bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Method of Developing In-Depth Permeability Modification Using Surfactant/Alcohol Blends
Authors: Llave Feliciano M. , Burchfield Thomas E. , Dobson Randy E. 
Published: December 2007

Summary
This paper describes the development of a novel method of in-depth permeability modification in porous media using specific surfactant/alcohol blends. The unique features of this method come from (1) the development of permeability modification primarily resulting from component separation of injected blends, (2) in-depth penetration of formations without premature injectivity loss, (3) the capability to propagate the permeability barrier farther through the porous media, and (4) ease of cleanup of the porous media. Laboratory studies showed that injecting these blends into porous media can reduce permeability significantly. The degree of permeability barrier penetration was controlled experimentally, and this barrier was propagated in-depth by subsequent injection of alcohol slugs. The permeability modification potential of these blends was comparable with that of conventional gelled-polymer treatments.
An Experimental and Modeling Study of Miscibility Relationship and Displacement Behavior for a Rich-Gas/Crude-Oil System
Authors: Mansoori John , Haag Gary L. , Bergman Dave F. 
Published: December 2007

Summary
This paper presents an experimental study that uses many slim-tube displacements to characterize the effect of hydrocarbon solvent composition on miscibility development. It was found that the minimum enrichment requirement can be estimated reliably with a previously proposed pseudocritical temperature, Tpc, concept. Tuning equation-of-state (EOS) parameters to match these results required incorporating rate and recoveries from selected slim-tube displacement tests in addition to conventional PVT data.
Testing Injection Wells With Rate and Pressure Data
Authors: Ramakrishnan T. S. , Kuchuk F. J. 
Published: December 2007

SummaryInjection tests can give such information as the effective mobilities of fluids, wellbore damage, and saturation change during displacement, which often require use of rate and pressure data. Although exact solutions for injection and falloff pressure response of a well in an infinite reservoir may be obtained for a constant injection rate, they are not readily extended for the general case of varying flow rates and bounded reservoirs. We present a perturbation theory for multiphase testing that leads to a weakly nonlinear convolution and give a technique to calculate pressure response rapidly for arbitrary flow rates for this form of convolution. The technique is specifically suited for solving inverse problems with nonlinear estimation. We present modifications to the solutions for positive and negative skin factors and demonstrate that the effect of wellbore storage is not easily accounted for in an injection test, unlike single-phase well testing. We give a procedure to correct the system response to storage and propose a variable-rate injection test to improve system parameter estimation. The main idea of the test is to excite the reservoir sequentially and continuously to keep it under strong transient conditions. We present interpretation results for such a sequential testing.
A Method To Derive Dips From Bedding Boundaries in Borehole Images
Authors: Antoine Jean-Noël , Delhomme Jean-Pierre 
Published: December 2007

Summary
This paper describes a computerized technique to derive reliable and accurate dips from high-resolution electrical images automatically, taking full advantage of their lateral continuity and azimuthal coverage. The quality of these dips can be checked by visual inspection. Results derived from three different geologic contexts illustrate the technique.
Improved Reservoir Characterization From Waterflood Tracer Movement, Northwest Fault Block, Prudhoe Bay, Alaska
Authors: Nitzberg K. E. , Broman W. H. 
Published: December 2007

Summary
Simulation models of the Prudhoe Bay Northwest Fault Block (NWFB) waterflood project, with core-plug-derived permeabilities, predicted that injected water would slump because of gravity segregation. Detailed analysis of surveillance logs and production data for one pattern identified tritium tracer breakthrough in surrounding producers without significant slumping. To duplicate the nearly horizontal movement of injected water, a kV/kH ratio that is an Order of magnitude lower than previously modeled is required. This improved reservoir characterization led to revision of the reservoir management strategy for the NWFB.
Well-Test Analysis in Solution-Gas-Drive Systems for Fractured Reservoirs
Authors: Camacho-V. Rodolfo G. , Raghavan Rajagopal 
Published: December 2007

