bluuebunny/crossref_metadata_2025_split huggingface dataset:
Through-Casing Reservoir Evaluation Using Gamma Ray Spectroscopy
Authors: North R. J. 
Published: December 2007

ABSTRACT
Induced gamma ray spectroscopy has proved to be a valuable tool for through-casing reservoir evaluations in California. The data have provided reliable fluid saturations and lithology information under a variety of conditions. This paper examines several applications of these measurements. Environmental considerations and logging limitations are discussed. The cased hole answers are compared with openhole logging measurements, core data, and production results.
Detection and Control of Hydraulic Fractures in Water Injection Wells
Authors: Holzhausen G. R. , Egan H. N. 
Published: December 2007

ABSTRACTHigh- and low-frequency pressure analysis, tiltmeter surveys and passive borehole seismic measurements comprise a powerful set of tools for detection and tracking of induced fractures in water disposal wells. Used singly or in combination, these methods provide the capability for continuous monitoring of subsurface fracture behavior during injection.
Use of Scrubber Waste as an Oxygen Scavenger in Thermal Water Plant Operations
Authors: Williams R. L. , Harris A. 
Published: December 2007

ABSTRACT
For the past eighteen months, Santa Fe Energy has successfully used sodium sulfite from scrubber waste as an oxygen scavenger in a 15,000 BWPD water plant in the Midway-Sunset Field. In using scrubber effluent as an oxygen scavenger, Santa Fe Energy has realized a $600/day cost savings from a reduction in chemical purchases for sodium sulfite (oxygen scavenger), scrubber effluent disposal costs, and vacuum truck charges, and an improvement in steam generator feedwater quality.
Commercial soda ash (sodium carbonate Na2CO3) is used in the scrubbing process to remove combustion by-products during steam generation. Sulfur dioxide is the primary target of this scrubbing process, and is generated when fuel oil with high (1–2% sulfur) content is burned in the generators. The spent scrubber effluent contains between 2.3–5.5% sodium sulfite and sodium bisulfite, which can be used for oxygen scavenging in boiler feedwaters. Between 1 to 2 barrels of scrubber effluent per 1,000 bbls of water are required to remove the 4 ppm of oxygen found in Santa Fe Energy's purchased water supply and provide a 30 ppm sodium sulfite residual from the water plant.
Details concerning the equipment used, installation costs, trial test, subsequent operating parameters and cost savings are provided in the discussion. Similar systems are being installed in other Santa Fe Energy water plants in the valley. Use of scrubber liquor to trim oxygen scavenging chemical consumption in our produced water systems is under evaluation.
An Experimental Investigation of Gas-Bubble Breakup in Constricted Square Capillaries
Authors: Gauglitz P. A. , St. Laurent C. M. , Radke C. J. 
Published: December 2007

ABSTRACT
Recent advances in enhanced oil recovery involve generating foam within underground porous media to displace the oil. We investigate experimentally the important snap-off mechanism of gas-bubble generation in constricted square capillaries. Sixteen mm movies record the snap-off of smaller bubbles from a larger bubble as it moves through the constriction. The time required for bubbles to snap off once they move past the constriction, and the length of the generated bubbles are obtained from viewing the movie frames. The bubble capillary number, μUT/σ, is varied from 10−5 to 5 (10−3) by adjusting the wetting fluid viscosity, μ, and the surface tension, σ, by the addition of aqueous surfactants to mixtures of glycerol and water, and by altering the bubble velocity, UT.
Results show that a dimensionless time to snap-off depends weakly on the capillary number, and that the generated bubble size increases almost linearly with increasing capillary number. Surfactants create dynamically immobile interfaces for surfactant solutions of 1 wt% sodium dodecyl benzene sulfonate (SDBS) and Chevron Chaser SD1000. Compared to the surfactant-free solutions, the time to breakup with surfactants increases by a factor of about three; generated bubble length increases by at most a factor of three.
Physical and Chemical Effects of an Oil Phase on the Propagation of Foam in Porous Media
Authors: Jensen J. A. , Friedmann F. 
Published: December 2007

