bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Tubing-Conveyed Perforating Method
Authors: Mason Justin , George Flint , Pacheco Eduardo
Published: December 2007

Two new innovations — an automatically released gun hanger, and a modular gun-deployment system — have recently been introduced to the oilfield to better support perforating needs in wells in which the completion configurations differ from the older, traditionally accepted designs.

The first design, an automatically-released gun hanger, was planned originally for monobore completions to allow a zone to be perforated and tested without imposing any downhole restrictions. This gun hanger can be used below a retrievable or permanent packer, a polished bore receptacle, or an electric submersible pump.

A new modular gun system has also been designed to be run in conjunction with the gun hanger. This system allows operators to deploy long gun intervals, a section at a time, into a well The guns are run into the wellbore individually and stacked on a gun hanger until the appropriate length is achieved. Since this method avoids any gun length restrictions that could be caused by a lubricator, it is ideal for rigless completions. In addition, the capability of the system to allow retrieval of any or all of the modules under pressure makes it ideal for use in wells with limited rathole.

The combined technological advantages of these new completion tools increase production capability of the wellbore by allowing 1) maximum tubular ID usage and 2) perforating capabilities that include maximum gun size, optimum shot patterns and density, and maximum underbalance or overbalance. These enhancements are in keeping with the current operational and economic needs in today’s oilfield.
Performance of Hydraulic Fracturing and Matrix Acidizing in Horizontal Wellbores – Offshore Qatar
Authors: Edwards M. G. R. , Pongratz R.
Published: December 2007

Considerable debate in the Middle East has centred upon what was previously felt to be two separate methods of enhancing revenues and daily production; hydraulic fracturing and horizontal drilling. In an effort to maximize return on investment, these two issues have been successfully combined in other areas of the world1.

In order to establish the suitability of this technology in this area, two horizontal wells with over 3,050m (10,000ft) of lateral section were drilled into the Cretaceous Kharaib formation, overlying the North Field, Offshore Qatar.

A massive stimulation program was performed in order to evaluate the most feasible stimulation method from both a technical and economical perspective for further field development considerations.

Three propped hydraulic fracturing treatments were performed using 183,500kg (403,7001b) of 20/40 mesh sand, and seventeen acid matrix treatments placing over 3,217,250/ (850,000gals) of HCL into the lateral sections of both wells.

This paper describes the performance, operation and logistical support required to complete this offshore operation within a minimal time frame. The use of a mobile offshore jack-up platform, whereby a land based fracturing spread was placed onto the deck of a converted drilling rig is described.
Applications of the Array Induction Tool in Saudi Arabia
Authors: Zainalabedin K. A. , Minh C. Cao
Published: December 2007

Since its introduction in Saudi Arabia in 1993, the Array Induction Tool (AIT*) has been run extensively in a wide variety of petrophysical environments. These include fresh mud, salty mud, high and low resistivity formations, hydrocarbon-bearing or water-bearing reservoirs in carbonates and clastics sequences. In some examples, the AIT was also run in conjunction with the Phasor Induction (PI ) or Dual-Laterolog for comparison purpose.

As with any resistivity device, the AIT’s primary product, an accurate Rt measurement, should not be overlooked. However, owing to the AIT’s multiple vertical resolutions and depths of investigation, we found that the tool yields additional information about the reservoirs that is not possible with older induction tools.

The AIT improves the estimation of Rt in cases of thin laminations, complex invasion profiles or when the borehole correction is critical (wash-out, salty mud, high resistivity). In many instances, permeable beds that are invaded are much easier to identify with the AIT than with dual depths of investigation induction or laterolog tools. A typical case is the interpretation of annulus. Finally, we show the AIT characteristic response in a thin magnetic marker.
The Universal Modular Platform
Authors: North R. Bruce
Published: December 2007

A new and patented design for offshore wellhead platforms has been developed to meet a ‘fast track’ requirement for increased offshore production, from field locations not yet identified. The new design uses modular construction to allow for radical changes in the water depth of the final location and assembly line efficiency in fabrication. By utilizing high strength steels and structural support from the well conductors the new design accomidates all planned production requirements on a support structure significantly lighter and less expensive than the conventional design it replaces.

