bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Continuous-Mix Process for Gelling Anhydrous Methanol Minimizes Hazards
Authors: Thompson J.E. , McBain C. , Gregory G. , Gerbrandt D. 
Published: December 2007

Summary
This paper discusses a novel approach to well stimulation with anhydrous methanol-based fracturing-fluid that significantly reduces hazards to personnel and equipment during the fracturing process. Research is presented on the various chemical and engineering process technologies used to develop and evaluate continuously mixed anhydrous methanol fracturing-fluid performance. Field case histories are also discussed.

Introduction
Since the development of hydraulic fracturing technology as a well completion technique hazardous fluids frequently have been used. These fluids include refined oils, formation condensates, crude oils, acids, alcohols, and a variety of other chemicals and additives. Batch mixing is a common technique used to formulate fluids for fracturing applications. The fluid viscosity is adjusted to the desired level by circulating the base fluid through blending equipment while adding the polymeric gelling agents, buffers, and other chemicals. The fluid must circulate through the equipment many times for the fluid to develop the desired viscosity. When hazardous materials are handled in a multiple-circulation process, the potential for accidents is high.
Technological advances in recent years have provided sophisticated fracturing-fluid systems and field equipment, along with microprocessor systems that monitor and control the pumping treatment. These advances have been implemented without compromising the efficiency of the total operation. In many cases, the overall system performance improved significantly. For example, the development of oil-slurried polymer concentrates and polymer hydration units led to the widespread application of continuous-mix processes to mix fracturing fluids.
The damage characteristics of any fracturing-fluid system are of paramount importance to successful reservoir stimulation. Formations that have low bottomhole pressure or contain significant concentrations of water-sensitive clays are typically candidates for stimulation with non-water-based fracturing fluids. Problems with clay swelling and migration commonly are encountered in formations containing significant amounts of smectite and illite-type minerals. The degree of formation sensitivity depends on the concentration and type of clay components, clay or mixed clay orientation in the pore channel, and the ion balance between connate water and clay minerals. In low-permeability formations, capillary forces can have a significant effect on production rate and total hydrocarbon recovery. Capillary forces increase proportionally with the surface tension of the formation fluid. When the capillary forces exceed the formation-fluid driving force, a water block may occur. The use of methanol has long been recognized as an effective technique to remove formation water blockage. The miscibility of methanol with formation fluids reduces surface tension, which promotes removal of the water block and enhances fluid recovery.
Evaluation of Gas Hydrate Formation and Deposition in Condensate Pipelines: Pilot Plant Studies
Authors: Dholabhal P. D. , Kalogerakis Nicolas , Bishnol P. R. 
Published: December 2007

Summary
A recirculation flow loop was operated to simulate the flow of light condensate oils in subsea pipelines at hydrate-forming conditions. Pressure drop across sections of the loop and the flow through the section were used to measure hydrate accumulation indirectly in addition to visual observations at a "see-through" section.
Surfactant-Based EOR Mediated by Naturally Occurring Microorganisms
Authors: Thomas C. P. , Duvall M. L. , Robertson E. P. , Barrett K. B. , Bala G. A. 
Published: December 2007

Summary
Oil recovery experiments using Bacillus licheniformis JF-2 (ATCC 39307) and a sucrose-based nutrient were performed with Berea sandstone cores (permeability 0.084 to 0.503 μm [85 to 510 md]). Oil recovery efficiencies for four different crude oils (0.9396 to 0.8343 g/cm3 [19.1 to 38.1°APr|) varied from 2.8% to 42.6% of the waterflood residual oil. Microbial systems reduced interfacial tension (IFT) ≍20 mN/m [≍20 dyne/cm] for all oils tested. After the microbial flood experimentation, organisms were distributed throughout the core, with most cells near the outlet.
Examination of a Cored Hydraulic Fracture in a Deep Gas Well
Authors: Warpinski N. R. , Lorenz J. C. , Branagan P. T. , Myal F. R. , Gall B. L. 
Published: December 2007

