bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling Severely Depleted Sands in the Gulf of Mexico: The Benefits of Cloud Point Glycols
Authors: McGill Mike , Seaton Simon , Valenziano Rob , Bruner Scott , Golden John 
Published: December 2007

Abstract
As mature hydrocarbon reservoirs become more depleted, drilling through depleted sands is becoming increasingly common. High levels of overbalance increase the risk of occurrence of lost circulation and / or differential sticking.
Recently, three Gulf of Mexico wells successfully drilled through depleted sands with overbalances ranging from 3500 to 4600 psi In each application, a glycol-enhanced water-based mud (WBM) was used. In this paper, the formulation and application of this specially formulated WBM are discussed and the results documented.
The use of glycols as additives in WBM has been increasingly common in the past several years. Work has focused on certain glycols that exhibit "cloud point" behavior. Although soluble at surface temperatures, under the correct downhole temperatures, these glycols become insoluble and form an emulsion. Dynamic filtration and lubricity data from the laboratory, coupled with field performance from the Gulf of Mexico wells indicate enhanced filtration properties. A theory for understanding the phenomenon in WBM is offered, one which exhibits many similarities to the performance of oil-based and synthetic based muds
Development of an MWD Hole Caliper for Drilling and Formation Evaluation Applications
Authors: Maranuk C. 
Published: December 2007

Abstract
Hole size measurements while drilling are difficult to make because the dynamic environment precludes the use of a truly mechanical device. Several MWD caliper tools, which utilize acoustic technology, are available to the industry but they typically have a limited operating range and are often integrated with other MWD sensors, such as a density or sonic tool.1,2,4
Technical issues which could preclude the use of acoustics for an MWD caliper tool include the noise associated with the downhole drilling environment, tool accuracy, tool reliability, and errors associated with mud attenuation and signal detection, tool eccentering, formation cuttings, gas, etc.
This paper describes the design and testing of a new MWD acoustic caliper tool. The tool has been designed with its own processor, memory, power supply, and surface communications port, so it can be run in a standalone mode or integrated with other MWD sensors. This new sensor utilizes new digital signal processing technology, which increases its accuracy and operating range, when compared to previous MWD acoustic caliper tools.
A Systematic Approach to Developing Engineering Data for Fracturing Poorly Consolidated Formations
Authors: Upchurch E.R. , Montgomery C.T. , Berman B.H. , Rael E.L. 
Published: December 2007

Abstract
This paper presents a methodology for acquiring the engineering data necessary to develop a successful fracture stimulation campaign in a soft unconsolidated formation. This methodology was applied to a zone containing highly laminated sand/shale sequences, in which the sands are unconsolidated and easily damaged. The methodology, however, could be applied to any zone. The zone of interest has historically produced at low rates and contains significant untapped oil reserves. Thus, it is an attractive candidate for fracture stimulation. The success of this new fracture program requires a fundamental understanding of reservoir properties and, necessarily, an efficient method for obtaining those properties. To fulfill such a need a systematic data development procedure was formulated and implemented.
This paper provides the reader with an understanding of the tests conducted the interpretation of the data, the design approach taken, the operational activities, and the resultant well performance.

Introduction
In April 1996, Thums Long Beach Company embarked on a program to fracture stimulate a highly laminated but unconsolidated shale/sand stone sequence. All prior completion and stimulation techniques were unsuccessful in yielding significant oil production from this zone. These unsuccessful completion attempts consisted of various open-hole and cased-hole gravel packing scenarios coupled with non-damaging drilling fluids and post-completion acid stimulations. The unsatisfactory productivity of these completions and the considerable remaining reserves in this zone are the impetus for this fracture stimulation program. The zone of interest is the lower half of the Ranger Zone in the Long Beach Unit of the East Wilmington Field.
The Long Beach Unit of the East Wilmington Field lies under and immediately off the coast of Southern California adjacent to the City of Long Beach (Fig. 1). The productive areas of the field cover 4900 acres (1983 ha). The Wilmington Field was discovered in the 1930's but development of the offshore portion of the East Wilmington Field was not initiated until 1965 with the construction of the Long Beach Unit oil islands.
The Long Beach Unit of the East Wilmington Field is composed of three major producing zones: the Ranger. the Terminal. and the Union-Pacific-Ford. Each is part of a northwest-southeasterly trending anticlinal structure that is highly stratified with interbedded shales and sandstones (Figs. 2 and 3).
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Triptank Levels After Pumping a Slug
Authors: van Wijk J. 
Published: December 2007

