bluuebunny/crossref_metadata_2025_split huggingface dataset:
Case Studies of Horizontal Well Design and Production Forecast
Authors: Wang Ben , Markitell B. N. , Huang W. S. 
Published: December 2007

ABSTRACT
This paper presents the observed and predicted performance of horizontal wells in four fields: (1) heavy oil reservoir - to increase productivity and reduce gas coning, (2) thin oil column with gas cap and bottom water - to minimize gas and water coning, (3) waterflood in a tight oil sandstone reservoir - to increase injectivity /productivity, areal sweep efficiency, and improve pressure maintenance (4) gas reservoir with bottom water - to increase productivity and minimize water coning.
A special program, named "HVWELL", was used in these studies to predict horizontal and vertical well production performance. HVWELL requires minimal reservoir and fluid information to create a complete input dataset for running a finite difference simulator. It is equipped with a unique automatic grid set-up option to create correct grid geometry to model various horizontal well lengths and well locations. The geometries relate to GOC/WOC, and hydraulic fractures perpendicular to the horizontal wellbore. The options can greatly minimize the input errors and reduce grid requirements by simulating a symmetrical element instead of a full pattern. HVWELL not only calculates well productivities, but also predicts 3-D, 3-P coning behavior for either vertical or horizontal wells. Short summary and graphical outputs are automatically generated for each run.
The horizontal well design and production predictions using HVWELL will be discussed in detail, and compared to field data for each case.
Horizontal Well Design in Wafra Field, Ratawi Oolite Reservoir
Authors: Menouar Habib , Huang W. S. 
Published: December 2007

Abstract
This paper presents the selection and design procedures for a side-tracked horizontal well in this semi-depleted reservoir. A commercially available black oil simulator was modified to account for the horizontal well simulation. After the pressure and production history match of the 40-year period, horizontal well production forecast was made.
Different horizontal well lengths, positions and bottomhole flowing pressures were used to study the production performance. Production rates, cumulative oil production and water oil ratios are resulting parameters in selecting the most suitable scenarios for decreasing pressure drawdown, and possibly improving the recoverable reserves.
Results indicate that: A 2000-foot horizontal well completed in the upper layers with maximum stand off from the water-oil contact would produce almost seven times more cumulative oil in 5 years than the vertical well in the same location. The potential starting oil production rate of this horizontal well is eight times that of the vertical well; in actual operation, we would limit pump sizes to produce the oil at less than the maximum capacity calculated.A 2000-foot horizontal well completed in the zone closer to the oil-water contact would lead to less oil and more water production.When the length of the horizontal well is increased to 3000 feet, the five-year cumulative oil production is increased by 15%, and more importantly, the cumulative water production amounts to only one quarter of that of the 2000-foot case. This is the recommended case for drilling a horizontal side track for this well.
Southern Arabian Basin Oil Habitat: Seals and Gathering Areas
Authors: Pierce W. H. 
Published: December 2007

Abstract
This regional investigation contributes to the understanding of the influence and relationship of gathering areas and seals to oil habitat in the Arabian Basin. Cross plots and cumulative frequency distribution plots characterize the hydrocarbon habitat and lead to the following inferences. Gathering or fetch area size and contemporaneous peak oil generation rank as important factors in the accumulation of giant Middle East oil reserves. The importance of excellent seals to Middle East oil abundance should be moderated by recognition of widespread peak oil generation to seal effectiveness.
The highest frequency of fields with several stacked reservoirs occurs in areas of modem peak source rock generation. Thin seals can be effective. Gross seal lithology is not as important as previously thought. Vertical migration through seals is an important process. Seals leak but are effective. Cross plots of original oil in place versus field gathering area identify areas of rich/thick source rock or sweet spots. Inefficiencies resulting from long distance migration are not apparent.
Sweetness map analysis, using gathering areas with assigned oil-in-place values, results in an inferred source rock distribution that contrasts with published source rock distributions.
Abqaiq Hajifa Reservoir: Geologic Attributes Controlling Hydrocarbon Production and Water Injection
Authors: Grover G. A. 
Published: December 2007

