bluuebunny/crossref_metadata_2025 huggingface dataset:
Marine Pipe Laying Methods
Authors: Dwyer Jolly
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A number of marine pipelaying techniques have developed over the years, but their potential for installing large diameter pipe in deep water is severely limited. A survey of present day technology is desirable to evaluate its limitations for the needs at hand, and to determine where new techniques are required.

All present day techniques have many elements in common. These can be combined in a variety of ways, and some of the combinations offer possible solutions to the problems of laying pipe in deep water. pipe in deep water. This paper describes the most common components of marine pipelaying systems, and discusses the present day combinations. The components include: barges, stingers, launchways, reels, winches, tensioners, pontoons, caissons, chambers and submersible vehicles. The combinations include: lay barges, tie-in barges, lowering barges, reel barges, and pull barges.

The paper then goes on to describe the potential applications of other systems to the problems of laying pipe in deep water. It suggests that economical solutions to those problems are within the capability of present day technology, without excessive developmental effort.

Introduction

When petroleum discoveries stepped from dry land into the marshes, and eventually into the sea, the associated pipelines had to go into the water as pipelines had to go into the water as well. Short lines in shallow water could readily be made up on shore and pushed or pulled into position. However, pushed or pulled into position. However, long pipelines, even through marsh lands, required a different solution, and the pipelaying spread took to the water pipelaying spread took to the water on a lay barge. From these beginnings various marine pipelaying methods have evolved and are in use today.

As the: need grows to lay pipelines of larger diameter in deeper water, even present day techniques are becoming present day techniques are becoming restrictive.
Designing and Selecting Wax Crystal Modifier for Optimum Field Performance Based on Crude Oil Composition
Authors: Singhai H. K. , Sahai G. C. , Pundeer G. S. , Chandra K.
Published: December 2007

The present paper deals with the studies of crude oil composition, physicochemical characterisation of pour point depressants (PPD's) and waxes to know the specific & selective performance of PPD on crude for designing wax crystal modifier according to requirement.

The study reveals that the performance of PPD is closely governed by composition of crude in respect of nuclei present mainly asphaltene, type & amount of waxes and the amount of distillates. The study indicates that PPD can be made more effective by compounding waxy crudes with light distillate fractions and vice versa by the change in PPD composition, degree and extent of polymerization and creating environment suitable for co-crystallization.

The chain length of the alkyl ester chain should corresponds with the carbon number ranging C20-C24. It has been observed that polymers having Mow molecular weights do not affect the rheology. The melting point of PPD should match with the melting point of the waxes for limiting the growth of the crystals. C22 to C29 normal paraffins are predominant in GS-16-4 & Bombay High crude oil. The studies may be helpful for selection of PPD’s for high wax content crudes.
Offshore Pipeline Risers and Their Adaptability To Deep Water
Authors: Faust Richard C.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Through the years as the offshore petroleum industry has developed and petroleum industry has developed and water depth increased, there has been an evolvement of pipeline riser type. This water depth now has reached the proportions such that pipeline riser proportions such that pipeline riser technique must now be looked at from a practical standpoint in order to economically produce through pipelines.

During the 20 years of pipelining offshore, various types of risers have been utilized by different companies, depending on their own needs.

It is the purpose of this paper to review the progress of the development of pipeline risers through the years with the intention of singling out those which the author feels are the most practical from a standpoint of deep water pipelining techniques.

The first wells offshore were sufficiently close to land that the production could be carried by production could be carried by pipe-lines across trestle-like pipe-lines across trestle-like structures from the offshore well to the mainland, however, this obviously was just an extension of the typical methods used in marshes and dry-land areas. Later as the wells advanced further offshore, still in relatively shallow water depths, pipelines were laid on bottom of the gulf and the extension of these lines up to the production decks of the structures were treated just as though it were a change in elevation within a plant site; that is, the line was brought up to the structure, a short radius elbow was attached to the end of the pipeline and a vertical run extended up the side of the structure to the production deck. This is the most commonly used riser in the Gulf of Mexico, even in deep water locations.

However, this is but one type riser - presently there are five basic types being used. The conventional riser (Figure 1) is attached to the structure by clamping after it has been welded to the horizontal run of pipe. pipe.
Optimizing the Completion Procedure To Minimize Sand Production Risk
Authors: Santarelli F. J. , Ouadfel H. , Zundel J. P.
Published: December 2007

A 3D Finite Element Code is used to model the near well bore region of a perforated well. The stress concentration around perforations is computed and related to the possibility of reservoir rock failure and hence to sand production risk. Results of a complete parametric study are used to show the influence of various controllable geometric features, such as perforation length and diameter, shot density, phasing, cementation quality, etc, on sand production risk. An optimization of the completion procedure is presented which maximizes IP expectations by lowering sand production risks, thus avoiding the use of sand control means when not strictly necessary from the production requirements.
Perforating Skin as a Function of Rock Permeability and Underbalance
Authors: Hsia T- Y. , Behrmann L. A.
Published: December 2007

Experimental tests were performed under simulated downhole conditions to determine the minimum underbalance necessary to obtain zero-perforation damage skin in two sandstones of different permeabilities. The objective of this paper is to study the transient cleanup resulting from the dynamic surge of fluid through the perforation immediately after perforating, prior to any postshot flow.