Abstract
Pumping a heavy slug is done to allow pulling of "dry" pipe. Pumping the slug minimises the mud loss on the floor and therefore improves mud volume measurements in the triptank. When pulling out of hole (POOH), the triptank volume is expected to decrease with the metal displacement of the pulled tubulars. A computer simulation showed that the triptank volumes do not always correspond to the metal displacement of the pipe when a drill string consists of components with different IDs.
Hydraulic Fracturing of High Productivity Wells in a Tectonically Active Area
Authors: Jackson M.R. , Rylance M. , Acosta L.G. 
Published: December 2007

M.R. Jackson, SPE, M. Rylance, SPE and L.G. Acosta, SPE BP Exploration (Colombia) Ltd

Abstract
The Cusiana and Cupiagua fields are located in the Casanare region of Colombia. Current daily production (June 1997) is of the order of 185,000 stb/d, with production due to increase substantially. The reservoirs are severely compacted quartz arenites, of low porosity but with large pore throats. This makes them extremely vulnerable to formation damage by mud invasion. The extremely high compressive strength of the rock reduces perforation penetration, resulting in high skin factors. The skin factors are rate dependent due to turbulence associated with the high production rates, production of oil below the bubble point (Cusiana) and condensate banking effects (Cupiagua).
The wells are costly to drill, so in order to maximise the production rates hydraulic fracturing has been applied. Post fracture well rates of up to 21 mstbpd have been achieved. At these rates non- Darcy flow in the fractures is extremely important, all the more so as problems with fracture-wellbore communication and the initiation of multiple fractures have been experienced at modest deviations, as a direct result of an extreme contrast between the two principal horizontal stresses. Wide variations in the minimum horizontal stress have also been encountered in this tectonically active area. The high Young's modulus of the rock limits the achievable fracture width and therefore proppant coverage. The paper outlines the progress made to date, and the results achieved in these economically significant but technically challenging fields.

Introduction
The first fracture treatment pumped by BP in Colombia was on a highly damaged exploration well, that succeeded in increasing the production rate from 1.6 mstbpd to 12.5 mstbpd plus associated gas. Following the success of this treatment it was decided to initiate a fracture programme in the Cusiana and Cupiagua fields. These fields tend to have high kh values, and therefore despite high skins can deliver reasonable production rates. However the high drilling costs, in excess of US $ 10 million per well, require high production rates to provide attractive economics. Large diameter tubing strings (usually 5.5"or 7" are run), and the challenge is to complete wells with the potential to deliver ca. 15 – 25 mstbpd.
Various techniques have been tried to overcome the severe formation damage, but to date hydraulic fracturing has proven the most successful method, despite it's associated problems. Results achieved so far are summarised below.
Results achieved to date
As at the end of May 1997 the total number of fracture treatments pumped was 13, namely:
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The Effect of Mixing and Gravitational Segregation Between Natural Gas and Inert Cushion Gas on the Recovery of Gas from Horizontal Storage Aquifers
Authors: Kumar Anil , Kimbler Oscar K. 
Published: December 2007

Abstract
It has been proposed in the literature that certain economies might result from the use of an inert cushion gas, such as flue gas, during the storage of natural gas in aquifers. Where cushion gas is used, two types of displacement occur:
- miscible displacement at the natural gas-cushion gas boundary and
- immiscible displacement at the cushion gas-water interface.
Mixing and gravitational segregation occur during miscible displacement with the result that not all of the stored natural gas can subsequently be recovered. A calculation procedure, which considers the miscible boundary only, has been developed to calculate the recovery efficiency. This is tantamount to assuming that the aquifer water contacts only cushion gas throughout the operation and has no effect on the dynamics of the mixed zone between the natural gas and cushion gas. The calculation procedure was validated by displacements in a horizontal three-dimension radial consolidated sand model utilizing miscible liquids of differing densities. Excellent agreement was found over two complete injection-production cycles. Thus validated in the laboratory, the mathematical model was applied to a hypothetical storage aquifer to investigate the effect on recovery efficiency of several of the more important variables, including aquifer permeability and thickness and the density difference between the gases. The recovery efficiency during the second cycle was greater than the efficiency obtained during the first storage cycle. The per cent of injected gas recovered during a per cent of injected gas recovered during a particular storage cycle should increase with particular storage cycle should increase with the number of years of operation of the storage project.