Summary
This study examines issues pertaining to two-phase (oil and gas) transient flow in fractured reservoirs. Dual-porosity and dual-permeability models are examined. Pressure, saturation, and flowing GOR behaviors are noted, and the influence of communication on these behaviors is documented. Methods to compute saturation as a function of pressure for the fracture and matrix systems are presented.
Gas-Cap Effects in Pressure-Transient Response of Naturally Fractured Reservoirs
Authors: Al-Bemani Ali Soud , Ershaghi Iraj 
Published: December 2007

Summary
This paper presents a theoretical framework of gas-cap effects in naturally fractured reservoirs. General pressure solutions are derived for both pseudosteady-state and unsteady-state matrix-fracture interporosity flow.
Deviation from the fracture or fracture-matrix response occurs as the gas-cap effect is felt. Anomalous slope changes during the transition period depend entirely on the contrast between the fracture anisotropy parameter,λ1, and matrix-fracture interporosity parameter, λ, and between the total gas-cap storage capacitance (1 − ω1) and oil-zone matrix storage (1 − ω).
A composite double-porosity response is observed for ω1 ≤ ω1c and 1.0 ≤ λ1/λ ≤ 1000. A triple-porosity response is observed for ω1 ≥ ω1c and 140 &lt; ωλ1/λ &lt; 1.0E05.
Case Study of the Effectiveness of Nitrogen Foam and Water-Zone Diverting Agents in Multistage Matrix Acid Treatments
Authors: Kennedy D. K. , Kitziger F. W. , Hall B. E. 
Published: December 2007

Summary
Several oil wells producing water have been stimulated successfully with multistages of mud acid, nitrogen foam, and water-zone diverting agents. This procedure has improved well performance significantly while having little or no effect on post-treatment water production. The diverters’ effectiveness was analyzed with radioactive tracers, gamma spectroscopy logs, and surface pressure equipment. Results indicate that water-zone diverters and nitrogen foam are effective diverters when used in matrix acid stimulations. Case histories and associated data are included in this paper.
Permeability Determination With a Multiprobe Formation Tester
Authors: Goode Peter A. , Thambynayagam R. K. Michael 
Published: December 2007

SummaryThis paper presents analytic models to interpret the pressure transients measured by a multiprobe formation tester. The multiprobe tester discussed consists of three probes. The sink probe generates a pressure pulse by withdrawing fluid from the formation while the resulting pressure response is measured at the sink probe and at each of two observation probes. One observation probe is positioned on the opposite side of the borehole on the same vertical plane as the sink, and the other is displaced vertically on the same azimuthal plane as the sink. The effect of the various reservoir parameters on the pressure response is discussed. Application of the models is demonstrated through an actual field example.
A Grouping Method To Optimize Oil Description for Compositional Simulation of Gas-Injection Processes
Authors: Danesh Ali , Xu Dong-hai , Todd Adrian C. 
Published: December 2007

Summary
This paper presents a grouping method that optimizes compositional description so that the modeling of the progressive phase behavior of injection gas and reservoir oil systems requires less computation. The method allows the retrieval of the full composition to select new groups for further calculations with very little effort and almost no extra computational time. A new mixing rule, based on the parameters of an equation of state (BOS), also has been developed and incorporated into the grouping method. Multistage experiments simulating the progressive compositional variations of injection gases and reservoir oils were used to evaluate the proposed grouping method.
Successful Inhibition of Deep, Hot, Sour-Gas Wells
Authors: Cameron G. R. , Katz D. C. , Hull J. E. , Barker D. E. , Eiser M. W. 
Published: December 2007

Summary
The sour-gas wells in the Big Escambia Creek (BEC) field of South Alabama have a production environment that consists of 280°F, 21% H2S, 40% CO2, and up to 190, 000 ppm chlorides in the produced water. The highly corrosive conditions demand the ultimate in a corrosion mitigation program to produce these wells safely and economically. This paper describes the background, technical development, and results of the downhole and gathering-system corrosion inhibition and monitoring programs: continuous downhole inhibition by means of annular injection of a water-dispersible inhibitor in the most aggressive wells; downhole batch treatments with nitrified tubing displacements of an oil-soluble inhibitor in the remaining wells; continuous injection of a water-dispersible inhibitor in the gathering lines to augment the batch treatments and in selected highly corrosive wells; monitoring of inhibitor residuals and plotting of trends to ensure the effectiveness of downhole treatments and to optimize injection rates; and flowline calipers and hydrotests to monitor the gathering-line inhibition programs. The paper also describes the computerized approach used in designing, calculating, and updating both the continuous downhole injection system and the nitrified batch treatments. The success of the inhibition and monitoring program is demonstrated by the tubing life achieved, field data on inhibitor residuals, and flowline and downhole calipers. The technical data presented will aid in the design and implementation of successful inhibition programs for highly corrosive production environments.
Performance of a Heavy-Oil Field Under CO2 Injection, Bati Raman, Turkey
Authors: Issever Kayhan , Pamir A. Necdet , Tirek Ali 
Published: December 2007