Single-shot perforation flow tests were conducted in nominally 100-md Gold and 200-md Berea sandstone cores under various underbalances. Prior to shooting, the virgin whole core diametral and axial permeabilities were measured. Perforation damage skin was determined using analytical and finite element models.

For each of the two basic rock permeabilities, (1) the minimum underbalance required to obtain zero-perforating skin without postshot flow was determined, and (2) a relationship of skin to perforating underbalance was obtained.

The experimental results were used to establish a Reynold’s number criterion for zero-perforation damage skin. Using the Reynold’s number criterion, a simple equation can be employed to predict, as a function of formation and fluid properties, the minimum underbalance to achieve zero-perforating skin prior to any postshot flow.
The Effects of Weather on Offshore Pipeline Construction in the Gulf of Mexico
Authors: McCarron J.K.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

The effect of weather on the construction of offshore pipelines has been analyzed by use of a computer simulation program. Results are given for hypothetical projects in terms of the average construction time to be expected for different seasons of the year and for the probability that any given construction time probability that any given construction time will be exceeded. The analysis includes variations in the capabilities of the construction equipment to evaluate the effect of equipment performance on construction time. performance on construction time. The accuracy of the simulation is dependent upon adequate weather statistics for the particular location, including both the frequency particular location, including both the frequency distribution and persistence of the weather. Graphs are presented showing both of these parameters for wave heights in the Gulf of parameters for wave heights in the Gulf of Mexico.

Introduction

In any type of construction work, weather plays an important part. This is especially plays an important part. This is especially true in offshore construction, where lost time as a result of bad weather can be quite costly. A contractor's expenses for laying an offshore pipeline are approximately proportional to the pipeline are approximately proportional to the total time on the job, including the time required for mobilization, traveling to and from the job location, and installation of risers, and the time required for actually laying pipe. The time expended on each of these operations, and hence the total cost for a project, is highly dependent upon the weather. project, is highly dependent upon the weather. If it were possible to predict the weather accurately on a long-range basis, it would be relatively easy to estimate total required time and the total cost for any given offshore job. Unfortunately, the art of weather forecasting Ins not yet developed to the point where this can be done. As a result, there is a certain weather risk associated with each estimate of an offshore project. Since most offshore pipeline contracts are let on a turnkey basis, pipeline contracts are let on a turnkey basis, the contractor is forced to assume this risk. In the long run, of course, the pipeline companies pay for the effects of weather, as the contractor pay for the effects of weather, as the contractor adds to his bid an allowance for bad weather. At present, with relatively few years of construction of offshore pipelines, there is insufficient experience from which to assess the real effects of weather. One of the purposes of this study is to develop a means to quantitatively determine the risk of bad weather for any given job.
Kinetic Model of Pour-Point Phenomena
Authors: Becker H. L.
Published: December 2007

Selection of crystal modifier chemicals to reduce the pour point of paraffinic crude oils and to provide paraffin deposition inhibition has, in the past, been accomplished by laboratory physical testing. This paper presents a method for selection of these chemicals based on a technique of modeling the cooling rate behavior of paraffinic crude oils. Using this method to model the cooling rate characteristics of various crystal modifier compounds and comparing them to the modeled characteristics of crude oils provides selection criteria for matching the best crystal modifier to a particular crude oil.
High-Permeability Fracturing at Prudhoe Bay, Alaska
Authors: Reimers D. R. , Clausen R. A.
Published: December 2007

High permeability hydraulic fracturing at Prudhoe Bay? This paper documents the results of a very successful fracturing program at Prudhoe Bay in which ARCO Alaska Inc., Unit Operator for the Eastern Operating Area (EOA), has successfully fracture stimulated over 100 wells, with a total oil rate benefit that has exceeded 100,000 STB/D. The more prolific stimulations have resulted in individual well responses of greater than 5000 STB/D. BP Exploration (Alaska), Unit Operator for the Western Operating Area (WOA), has also instituted an aggressive fracturing program. The field wide program has significantly contributed to maintaining Prudhoe’s production rate at the onset of the field’s decline.