Introduction
The underground storage of natural gas during the summer months is widely used by the natural gas industry to supplement the increased winter demand in urban areas. Furthermore, it enables pipe lines to be operated at nearly a 100 per cent load factor throughout the year. The increasing scarcity of depleted oil and gas fields has directed attention to the use of aquifers for such storage.
When aquifers are used, gas injected from the surface under sufficient pressure will desaturate the pore space and provide storage for the gas. Ultimately, the water saturation in the gas swept region may approach an irreducible minimum value.
Revitalization of Mara Field
Authors: Carmona R. , Graterol J. , Pina N. , Suarez O. , Lacazette A. , Frost E. , Gomez G. , Quinn T. 
Published: December 2007

Abstract
The Mara field is located onshore on the western side of Lake Maracaibo in Western Venezuela and the PDVSA affiliate, Maraven, S.A., holds the concession rights for the field. The field was discovered in 1951 and has been producing since that time, but has always been considered a marginal prospect at best since its inception. The advent of new technology in seismic, wireline logs and in detection and identification of natural fractures in the reservoirs has now made it possible to revitalize the field's production potential and significantly extend its productive life.
The reservoir rocks are of Cretaceous age, consist of carbonate lithofacies and are partially fractured. The new data and information from modern open hole wireline logs combined with the existing logs from the older wells, cores and production logs and borehole images were utilized to develop updated geological and petrophysical models. These models formed the basis for the Mara field rejuvenation and development plan. The new logs included Nuclear Magnetic Resonance (NMR), acoustic and borehole image logs. The borehole image logs were particularly useful in clearly identifying fracture zones as well as porous intervals that contribute to production. The NMR logs were useful in detecting the movable water zones for exclusion from the production intervals.
Additional core analysis including determination of pore shapes and sizes were used in developing the petrophysical model. Fracture density and orientation were successfully correlated with regional tectonic events to update the geologic model. The production history and recent production logs confirm the validity of these new models.

Introduction
The Mara field of western Venezuela provides an excellent opportunity to assess the impact of modem logging technologies on field development strategies because a large variety of various vintages of logs were collected during the long history of field development. Since discovery of the field in 1951, a variety of logs have been utilized to describe the reservoir and to develop geological, petrophysical, and reservoir models.
Only older E-logs were collected during the first phase of discovery and development although one density and two neutron logs were run in the last wells that were drilled (circa 1980). Suites of porosity, spectral gamma ray, resistivity, production, image, and Nuclear Magnetic Resonance logs have been run since reactivation of the field began in 1995.
The modern log information proved critical for developing updated geological and petrophysical models in this complex and highly variable carbonate reservoir. These models have improved the success and production rates of new wells, and provide a rational for future development of the field.
Use of a Computer to Predict the Results of an Explosive Stimulation in Oil and Gas Wells,
Authors: Laspe Charles G. 
Published: December 2007

Abstract
Economic application of the Talley-Frac method for the stimulation of production from oil and gas wells, production from oil and gas wells, requires careful engineering analysis of each application. A feasibility study should be made on each candidate well to determine the technical efficacy of such a treatment and to arrive at the optimum amount of explosive slurry to be loaded. This optimum should be synonymous which the greatest rate of return upon the well-stimulation dollar. Since the answer to the above questions involves an extensive amount of computation in their evaluation, automation of this evaluation by means of a digital electronic computer can extend the base of applicability. DATAFRAC is such a computer program written in FORTRAN IV language, and is capable of being run either on time-shared computers or in the batch mode on computers running in this environment. In just a few seconds, a complete economic feasibility study is performed which will determine whether or not a given well is a good candidate for explosive fracturing and the optimum amount of explosive to load in case the answer is in the affirmative.

Introduction
The technical and economic feasibility of using the TALLEY-FRAC explosive method for stimulation of the production of oil and gas wells can now be established using a recently developed computer program.
Delivery Prediction for Scheduling Operations
Authors: Hanson Donald H. , Root J. Paul 
Published: December 2007

Abstract
This paper describes an adaptive process which could be applied to the process which could be applied to the problem of delivery scheduling from gas problem of delivery scheduling from gas storage fields. Conceptually, the general problem is viewed as one of operating a system to fulfill specified requirements. A specific example is that of scheduling withdrawals from gas storage fields according to a forecasted schedule based on forecasted demand and peak day requirements. Interruptions peak day requirements. Interruptions or alterations in the planned schedule require an operating response and a technique for determining the optimum response. This paper presents a method that can serve as a tool applicable to the delivery prediction aspect of the scheduling problem.

