bluuebunny/crossref_metadata_2025_split huggingface dataset:
Case History of Integrating Multisource Data for Pore Pressure Prediction
Authors: Smith John Rogers 
Published: December 2007

Abstract
The abnormally high formation pressures encountered in the deeper sections of many sedimentary basins influence both the accumulation of hydrocarbons and the drilling cost to develop the hydrocarbons. Consequently, accurate pore pressure prediction can be important to the economically successful exploration and development of deep reserves. This report focuses on the integration of pressure-related data and interpretations from multiple sources and disciplines to successfully predict pore pressures for a proposed drilling well.
A logical, consistent process of identifying, acquiring, interpreting, and integrating drilling, logging, production, geophysical, and geological data is described. This integrated approach to pore pressure prediction can provide a higher quality prediction than is possible with a single data source or method and can help to explicitly quantify uncertainties. The case history of a prediction for an actual well, including the results, is used to exemplify how the process can be applied. The well was drilled, in a previously troublesome area, for 20 per cent less cost than expected and without taking any kicks.
Milling Variable Window Openings for Sidetracking
Authors: Desai Praful C. , Dewey Charles H. 
Published: December 2007

Abstract
Historically, the profile of the window milled with a conventional whipstock system resembles an inverted tear drop shape. The resulting full gage window opening is relatively cramped for subsequent drilling assemblies and liner completions. For example, in 7" casing the total window opening is usually 10 feet long out of which only about 2 feet of the opening has full diameter access for drilling and completion tools.
This paper presents a unique whipstock design and milling tool design, the combined performance of which produces a full gage window opening of up to 85% of the total window length and thereby provides an abundant clearance for drilling assemblies and liner completions. Test conducted on 7"-29 lbs./ft. casing resulted in a total window opening of 9.8 feet (118") out of which 7.5 feet (90") was a full gage 6.00" opening. Test on 9-5/8"-47 lbs./ft. casing produced 16.83 feet (202") total window length of which 14.50 feet (174") of the opening measured full gage width of 8.50".
The whipstock can easily be modified to produce the desired length of full gage opening. Optionally, the window can be milled without the need for drilling a rat hole.
The benefits of a longer full gage window are (1) trouble free entries and re-entries through the window for drilling and completion of lateral, (2) ideal for short radius departure, (3) allows sidetracking in hard formation without drilling rat hole, (4) compensates for any mismatch in depth tally calculations, and (5) eliminates problems associated with skewed window (longer full gage window is vertically straight).
The paper details the test set up, test results, photograph and profile of actual milled windows and summarizes field run results.
Ream While Drilling Technology Solves Difficult South Texas Drilling Problem
Authors: Kelley Scott , Swadi Mohammad , Charles Chris 
Published: December 2007

Abstract
The authors will discuss the use of ream while drilling (RWD) technology in two wells, the S.K. East #4 and #5. RWD technology was used to reduce problems associated with drilling through several Frio sands from 11,000 ft to 14,000 ft, in the Sarita Field, Kenedy County Texas. This hole section has reservoirs that are difficult to drill, log and case due to a high potential for differential sticking (e.g. drillpipe, liner, openhole logging tools). Additionally, because the reservoir pressure is close to the fracture gradient, it was necessary to minimize equivalent circulating density (ECD) during both drilling and cementing operations. Another challenge in this interval is the tendency for some reservoirs to compact, reactivating faults. Finally, deviation tendencies were critical because of complex geology and lease constraints.
The operator selected to drill an oversized hole with a 12¼" RWD tool as a contingency to address the problems described above. Overall, sticking tendencies were eliminated, and lower ECD's allowed the interval to be drilled and cased with reduced lost returns. After drilling the section, caliper logs indicated a nearly in gauge hole diameter, and the deviation tendency of the interval was reduced compared to offset wells. The final survey showed only ½°and 1/3° of divergence from vertical for wells SKE #4 and SKE #5 respectively.
Managing the Client/Contractor Relationship to Maximise Safety Performance
Authors: Allwright Tony 
Published: December 2007

Abstract
Managing and developing the relationships and mutual understanding between clients, drilling contractors and service contractors can lead to the next significant breakthrough in improving the safety performance of drilling operations. Though demanding much personal effort on the part of managers, it is a low-cost high-impact approach. It will also impact favourably on technical and operational performance.
The contractor must develop his own safety identity, apply his own solutions and totally believe in what he is doing, albeit in full cooperation with his client. But this will work only if in turn the client understands and respects the needs and contribution of his contractors and sub-contractors.
Screening and Coreflood Testing of Gel Foams to Control Excessive Gas Production in Oil Wells
Authors: Wassmuth F. R. , Hodgins L. H. , Schramm L. L. , Kutay S. M. 
Published: December 2007