Relatively long, highly conductive fractures have proven quite effective at bypassing extensive formation damage and also accelerating oil production on the less damaged wells. This paper documents the development of the fracturing program which illuminates the potential for successfully fracture stimulating higher permeability reservoirs.
New, Delayed Borate-Crosslinked Fluid Provides Improved Fracture Conductivity in High-Temperature Applications
Authors: Brannon H. D. , Ault M. G.
Published: December 2007

Moderate to high-temperature reservoirs frequently require hydraulic fracturing stimulation to be effectively produced. Temperature-stable viscosified fluids are needed to successfully execute treatments in these harsh downhole environments. The evolution of high-temperature fracturing fluids has led to the use of organometallic-crosslinked, aqueous-based guar or derivative guar gels. These fluids yield high viscosities for long periods of time at elevated temperatures and have received widespread application.

Unfortunately, several recent studies illustrated that organometallic-crosslinked fluids can cause significant damage to the permeability of the proppant pack. An industry consortium reported that the proppant pack permeability damage is often greater than 80% when these fluids are applied. Damage of this magnitude dramatically reduces the effectiveness of the stimulation treatment. Delayed breaker systems, recently introduced to reduce the permeability damage, have limited applicability at temperatures greater than 200°F and, where applicable, greatly increase treatment costs.

A guar-based fluid utilizing a new, organically-complexed borate crosslinking system has recently been developed. Laboratory evaluations of this new system demonstrate superior rheological properties at temperatures exceeding 300° F. More significantly, the new fluid has been observed to be much less damaging to the proppant pack permeability than conventional organometallic-crosslinked fluids. Retained permeabilities greater than 85% have been observed, without breaker, at 250°F.

The rheological, proppant transport, fluid loss and retained proppant pack permeability performance of the high-temperature borate-crosslinked fluid are described and compared to conventional fluids. Field case histories are provided to support the laboratory data.
Modeling of Formation Damage Due to Physical and Chemical Interactions between Fluids and Reservoir Rocks
Authors: Chang Frank F. , Civan Faruk
Published: December 2007

A phenomenological model for formation damage in petroleum reservoirs is presented to describe the rock/fluid interaction processes including particle migration, physico-chemical interactions between invading fluid and reservoir rock, and geochemical reactions. Chemical reactions involving dissolution/precipitation and ion exchange are modeled. The precipitates are considered movable and mixed with other fine particles to contribute to the pore throat plugging. Size distribution of both precipitates and clay fines are accounted for by a bimodal distribution function. A probabilistic approach is used to calculate the fraction of the plugged pore throats. The model parameters are determined through an optimization method by fitting with experimental data.

The capability and validity of the model are demonstrated by comparing the predictions obtained from this model with previously published experimental data. The specific case considered addresses the effect of injection fluid composition. The predicted and the experimental data are shown to be in good agreement. This new model has a broader applicability in diagnosis, evaluation, and simulation of formation damage during drilling, production, and EOR processes. It can also be used to predict the performance of acidizing and other chemical flooding processes.
X-Ray Microtomography: A New Tool for the Characterization of Porous Media
Authors: Dunsmuir J. H. , Ferguson S. R. , D’Amico K. L. , Stokes J. P.
Published: December 2007

In this paper we describe the application of a new high-resolution X-ray tomographic microscope to the study of porous media. The microscope was designed to exploit the properties of a synchrotron X-ray source to perform three dimensional tomography on millimeter sized objects with micron resolution and has been used in materials science studies with both synchrotron and conventional x-ray sources. An overview of the microscope design, operating modes, the reconstruction algorithm and the data display will be presented. The performance of the microscope using conventional and synchrotron sources will be compared. In this work we have applied the microscope to measure the three dimensional structure of fused bead packs and berea sandstones with micron resolution and have performed preliminary studies of flow in these media with the microscope operated in a digital subtraction radiography mode. Computer graphics techniques have been applied to the data to visually display the structure of the pore body system. Tomographic imaging after flow experiments should detect the structure of the oil-water interface in the pore network and this work is ongoing.
Reservoir Fluid Characterization Using Ultrasonic Velocity
Authors: Ye S. , Lagourette B. , Alliez J. , Saint-Guirons H. , Xans P. , Montel F.
Published: December 2007

Reservoir fluids are usually characterized by phase equilibria measurements and volumetric properties. In this paper, we show that integrating ultrasonic velocity in the database increases the predictability of the model. Acoustic sensitivity to the fluid characteristics also permits direct detection of phase transitions.

Ultrasonic velocity is related in a simple way to isenthalpic and isentropic compressibility, hence the importance of its measurement and modelling in temperature and pressure ranges encountered in oil and gas processing where choke (mainly isenthalpic) and compressors (mainly isentropic) are widely used.