Summary
Batı Raman heavy-oil (12°API [0.986 g/cm3]) field, with 1.85 × 109 STB (294 × 106 stock-tank m3) original oil in place (OOIP) and poor primary recovery (1.5% OOIP), was a good candidate for EOR applications. Detailed studies resulted in application of an immiscible CO2 injection in a 33-well pilot area. An initially planned huff ‘n’ puff became a successful continuous CO2 flood and encouraged us in our decision to widen the project to the central part of the field. Incremental oil production of 5.742 × 106 STB [913 × 103 stock-tank m3] resulted from 28-MMscf [7.9 × 105 std m3] CO2 injection. Oil production increased from 900 STB/D [143.1 stock-tank m3/d] primary production to 10, 500 STB/D [1669 stock-tank m3/d] in the treated area.
Thermally Induced Fracturing off Ula Water Injectors
Authors: Svendsen A. P. , Wright M. S. , Clifford P. J. , Berry P. J. 
Published: December 2007

Summary
This paper describes the impact that thermally induced fracturing (TIF) has had on the North Sea Ula field injection wells, allowing higher than anticipated water injection rates to be achieved. This work also discusses how thermal stress reduced fracture propagation pressures by 2, 000 psi and how a 3D simulation code developed to model TIF was used. Injection-water-quality specifications and techniques to optimize TIF are presented.
Improving the Reliability of Cement-Setting-Time Tests by Taking Into Account the Influence of Shear
Authors: van Kleef R. P. A. R. , van Vliet J. P. M. 
Published: December 2007

Summary
During a laboratory API thickening-time test of a cement slurry, temperature and pressure are simulated according to downhole conditions. However, the shear rate applied to a slurry in the API test generally differs considerably from the shear rate in actual field cementations. This leads to inaccurate prediction of slurry setting time. Cement setting times should be determined in a laboratory test under realistic conditions of temperature, pressure, and shear.
Whirl and Chaotic Motion of Stabilized Drill Collars
Authors: Jansen J. D. 
Published: December 2007

Summary
Stabilized bottomhole assemblies (BHA's) often exhibit complicated lateral vibrations. This paper aims to clarify this behavior with the theory of rotor dynamics. The motion of the collars varies from simple whirling motion, like that of an unbalanced centrifuge, to highly irregular motion caused by nonlinear effects of fluid forces, stabilizer clearance, and borehole-wall contact. In the extreme case, the vibrations can be classified mathematically as chaotic. The results presented in this paper are important in the interpretation of field measurements and indicate the limits of large-scale computer simulations for the prediction of directional tendencies.
Fracturing of High-Temperature, Naturally Fissured, Gas-Condensate Reservoirs
Authors: Cikes Marin , Economides Michael J. 
Published: December 2007