Abstract
The use of foams for controlling gas oil ratio (GOR) has been tested successfully in the North Sea,1,2 and North America.3,4 However, foams have a limited lifetime (weeks to months), and the treatment often needs to be repeated. A more permanent solution, with the same placement advantage, is to use gelling foams. During the gelation processes the foam structure solidifies, imparting greater stability and increased gas blocking ability to the gel-foam.
In this work, several polymer-enhanced foam and gel-foam formulations were screened, and tested for their gas blocking ability under reservoir conditions. Initially, chromium crosslinked gelation experiments were undertaken to obtain suitable gelation times at 85 °C. Polymer-enhanced foam and gel-foam formulations were injected into Berea sandstone cores, and carbonate packs (in the presence and absence of oil), to examine their injectability, and gas-blocking capability. In addition, the effects of shear degradation, permeability, and flow rate on the effective viscosity of polymer-enhanced foams were investigated. It was determined that gel-foams, with suitable gelation delay, can be injected, and propagated into packed cores in a similar manner to polymer-enhanced foams. The gas blocking ability of cured gel-foam was far superior to that of polymer-enhanced foam. The gel-foam blocked gas flow completely, even in the presence of oil, and a significant pressure differential had to be exceeded before the gas could channel through the gel-foam and flow through the core.
Modelling of Foam Flow in Porous Media Based on Multivariate Statistics
Authors: Alexandrov Alexander V. , Currie Peter K. , Nguyen Quoc P. , Zitha Pacelli L. J. 
Published: December 2007

Abstract
The objective of this study is the development of a mechanistic foam flow model which is based on the reconciling of the most important pore level phenomena. Pore morphology is described statistically by a correlated bivariate probability distribution of pore throats and aspect ratios. Pore level mechanisms such as snap-off, lamella mobilisation and destruction, are used to partition pore space. The pore space is partitioned into pores occupied by liquid only and pores occupied by foam (gas and lamellae). The pores occupied by foam are partitioned into those that contain mobile, immobile lamellae or no lamellae at all. The described above occupancy statistics is imposed on a network to determine gas relative permeability in presence of foam. Bretherton's theory is used to determine gas viscosity.
Enhancement of Oil Recovery Using a Low Concentration of Surfactant to Improve Spontaneous and Forced Imbibition in Chalk
Authors: Spinler E. A. , Zornes D. R. , Tobola D. P. , Moradi-Araghi A. 
Published: December 2007

Abstract
A study was undertaken with the objective of evaluating the use of low concentrations of surfactant to improve oil recovery. Various concentrations of commercial surfactants were screened for long term stability at high temperature in seawater. Cloud points, precipitation, and the stability of surface tension were used as screening criteria. Spontaneous imbibition tests at ambient and reservoir temperatures were conducted using reservoir chalk plugs that were moderately water-wet. A selected surfactant, when added at low concentrations (100 to 500 parts per million of active surfactant) to the imbibition water reduced the residual oil saturation over imbibition tests conducted without surfactant. Acceleration of spontaneous imbibition was observed in tests that had improved oil recovery. Forced imbibition tests for viscous displacement were conducted by flow tests. Although low concentrations of surfactant did not lower oil-water interfacial tension below single digits, a reduction in residual oil saturation was obtained in the forced imbibition tests over tests without surfactant. Measurement of surfactant adsorption indicated that low adsorption at reservoir conditions could be obtained below the critical micelle concentration (CMC) of some surfactants. The combination of improved recovery with low adsorption suggests that the addition of surfactant to injected water may improve the economics of surfactant-enhanced waterflooding under appropriate conditions.
Effect of Viscous Forces and Initial Water Saturation on Water Injection in Water-Wet and Mixed-Wet Fractured Porous Media
Authors: Tang Guo-Qing , Firoozabadi Abbas 
Published: December 2007

Abstract
A systematic study of the effect of wettability and initial water saturation on water injection and imbibition was made in Kansas outcrop chalk samples. Water injection tests were conducted at different rates and at different pressure gradients to study the effect of viscous forces. Based on a large number of carefully conducted tests, the following conclusions are drawn.
Initial water saturation has a very pronounced effect on water injection in an intermediate-wet chalk. This effect is much less pronounced for a strongly water-wet chalk. The effects are also in opposite directions. Viscous forces have a very strong effect on water injection performance on intermediate-wet chalks.
Our interpretation of the above experiments lead to the conclusion that the performance of the chalk reservoirs may be nearly independent of wettability state. The results from the experiments also reveal that there is no relation between laboratory measurements of spontaneous imbibition and field performance even when wettability state is perfectly restored in the laboratory.
A New Methodology for Designing Instrumentation of Production Wells for Inflow Profile Estimation
Authors: Nævdal G. , Vefring E. , Berg A. , Mannseth T. , Nordtvedt J. E. 
Published: December 2007