Ultrasonic velocity measurements have been performed on pure hydrocarbon compounds, binary mixtures and reservoir fluids at different temperatures and pressures up to 130°C and 70 Mpa. The measurements are much more accurate than for any other thermodynamical property, the accuracy of our determination is about +/− 0.5 m/s and the typical range is from 1000 to 1500 m/s.

Furthermore, phase transitions are determined easily by this method even in the case of liquid/liquid equilibria.

The experimental results are compared to the values calculated using different thermodynamic models and different mixing rules. A calculation procedure, applicable in the case of any model, is described.

It is shown that cubic Equations of State, poorly adapted to the description of pure compounds and binary mixtures, are very reliable to model the behaviour of complex mixtures such as reservoir fluids.
Characterization of Swirling Flow and its Effects on Orifice Metering
Authors: Shen J. J. S.
Published: December 2007

The effects of swirling flow on the measurement accuracy of a 152 mm (6 inch) orifice meter are presented in this paper. The test was conducted in a low-pressure air flow calibration facility with swirls generated by an axial vane-type swirler. The flow fields inside the orifice meter were characterized by a multiport pitot-static probe traversing across the meter run. The orifice meter performance was compared with reference critical flow nozzles.

The salient features of the observed flow fields compared quite closely with swirling flows generated by two close, out-of-plane elbows reported in the literature. The axial velocity profile was shown to be generally flatter than the fully-developed one. The swirl angle measurements delineated a secondary flow pattern of solid-body rotation. Without a flow conditioner in the line, the orifice meter was found to under-measure the true flow rate in a swirling flow. The deviation in flow measurements increased with increasing swirl angle. The tube bundle flow conditioner was very effective in removing swirls in the flow but not rectifying the deficient axial velocity profile. Based on the collected swirling flow data, a method was proposed to estimate possible swirl-induced flow rate errors for orifice meters in field use.
Modeling of Wellbore Heat Losses in Directional Wells Under Changing Injection Conditions
Authors: Chiu K. , Thakur S. C.
Published: December 2007

Although many analytical wellbore heat loss models have been presented, none has addressed the problems associated with (i) directional wells and (ii) changing injection conditions. Today, more and more wells are drilled directionally. Moreover, the injection rate, pressure, temperature and steam quality seldom remain constant throughout the injection period. This paper presents a semi-analytical model which can determine heat losses from directional wells (deviated or horizontal wells) under changing injection conditions.

To model directional wells, the well is divided into a number of segments whose inclination angle can be varied with depth. The energy and pressure equations are coupled and solved iteratively for each segment. The changes in injection variables (rate, pressure, temperature and steam quality) are approximated by step functions and the method of superposition is used. A new empirical expression is used to determine the transient heat loss to the formation. This simple expression is valid for all times and gives results closer to the exact solution than the more commonly used long time asymptotic solution.

The sample calculations in this paper illustrate the differences in heat losses between vertical and directional wells and demonstrate that the assumption of constant wellhead conditions may give unsatisfactory results in cases where the injection conditions vary.
An Experimental and Fundamental Interpretation of Fracturing Filter-Cake Fluid Loss
Authors: Mayerhofer M. J. , Economides M. J. , Nolte K. G.
Published: December 2007

Interpretation and modeling of filtercake leakoff experiments are presented. Crosslinked polymer fracturing fluids were used under static conditions. Relationships between ratios of leakoff coefficients and polymer loadings were determined. These can lead to the calculation of any value if one is obtained experimentally. It was determined that the filtercake behavior deviated from the square-root of pressure dependence for an incompressible cake. Experiments, using a constant pressure differential across the cake, indicate relationships between leakoff coefficient and pressure raised to powers approximately 0.25 or less depending on the pressure value, whereas previous work reported a single proportionality for all pressures. Since pressure varies continuously throughout the pumping and closing of a fracture treatment it was imitated experimentally resulting in different pressure differentials at different times. The observed behavior is explained introducing the concept or filtercake resistance. Data interpretation for changing pressures indicates an apparent fluid-loss hysteresis, characterized by the behavior of polymer cakes subjected to changing pressures and by additional cake build-up. A more fundamental interpretation is provided from the theory of viscoelasticity. The hydraulic filtercake resistance, proportional to a rate-normalized pressure difference, leads to a stress-sensitive skin-effect, exactly analogous to similar situations in pressure transient analysis.
A Method for Gas Well Decline Analysis Under Constant Pressure Conditions and High-Velocity Flow
Authors: Vega P. J. , Samaniego V. F. , Berumen C. S.
Published: December 2007