ABSTRACT
The Hanifa reservoir at Abqaiq Field consists entirely of mud-supported limestones that lack megascopic pore spaces. Porosity in the Hanifa reservoir is in the form of micropore spaces, spaces ≤10 microns in size. Microporosity is evidenced by high porosities (5-32%) within these fine-grained rocks based on porosity logs and coreplug analyses, absence of any visible porosity (even in thin sections) to account for the high pore volumes, and 2000X SEM images that show a crystal framework texture composed of microrhombic (day-size) caldte crystals with 2-5 micron size pore spaces between caldte crystals. The microporosity is considered to reflect retention of primary intercrystalline spaces within the precursor lime mud sediment, and with little introduction of allochthonous caldte to ocdude pore spaces.
Flow meters indicate that the reservoir is capable of produdng/injecting large volumes of oil/water, but with no stratigraphic predictability to the flow, and that thin (2-10 ft) low porosity (&lt;15%) intervals can contribute over 60% of the entire flow. These reservoir attributes, coupled with the low "matrix" permeabilities (0.1-10 md) of the reservoir indicate the presence of an apparent permeability that is controlling fluid flow. Core studies revealed that this apparent permeability is in the form of high angle fractures. The fractures are ≤ 1 mm wide, contain hydrocarbon residue and caldte cement, and many are in dose assodation with high amplitude stylolites, suggesting a genetic link between stylolitization and fracturing. Bore hole imaging log data is providing value insight into fradure location, abundance, orientation, and size in non-cored wells.
The Hanifa is separated from the giant Arab-D reservoir by over 450 feet of fine-grained and impermeable carbonates of the Jubaila Formation. However, these two reservoirs are in pressure-fluid communication via a network of fractures through the Jubaila carbonates. This reservoir communication together with the reservoir heterogeneity of the Hanifa, in the form of micropores and assodated fractures, provides a challenge for reservoir geology and reservoir engineering to formulate a development plan, involving horizontal producers, to mitigate reservoir communication and to effidently and effectively extract the reserves within the Abqaiq Hanifa reservoir.
Implication of Wrench Tectonics on Hydrocarbon Reservoirs, Abu Dhabi, U.A.E.
Authors: Marzouk I. M. , Sattar M. A. 
Published: December 2007

ABSTRACT
Wrenching is one of the main tectonic styles that affected East Arabia during the Geologic history.
Primary and secondary Wrench related structures were identified at several localities in Abu Dhabi.
Shape, orientation and size of several oil and gas fields are mainly controlled by primary Wrench Tectonics.
Secondary Wrench related structures i.e. strike-slip faults, dip-slip faults, associated fracture systems and other deformations have significant impact on hydrocarbon reservoirs in Abu Dhabi.
Examples of these implication are: -Enhanced reservoir quality at predictable trends.-Directional permeability and early water breakthrough.-Hydraulic communication between separate reservoirs and production/injection problems.-Reservoir discontinuity and development problems.
Practical field examples from Abu Dhabi oil and gas fields were discussed.
Reservoir Characterization Integrating Borehole Imagery and Conventional Core Data, Unayzah Fm., Hawtah Field, Central Saudi Arabia
Authors: Heine C. J. 
Published: December 2007

ABSTRACT
The use of borehole imagery along with core data has significantly improved the reservoir mapping within the Hawtah Field. Borehole imagery provides an azimuthal direction to the core based depositional model. Net sand isopach maps contoured using the oriented geologic model provide a quality set of maps suitable for geologic modelling and ultimately reservoir simulation. When core is absent, borehole imagery can be used to help identify the lithofacies present, particularly in fields where several wells have both conventional core and borehole image data. The accurate tying of core porosity and permeability back to logs has always been an educated guess, especially when there is less than 100% core recovery. The recognition of sedimentary structures and textures on borehole images add confidence to the log-core correlation and porosity-permeability adjustments to logs.
Turnkey Drilling in Lekhwair
Authors: Oude Essink W. H. , Wijsbeek H. J. , de Lange J. L. 
Published: December 2007

ABSTRACT
In 1990 PDO awarded the world1! biggest Turnkey Drilling Contract with a scope of work for 112 wells for the development of the Lekhwair field. An option to drill an additional 56 wells was included.
This paper gives an overview of the strategy and objectives that led to the award of this Turnkey Contract.
The Lekhwair Turnkey Contract, which covers a large number of wells, was supported by the preparatory work of a Multi-Discipline task force. The team, consisted of staff from Drilling Engineering, Production Engineering as well as Petroleum Engineering. The main issues addressed by the task force were: to agree on the well designs in relation to the field development concept and to formulate the basic input for the scope of work for a Turnkey type Drilling Contract
The paper discusses the Management principles for Turnkey Drilling Operations whereby the focus is given to Management of the Turnkey Contract, Quality of the Product, Health, Safety and Environment (HSE) issues and the Performance of the Turnkey Contractor.
Finally a summary of learning points, including innovations in the rig design as well as the novel approach to the management of subcontractors in this Turnkey concept are presented.
2D and 3D Well Planning for Horizontal Wells
Authors: Kikuchi Shuichi 
Published: December 2007