SummaryA hydraulic fracture stimulation conducted during 1983-84 in nonmarine, deltaic, Mesaverde strata at 7, 100 ft [2164 m] was cored in a deviated well in 1990. The observed fracture consists of two fracture intervals, both containing multiple fracture strands (30 and 8, respectively), abundant gel residue on the fracture surfaces, and many other complexities.
Injection-Above-Parting-Pressure Waterflood Pilot, Valhall Field, Norway
Authors: Ali Nazir , Singh P. K. , Peng C. P. , Shiralkar G. S. , Moschovidis Z. A. , Baack W. L. 
Published: December 2007

Summary
This paper discusses the execution, analysis, and results of an unconventional waterflood pilot in a major, naturally fractured chalk, oil reservoir in the North Sea. Pilot operation above formation parting pressure (FPP) solved the low-injectivity problem but required use of new and innovative techniques to interpret and to predict pilot behavior properly.
Performance Review of Brazeau River Nisku Dry-Gas Miscible-Flood Projects
Authors: Lee Jong I. , Astete Ernesto L. , Jerhoff Tim F. 
Published: December 2007

Summary
This paper reviews 10 years of dry-gas miscible-flood operations in three Brazeau River Nisku pinnacle reefs in Alberta. In addition, actual pool performance is compared with the original black-oil-model simulation forecasts. Through June 1991, the pools recovered 50% to 70% of original oil in place (OOIP), exceeding estimated waterflood recovery for each pool. Ultimate recoveries are expected to be 60% to 80% of OOIP, the range originally predicted.
A Single-Well Tracer Test With In-Situ-Generated CO2 as the Oil Tracer
Authors: Wellington S. L. , Richardson E. A. 
Published: December 2007

Summary
A single-well tracer test (SWTT) that uses soluble amounts of in-situ-generated CO2 as the oil tracer is described. Water-soluble-only injectants simplify test interpretation and improve residual-oil-saturation (ROS) determination. The CO2-generator chemistry allows the test to be tailored over a wide range of injectivities and reservoir temperatures.
Aspects of Wellbore Heat Transfer During Two-Phase Flow
Authors: Hasan A. R. , Kabir C. S. 
Published: December 2007

Summary
Wellbore fluid temperature is governed by the rate of heat loss from the wellbore to the surrounding formation, which in turn is a function of depth and production/injection time. We present an approach to estimate wellbore fluid temperature during steady-state twophase flow. The method incorporates a new solution of the thermal diffusivity equation and the effect of both conductive and convective heat transport for the wellbore/formation system. For the multiphase flow in the wellbore, the Hasan-Kabir model has been adapted, although other mechanistic models may be used. A field example is used to illustrate the fluid temperature calculation procedure and shows the importance of accounting for convection in the tubing/casing annulus. A sensitivity study shows that significant differences exist between the predicted wellhead temperature and the formation surface temperature and that the fluid temperature gradient is nonlinear. This study further shows that increased free gas lowers the wellhead temperature as a result of the Joule-Thompson effect. In such cases, the expression for fluid temperature developed earlier for single-phase flow should not be applied when multiphase flow is encountered. An appropriate expression is presented in this work for wellbores producing multiphase fluids.
Water Input Profile Determinations on Injection Wells in Secondary Recovery Fields
Authors: Adamson Bliss , Brown Bob Diggs 
Published: December 2007

Abstract
The knowledge of the distribution of input water in injection wells is important to the success of water flood secondary recovery projects. The presence of thief formations, the lack of complete well history, and improper completion methods all contribute to diverting the flood water from the producing horizon. Through the use of known tools and procedures, input profiles can be obtained.
The interface velocity procedure coupled with caliper and correlation logs give satisfactory input profiles. These provide the data to detect the presence of the undesirable conditions and for the method of correction. Under normal conditions the correlations between profile data and permeability data from cores is good.