ABSTRACT
Laboratory experiments were performed to determine the effects of a residual oil phase to hot nitrogen flood on the propagation of surfactant foam in Berea sandstone rocks. Static phase behavior-type tests were performed in support of the displacement tests. In the static experiments, surfactant partitioning into the oil phase and thermal degradation losses were measured. The chemical and physical properties of the oil phase were varied by the employment of four crude oil and two synthetic oil samples. The chemical properties of the surfactant phase were varied by the employment of three different foaming sulfonate surfactants. Each oil was analyzed for composition and physical and interfacial properties were measured. The effect of the presence of an oil phase on foam propagation was found to be strongly surfactant-specific. Implications of the results on the mechanisms controlling oil production in reservoirs containing steam override zones and channels are discussed.
Salt Cements for Improved hydraulic Isolation and Reduced Gas Channeling
Authors: Lewis W. J. , Rang C. L. 
Published: December 2007

ABSTRACT
Inflows of gas into the primary cement slurry column of wells in the Ten Section field of Kern County have severely damaged the cement integrity. An inexpensive cement slurry and process design has been implemented that minimizes gas flows into the cement and eliminates the need of expensive remedial squeeze work.
Transient Pressure Behavior of Multiple-Fractured Gas Wells
Authors: Choo Y. K. , Wu C. H. 
Published: December 2007

ABSTRACT
Virtually all studies on transient pressure behavior of fractured gas wells assumed a single fracture of equal half-length emanating from the opposite sides of the wellbore. However, multiple fractures may result from explosive, tailored-pulse fracturing, and hydraulic fracturing treatments. This paper presents the results of using a polar-coordinate simulator to investigate the transient pressure behavior of gas wells with 4-wing, 6-wing, and 8-wing multiple fractures.
Results show that the dimensionless pressure, PwD, can be correlated with the dimensionless terms Cr = wkf/πkxf and xfrl2 = xf1/xf2 where Cr is the dimensionless fracture conductivity and Xfr12 is the fracture half-length ratio. The symbols, xf1 and xf2, represent the half-length of the primary fracture and the auxiliary fracture, respectively. Results also show that when Cr ≤ 10, multiple fracture transient pressure behavior is significantly different from that of a single-plane fracture.
A family of type curves was constructed using cross-plots of pwD vs. tDxf. Transient pressure data can be analyzed using these type curves to estimate the number of multiple fractures in addition to formation permeability, fracture length, and fracture conductivity. Errors of about 5% in fracture length and 28% in formation permeability could result from the use of singlefracture type curves.
Low-Permeability Reservoirs Development Using Horizontal Wells
Authors: Giger F. M. 
Published: December 2007

ABSTRACT
In recent years, horizontal wells have played an increasing role as alternate production tools to vertical or slanted wells. Do they provide anything new to exploitation strategies for low permeability reservoirs ?
In this paper, we will contribute to answering this question by presenting results of analytical derivations pertaining to cases favorable to development with horizontal wells.
The effects of anisotropy related to shaly interbedding and natural fissuring will be discussed. The solutions and criteria are derived independently from the nature of the drive mechanisms because of their strong influence on the production profile of horizontal wells.
As some basic concepts usually applied in classical reservoir engineering to production with vertical wells have to be drastically re-evaluated when dealing with horizontal wells, the economic assessment of their spudding must be evaluated with new criteria. The new criteria, such as areal productivity and replacement ratio of vertical wells by horizontal wells, are introduced in order to help the decision-maker responsible for the exploitation of a low permeability reservoir.
The chief technical contributions of the paper are: –Criteria for comparing horizontal and vertical well productive efficiency.–Spatial depletion profiles around the horizontal well.–Areal productivity index and replacement ratio equations.
Devonian Shale Horizontal Well: Rationale for Wellsite Selection and Well Design
Authors: Yost A. B. , Overbey W. K. , Salamy S. P. , Okoye C. O. , Saradji B. S. 
Published: December 2007