Twenty two platforms based on the new design were ready for installation within 18 months of the project start. Installation of the new platforms began in 1992 for drilling support and 1993 for production support. The new design has become the Company standard for all future production platforms. Large savings in construction costs have been realized through its light weight, flexibility in both positioning and water depth, and its modular construction.
Modeling of Downdip Oil Pockets Trapped Behind Flood Front
Authors: Liu J. S. , Al-Abdulkarim A. A. , Barber R. M. , Fontanilla J.
Published: December 2007

The area of interest, located on the downdip flank area of a large carbonate reservoir, is geologically complex. Present at the northwest corner is a structural low which falls below the oil-water contact (OWC). On the southeast corner, the reservoir is known to be communicating with deeper reservoirs. This allowed water to enter the reservoir updip when the reservoir pressure fell prior to the initiation of water injection. Several wells drilled in this area have had significant oil columns in spite of the fact that they were planned as water injectors. The salinity map generated for reservoir management purposes also reveals the complexity of fluid flow in this area. The high total dissolved solids (TDS) content observed for these wells corroborates that the area was nearly stagnant since the production first began in the field. So far, three lagged oil areas have been identified.

A high resolution window model for this area was constructed to define the areal extent of the lagged oil trapped behind the flood front as well as to determine if any other unswept oil exists in the downdip area.

After a satisfactory history match was obtained, the cause of formation of the downdip trapped oil also became apparent and the areal extent of the lagged oil was defined more accurately. The model was thus used to formulate a depletion strategy to recover the lagged oil. A series of prediction cases were run to investigate various issues related to the recovery of the downdip trapped oil and the impact of future reservoir development plans on the lagged area.
Targeting New Wells In A Mature Field
Authors: Javed Mohammad S.
Published: December 2007

It has been estimated through a simulation study that about 20 million STB of oil can be recovered through infill drilling in the flank areas of one of the prolific, but depleting reservoirs (Arab C) in a Qatar offshore field. The area where this appreciable amount of oil (known as "Cellar Oil") exists, has been left unswept by the non-ideal location of the "Dumpflooders" - injection wells, for pressure maintenance, which gravitate water from a source formation directly into the producing reservoir.

This paper highlights the results of the simulation study of this mature reservoir, studied together with the underlying Arab D, where high oil concentrations are shown in the flank areas, between the OWC and the dumpflooders. Although, the existing flank production wells have been performing satisfactorily, it was found, from the study, that even prolonged production through these would not drain this trapped Cellar Oil; new wells must be drilled to recover it. The infill wells, proposed for this purpose, happen to be located in areas such that they can be completed dually in a horizontal mode with another underlying reservoir (Uwainat) having an oil rim, thus, further increasing the attractiveness of the project. The study also indicates the necessity of infill drilling in other parts of the Arab C and Arab D.
Case History: Relief Well Control of Underground Blowout In Bahrain
Authors: Flak Larry H. , Muhanna Ghassan A. , Al-Qassab Mohamed
Published: December 2007

As producing wells in the Middle East mature, downhole corrosion problems are causing increased blowout risk. Well 159 was drilled in 1959 and was completed within the shallow "Ac" sandstone reservoir with perforations at 2029’ to 2062’. External casing corrosion and tubing failure lead to an underground blowout. Casings near surface had deteriorated to the point that wellbore access from surface was no longer possible to control the blowout. An estimated 8 MMscfpd gas containing 1000 PPM H2S and 6% CO2 was blowing into a shallow brackish water aquifer (150’ to 700’). Well 159 wellhead vibrated at surface from subsurface flow. Gas leaked out of the aquifer into cellars of Well 159 and surrounding wells. This complicated field operations and placed offset wells at increased risk. This paper describes a case history of the relief well used to successfully control the underground blowout of Well 159.
Core-Log Integration For A Saudi Arabian Sandstone Reservoir
Authors: Saha Souvick , Al-Kaabi Abdulaziz U. , Amabeoku Maclean O. , Al-Fossail Khalid
Published: December 2007

For a detailed characterization of a reservoir, core-log integration is essential. In this paper, data integration from logs and cores of a Saudi Arabian sandstone reservoir is discussed with particular attention to effects of clay on resistivity logs and water saturation. There are four sources of data, namely, core resistivity measurement, clay study from cores (XRD, CEC), spectral core gamma ray, and well logs. In order to generate continuous cation exchange capacity (CEC) with depth, spectral gamma ray measurements (both from core and downhole log) and CEC from cores are correlated. Qv (CEC per unit pore volume) values are calculated utilizing only well logs by applying Waxman-Smits equation in water bearing zone. Log derived Qv values from water zone were then correlated with porosity to generate Qv values in the oil column and compared with core derived Qv. Finally, data from well logs (porosity, resistivity and qv) and cores (resistivity parameters m, n, and Qv) were integrated for more accurate water saturation calculation. The core-log correlation can be applied to other wells avoiding expensive core analysis, and the technique developed in this project can be used in other sandstone reservoirs.
Prediction of Three-phase Coning Behaviour for Horizontal Wells in Naturally Fractured Reservoirs
Authors: Verbruggen M. H. W. , Schulte A. M.
Published: December 2007

A semi-analytical model has been developed that predicts the production behaviour of horizontal wells in a naturally fractured reservoir. A water zone is assumed to underly the reservoir, and the pressure is assumed to be maintained by gas injection at the reservoir’s crest. The model combines the recovery processes of gas/oil and water/oil gravity drainage in the matrix system with three-phase coning in the fracture system. The offtake rate is assumed to be subcriticai or critical with respect to gas coning, in order to avoid gas cycling. With respect to water coning, the offtake rate may be either subcriticai or supercritical. The validity of the new model is confirmed by numerical simulations of such fractured reservoirs.