Introduction
The application of secondary recovery methods to oil production has spread rapidly throughout the oil fields of the United States. This has created a desire for greater knowledge of the behavior of the oil reservoir under a secondary recovery program. In the case of water flooding projects and particularly during the early stages of pilot flood work, it is important to know the water is being directed through the proper zone.
In a recent paper on secondary recovery water flood projects which had been classified as unsuccessful, it was shown that a considerably larger quantity of water had been injected than fluid recovered. This indicated that the flood water was going into zones which were not part of the oil reservoir. Confirmation of this was not established since no attempt had been made to determine the distribution of the input water into the zone being flooded.
The need for this type of information on many water flood projects has caused the secondary engineers to seek means of obtaining this data in an effort to better understand and evaluate their various floods.
This would require a procedure which would work satisfactorily on wells completed either through perforations, open hole, or shot hole under the following water flooding conditions, namely:Surface injection of flood waters under pressure;Surface injection of flood waters at atmospheric pressure;Dump flood wells using water for flooding from a zone above the oil reservoir.
In addition, any tool involved would have to be small enough to work through 2-in. tubing, since a large number of injection wells have tubing in them. In some cases it is not desirable and in others it is not possible to remove it.
Successful High-Temperature/High-Pressure Well Testing From a Semisubmersible Drilling Rig
Authors: Davidson A. R. , Prise Gavin , French Clive 
Published: December 2007

Summary
In 1990, Hamilton Oil Co. Ltd. (HOC) drilled and tested three high-temperature/high-pressure (HTHP) wells from a semisubmersible drilling rig in the North Sea. This paper identifies the main pitfalls encountered when planning and implementing an HTHP well test with reference to three case histories. These cases demonstrate the benefits of defining a clear philosophy of safety and simplicity to test such wells successfully.
Components of Produced Water: A Compilation of Industry Studies
Authors: Stephenson M.T. 
Published: December 2007

Summary
Produced water contains many different constituents. Each has a different impact on the environment when present in discharged water. All these components have been studied at various times and for diverse reasons by several organizations. These studies, which cover dispersed and soluble oil, radionuclides, production chemicals, and heavy metals, are brought together here production chemicals, and heavy metals, are brought together here along with new data to present a complete picture of produced water. Many constituents of produced water have no known environmental effects, while others have only minor effects. In general, produced water is not harmful in the offshore environment where produced water is not harmful in the offshore environment where more than adequate dilution occurs.

Introduction
Produced water is the largest waste-stream source in the entire Produced water is the largest waste-stream source in the entire E and P process. Over the economic lift: of a producing field, the volume of produced water can be more than 10 times the volume of hydrocarbon produced. With volumes of this magnitude, the disposal of produced water becomes very important to the operator and the environment. The preferred disposal method for produced water is the one that adequately protects the environment at the lowest cost to the operator. Regulatory constraints often limit the options of the operator to methods that may not be necessary for environmental protection.
In many onshore areas of the world, produced water is injected into underground formations that contain water unsuitable for human consumption. In other onshore areas, in many wetlands, and offshore, produced water is discharged to the environment. The discharge of such large volumes of waste into the environment has caused concerns about uncontrolled, irreversible, and dreadful pollution in both government agencies and nongovernment organizations. pollution in both government agencies and nongovernment organizations. The basic source of these concerns is a lack of knowledge about the constituents of produced water and their effects. The basic components of produced water can be grouped into the following main categories: oil, heavy metals, radionuclides, treating chemicals, salt, and dissolved oxygen.

Oil
Oil is the common term applied to organic material that is dispersed or dissolved in produced water at the time of discharge. Dispersed oil consists of small discrete droplets suspended in the water while dissolved or soluble oil is present in the dissolved form. All oilfield water-treating equipment in use today is designed to remove these droplets from the water under Stokes' law. These devices operate by taking advantage of the difference in density between oil droplets and water. In addition to density, the other main parameter of concern in this separation is the size of the oil droplet. According to Stokes' law, the velocity at which the oil droplet rises through the water also varies directly with the square of the droplet diameter.
Offshore Disposal of Oil-Based Drilling-Fluid Wastes An Environmentally Acceptable Solution
Authors: Malachosky Ed , Shannon B. E. , Jackson J. E. , Aubert W. G. 
Published: December 2007