SummaryEleven hydraulic fracture treatments were performed in deep (3300 to 3800 m [10, 830 to 12, 470 ft]), extremely high-temperature (180 to 195°C [356 to 383°F]), naturally fissured, gas-condensate reservoirs. Formation permeabilities at the fracturedwell locations range from 0.003 to 0.2 md, while the initial formation pressure gradient is about 0.13 bar/m [0.57 psi/ft]. The producing fluid is high-gravity gas (0.83 to 1.15 to air) and contains up to 22% CO2 and up to 4% H2S. Job sizes have ranged from 300 to 2000 m3 [80, 000 to 528, 400 gal] of fluid and 50 to 600 Mg [110, 130 to 1, 321, 590 lbm] of high-strength proppant. This paper emphasizes the general approach to well completion and stimulation treatment design, treatment execution, and evaluation. Interesting items include the engineering of the fracturing fluids to sustain their viscosity at the extreme temperatures and to reduce leakoff in these highly fissured formations. An outline of the reservoir description is also given.Post-treatment well production has been excellent in most cases. Well PI's increased from 0.01 to 0.6 m3/d·bar2 [0.0017 to 0.1 scf/D-psi2] to 0.235 to 7.83 m3/d·bar2 [0.04 to 1.3 scf/D-psi2]. Treatment results suggest that leakoff can be controlled with particulate agents, that delayed crosslinking is the only way to execute these treatments, and that hydraulic fracturing can greatly improve the production from naturally fissured formations. Fracture design and the predicted well production are compared with post-treatment performances in selected wells.
Imaging the Effects of Capillary Heterogeneities on Local Saturation Development in Long Corefloods
Authors: Graue Arne 
Published: December 2007

Summary
Experiments on the effects of capillary heterogeneities and permeability variations on local saturation distributions were conducted using a nuclear saturation imaging technique. Capillary heterogeneities were obtained in alternating sand layers with different permeabilities in the direction of displacement. The paper reports wetting-phase accumulation at the transition zones, step-like saturation profiles, various recovery efficiencies, and different local residual saturations.
Free-Fall-Effect Calculation Ensures Better Cement-Operation Design
Authors: Campos Wellington , Lage A. C. V. M. , Poggio Ademar 
Published: December 2007

Summary
A cement-operation simulator was developed that takes the free-fall effect into account. This simulator allows prediction of well-fluid behavior and pressure, making proper field-operation design possible. The proposed mathematical model was derived from mass and momentum conservation laws by means of a macroscopic balance that reduces field equations to a ID model. The resulting initial value problem is solved numerically with the Runge-Kutta method. Special care is taken to control the interfaces between two different fluids while the system is in free fall. A microcomputer program has been implemented with a user interface that permits complex well geometries. Other models are compared with the program to demonstrate its software capabilities.
Mothballing and Demothballing of an Onshore Oil Field
Authors: Benbrahim A. A. 
Published: December 2007

Summary
This paper analyzes recent experience gained after mothballing and demothballing the Bab onshore oil field. It reviews the type and method of protectionlinhibition applied to the wells, flowlines, production and water injection facilities, and other related equipment. The work carried out during shutdown and field recommissioning is discussed along with reservoir engineering aspects, including the monitoring program and performance review. The method used to check the tubing integrity also is addressed. The impact and consequences of mothballing an onshore oil production field are presented, together with the findings and work done to recommission the field. The paper discusses the procedures used to protect the field facilities to minimize equipment deterioration and to optimize the cost of mothballing. The time required to recommission the field also is discussed.
Quantitative Monitoring of Gasflooding in Oil-Bearing Reservoirs by Use of a Pulsed Neutron Tool
Authors: Ruhovets Naum , Wyatt D. F. 
Published: December 2007

Summary
We developed a new method to monitor gasflooding of oil reservoirs. The method is based on computing two porosities: the base true porosity determined before gasflooding and monitor-apparent neutron porosity determined after gasflooding. The base and monitor porosities provide determination of a hydrogen index of the reservoir fluid after the flooding. The hydrogen index is then used to determine saturation of the flood agent after flooding and, consequently, saturation of water and oil after flooding. An example of quantitative analysis of base and monitor logs illustrates monitoring of CO2 flooding by use of the described method.
Resource Description and Development Potential of the Ugnu Reservoir, North Slope, Alaska
Authors: Hallam R. J. , Plekenbrock E. J. , Abou-Sayed A. S. , Garon A. M , Putnam T. W. , Weggeland M. C. , Webb K. J. 
Published: December 2007

Summary
The Ugnu deposit, located on the North Slope of Alaska, contains more than 6 billion bbl [954 × 106 m3] of oil in place (OIP) in the Kuparuk area. The oil has been biodegraded. At reservoir temperature, the dead-oil viscosity varies from 100, 000 to 10, 000, 000 cp [100 to 10 000 Pa·s]. The paper provides reservoir and geological descriptions of the resource and discusses the key aspects affecting development. These aspects include high-temperature formation damage, the projected production performance, and the design considerations for injecting steam through a thick permafrost interval.
Large-Diameter Glory-Hole Drilling: Evolution From 12- to 20-ft Diameter
Authors: Shields Roger 
Published: December 2007