The model allows a quick investigation of how, e.g., oil zone thickness, offtake rate, well spacing and well location affect the oil recovery. As such, it can be used as a fast and simple screening tool. On the basis of its results, more detailed numerical simulations that include the full geology and flow equations can then be used for further optimisation and economic evaluation.
Analysis of Well Tests From Naturally Fractured Reservoirs by Automated Type-Curve Matching
Authors: Menekse K. , Onur M. , Zeybek M.
Published: December 2007

Due to the diversity of existing idealized naturally fractured reservoir models, e.g. double porosity models with transient or pseudo-steady interporosity flow, etc., and the large number of parameters needed to be estimated in these models, the analysis of well test data from naturally fractured reservoirs by the well-known conventional graphical techniques is often difficult if not impossible. In recent years, the computer-aided automated type curve matching techniques based on nonlinear regression methods (e.g. least-squares, least absolute value, etc.) have been increasingly popular in estimating well/reservoir parameters from transient well test data.

In this work, we explore in detail the applicability of nonlinear regression techniques to obtain the parameter estimates from well-test pressure data from naturally fractured reservoirs. We implement both the nonlinear regression technique based on L2 norm (least-squares) minimization and the nonlinear regression technique known as "robust" regression based on L1 norm (least absolute value) minimization. Important characteristics of these nonlinear regression methods are discussed. In modeling the pressure data, we consider the most commonly used double porosity models such as Warren and Root’s pseudo steady state interporosity flow model as well as transient interporosity flow models with slab and spherical matrix blocks (with or without interporosity skin effects) including wellbore and storage effects. The analysis of multi-rate tests by nonlinear regression techniques is also given. As model functions, pressure (or pressure change), conventional pressure derivative, pressure plus pressure derivative, pressure/pressure derivative ratio and integral pressure functions are considered in regression. The advantages and disadvantages associated with use of each function in the analysis are discussed. It is shown that the pressure/pressure derivative ratio increases the chances of obtaining a unique fit, that is, that it is not very sensitive to different initial guesses for parameter values unlike the other model functions. In addition, we show that the regression method using the integral functions yields more accurate estimates (with narrower confidence intervals) than the methods based on pressure derivative in cases where the pressure data is very noisy. Guidelines for the effective use of nonlinear regression techniques when analyzing well tests from dual porosity reservoirs are also provided. The applicability of the proposed methods is demonstrated by analyzing several sets of synthetic and field data.
Performance Prediction Using Geostatistics and Window Reservoir Simulation
Authors: Fontanilla J. P. , Al-Khalawi A. A. , Johnson S. G.
Published: December 2007

This paper is the first window model study in the northern area of a large carbonate reservoir in Saudi Arabia. It describes window reservoir simulation with geostatistics to model uneven water encroachment in the southwest producing area of the northern portion of the reservoir. In addition, this paper describes performance predictions that investigate the sweep efficiency of the current peripheral waterflood.

A 50 × 50 × 549 (240 m. × 260 m. × 0.15 m. average grid block size) geological model was constructed with geostatistics software. Conditional simulation was used to obtain spatial distributions of porosity and volume of dolomite. Core data transforms were used to obtain horizontal and vertical permeability distributions.

Simple averaging techniques were used to convert the 549-layer geological model to a 50 × 50 × 10 (240 m. × 260 m. × 8 m. average grid block size) window reservoir simulation model. Flux injectors and flux producers were assigned to the outermost grid blocks. Historical boundary flux rates were obtained from a coarsely-gridded full-field model.

Pressure distribution, water cuts, GORs, and recent flowmeter data were history matched. Permeability correction factors and numerous parameter adjustments were required to obtain the final history match. The permeability correction factors were based on pressure transient permeability-thickness analyses.

The prediction phase of the study evaluated the effects of infill drilling, the use of artificial lifts, workovers, horizontal wells, producing rate constraints, and tight zone development to formulate depletion strategies for the development of this area. The window model will also be used to investigate day-to-day reservoir management problems in this area.
On the Theory of Polymer Solution Flooding Process
Authors: Sarem A.M.
Published: December 2007

Certain polymeric waterflood additives, such as partially hydrolyzed polyacrylamide, impart a useful but seemingly "abnormal" resistance to flow of flood water through porous rock. This "abnormal" resistance has resulted in a substantial increase in waterflood oil recovery—beyond what could normally be expected from the viscosity increase that the polymer causes in the flood water.