The correlation most widely used for predicting the rate decline of gas wells is that of Lee, Logan and Tek, which was derived from results of different constant rate production conditions. This paper presents the results of a study aimed at obtaining a correlation of the turbulent term coefficient D(μ) for constant pressure bottomhole conditions. Results were acquired through a radial real gas flow simulator, carefully tested for pseudosteady state conditions. The skin effect considered varies from 0 to 10. Two different gases are considered and other variables are the constant pressure, the reservoir size re/rw and formation permeability. The correlation is presented by means of log-log straight line fits of D(μ)qsc/Fμ (1-rw/rd) in the vertical axis and for the horizontal axis two options are considered: a) D(μi,s)qsc where D(μi,s)=D(μi)f (k/ks),f(k/ks)=β(ks)/β(k) (1–rw/rs)+rw/rs–rw/re, for the case of available estimates for ks and rs and b) sD(μi)qsc if the above mentioned estimates are not available; the correlation coefficient was 0.99968 for option a) and 0.99920 for option b) An easy method for predicting rate decline under transient and pseudosteady state conditions is presented.
Analytic and Numerical Model Studies of Cyclic CO2 Injection Projects
Authors: Emanuel A. S. , Tang R. W. , Fong W. S. , Langston M. V.
Published: December 2007

This paper describes two methods for modeling cyclic CO2 injection projects: (1) analytic, based on decline curve analysis, and (2) numeric, based on 2D and 3D compositional radial models derived from detailed geostatistical analysis of near wellbore properties. The application of the decline curve analysis is shown for several published and unpublished CO2 Huff-Puff projects. The numeric models are described for successful and unsuccessful field trials.
An Approach to Screening Development Concepts for Static Resources
Authors: Dubose L. W. , Hordern M. J. , Hoh C. F.
Published: December 2007

This paper describes the approach taken by Esso Production Malaysia Inc. (EPMI) recently to review its portfolio of marginal oil resources (or "statics") associated with existing fields. This review was conducted in light of the latest technology to identify feasible development concepts and generate a seriatim of activities that could be undertaken, given an appropriate economic environment. A three man multi-discipline core team met with staff members to identify all current reserves additions ideas and address the concerns involved in their development. Preliminary development concepts were formulated and then refined using ideas and advice obtained from Exxon's international affiliates via the company's worldwide computer mail system. Applications of technologies ranging from extended reach drilling from existing platforms to use of mini-platforms and subsea wells were considered. Based on screening analysis, a seriatim of technically feasible projects was developed.

This paper also discusses EPMI and industry extended reach drilling experience, the evolution of EPMI'S approach to platform design concepts, and some affiliate experience in the areas of small offshore structures and subsea wells.
Gas Gathering: Toward a More Efficient Use of Western Australia's Energy Resources
Authors: Morhall J. P. , Parkhurst N. H. , Ryan D. P. , Yap D. C-L.
Published: December 2007

This paper briefly describes the history of gas development in Western Australia (WA) and overviews the Harriet Gas Gathering Scheme now under construction, which is the first project to collect associated gas in conjunction with non associated gas. The economics of gas gathering schemes are illustrated by reference to a case study and an approach to a gas flaring and gas gathering strategy for Western Australia is proposed. The implications of such a strategy for the petroleum industry and the development of WA are outlined.
The Role of Coiled Tubing in the Western Operating Area of the Prudhoe Bay Unit
Authors: Walker E. J. , Schmohr D. R.
Published: December 2007

Coiled Tubing is used in over 1000 operations a year in the western half of the Prudhoe Bay Unit. Fishing operations, well cleanouts, inflatable packers and bridge plugs, cement squeezes, logging, N2 lifts and jet pump operations are routinely performed year round. Special considerations taken into account include temperatures to −60° F, winds to 100 mph and the environmental sensitivity of the area.

Since 1980, when coiled tubing was first used at Prudhoe, it's use has expanded from simple corrosion inhibitor and acid pumping treatments to include the full range of operations listed above. In this time frame procedures have been worked out to ensure safe, trouble free operations. Accounting for the extreme environmental sensitivity of the area, for example, all rig ups employ flanged connections from the wellhead to the four ram BOP stack. Limits have been set on coil longevity and BHA's (Bottom Hole Assemblies) use safety equipment including hydraulic releases and check valves.