Abstract
A new methodology for designing the instrumentation of production wells is presented. Using a well flow simulator, we can estimate the inflow profile of a production well, solving the inverse problem associated with the mathematical model for fluid flow in the well and the data. The accuracy in the estimated inflow profiles using different design of instrumentation can be computed, and an efficient way of searching for good designs of instrumentation is presented.
Slowing Production Decline and Extending the Economic Life of an Oil Field: New MEOR Technology
Authors: Brown L. R. , Vadie A. A. , Stephens J. O. 
Published: December 2007

Abstract
This paper depicts the results of a forty-five month field demonstration of a microbial permeability profile modification (MPPM) technology to enhance oil recovery from a fluvial dominated deltaic reservoir. Simply stated MPPM involves adding nitrogen- and phosphorus-containing microbial nutrients to the injection water of a conventional waterflooding operation. The resulting microbial growth redirects water flow from the more porous zones to new unswept oil-bearing channels, thereby increasing the efficiency of the waterflood. The success of the technology was shown by the recovery of 69,000 bbl of incremental oil during the first 42 months with a projected recovery of 400,000-600,000 bbl and an extension of the economic life of the field by 60-137 months. Attractive features of the MPPM are that it (1) may be employed in many geological formations amenable to waterflooding, (2) does not interfere with normal waterflooding activities, (3) is environmentally friendly, and (4) is the least expensive of all EOR processes in terms of cost per barrel of incremental oil recovered.
Bacterial Profile Modification With Bulk Dextran Gels Produced by the In-Situ Growth and Metabolism of Leuconostoc Species
Authors: Jenneman G. E. , Lappan R. E. , Webb R. H. 
Published: December 2007

Abstract
Laboratory core floods in highly permeable ceramic and sandstone field cores (1 - 2 μm2) were used to demonstrate the effectiveness of biogenic, bulk dextran gels at reducing indepth permeability. Nutrient formulation, bacteria type, bacteria growth stage, and bacteria concentration were found to influence bulk gel formation.
Growth of Leuconostoc mesenteroides in a sucrose-based medium supplemented with proteins and amino acids essential for its growth resulted in production of rigid, bulk dextran gels containing over 90% water (wt/wt) that were retained on an 18-mesh sieve. Whereas, results from the growth of L. mesenteroides on a beet-molasses medium similar to that used in a previous bacterial profile modification field test produced loose, colloidal gels that easily passed through the 18-mesh sieve. Substitution of inexpensive protein hydrolysates for expensive laboratory-grade proteins resulted in formation of the best bulk gels. Also, bacteria in an early stage of growth produced better bulk gels than bacteria from a later growth stage. Corefloods indicated that conditions supporting formation of bulk dextran gels resulted in greater in-depth permeability reductions (&gt; 90%) than conditions supporting formation of loose, colloidal gels. Batch-wise addition of nutrients (&lt; 5 pore volumes) to ceramic cores inoculated with L. mesenteroides resulted in production of stable in-depth plugs whereas, continuous injection of nutrients was required to achieve in-depth permeability reductions in sandstone field cores flooded to residual oil saturation. These results suggested that the in-depth transport of bacterial cells in field cores was limiting to in-depth gel formation and permeability reduction.
These results are significant in that they are the first to discuss the formation of bulk dextran gels produced during the in-situ growth of Leuconostoc sp., their importance in establishing in-depth permeability reduction, and factors controlling their formation.
Interpretation of Three-Phase Relative Permeability Measurements by Front Tracking
Authors: Haugse Vidar 
Published: December 2007

Abstract
A new algorithm for analysis of laboratory experiments with flow of three phases through a porous medium is presented. The method is based on discrete measurements. Saturation and fractional flow profiles that match the measured recoveries exactly are constructed from measured average fractional flow values. The profiles are piecewise constant in the part of the solution that reaches the outlet during the experiment. The total mobility along the saturation path is estimated from the measured pressure drops. Application to synthetic examples and measured data show that the method is a powerful tool to estimate relative permeabilities along the saturation path of an experiment.
Rheological Screening of Low-Molecular-Weight Polyacrylamide/Chromium(III) Acetate Water Shutoff Gels
Authors: Broseta D. , Marquer O. , Blin N. , Zaitoun A. 
Published: December 2007