A theory has been formulated and qualitatively tested on laboratory data to explain this beneficial "abnormal" property in terms of interaction between molecular coulombic and ionic forces. The theory is used to show how the polymer can reduce the mobility of water but not that of oil. The application of the theory for tailor-making more effective polymers is also discussed.

In line with the above-mentioned theory, a study of the adsorption of polymer on the pore surface of porous media has shown that more polymer is adsorbed from salt-containing water than from fresh water. Also, the amount of polymer adsorption and the length of polymer retention time on low-surface-energy teflon beads was found to be considerably less than on a high-surface-energy fired sand.
Opportunities for Petroleum Company Leadership in Host Nations Sustainable Petroleum Economic Development Business
Authors: Stultz-Karim S. P.
Published: December 2007

This paper examines the dynamic international political economic environment in which petroleum exploration and production companies must operate when considering investments in the economically transitional nations of the former Soviet Union or developing nations. In this period of critical global changes low oil prices is only one factor with which petroleum companies must be concerned in their investment decisions Other factors include the transition from a Dipolar world to a multipolar world of free trade zones, the general malaise of the international economy, public and political recognition that nations and industries can no longer practice environmental "beggar-thy-neighbor" policies, and the rejection of aggregate national economic growth policies for sustainable economic development policies in both the developed and developing world This paper focuses on actions which investing petroleum exploration and production companies can take in order to gain a leadership role in the sustainable petroleum economic development business, to work with host countries’ regulations, and to develop a cooperative environment with host countries so that both the investing company and the host country can progress, not just survive.
Analysis of the Economic Benefits and Strategy of Exploration and Development of China's Oil and Gas
Authors: Sun Qirui , Lei Huanming
Published: December 2007

On one hand, the population of China accounts for one-fifth that of the world, whereas the proved oil reserve for an average person in China makes up less than one nineth that in the world. And the average natural gas reserve per person of China is only one twentieth that of the world. On the other hand, the yearly oil output of China has risen from 120,000 tons to 139,000,000 tons, which has made China one of the largest oil countries in the world, presenting a striking contrast with the former. This is a problem which is worth noticing. More and more oil and gas are needed for the continued economic development of China, but the oil industry of exploration and development is faced with such contradictions and difficulties as lack of reserve volume, imbalance of the ratio of reserves and production, shortage of funds, surplus of staffs, low labour productivity, and so on. For this reason it is necessary to analyse the economic benefit and strategy of China's oil and gas exploration and development. With a series of data and charts this paper analyses the economic benefit of the exploration and development of China's oil and gas and proceed to study the strategy of "Stabilising the Eastern Part and Developing the Western Part of Oil Zones " and "Starting the Second Oil Undertaking and Opening the Second Battlefield for Oil Production". And in this paper the author comes up with his own points of view.
Matrix Flow Evaluation Technique For Water Control Applications
Authors: Novotny Rudolf J.
Published: December 2007

Rudolf J. Novotny*

Production of unwanted water from oil and gas wells has consistently burdened the industry. Many chemical systems have been developed to selectively reduce the flow of water into the wellbore 1 but not appreciably affect the production of hydrocarbons. Although these systems work well in the laboratory, many field applications have proven less than successful. The limited success of these types of systems may not be due to product failure but to poor candidate selection. The functioning mechanism of the chemical systems limits their application to wells where the production of water moves through the formation matrix, not from a channel or fracture.

A methodology has been developed utilizing production data and Darcy's flow equations to evaluate well candidates for these and other matrix applications. This evaluation technique will assist the engineer in deciding the potential mechanism of excessive water influx. Once the source or conduit for water production is determined, the appropriate type of water control application can be designed and applied. Examples of candidate evaluations and field application results are presented.

Introduction

Many oil and gas wells also produce water. This water production can occur on initial completion or later in the life of the well. A small amount of water production does not create a problem and in some instances is beneficial; however, when water production becomes excessive, then consideration for reducing it should be made. Excessive water adds cost to the production of the well. More water means additional lifting, treatment, and separating cost. It can also reduce the hydrocarbon production, by increasing the head in the wellbore, reducing the drawdown, or in gas wells, higher density water in the production string can lead to early shut-in or the necessity to install artificial lift.

Fluid distribution vertically in a reservoir is important. The relative amounts of oil, water, and gas present at a particular level in the reservoir determine the fluids that will be produced by a well completed at that level, and also influence the relative rates of fluid production. In most "water wet" sandstone formations, the water saturation varies from 100% below the oil zone to progressively lower percentages at points higher in the oil zone. The zone from a point of 100% water saturation to some point above where water saturation is fairly constant is called the transition zone. Relative permeability relations permit both water and oil to be produced from the transition zone.