It is the purpose of this paper to discuss the evolution of coiled tubing operations in the WOA (Western Operating Area) of the Prudhoe Bay Unit. Upon completion of the paper one will have an excellent understanding of the wide range of uses for coiled tubing and the type of equipment / procedures necessary to do the job.
Rod Pumping Optimization in Duri Field
Authors: Nagy T. A.
Published: December 2007

This paper details a program that has improved the quality, quantity, and usage of dynamometer surveys in the Duri Field. The programs' evolution, from an evaluation of various dynamometer data gathering systems, to a comprehensive well surveying and lift system optimization program, is detailed. This comprehensive system includes routine well monitoring, problem evaluation, minicomputer database, and personnel training. This program has resulted in significant improvements in individual well profitability, optimum utilization of well servicing equipment, and superior engineering design data.
Workover Techniques in Bass Strait
Authors: Bisset S. J.
Published: December 2007

Over 200 workovers have been completed In Bass Strait since 1987. These workovers have been a major factor in arresting the decline of Bass Strait oil production. The work has been performed with a variety of equipment, including wireline, coiled tubing, hydraulic concentric and jack-up rigs. Individual costs have ranged from less than A$ 1k up to A$ 4M.

Bass Strait has 300 completions with an average age of 12 years, giving rise to numerous workover opportunities. Due to the isolation of Bass Strait, conventional workovers have proved expensive with long lead times. Hence effort has been placed on innovative wireline or concentric workover techniques, that have restored wells to production without resorting to conventional workovers.
Pressure Mapping as an Aid to Understanding Reservoir Drainage
Authors: Anderson J. S.
Published: December 2007

This paper outlines an analytical technique for estimating well drainage areas in bounded or "semi-bounded", multiple well reservoirs. The technique is based on calculating reservoir pressure throughout the field in question and producing pressure maps over that field. From the pressure mapping, streamlines tracing the path of fluid towards the well can be plotted and drainage areas discerned. A method has been derived whereby the areal water cut development of a well and sweep efficiency can be estimated.

The technique is applied to a number of problems including the effect of flowrate variation on well drainage areas, infill drilling, well abandonment, water injection and horizontal well drainage in the vertical plane.
An Interpretative Method for Production Logs in Three-Phase Flows
Authors: Hai-Min Guo , Cheng-Dang Zhou , Zhen-Wu Jin
Published: December 2007

Most of oil fields in China have been in the mediate and later production stages during which flowing pressure is usually lower than bubble point pressure and hence the production zones produce usually in the form of oil, gas and water three-phase flows. In three phase flows, the difference among oil, gas and water properties such as density, viscosity and in-site velocity causes the complex response of production logging tool(spinner flowmeter, watercut meter). Consequently, how to determine the accurate oil, gas and water production rates of each perforated interval is a key problem in the comprehensive interpretation of production logs and well performance monitoring.

Based on experimental result from flow loop, theoretical analysis as well as practical data, the paper presents a new interpretive method for three phase flow with the inflatable diverter production logging instrument and the new response equations of water cut tool and spinner flowmeter in multiphase flow, and how to use production logging data for determining flow pattern is also given in this paper.

The field example from Chinese oil field has demonstrated the dependability of the developed method, and the interpretation results are considerably satisfied.
Revitalization of the Gidgealpa Oil Field (South Australia)
Authors: Chen K. L. , Lonergan T. P.
Published: December 2007

Appraisal drilling in the Gidgealpa Field which has a 20 year production history has confirmed the existence of a significant oil rim underlying the Permian Age Tirrawarra Sandstone gas reservoir and a large extension of the Jurassic Age Hutton Formation oil reservoir.

An oil leg to the Tirrawarra Sandstone reservoir gas pool in the South Dome could be inferred from the geophysical, geological, and production performance data obtained from Gidgealpa-7 and Gidgealpa −16. A PVT analysis of a gas sample collected more recently from Gidgealpa-34 was strong evidence to support this interpretation. Gidgealpa −41 drilled on the northeast flank of a four way dip closed anticline flowed oil at 600 BOPD from clastic Permian aged Tirrawarra Sandstone, consequently confirming an oil leg to a known gas cap.

The relatively low decline in production performance of the southern region of the Hutton Sandstone oil pool indicated a reservoir extension. Alternate seismic mapping techniques using isopachs and recognition of high velocity layers were successful in eliminating high velocity calcareous zones in the Jurassic Age Namur Sandstone Member which previously hampered mapping of the field. Appraisal drilling successfully extended the Hutton reservoir limit by 1.5 kilometres to the south.