ABSTRACT
Horizontal well planning involves so many factors and constraints such as target, kick-off or sidetracking point, build-up rate, reservoir formation dip in horizontal section, etc. Each of them must be considered separately. A specific well course planning is the key to drill horizontal well successfully as well as optimizing the directional tools and procedures. As a result, it leads to improve the drilling efficiency significantly and minimize the overall cost for horizontal drilling. However, the process of using an analytical approach in developing and finalizing the plan is time consuming. Therefore, it is vital to make use of a computer model for faster and easier process. For this purpose, '2D' and one of '3D' models with geological data base have been developed and their integrity has been confirmed by bench mark tests. A unique feature of these models is that they can produce not only a well profile but also supplemental requirements, i.e., the estimation of intersection with a certain single or multi-dip formation, the vertical distance between well course and reservoir formation top in horizontal section and casing setting depths. This paper describes theoretical equations adopted for the in-house computer models and presents the results obtained using planned well data.
Log Determination of Residual Oil Saturation in the Mauddud Zone, Bahrain Field
Authors: Wolff Martin , Al-Jalahma A. M. , Hook P. F. 
Published: December 2007

ABSTRACT
Sixty years of crestal gas injection in the Mauddud zone of the Bahrain field has been instrumental in maintaining reservoir pressures and preventing water encroachment. Oil drainage from the gas cap has been a very successful and efficient means of oil recovery. Determining an accurate residual oil saturation in the gas cap is vital for refining reserves estimates and calculating EOR targets.
Various methods for this determination have been used in the past and are being used now including open-hole log evaluation, capillary pressure data, relative permeability data, and cased-hole log evaluation. This paper presents the first application in this reservoir of new- generation pulsed neutron capture logging tools with sufficient accuracy to allow quantitative determination of oil saturations in the gas cap. Results of a multi-well study are presented including a statistical analysis of measurement and interpretation parameter errors.
An Integrated Approach to Production Log Interpretation
Authors: Catala G.N. , Torre A.J. , Theron B.E. 
Published: December 2007

Abstract
The classical practice in quantitative production log interpretation involves the use of the tandem flow and density measurements. The usual companion logs such as temperature and pressure are traditionally only exploited qualitatively and for the determination of insitu fluid properties.
This paper presents a scheme and its associated algorithms that handles all available measurements. It is flexible enough to accommodate non traditional and upcoming sensors. Such capabilities are needed in light of the complexities associated to multiphase fluid flow in deviated wells.
The method is based in a process which seeks to reconstruct all available measurements. It uses an iterative procedure which at each step assumes the solution, i.e., the individual phase flow rates. The algorithm uses a minimization technique aimed at obtaining a minimum difference between the theoretical sensor responses and the measured log responses. The resulting output is a flow profile versus depth of the individual liquid and gas phases. This method has been successfully applied worldwide and in particular in the Middle East.
To illustrate the capabilities of the method, four Middle East examples are presented in this paper. The first example shows how the temperature sensor can compensate the hampered spinner measurement due to the high deviation of the well. The second one demonstrate the integration of standard production logging sensors in a three-phasic case. The third example shows the use of a non-traditional measurement, Water Flow Log (WFL*), in a three phase flow situation. The last one, also a triphasic case, includes a tracer ejector and a capacitance meter in addition to the standard string.

Introduction
Production logging is intended primarily for measuring the performance of producing and injecting wells. It provides diagnostic information, pinpoints where fluids such as water, oil and gas are entering a well, and gives an indication of the efficiency of perforations.
In vertical wells, where there are relatively high flow rates and one or two fluid phases, traditional production logging analysis produces reliable results. However, if spinner readings are unavailable or suspect, the logging analysis can be severely hampered. In such cases, the fluid flows from various intervals cannot be quantified. This could happen in low-flowing or highly deviated wells.
Figure 1 shows a typical production log where the spinner measurements have been severely affected by three adverse conditions -low flow rate, highly viscous fluid and high deviation.
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Partnering Creates Network for Continuous Improvement
Authors: Prehoda G. D. , Bowman M. D. , Porterfield N. L. , Greenwalt W. R. 
Published: December 2007