P. 161
Calculating The Distance To A Discontinuity From D.S.T. Data
Authors: Gibson J.A. , Campbell A.T.
Published: December 2007

Pressure build-ups from properly conducted drill stem tests have provided the well owner an ever increasing amount of useful data in regard to formation evaluation. The distance to a discontinuity is a significant formation parameter that can be calculated from drill stem test data. This study investigates the various methods available for calculating the approximate distance to a discontinuity. The transient response curves obtained during a drill stem test exhibit more than one slope if the flow periods and shut-in periods are sufficiently large. The distance to the discontinuity can be calculated by picking the point of deviation from the straight line portionT +0 of a well bore pressure vs. log ------ plot.0

Calculations are shown for a theoretical example of a build-up curve and two field examples of drill stem tests.

Introduction

A need has existed for an accurate method of determining the distance from a well bore to a discontinuity. Many advantages will be afforded the well owner if he can determine the distance to a discontinuity. For, example, a much higher permeability section may be indicated at some distance from permeability section may be indicated at some distance from the well bore as shown in Figure 1. Calculating the distance to the higher permeability section will provide the answer as to whether or not the section can be reached with a stimulation treatment such as hydraulic fracturing. Also, assume a test of a water bearing section indicates a gas-water contact as shown in Figure 2. The distance to the contact will determine whether a new well must be drilled higher on the structure or whether a side track from the original hole is feasible for penetrating the formation above the gas-water contact. Additional examples of common discontinuities are shown in Figures 3 and 4.

One of the prime objectives of a drill stem test is to determine the flow capacity of the zone being tested. The flow capacity is directly related to the transmissibility of the formation which is directly related to the effective reservoir permeability and effective formation thickness, and inversely permeability and effective formation thickness, and inversely proportional to the viscosity of the flowing fluids. The flow proportional to the viscosity of the flowing fluids. The flow capacity is further affected by the amount of well bore damage present. present. Drill stem tests are usually comprised of a sequence of flow periods followed by shut-in periods. The shut-in periods (build-up curves) provide the basic data which is utilized in calculating values for transmissibility and well bore damage.
Data Analysis For High Influx Wells
Authors: van Poollen H.K. , Weber J.B.
Published: December 2007

During drillstem tests, fluid influx into the drillstem is measured as flowing pressure increases. On moderate liquid producers, the influx is essentially constant and the final flowing pressure is in the order of 10 to 30 percent of the reservoir pressure. In good oil percent of the reservoir pressure. In good oil wells, flow will reach the surface and the final flowing pressure will be up to 80 percent of the reservoir pressure. In both instances cited, a subsequent pressure buildup will allow transmissibility and wellbore damage calculations.

Good producers of high density fluids, such as water, will show an initially high influx rate which slowly decreases to essentially zero and the final flowing pressure is about equal to the reservoir pressure. The same is true for a high permeability oil well with low reservoir pressure. The resultant test data cannot be interpreted with conventional methods.

Presently a method is given which makes use of type curves to interpret tests where the well kills itself during the flowing period of a drillstem test.

Introduction

Drillstem tests are often the only source of information available for reservoir data, especially early in the life of the field or when the test is in the aquifer portion. In the case of wells in the aquifer, subsequent data are not usually obtained, even in later stages of development when the aquifer properties are needed for performance studies. properties are needed for performance studies. In testing good producers of high density fluids, such as water, the fluid influx into the drillstem will be at an initially high rate, but will decrease to almost zero. In this case, the final flowing pressure will be nearly equal to the reservoir pressure. When this happens, the subsequent buildup portion of the test does not lend itself to conventional interpretation to determine transmissibility. The same situation is true for high permeability oil wells with low reservoir pressure.

Because drillstem test data on wells that kill themselves are available, but not easily solved, an investigation was made to find a way to use this source of information. A method of analyzing DST's for this type of well is presented. The method uses type curves as presented. The method uses type curves as developed by ground water hydrologists and provides for determination of both provides for determination of both transmissibility and storage.
Creating Field Management Information Systems Using Microsoft ® Software
Authors: Handsel-Johnson P. L. , Schroeder C. Y.
Published: December 2007

A field management information system (FMIS) was created for the Trinidad Resource Development teams in Amoco's International Operations Group. This application uses Microsoft Access ® 2.0 and the other Microsoft Office 4.2 software products. The purpose of this information system is to assist these teams in the management of their producing oil and gas fields. This is accomplished by providing: centralized data storage◊for a variety of data, such as well, production, engineering and geologic◊in various forms, including raw, interpreted and derived,customized analysis, planning and reporting tools, such as reservoir performance summaries and dynamic field management plans, andthe capability to easily exchange data with a variety of engineering and geoscience analytical software.