Renewed focus has thus centred on these two (Hutton and Tirrawarra) oil pools which require separate development strategies.
The Angel Project: An Effective Gas Appraisal Campaign
Authors: Hann J. H. , Paterson G. A. D.
Published: December 2007

The technical approach to a successful gas appraisal campaign is presented in this paper. In 1990, appraisal of the Angel Field increased the technically proven reserves from 0.6 Tcf to 1.1 Tcf. The campaign was achieved on time and at a cost of A$9 million. A carefully planned program of seismic acquisition and an optimally positioned appraisal well was required to achieve the reserves target. These appraisal activities were optimised by use of a Monte Carlo program specifically written to model geological uncertainties.
A Design of Mono-Column-Type FPSO
Authors: Miyagawa M. , Isozaki Y. , Yokokura K.
Published: December 2007

A new concept of a hull form, composed of a disk-type lower hull with a circular well at its center and a cylindrical hollow column, with small motions in waves, a big displacement and a simple hull form, has been developed, which is most ideal for the FPSO.
The Impact of PVT Data Quality on Hydrocarbon Recovery Predictions
Authors: Trengove R. D. , Hann J. H. , Skates J. R.
Published: December 2007

The effect of PVT data quality on simulator estimation of liquid hydrocarbon recoveries under various gas sales scenarios was investigated. An extended black oil reservoir simulation model together with the fluid model from the Third SPE Comparative Solution Project1 and a gas condensate fluid from Drohm et al2 were used.

Experimental constant volume depletion (CVD) liquid saturations were modified by the method of Drohm et al2. The unmodified and modified gas condensate data sets were used to generate equation of state (EOS) characterisations and black oil PVT tables for input to reservoir simulation.

The EOS characterisations were constrained to reproduce the liquid saturations. For the modified data it was possible to match both the observed dew point and the modified liquid saturations. However, the EOS characterisation which was matched to the raw liquid saturations underpredicted the experimentally measured dewpoint.

The applicability of the black oil simulation model is discussed and various scenarios are compared to show the influence of data corrections on simulation results.
Completion Design For Corrosive Well Conditions
Authors: Callihan R.B.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

In certain producing fields in the United States, Canada and other countries with severe corrosive conditions, special downhole equipment installations have been developed to meet the requirements of production and stimulation. This paper classifies corrosive well conditions and associated theoretical considerations, and describes packer and tubing equipment being successfully used for these conditions. Certain guide lines are established for designing completions for a wide range of corrosive conditions in producing wells.

Introduction

Throughout the producing areas of the world, a variety of special equipment is employed to combat corrosive well conditions. The design of special packers and tubing strings is dictated by the nature and severity of the corrosive environment in addition to the normal requirements of production or injection.

Corrosive environments consist primarily of produced fluids containing varying amounts of H2S produced fluids containing varying amounts of H2S and CO2 at a wide range of pressures and temperatures. Even so, there Is enough similarity of downhole conditions, such that, classification of successful equipment installations has been very helpful in designing equipment for other corrosive areas.

So many corrosive producing formations require stimulation by acidizing or fracturing to improve production. Rig time can be saved by equipping the well to stimulate after initial completion. Special equipment has been developed to permit tubing expansion during stimulation and accommodate inhibitor injection while on production. production.

TYPES OF CORROSIVE WELL CONDITIONS

Corrosive conditions in producing wells can usually be described as sour or sweet corrosion. Sour corrosion is due to hydrogen sulfide in production, while sweet corrosion is primarily a production, while sweet corrosion is primarily a result of carbon dioxide in produced fluids.

H2S Conditions

In the presence of moisture, H2S in production can result in iron sulfide corrosion and hydrogen stress cracking. Iron sulfide is a general corrosion which appears as a black powder or scale on exposed steel surfaces. Hydrogen stress cracking is a failure of high strength steels due to hydrogen embrittlement which can occur without visible corrosion damage. It has been found that only a trace of hydrogen sulfide is necessary to cause hydrogen stress cracking.

CO2 Conditions

When CO2 and water are present in production, a resulting acid condition may cause iron carbonate corrosion. Damage to well equipment normally takes the form of deep pitting where corrosion-erosion occurs.
Horizontal Well Completion Recommendations Through Optimized Formation Evaluation
Authors: Ahmed U.
Published: December 2007

Use of horizontal well completion to enhance hydrocarbon recovery has increased considerably in the past several years. Projections for future horizontal wells hold considerable promise as long as well productivity enhancement outweighs the incremental cost. The success of horizontal wells to date appears to be related to the development and application of specific technology. Optimized completion techniques are on top of the list of such required technology. Recent publications clearly demonstrate that without proper formation evaluation, adequate completion is typically unachievable and often results in premature well abandonment.

This paper targets the three most common horizontal well formations subject to completion: naturally fractured, matrix permeability dominated systems and formations bounded by a gas cap or an aquifer or both. The formation parameters that best define matrix permeability dominated systems are quite different than those associated with naturally fractured formations. The paper first identifies the parameters that best define individual formations. Possible completion options for these formations are then discussed.