Summary
To drill for oil and gas in shallow, ice-infested waters, a hole needs to be excavated in the seafloor to protect subsea blowout preventers (BOP's) from ice-scour damage. Canadian Marine Drilling pioneered the use of large-diameter glory-hole drilling systems by designing, building, and patenting a 12-ft [3.7-m] -diameter prototype bit system, a 17-ft [5.2-m] -diameter upgrade, a 20-ft [6.1-m] -diameter standard system, and a 20-ft [6.1-m] -diameter enhanced system. The enhanced bit design incorporates high-pressure jetting, boulder storage, pilot-hole centering, and other features that allow a 36-in. [0.91-m] hole to be drilled through the body of the bit. An optional feature is the ability to drill and case the glory hole simultaneously. To date, penetration rates up to 4.5 ft/hr [1.37 m/h] in soils with a shear strength 5,000 lbf/ft2 [239 kPa] have been obtained. Glory-hole drilling times have been reduced from more than 20 days in 1978 to approximately 1% days since 1986.
Stochastic Characterization of Gridblock Permeabilities
Authors: Gómez-Hernández J. Jaime , Journel André G. 
Published: December 2007

Summary
Permeability is generally measured at the core scale and only at a few sites. By using geostatistical techniques, one can generate alternative high-resolution images of the reservoir at the measurement scale. These images will honor both the data values at the data sites and some prior structural information as modeled, for example, by a covariance function. However, these images must be averaged to the scale of the flow-simulation gridblocks. Two questions arise: (1) how should averaging be carried out? and (2) could the gridblock values be generated directly from the core or log without the intermediary step of small-scale imaging? This paper proposes avenues to answer both questions. First, we propose an averaging technique from point to block permeabilities, accounting for the tensorial character of permeability. Second, we propose a method to infer the covariances and cross-covariances among the different components of the block permeability tensor, and the cross-covariances between these block values and the point measurements. This set of covariances and cross-covariances is then used to generate directly multiple, equally likely spatial realizations of gridblock permeability tensors conditioned to the point measurements. The method is not constrained by small variability of the underlying point permeability distribution, nor does it require a multi-Gaussian-related hypothesis.
A Laboratory Investigation of Permeability in Hemispherical Flow With Application to Formation Testers
Authors: Ramakrishnan T. S. , Dave Yogesh , Cappiello Alphonse 
Published: December 2007

SummaryWe use borehole and laboratory measurements with a probe to obtain local permeability estimates. Under ideal conditions sufficiently far from the probe, the flow induced is hemispherical. We describe an experimental apparatus that can flow fluids through a probe under isotropic confining stresses and present an analysis to deduce the optimal dimensions of a finite cylindrical rock to simulate hemispherical flow like that in a semi-infinite medium. We derive equations for permeability interpretation of laboratory measurements.We made pressure measurements on a number of synthetic and natural rocks as functions of confining stress, probe size, flow rate, and flow direction. For synthetic rocks, the calculated permeability shows little dependency on these factors. For natural media, however, flow direction appears to have a major effect at high rates that increases with decreasing probe size. On the basis of these data, we propose a fines-migration mechanism. As expected, permeabilities show a hysteretic dependence on confining stress.Hemispherical flow measurements with homogeneous porous media indicate that fluid injection would yield permeability close to the true value. Furthermore, sequential injection of multiple phases shows that endpoint effective permeabilities may also be obtained.
Comparison of Different Techniques for Obtaining Capillary Pressure Data in the Low-Saturation Region
Authors: Melrose J. C. , Dixon J. R. , Mallinson J. E. 
Published: December 2007

Summary
Capillary pressure data obtained by different methods in the low-saturation range are compared at the same values of the Leverett J function. The paper shows that in this range, saturations obtained by the mercury-injection method are significantly lower than saturations obtained by other standard methods.