Additional benefits provided to the Resource Development teams by this approach are: improved data accuracy and accessibility from a centralized, relational database,enhanced efficiency as a result of the application being tailored to the teams’ operating environment and work processes, andaccess to an expanded knowledge base by consolidating information from several fields into one database.

In short, this product was developed in response to the Trinidad Resource Development teams’ need to improve their data integrity, efficiency and analysis and planning capability. The resultant application is not just a database, but rather, a field management information system.
SPE-Electronic Publishing Committee 1995 Update on Initiatives
Authors: Thrasher T. S. , Kemp B. D.
Published: December 2007

The primary mission of the Society of Petroleum Engineers (SPE) is to disseminate petroleum engineering technology. One of the most important sources of petroleum engineering technology is the extensive inventory (over 30,000) of SPE technical papers. In October 1991 the SPE Board authorized the Ad Hoc Electronic Publishing Committee (EPC) to explore how electronic publishing technologies might help the SPE promote the dissemination of petroleum engineering technology. The purpose of this paper is to update members on the progress of the SPE Electronic Publishing Committee, current projects and initiatives, vision for the future, and to encourage member support.
Productivity And Profitability From Mature North Sea Fields
Authors: Leggate John S. , Gregory John B. , Bennett Simon C.
Published: December 2007

John S. Leggate*, John B. Gregory*, Simon C. Bennett * SPE Members

BPX recognised that a radically different approach was required in the management of its mature North Sea oil fields. In January 1994 the Beatrice, Buchan, Clyde and Thistle fields were brought together into a single mature asset - MAST - with the objectives of maximising economic recovery, extending the delivery of positive cash flows and deferring non-value adding abandonment expenditure. During 1994 the MAST team has achieved top quartile business performance when compared to other North Sea operators and aims to be best in class by the end of 1995. This has come about through aggressive cost reduction and maintaining/enhancing oil production, yet sustaining an already good HSE performance.

Key to this success has been the use of benchmarking data, the setting of extra-ordinary targets, the proactive evolution of the market place, the use of novel organisational structures and the encouragement of certain behaviours within the team. Success to date has provided the space to consider opportunities for growth such that there is now confidence that the MAST business will continue to make a positive cash flow contribution to BPX into the next millenium.

During the second half of 1993, in the face of the oil price collapsing to its lowest real level for 20 years, BP reviewed the shape of its UKCS upstream portfolio and identified four mature assets from which financial returns were extremely limited in comparison with the effort involved in managing them. Typically, the fields in question were producing between 10,000 and 25,000 barrels of oil per day, off a cost base which, by UKCS standards, was probably no better than average. Clearly, something different was required to improve the cash generation of these assets, so top quartile operating cost targets were set and the fields placed under the management of a small, highly-incentivised team (MAST), whose emphasis was placed clearly on performance delivery. This paper describes the events of 1994, which have resulted in significant improvements in business performance and some extremely important and value-adding learning from BP's perspective.

THE PRE-MAST COMPLEXITIES

Prior to a new approach being taken with Beatrice, Buchan, Clyde and Thistle, the contribution of these fields amounted to just 4% of BP's upstream UKCS production, yet accounted for more than 17% of the resource base (operating costs, people, etc.). More than 1000 individual service contracts were in operation in the marketplace and we were handling 50,000 invoices each year. The organisation was characterised by complexity, many interfaces, unclear accountabilities and large staff numbers. Additionally, there were complex partnerships with no fewer than 14 different Partners. Overall BP equity share across the four fields was round one third.
Evaluation of Gelatinous Fluids as Insulator for Steam Injection
Authors: Suarez Simon , Rios Carlos , Layrisse Ignacio
Published: December 2007

Simon Suarez,* Carlos Rios, Ignacio Layrisse*

SPE Members

The theoretical, experimental and operational foundations related to the development of the Gel-IntTM thermal insulator are presented. This thermal insulator is a product patented by INTEVEP, S.A and is employed as an insulating medium in the cyclic steam injection process, in oil-producing wells.

The activities carried out, included the experimental evaluation of different insulating mixtures and the performance of field tests. As a part of the experimental development 19 insulating mixtures were evaluated in test cells, including a commercial brand mixture a widely used. During the experimental evaluation, the insulating mixtures were studied from the thermal and rheological behavior point of view.

The experimental activities concluded with the formulation of the Gel-IntTM thermal insulator. Subsequently, a field evaluation of this formulation confirmed, under real steam injection conditions, the thermal and rheological properties experimentally established.