ABSTRACT
This paper discusses the rationale for selection of a well site where geologic and reservoir conditions are favorable for a horizontal well to increase gas recovery efficiency over that of vertical wells. In this effort, an area of favorable geology was selected and a multi-site reservoir evaluation study was conducted to determine an appropriate location for a long horizontal wellbore in the Devonian shale in southwestern West Virginia. Within a candidate reservoir, existing wells and their suspected directional properties were analyzed to develop the best candidates for location of the horizontal well. Reservoir data from over 38 wells in the area were used to establish areas of high flow capacity. A 3-dimensional gas flow simulator capable of modeling both fracture and matrix porosity and permeability and desorption were used to investigate both the adjacent well interference and production performance of a 2,000-foot horizontal wellbore. Final well location selection was based on minimum interference, high expected recovery efficiency, and reasonable access in rugged terrain.
Once site selection was completed, a well-planned drilling approach was developed based on a complete review of horizontal well drilling technology with particular emphasis on methods to directionally drill on air or air/mist to intersect the inherent fracture system (based on regional mapping trends), horizontal coring for natural fracture spacing, and multiple hydraulic fracturing horizontal boreholes through cemented casing. The lessons learned in this effort are that horizontal wells can be achieved in naturally fractured formations, but good reservoir studies are required to increase the probability of success in achieving noteworthy production.
Long-Term Performance of Proppants Under Simulated Reservoir Conditions
Authors: Much M. G. , Penny G. S. 
Published: December 2007

ABSTRACT
The insitu performance of two classes of commonly used fracture proppants has been evaluated in the laboratory. Identification of the effects of time and stress on fracture proppants was determined and further, the effects of embedment and gel damage under downhole conditions was evaluated. Accurate fracture proppant parameters are now available.
Successful Field Application of High-Temperature Rheology of CO2 Foam Fracturing Fluids
Authors: Phillips A. M. , Couchman D. D. , Wilke J. G. 
Published: December 2007

ABSTRACT
High temperature rheology of carbon dioxide foam fracturing fluids has been developed in the laboratory and successfully applied to improve the design of foam fracturing treatments of tight gas sands.
In the laboratory phase of the project, carbon dioxide foam properties were measured to 250°F (121°C) in a high temperature, high pressure pipe viscometer. The effects of foamer type and concentration on high temperature carbon dioxide foam rheology were determined. It was found that, above a certain level, further increases in foamer concentration provide little corresponding increase in foam stability or rheology. Carbon dioxide foam stability can be improved by the use of higher concentrations of gelling agent.
Test data indicates that higher concentrations of foamer and gellant are required to produce stable carbon dioxide foams, as compared to nitrogen foams. It was found that rheological data generated for nitrogen foams will not be sufficient to describe the same system when pumped as a carbon dioxide foam, as had been previously assumed.
Historically, foam fracturing design and fluid composition (gellant and foamer) have been based on rules of thumb and common area practice. The laboratory generated foam rheology and stability data were used to modify fracturing design and fluid composition. These design changes have resulted in more successful carbon dioxide foam stimulation treatments and have drastically reduced screen-outs. Examples of successful treatments utilizing the new design data will be compared and contrasted with historic treatments in several tight gas sands.
Examination of Potential Mechanisms Responsible for the High Treatment Pressures Observed During Stimulation of Coalbed Reservoirs
Authors: Jones A. H. , Bell G. J. , Morales R. H. , Schraufnagel R. A. 
Published: December 2007

ABSTRACT
Treatment pressures observed during hydraulic fracturing of coal seams are often different than for conventional formations. In particular, there is usually an early, steep pressure rise and overall treatment pressures often exceed the lithostatic pressure, but produce surprisingly little vertical fracture extension. In addition, instantaneous shut-in pressures are high following a fracture treatment, while closure pressures after treatment are in good agreement with in-situ stresses determined prior to initiating hydraulic fracture stimulation. These responses cannot be explained by conventional modeling approaches. On the other hand, there are cases for coal treatments where pressures remain at levels comparable to other formations.
An investigation into the physical causes of the unusual behavior of coal seam stimulations resulted in the identification of a new physical mechanism for further consideration. The accumulation of coal chips at the wellbore and partial plugging of an advancing fracture tip by coal fines carried ahead of or within the fluid treatment pad are mechanisms which consistently explain all of the observed behavior.
Hydraulic fracture design codes, which include the description of the coal fines accumulation at the fracture periphery, were used to assist in the design of hydraulic fracture treatments at the Gas Research Institute, Multiple Coal Seam Field Project, at Rock Creek in Alabama, and were used to analyze the actual treatments.
On the Stimulation of a Northern North Sea Tight Sand
Authors: Despax D. , Charlez P. , Clinkemaillie J. , Economides M. J. 
Published: December 2007

