid is required in the fracture for several reasons, primarily to suspend the proppant and to minimise fluid loss into the formation.

This paper describes a new method which can be used to model the gelation reaction of crosslinking fluids. By modelling the dynamic properties of the fluid it is possible to predict the physical state of the fluid at any time during a fracturing treatment. Small amplitude oscillatory measurements are applied to fluid samples in a cone-and-plate geometry. The change in the dynamic properties with time can be fitted to a simple model which can then be used to determine the gel time for th6 fluid. Methods used to distinguish between the liquid and gel state are also discussed.
A State-of-the-Art Production Information Management System: Conception to Completion
Authors: Parker A. R. , Corston S. P. , Abdallah F. F.
Published: December 2007

The task of hydrocarbon production accounting for oil and gas development projects can be extremely complex and time consuming, especially if Joint Venture Partner (JVP) ownership varies over several inter-related producing projects. For this task to be carried out quickly and accurately a diverse range of computer software and hardware is usually employed. This paper explains the planning, specifications and construction of an online Management Information System for hydrocarbon production balancing, reconciliation and reporting over the North West Shelf Gas Project.
Carbon Dioxide Foam Flood Studies Under Australian Reservoir Conditions
Authors: Tortopidis Sofie , Tortopidis D. C.
Published: December 2007

Carbon dioxide flood sweep efficiency may be enhanced by the use of foam-forming surfactants.This paper describes an experimental program conducted to study the potential of foams to enhance oil recovery within Australian reservoirs. Laboratory bench-top scale equipment was used to simulate such conditions. Initial tests to determine the foam-forming ability of seven different surfactants were conducted in a one-dimensional quartz sand packwith no oil present. Further experiments were conducted on three of the surfactants in the presence of a light crude oil. Subsequently tests were performed in a simulated reservoir construction made of the sands taken from an actual Australian reservoir. A surfactant has been identified that generates a stable foam under the conditions that exist within an Australian petroleum reservoir.