Abstract
Low-molecular-weight polyacrylamides crosslinked with chromium(III) acetate are widely used in the oilfield industry to seal off watered out zones in matricial reservoirs. These products are usually mixed in surface facilities, then pumped downhole through coiled tubing and injected into the formation over a depth of several feet. For the operators, gelation time and gel consistency after well shut-in are the two most important parameters to control. The pumping time cannot exceed the gelation time and the maximum pressure drawdown sustainable by the gel is related to gel consistency (as measured, for instance, by the yield stress). Both are known to depend on temperature, polymer concentration and structure (molecular weight, hydrolysis degree), and crosslinker concentration.
A systematic screening of these parameters has been undertaken by means of rheological measurements using a cone-and-plate rheometer. The procedure for determining gelation time consisted in monitoring the viscosity of the polymer and crosslinker solutions mixed at time t=0 and then submitted to shearing at a constant rate. The gelation time, which corresponds to a sudden rise in the viscosity, was observed to be independent of the applied shear rate but to strongly vary with temperature and, to a lesser extent, with polymer hydrolysis degree, concentration and molecular weight and crosslinker concentration. From the set of data obtained, simple correlations or rules of thumb for the gelation time variations are given, which can be used to optimize the formulation for a given field application.
To evaluate gel consistency, some yield stress measurements were performed after a resting (shut-in) time of about 10 hours. The yield stress is related to the maximum drawdown sustainable by the gel in a formation through a simple relationship.
Performance Evaluation of a Mature Miscible Gas Flood at Prudhoe Bay
Authors: McGuire P. L. , Spence A. P. , Redman R. S. 
Published: December 2007

Abstract
This paper summarizes the acquisition, conventional and compositional core analysis, and reservoir simulation history match of a core taken roughly 300 ft from a production well in the most mature area of the Prudhoe Bay Miscible Gas Project (PBMGP). Fine-gridded reservoir simulations yielded a good match of the offset well production rates and also of the observed compositional behavior of the core. The data showed that roughly 70% of the cumulative EOR came from reducing the residual oil saturation near the injection well. The remaining 30% was due to oil swelling. The swelling mechanism was especially important near the production well where the core was taken. Both simulation and field data show that additional miscible gas injection into this area would yield very little incremental EOR.
A Mechanistic Study of Single-Well Steam Assisted Gravity Drainage
Authors: Singhal Ashok K. , Das Swapan , Goldman Jon , Turta Alexandru T. 
Published: December 2007

Abstract
Single Well Steam Assisted Gravity Drainage (SW-SAGD) process was evaluated by closely examining performance of field projects in the public domain, physical modeling and numerical simulation.
It was seen that in order to be economically acceptable, field implementation emphasizes the "Single Well (SW) aspects" (near well bore heating), as opposed to the "SAGD aspects" (creation of a large steam chamber).
The reported steam-oil ratio of about one for SW-SAGD field projects includes contributions due to primary production. Obviously, the performance will be attractive where the primary production is strong. Presence of mobile water or gas in the vicinity of a target location will have a negative effect on performance.
The economic performance can be stronger than that for primary and cyclic steam stimulation but perhaps not as strong as for a dual well steam assisted gravity drainage. Therefore targets should typically have a continuous pay thickness of 10 to 15 m.
Potential improvements can be obtained from optimizing well bore configurations by way of reducing steam by-pass and extending the effective well length utilized for production during the process. Other optimizing ideas involve the use of gases as steam additives and injection-production rate scheduling.
The process is essentially a variation of cyclical steam stimulation (CSS) rather than of SAGD. Using certain elements of the SW-SAGD process, one should be able to profitably modify the cyclic steam stimulation (CSS) process while using horizontal wells.

Introduction
The Single Well Steam Assisted Gravity Drainage (SW-SAGD) process is a steam injection based oil recovery process in which the same horizontal well is used for steam injection, as well as for oil production. Steam is injected through insulated tubing, whereas hot oil and condensed water are pumped to the surface through a separate tubing string. It was initially thought of as a variation of the dual well Steam Assisted Gravity Drainage process (SAGD). In SAGD, steam is injected via a horizontal well and heated oil and condensate produced via another horizontal well, placed directly underneath the injector. The main driving mechanism being gravity.
Integrated Reservoir Description for Boonsville, Texas Field Using 3D Seismic Well and Production Data
Authors: Tanakov M. Y. , Kelkar M. 
Published: December 2007

Abstract
It is generally believed that integration of different types of data can significantly improve reservoir description. To verify this hypothesis, a field case study was conducted on the complex Boonsville reservoir system located in the Fort Worth Basin in North-Central Texas. The zone of interest, Caddo, was interpreted in 3D seismic post-stack data using geophysical means, and different windowed seismic attributes (SA) were extracted around the time horizon. The structure and pay thickness maps were created using both seismic and well data. Correlation between well porosity and SA was established and utilized to generate porosity maps using several geostatistical techniques such as ordinary kriging, kriging with an external drift, and co-kriging. The technique of alternating conditional expectations (ACE) was implemented to maximize the correlation between well porosity and seismic attribute in a transformed space. Integration of this static reservoir model with dynamic (production) data was performed using the flow simulator, ECLIPSE. It was observed that large-scale features played much more important role in matching historical data than small-scale features. Incorporation of seismic data did not significantly improve the history match; however, it may be useful in drilling step-out wells.