Summary
Oily cuttings and waste fluid are byproducts of oil-based drilling muds. In such difficult drilling environments as the Gulf of Mexico, where oil-based fluids often are preferred, personnel safety, environmental, and economic concerns are exacerbated by the necessity to transport these cuttings and fluids to shore for disposal. This paper describes a process for on-site preparation and subsequent disposal of a slurry of cuttings by annular pumping. The disposal includes all cuttings and waste oil mud generated during drilling with oil-based fluids. Wastes are displaced down a casing annulus and into permeable zones below the surface casing setting depth. Descriptions of environmental and safety problems arising from onshore disposal, benefits of annular pumping, and equipment used for slurry preparation and pumping are described. This technique eliminates the need for platform cuttings storage, cuttings transportation to shore, and the environmental effects of onshore disposal.
Wettability Determination and Its Effect on Recovery Efficiency
Authors: Donaldson Erle C. , Thomas Rex D. , Lorenz Philip B. 
Published: December 2007

Abstract
A quantitative method for measuring the wettability of porous media containing brine and crude oil has been developed by the USBM using capillary pressure curves determined with a centrifuge. These measurements were reproducible within a standard deviation of 8.2 percent. The determination of fractional wettability has been compared with a method involving a combination of imbibition and displacement. Results are in agreement qualitatively as to whether a sample was water-wet or oil-wet.
When tested with outcrop cores of Torpedo Sandstone, wetting tendencies of oils from widely different fields range from highly water-wet to almost neutral. Silicone-treated cores vary in extent of wettability in a predictable manner, becoming more oil-wet as the concentration of silicone used in core preparation is increased.
Wettability, used as a parameter in designing linear mathematical models for predicting recovery efficiency, is equal in significance to viscosity and permeability.

Introduction
Wettability is one of the major factors that influences oil recovery. The importance of maintaining a water-wet condition in a field under water drive has been discussed by many authors. These authors have shown that oil recovery, as a function of the water injected, is greater from water-wet cores than from oil-wet cores. A few authors have indicated that recovery from strongly water-wet or oil-wet cores is less than recovery from cores that are at some intermediate wettability. One reason that the significance of wettability to oil recovery is still being evaluated is because a quantitative measurement of wettability has not been available when crude oil is involved.
Mobility Control Experience in the Joffre Viking Miscible CO2 Flood
Authors: Stephenson Derril J. , Graham Andrew G. , Luhning Richard W. 
Published: December 2007

Summary
This paper discusses mobility control in the Joffre Viking field miscible CO2 flood. Since 1984, three injection strategies have been tried: water-alternating-CO2 (WACO2), continuous CO2, and simultaneous CO2 and water. The studies showed that simultaneous injection results in the best CO2 conformance. CO2-foam injection has also been investigated.
A Method for Handling Spatially Varying Fluid Properties in a Simulation Model for a Fissured Reservoir
Authors: Sibley W.P. 
Published: December 2007

Abstract
The high relief, fractured carbonate reservoirs of the Asmari formation in Iran have extremely thick oil columns, with a large vertical change of reservoir temperature. This large change results in a significant effect on reservoir fluid properties. In contrast, there is a remarkable uniformity of PVT properties on a horizontal plane. Therefore, to properties on a horizontal plane. Therefore, to obtain meaningful results from reservoir engineering studies, PVT properties must be carefully weighted vertically.
Intensive study of the known oil recovery mechanisms within these highly fissured systems resulted in a sophisticated reservoir simulation model. The model is programmed to include these recovery processes, which occur essentially in horizontal layers or zones. It also includes a technique for volumetrically weighting the large vertical variation of the PVT data. A description of this weighting process is the primary purpose of this paper.