Background

One of the most widely applied methods for the enhanced oil recovery of heavy and extra heavy crudes is the steam injection. This method consists mainly in injecting steam into the producing sand with the purpose of reducing the crude's viscosity and facilitating its mobility. Steam is injected at temperatures between 300 and 500 C, and at pressures within the range of 1000 and 1500 psi.

In order to keep a steam quality that guarantees the best utilization of its latent heat, a thermal insulator is required in the annular space (space between the casing and the injection tubing). This insulator would reduce the heat losses towards the formation, and at the same time, would provide an adequate thermal protection to the casing.

In the Orinoco Belt, in the Morichal area, liquid thermal insulators with gel characteristics have been normally employed. With the purpose of substituting the most commonly commercial brand used, Intevep initiated some research activities in 1984 on gel thermal insulators. The result of these activities was the development and patent of a thermal insulator known as Gel-IntTM, which is used by Lagoven in Morichal.

EXPERIMENTAL PROCEDURE

Description of the experiment

The experimental tests were based on the methodology developed by S. Suarez, et al as regards the thermal evaluation of the different insulating mixtures. This method includes the use of two test cells described as qualitative and quantitative.

In the qualitative cell, evaluations of temperature and qualitative behavior profile of the insulating mixtures were performed (solid precipitation, pressure increments in the annular space, times to reach stationary conditions and degradation of the mixtures components).

In the quantitative cell, temperature gradients in stationary conditions were registered in order to determine the equivalent thermal conductivity of the evaluated mixtures.

P. 169
Environmental Aspects Of Gas-Stimulation Experiments Using Nuclear Explosives
Authors: Stead Frank W.
Published: December 2007

Projects Gasbuggy, at 4,200-foot depth, and Rulison, at 8,400 feet, both experiments in low-pressure gas reservoirs, provide significant data on the space-time distribution of radionuclides a present major environmental concern of Government, industry, and the public. Following initial explosion-produced distribution of radionuclides in solid and fluid phases of the reservoir, later transport of radionuclides contained in the fluid phases depends on regional ground-water movement and on gas flow during production tests. production tests. Data from Gasbuggy and Rulison indicate that the major radionuclides in highly mobile fluids, water vapor, and gases, are tritium (T), krypton-85, carbon-14, and argon-37, -39; of these., of principal concern is tritium, distributed about 90 percent as tritiated water (HTO) and 10 percent in natural gas and hydrogen gas (HT). Data also indicate that, except for a transient high-pressure pulse accompanying early-time explosion pulse accompanying early-time explosion effects, the pressure in the cavity-chimney void volume does not exceed ambient reservoir pressure, and is thus insufficient to increase pressure, and is thus insufficient to increase groundwater movement and concurrent transport of radionuclides. Regional ground-water movement is in general uncontrollable and requires full documentation of the geohydrologic environment prior to nuclear explosions to permit prediction of where and under what permit prediction of where and under what conditions ground-water transport of possible hazardous radionuclide concentrations could occur; in contrast, gas flow during production tests with concurrent transport of radionuclides is controllable, in release to the surface environment, to meet concentration levels set by present radiation standards.

Projects Wagon Wheel and Wasp, proposed gas stimulation experiments at depths of about 12,000 feet and at reservoir pressures above hydrostatic equivalent, should provide additional data on effectiveness of fracturing and chimney formation, and on distribution of radionuclides. Possible transport of radionuclides by relatively high-pressure gas drive toward the surface along explosion-produced fractures has been evaluated and seems not a stringent limitation.
Commercial Heavy Oil recovery by Cyclic Steam Stimulation in Kuwait
Authors: Al-Qabandi Salman , Al-Shatti Younis , Gopalakrishnan P.
Published: December 2007

The heavy oil deposit of Kuwait consists of a viscous low API Gravity Crude occurring at shallow depths. The reservoir Temperature is low because of the shallow depths. The areal extent of this deposit is quite large as this is encountered in every well in the entire area, covering several fields.

The Geological age of the deposit is middle Eocene and corresponds to the well Known Asmari Limestone of Iran. The sequence of reservoir stratigraphy from top to bottom can be descrihed as: Cap rock shale which acts as the top of entrapmentUpper tongue of reservoir sandIntermediate shale memberLower tongue of the reservoir sandBottom shale, which is the reservoir boundary.
Casing Window Milling With Abrasive Fluid Jet
Authors: Vestavik O. M. , Fidtje T. H. , Faure A. M.
Published: December 2007

Methods for through tubing re-entry drilling of multilateral wells has a large potential for increasing hydrocarbon production and total recovery. One of the bottle-necks of this technology is initiation of the side-track by milling a window in the casing downhole. A new approach to this problem has been investigated in a joint industry project.