ABSTRACT
Thick reservoirs (about 100 m, 330 ft) have been discovered in the northern part of the North Sea, with effective permeabilities less than 0.1 md. In spite of this poor transmissivity, it has been planned to study the development of these blocks, lying under 160 m (525 ft) of sea water. Reservoir engineering evaluations have already suggested that profitability could be reached, but only if the wells are significantly stimulated. This is why an extensive fracturing feasibility study, focused on the Brent formation, was carried out.
The Brent formation appears to be a sandstone which would easily be stimulated using normal hydraulic fracturing techniques and this study has revealed (1) that sufficiently conductive propped fractures with fracture half-lengths at least equal to 150 m (500 ft) are feasible and have a reasonable chance of success, and (2) that this size of treatment will satisfy the production increase requirements.
However, it is not possible with the data available today to guarantee that this design would in fact reach the expected target in all drilled and planned wells. The main reason is that the minimum horizontal in-situ stress profile versus depth is not known and, that fully three-dimensional numerical simulations based on laboratory results have emphasized that 50 bar (725 psi) is the minimum excess pressure to contain a facture to less than 10 m (33 ft) of vertical growth and thus, to prevent fluid penetration in the underlying coal strata during the pumping period. In a coal layer, horizontal stresses are suspected to be very low and in the case of connection between such a layer and the perforations, the gel would preferentially fracture the coal rather than the sandstone, thus setting the proppant out of the pay zone. In-situ measurements of stress become essential for each relevant layer.
Drilling Contractor Proposes New Methods for Mud Solids Control Optimization on the Rig
Authors: Rodt G. , Cahuzac J. P. 
Published: December 2007

Abstract
In recent years the development of more sophisticated mud systems in the North Sea has drastically changed the concept of mud solids control on the rig. Getting a "better handle" on mud costs and reducing the pollution associated with losses on surface have become major concerns for the Operator and have resulted in a focus on the efficiency of mud mechanical treatment equipment.
This paper shows how an extensive and full scale test campaign has allowed a Drilling Contractor to develop new methods for the optimization of the use of shale shakers / mud cleaners / centrifuges. After a brief review of laboratory results, it describes field trials and shows how the use of sophisticated measurement devices and on site computer evaluation can lead to significant improvements in typical North Sea system operations.
Controlled Make-Up Procedures for Improved Workovers and Completions
Authors: Stewart A A 
Published: December 2007

ABSTRACT
New developments in traditional equipment and practices in connection make-up have been analysed using a large-scale data-base gathered from a wide variety of locations in NW Europe. For the first time this has allowed valid comparisons of field performance from which practical recommendations can be produced and equipment specifications developed to improve the procedures for completions and workovers.
Two Years Experience with Use of Seabed Diverter
Authors: Klavenes P T , Leistad G H 
Published: December 2007

ABSTRACT
Experience has proven traditional procedures for handling of shallow gas to be inadequate with respect to safety of operations. Equipment for diverting gas at the seabed was developed and put to use. Experience gained during two years now confirm that the seabed diverter improve safety of operations by offering preventive as well as corrective advantages. Shallow gas formations can be drilled using mud with density adjusted to formation integrity and pressures. In case of a shallow gas blowout gas can be kept away from the rig by diverting to the sea. If necessary the well can be shut in and the rig pulled off location in a controlled way.
Applications of Subsea Bottom-Hole Pressure Monitoring Systems in Reservoir Appraisal and Development
Authors: Scofield J. R. , Baxter C. F. G 
Published: December 2007