Introduction
Oilfield structures found in Iran have been described as very long, high relief, assymmetrical anticlines that contain unusually thick oil columns (see Fig. 1). The oil reservoirs generally are capped with large primary gas accumulations and are often affected by natural water drive. Producing formations include the Asmari, Bangestan, and Khami carbonates, with the Asmari being by far the most common and prolific. Although some Asmari reservoirs have been discovered that contain sandstones interbedded within the limestones and dolomites, most reservoirs in Iran contain the bulk of the oil in compact carbonates that have been contorted and highly fractured during structural deformation. The resulting anticlinal oil accumulations are produced mainly from complex fracture systems, which apparently exist quite uniformly throughout the dense matrix.
Study of surface rocks, cores and well producibility show that well developed fissure producibility show that well developed fissure systems are responsible for the excellent fluid communication. Because the fissures contain relatively little oil, maintenance of such prolific rates is dependent upon rate of oil replenishment from the adjacent matrix. The various productive mechanisms determine the rate of replenishment and duration.
Modeling of Fractal Patterns in Matrix Acidizing and Their Impact on Well Performance
Authors: Frick Thomas P. , Kürmayr Thomas P. , Economides Michael J. 
Published: December 2007

Summary
This paper describes a model where wormholes, the primary feature of carbonate acidizing, are considered as fractals. The influences of acid volume, injection rate, fractal dimension, porosity, and the ratio of undamaged to damaged permeabilities on well performance are studied. Exact expressions of post-treatment skin effects are developed for vertical and horizontal wells.
Revised Casing-Design Criteria for Exploration Wells Containing H2S
Authors: Marshall D. W. , Asahi Hitoshi , Ueno Masakatsu 
Published: December 2007

Summary
Sour-service casing is designed to meet standards set by the Natl. Assn. of Corrosion Engineers (NACE), as outlined in detail in NACE Standard MR 0175-91. However, rigorous application of this standard to casing design in exploration wells containing H2S can result in very conservative designs. This paper describes empirical and theoretical results that show under which circumstances the NACE standard is too conservative or too lax. A revised set of criteria was developed from these data specifically for application to sour-service casing design in exploration drilling. The paper also describes the application of this technique to the drilling of high-pressure, high-temperature (HPHT) wells in the North Sea and shows how casing with minimum internal yield strengths of 125,000 psi [862 MPa] may be used in exploration wells that may contain sour gas.
The Effect of Heat on Some Mechanical Properties of Igneous Rocks
Authors: Barbish A.B. , Gardner G.H.F. 
Published: December 2007

Abstract
The elastic moduli of most igneous rocks are greatly reduced by heating and depend, at room temperature, on the highest temperature to which they have been previously heated. This phenomenon was investigated by measuring velocity, attenuation, bending strength, and point penetration as functions of moisture point penetration as functions of moisture content, pore pressure, confining pressure, and highest previous temperature for a series of gabbro samples from French Creek, Pa. it was concluded that heating introduces a system of macrocracks between grains that is distinct from a system of microcracks that exists within grains. Thus bending strength is reduced by the introduction of macrocracks, but resistance to indentation, which depends on the microcracks, is not.
It is suggested that from the measurement of velocity and attenuation alone, the macro and microcracks can be detected and distinguished.

Introduction
In 1937 J. M. Ide reported on how heat affects the elastic constants of a wide variety of rocks. He found that the constants (Young's modulus and Rigidity modulus, measured at room temperature) were permanently reduced to values determined by the highest temperature to which the rock had been previously heated. He suggested that this might be explained by the development of microcracks in the framework of the rock. The microcracks would be caused by the unequal expansion of the various minerals in the rock. The greatest reduction of elasticity occurred with gabbros, which are composed of roughly equal mixtures of feldspars and pyroxenes. Almost no reduction in the constants was found for limestones.
In more recent years a revival of interest in this subject has followed the development of high power laser beams. The destructive effect of laser beams has been attributed primarily to the rise in temperature of the irradiated rock. This has two effects. One is the initiation of macrocracks by the creation of large tensile stresses. The other is the reduction of elasticity by microcracks, as noted by Ide.