An experimental set-up has been built for milling a 4" window in a 7" steel casing at surface in the laboratory. A specially designed bit developed at RF using abrasive jet cutting technology has been used for the window milling. The bit has an abrasive jet beam which is always directed in the desired side-track direction, even if the bit is rotating uniformly. The bit performs the milling with a combined mechanical and hydraulic jet action.

The method has been successfully demonstrated. The experiments has shown that the window milling can be performed with very low WOB and torque, and that only small side forces are required to perform the operation. Casing milling has been performed without a whipstock, a cement plug has been the only support for the tool. The tests indicate that milling operations can be performed more efficiently with less time and costs than what is required with conventional techniques. However, the method still needs some development of the downhole motor for coiled tubing applications. The method can be used both for milling and drilling giving the advantage of improved rate of penetration, improved bit life and increased horizontal reach. The method is planned to be demonstrated downhole in the near future.
Fracturing Behavior in Soft Layered Formations
Authors: Morales R. H. , Stewart B. R. , Mullen M. E. , Ali S. A. , Norman W. D.
Published: December 2007

An increasing number of tip screenout hydraulic fractures are being performed in the un-consolidated hydrocarbon reservoirs of the Gulf Coast of Mexico and other regions. These sands are often bounded by shales that exhibit higher modulus and higher closure stresses. Because of the modulus and stress contrasts, the fracturing stimulation of layered reservoirs often results in the propagation of several fractures. Each fracture is contained between two bounding shales, and thus, is isolated from the others by the bounding shales. This is in contrast to parallel fractures which may interact with each other. This paper describes the modeling of systems of layered fractures. The technique is demonstrated using a field application in which downhole data is acquired.
Drilling Plastic Formations Using Highly Polished PDC Cutters
Authors: Smith R. H. , Lund J. B. , Anderson M. , Baxter R.
Published: December 2007

Highly plastic and over-pressured formations are troublesome for both roller cone and PDC bits. Thus far, attempts to increase penetration rates in these formations have centered around re-designing the bit or modifying the cutting structure. These efforts have produced only moderate improvements.

This paper presents both laboratory and field data to illustrate the benefits of applying a mirror polished surface to the face of PDC cutters in drilling stressed formations. These cutters are similar to traditional PDC cutters, with the exception of the reflective mirror finish, applied to the diamond table surfaces prior to their installation in the bit.

Results of tests conducted in a single point cutter apparatus and a full-scale drilling simulator will be presented and discussed. Field results will be presented that demonstrate the effectiveness of polished cutters, in both water and oil-based muds. Increases in penetration rates of 300-400% have been observed in the Wilcox formation and other highly pressured shales. Typically, the beneficial effects of polished cutters have been realized at depths greater than 7000 ft, and with mud weights exceeding 12 ppg.
The Evolution of Hydraulic Fracturing in the Almond Formation
Authors: Cramer David D.
Published: December 2007

This study draws from a database of over 600 wells to evaluate reservoir, production and treatment characteristics in the low-permeabil¡ty, naturally-fractured Almond formation. Treatment-induced damage can be significant; damage mechanisms are discussed and ways are shown to mitigate these problems. An effective fracture stimulation design combines proppant scheduling of the late 1970’s with fluid and gel-breaker systems of today.
Drill Pipe Rotation Effects on Frictional Pressure Losses in Slim Annuli
Authors: Hansen Svein A. , Sterri Njål
Published: December 2007

The effect of rotation on the frictional pressure loss in an annulus has been studied experimentally. A direct comparison with results obtained with a 3D CFD (computational fluid dynamics) code has been performed for laminar flow. Experimental results for three fluids are presented. In this paper we will focus on two effects of rotation in a slim hole annulus. The increase in the frictional pressure loss with high rotation rates for low viscosity fluids which is caused by the onset of centrifugal instabilities. The reduction of the frictional pressure loss with rotation for high viscosity shear thinning fluids.
Technical and Economical Feasibility of Coiled Tubing Drilling
Authors: Gary S. C. , Doremus D. M.
Published: December 2007

The technique for evaluating coiled tubing (CT) drilling prospects is described. The technical and economic factors involved are discussed using a flowchart to guide the operator in the decision making process.

In the technical analysis, the parameters limiting the feasibility of using CT for a given drilling project are reviewed. These parameters include CT tension, helical buckling which limits the weight on bit (WOB) and the horizontal reach, CT collapse pressure when drilling underbalanced, CT fatigue, and the usual hydraulic parameters such as annular velocity and pumping pressure.

In today’s business environment, some projects, while technically feasible, may not be economically feasible. In the economic analysis, the competitiveness of each CT drilling application versus conventional solutions is evaluated, and factors such as project duration and equipment use are reviewed.

The equipment normally required for a CT drilling job and the costs associated with mobilizing this equipment are discussed.