Optimized completion recommendations are presented for each of the formations through use of case studies. Recommended completion procedures for naturally fractured formations require use of external casing packers and alternating perforated or slotted and blank pipes. Zonal isolation is of prime importance in matrix permeability dominated systems, especially when the pay interval is bounded by a gas cap or an aquifer or both. The recommended completion procedure for these types of formations uses cemented casing and selective perforating.
Development of Oilfield Facilities on a Nature Reserve: The Airlie Island Experience (Onslow, Western Australia)
Authors: Long P. J. , Long V. L.
Published: December 2007

Airlie Island is a small (26 hectare) sand cay, located 35km north of Onslow in Western Australia. In common with other islands in the region, Airlie is a nesting site for seabirds and turtles, but its two primary conservation resources are the large Wedge-tailed Shearwater rookery which covers 64% of the island and an endemic skink species. Its conservation values have prompted the Western Australian State Government to declare the entire island a nature reserve set apart for the preservation of flora and fauna.

In 1987 Western Mining Corporation Pty Ltd developed the South Pepper and North Herald oilfields and part of this development included the siting of an oil terminal on Airlie Island.

It may be expected that the conservation resources of the island and the Company's requirements for land would be incompatible. However, a careful study of the local environment and the creation of a detailed plan to manage this environment resulted in an acceptable compromise. The vegetated area of Airlie Island was reduced by 3.1 hectares, or 12%, and appropriate siting and design of the facility minimized the impact on wildlife. Disciplined execution of the management plan during construction was an essential part of the overall environmental success of the project.

This case study shows that conservation and exploitation can be compatible if appropriate management strategies are developed and strictly implemented.
Planning and Drilling Australia's First Medium-Radius Horizontal Wells
Authors: Moo T. J. , Tweedy M. W.
Published: December 2007

During early 1991 West Australian Petroleum Pty. Limited acting as joint venture operator for Chevron Asiatic Limited, Texaco Oil Development Company, Shell Development (Australia) Pty. Limited, Ampol Exploration Limited and Western Mining Corporation Limited successfully drilled the first two medium radius wells in Australia.

The two wells G88B and Cowle No.2 were very different in many aspects.

The first well G88B achieved a 500m horizontal well bore at 615m true vertical depth (TVD) using build up rates to horizontal in excess of 10 degrees/30m(5.818E-03rad/m). The well was drilled onshore using a relatively small drilling rig with minimal additional equipment.

The Cowle No.2 well achieved a 1002m horizontal well bore at 1098mTVD using a build up rate of 9 degrees/30m(5.236E-03rad/m). This offshore well utilized a significantly higher capacity/capability drilling rig than that used on the G88B well.

Both wells were able to be horizontal within 240m of their surface locations representing a significant decrease in horizontal and vertical displacement required to build to horizontal.

Horizontal wells drilled within Australia had previously utilised long radius builds which require greater horizontal and vertical distances before reaching horizontal, longer well paths and generally longer drilling times1.

The success of the first two medium radius build to horizontal wells in Australia confirms that horizontal sections can be accurately drilled with shorter horizontal displacements and vertical sections than previously thought possible. The practicality of drilling shallow horizontal wells onshore using available drilling rigs is also confirmed.
Drilling Extended-Reach Wells, Northwest Shelf, Australia
Authors: Scott P. W. , Lintern G. A. , Embury J. E.
Published: December 2007

Woodside Offshore Petroleum has taken advantage of state of the art drilling technology to construct extended reach wells from fixed platforms to access more distant sections of reservoir. Well design has been optimised to reduce friction forces; strength and power of rig equipment and tools have been increased to handle higher design loads; drilling techniques have been adopted or developed which allow better control of the drilling process; and training has been used to prepare personnel for the changes, enhancing safety and efficiency.

The changes made to one platform were constrained by existing rig design making compromises necessary. The other rig was purpose designed to drill extended reach wells and is presently under construction. Its capability will be significantly greater.

Drilling and completion times on extended reach wells drilled to date have been shortened, thereby lowering well costs.
Contribution of Maintenance to the Safeguarding of Technical Integrity
Authors: Officer W. S.
Published: December 2007

The exploration and production upstream sector has adjusted to the oil price collapse of 1986 and has entered the new decade with a rationalised and restructured business portfolio. There has been a considerable drive to reduce cost and consolidate the business around the core activities, with increasing emphasis being placed on the maintenance contribution to the business objectives.

The prime role of maintenance is accountability for management of the safeguarding of technical integrity, and ensuring the required long term facility availability at optimum cash flow.

The oil industry entered the new decade having gained valuable lessons from the turbulent experiences of the later 80s period, demonstrating an ability to adapt and be sensitive to the need to "manage change"

There is now a growing realisation that a number of issues need to be addressed, in order to safeguard the long term technical integrity of assets.

This activity is made the more challenging by the number of facilities approaching design half-life, and the ever changing demands in production profile necessary to gain further commercial advantage.