Abstract
Drilling/completion procedures and well productivity are always the major concerns in any oil company. The enhancement of these concerns led to the partnering of operator/service company personnel. Partnering, alliances, and integrated services have become effective methods in the nineties for creating the network necessary to implement total quality management in our industry. This paper presents a one-year analysis of the objectives, results, improvement process, and technical advances made through a team effort (major operator/multi-functional service company) utilizing an in-house engineer. To increase value received from the investment was the objective measured by the partnership. Enhanced communication and technology applications compressed the vision which prompted the placement of a service company engineer directly in the operator's office. A complete line of service company computer design and evaluation software and required hardware were installed. The in-house engineer became a full team member within the operator's organization and complete integration of the two companies began on a daily basis.
Primary/remedial cementing, stimulation, gravel pack, and tool design are all services that have been impacted by this partnership. New techniques were jointly developed along with detailed procedures to help the field perform successful treatments. Well-productivity increases were another direct benefit. Productivity-versus-cost ratio was improved as over-expenditures decreased. The handling of multi-service responsibilities became centered under one person. The inhouse engineer concept allowed a quick and accessible response to areas needing immediate attention. The infusion of both companies' technology, methods and creativity generated cost saving ideas, procedures, new equipment designs, as well as stronger emphasis on the evaluation process. Design, execution and evaluation reports were completed on all wells, setting up the criteria to begin the benchmarking of results and the subsequent tracking for improvement comparison on future wells. The paper addresses how each of the processes helped create the network for continuous improvement.
CaO- and/or MgO-Swelling Cements: A Key for Providing a Better Annular Sealing?
Authors: Ghofrani Reza , Plack Heiko 
Published: December 2007

Abstract
The use of expanding cements for improving the sealing efficacy of annulus cementing has been considered for a long time as a possible solution to existing problems. In this paper, the processes of volumetric shrinkage of cements due to hydration as well as the effective mechanisms of CaO and MgO swelling cements are explained. Preliminary results of the current investigations at ITE for testing cement systems of this kind for application in the borehole are presented. The expansion of the cement matrix has been determined with the use of atmospheric and HPHT expansion cells specially developed for this purpose. Further parameters under investigation include the permeability of the system comprising the cement and steel pipe as well as the strength properties.
Formation of voluminous Ca(OH)2 and Mg(OH)2 crystals on the surfaces of the cement particles resulted in matrix expansion by more than 10 percent, even under a hydrostatic pressure of 120 MPa and at borehole temperatures up to 175°C. The swelling cements under investigation exhibited especially high shear bond strength. The test results hitherto obtained already indicate that the sealing action of annulus cementing can be improved with CaO swelling cements when employed preferentially in storage wells with BHST up to 70°C, and with MgO swelling cements in deep gas wells with BHST up to 175 °C.
Solved Problems of High-Density and High-Temperature Drilling Fluid in an Environmentally Sensitive Area
Authors: Cesaroni Renzo , Repetti Umberto 
Published: December 2007

Abstract
A new approach was taken to develop drilling fluid systems which were applied on the Villafortuna/Trecate Oilfield in the Po Valley.
The necessity to provide adequate environmental protection and at the same time facilitate optimum drilling performance is described. Hell conditions require drilling fluids of high density which are stable to high temperatures. At the same time, the drilling sites were located in the environmentally sensitive Ticino River National Park.
Although the usage of oil base fluids in 1983, at the beginning of production drilling operations, would have allowed for satisfactory well conditions throughout the program, it was decided to pursue the usage of water base fluids that would ensure better drilling performance and the minimum of environmental risk, leaving oil base mud only for directional drilling.
The fluid systems that were ultimately used were based upon both field and laboratory experience. The paper outlines the rationale of how this experience was applied and relates field results to the approach taken.
The technology that is discussed in the paper describes the water base fluid that was eventually used, the solids control equipment and the actions taken to operate in accordance with the environmentally protective approach.
Mechanism for Wellbore Stabilization With Lime-Based Muds
Authors: Hale A. H. , Mody F. K. 
Published: December 2007

ABSTRACTThe lime-based mud was one of the earliest drilling fluids developed. It has been utilized not only when drilling CO2-containing formations and other potentially harmful contaminants but also for borehole stability. Data are shown which support a fundamental mechanism whereby lime impacts borehole (in)stability. The data demonstrate specific alterations in rock strength and chemistry as a function of drilling fluid composition. Hot rolling dispersion tests and triaxial compressive tests show that shales, treated with a variety of lime-based combinations, harden with time and temperature. These changes in rock strength occur concurrently with changes in cation exchange capacity, composition, and water reactivity of the shale. These results suggest that changes in rock strength are related to the changes in mineral composition. The data indicate that lime-based systems not only can be formulated to minimize the amount of borehole instability but in fact actively stabilize the hole.
Advanced Influx Analysis Gives More Information Following a Kick
Authors: Billingham John , Thompson Martin , White D. B. 
Published: December 2007

ABSTRACT
We present an efficient, new procedure for characterising a kick by analysing changes in surface pressures, surface mud flow rates and pit level. This procedure allows us to determine, faster and more reliably than is possible with conventional methods: the times when the influx started and stopped, the formation pressure, the influx type (even for a horizontal well), the formation permeability and the maximum casing shoe pressure. The performance of this procedure has been tested using data from both a gas kick simulator and a series of controlled experiments in a 4500 ft test well. We present examples of our results, which show good agreement between predictions and observations. This analysis has been implemented in a rig based monitoring system, [1].