ABSTRACT
This paper discusses the field performance of a remotely operated bottom-hole pressure monitoring system installed in a subsea appraisal well in the North Sea. Topics covered include vessel station keeping requirements during system interrogation, data recovery utilizing subsea accoustic telemetry, performance of the wellhead mounted data acquisition units, and downhole pressure gauge and electrical circuit reliability.
The paper also describes several applications for using subsea exploration wells as remote bottom-hole pressure and temperature monitoring systems to aid in reservoir appraisal and development. Applications covered include interference testing, extended pressure build-up surveys and waterflood pressure response monitoring. Completion techniques and measurement and recording systems are discussed which will permit single or multi-zone pressure and temperature readings to be made over specified time intervals for static bottom-hole conditions up to 15000 psia and 300°F. In addition, methods of employing the pressure monitoring completion to perform drill stem tests are detailed.
Lastly, there is a discussion of recommended improvements to completion installation techniques and data logging capabilities which will enhance overall system reliability and usefulness.
The Removal of Abandoned Beryl Field Pipelines and Structures
Authors: Brown A. R. , Peacock D. A. 
Published: December 2007

ABSTRACT
Within the last 2 years Mobil North Sea Limited (MNSL) has removed from the Beryl field:- 7 kilometres of abandoned untrenched Coflexip flowline, and2300 tonnes of steel and concrete debris from a failed single point mooring – SPM1.
The Coflexip flowline was refurbished, tested and is being reused in the field this year. Recovery of SPM1 debris represents the first practical experience of large scale removal operations in the Northern North Sea.
With the passage of the Petroleum Bill the future removal of abandoned pipelines and structures is likely to be a major offshore activity. It is hoped that the experience presented herein will be of interest to operators, companies and legislative bodies.
Advanced Front-End Recovery Object or Simple Temporary Topside Facilities for Oil Production from the Rolf Field, Offshore Denmark
Authors: BRINK J 
Published: December 2007

SUMMARY
Crude oil (c. 10,700 BOPD) was produced through temporary topside facilities in the Rolf Field offshore Denmark from January 7th to September 27th, 1986. These simple, unmanned and remote controlled facilities were a low cost solution to a problem caused by delays of the permanent topside facilities. Project execution time was two months from start of conceptual design until start-up of oil production. Installation works were performed from a jack-up drilling rig – in part simultaneously with drilling operations. Materials and equipment installed were obtained with very short delivery times. The facilities which were certified by a Certification Society and approved by the Danish Authorities included all necessary safety features. Total costs for the facilities amounted to c. 1 million US$ (excl. rig time for installation). Due to simplicity high reliability of the production system was obtained. Availability of the facilities for the entire period from start-up was 99.6 percent. The facilities were manned 3.2 percent of the total operating time mainly due to wireline work for reservoir monitoring.
It is considered that the experience with the concept applied for the early production from the Rolf Field could form the basis for more simple and cost effective topside facilities for minor offshore fields.
High-Pressure Universal Volume Flowmeter for Cementing, Stimulation, Drilling, and Production
Authors: Codazzi D. , Mioque J. L. , Moncharmont J. A. , Montaron B. 
Published: December 2007

ABSTRACT
A sensor capable of measuring the flowrates of fluids under pressure up to 15 000 psi (103.4 MPa) with an accuracy of ± 1% of the full scale, adjustable between 5.0 and 30.0 bbl/mn (0.79 and 4.77 m3/mn) in a standard 3″ line is presented. The device is completely non intrusive and operates with any kind of fluid encountered in the oilfield environment irrespective of its properties (e.g. electrical conductivity, rheology, presence of solid particles).
Applications of the flowmeter are discussed. Besides better control and evaluation of pumping operations, in cementing, stimulation and drilling, the readings are used to ascertain important parameters such as the bottom hole pressure or the total volume pumped. Another application more specific to cementing concerns mud removal. In addition, when the device is coupled with a flowmeter on the return line, differential flow measurement can be made permitting circulation losses and well kick detection.