Introduction
The control of systems through adaptive control process methods is gaining in scope and application. A synthesis of computer and mathematics has evolved heuristic techniques which permit the "law" governing the permit the "law" governing the optimization of a system to be abstracted. Applications include continental air defense, automobile traffic control, airline traffic control, fire control and long range missile control.
In order to optimize a system, a function must be developed which can be maximized or minimized in accordance with an objective. This function can include two classes of parameters. one class describes the dynamics of a physical system. The other class can be physical system. The other class can be considered external to the system but capable of influencing it.
Of particular interest to reservoir engineers is the problem of scheduling offtakes from a number of gas storage fields. In this case the external parameters are the demand schedule and the parameters are the demand schedule and the peak day requirement. peak day requirement.
Design and Implementation of a 22,600 ft Underbalanced Coiled Tubing Scale Cleanout in the Gomez Field, Pecos County, Texas
Authors: Adams L.S. , Overstreet C.C. 
Published: December 2007

Abstract
This paper reviews the design, implementation, and results of a 22,611 ft underbalanced coiled tubing scale cleanout project for the wellbore of the Fort Stockton Gas Unit 5–1. The Fort Stockton Gas Unit 5-1 is a deep, low pressure, high temperature, Gomez (Ellenburger) Field gas well.
Ellenburger formation is a fractured dolomite of Ordovician age. The formation has an average gross thickness of 1,600 ft with an average reservoir temperature of 335 F.
No remedial operations have been performed on the FSGU 5-1 since its completion in March 1970 (Figure 2). In July 1993, during bottomhole pressure data acquisition, an obstruction was tagged at 21,164 ft from surface. An attempt using a 1.5 in. bailer deployed on slickline was unsuccessful in obtaining any type of sample. However, on the basis of offset well data, an assumption was made that scale with major physical characteristics of calcium carbonate and iron oxide was causing the restriction. In August 1993, the well was acidized for the first time since initial completion with no effect to its production characteristics. Because the FSGU 5-1 was considered a prolific producer relative to offset production, it was determined to remain risk adverse and not attempt any further remedial activity.

Introduction
The recent development of reliable 100,000 psi minimum yield strength coiled tubing has provided an economic avenue for performing deep underbalanced workover operations. Coiled tubing technology can provide significant economic and technical enabling qualities versus conventional workover methodology.
Major areas of impact are, lower transportation cost, reduced rigup & teardown expense, less logistical coordination, reduced trip time of tubulars, elimination of kill fluids, reduction/elimination of reservoir damage, and elimination/reduction of safety hazards.
The Fort Stockton Gas Unit No. 5–1 (FSGU 5–1) produces from the Gomez (Ellenburger) Field located in the Delaware Basin on the southwest flank of the Central Basin platform (Figure 1). Development of the Gomez (Ellenburger) Field was initiated in 1963. The Average daily production from the FSGU 5–1 was 4.7 MMcf/D during the first quarter of 1996 with 900 psig well head backpressure Based on a detailed nodal analysis simulation study performed in August 1996 on the well, wellhead compression was installed reducing wellhead backpressure from 900 psig to 500 psig. Although a 1.6 MMcf/D production increase was realized from this compression project, the nodal analysis simulation study indicated the well's production could still be optimized by approximately 2.0 MMcf/D.
Based on offset well information, a 94% soluble scale interval beginning at 21,164 ft from surface existed and was restricting the well's inflow performance. From historic data, the probability that a surface acid treatment contacting enough scale surface area to dissolve it was minimal.
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Business Analysis – A Hotbed for Strategy Ideas
Authors: Menghini Paul , Stang Roy 
Published: December 2007

Abstract
The rapidly changing business environment of the 1990's forced the oil and gas industry to develop new corporate and regional strategies to remain competitive. In support of strategy development, much attention has been given to analytical tools such as decision and risk analysis and probabilistic modeling What is often overlooked, however, is that for these tools to be effective, a solid foundation of information and a thorough understanding of the underlying business environment is required. The process of Business Analysis provides this understanding and serves as a "hotbed" for new strategic ideas.
This paper presents several business analysis tools which enhance awareness of the business environment and provide the foundation of information necessary for sound strategic modeling. Examples from a recent study show how tools such as influence diagrams, value chain analysis, benchmarking, competitor analysis, scenario development, and strength and weakness analysis are used.