bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of In-Situ Combustion Process Variables by Use of TGA/DSC Techniques and the Effect of Sand-Grain Specific Surface Area on the Process
Authors: Vossoughi Shapour , Bartlett Gordon W. , Willhite G. Paul 
Published: December 2007

Abstract
This paper describes a new technique to predict the parameters that govern the performance of the in-situ combustion process. This prediction is accomplished by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of the crude-oil combustion. The effect of surface area on the in-situ combustion-tube runs was also investigated.
The crude oil studied was from Iola field, Allen County, KS. This oil has a gravity of 19.8°API [0.94 g/cm3] and a viscosity of 222 cp [0.222 Pa·s] at 100.4°F [38°C] and 98 cp [0.098 Pas] at 129.2°F [54°C].
At a bulk density of the combustion-tube pack of 104.26 lbm/cu ft [1.67 g/cm3], the minimum crude-oil content to support an adiabatic combustion process was estimated to be 7.1 wt%. This translates into 34.4% oil saturation for the sandpack of 37% porosity and the crude-oil gravity of 19.8°API [0.94 g/cm3]. However, the combustion front, in a sandpack of 70 mesh (specific surface area of 76 cm2/g [7.6 m2/kg]) with an oil content even greater than the required minimum oil content predicted by the present approach, did not sustain itself. Additional tube runs were performed with finer sand grains having specific surface areas of 317, 1,120 and 3,332 cm2/g [31.7, 112, and 333.2 m2/kg]. A strong, sustained combustion front was observed only in the last run—i.e., the greatest specific surface area.
TGA was applied to the samples taken at 1- to 2-in. [2.54- to 5.08-cm] intervals ahead of the front to study crude-oil distribution. In the case of unsuccessful runs, the amount of the crude oil ahead of the front decreased to a level that sufficient fuel could not be laid down to sustain the front. In the self-sustained run with the greatest surface area, crude-oil content immediately ahead of the front was even higher than the original sand/oil mixture. Therefore, a minimum surface area is required to provide conditions for sufficient fuel to be laid down by the coking process.
This finding is believed to be important in revealing the mechanism responsible for the lack of self-sustained combustion in sandpacks or porous rocks with low specific surface area. It also reveals the importance of the specific surface area available to the crude oil for determining whether a self-sustained combustion could be achieved.
Primary Cementing by Reverse Circulation Solves Critical Problem in the North Hassi-Messaoud Field, Algeria
Authors: Marquairi R. , Brisac J. 
Published: December 2007

Abstract
After usual cementing techniques failed to give satisfactory results, a systematic analysis of difficulties resulting from high pressures and weak down-hole formations led to the development of a reverse cementing technique. This method has now been used successfully for the past two years on all development wells drilled in the North Hassi- Messaoud field in Algeria. Its application required a modification of the regular differential fill-up equipment and wellhead assembly. The particular drilling and cementing problems encountered in this field are described in detail along with the technique and equipment used to solve them.
Introduction
A regular drilling schedule for a North Hassi-Messaoud well can be divided into four main steps (Fig. 1):1. A 17 3/8-in. hole is drilled from 0 to 750 ft using a 10 lb/gal bentonite mud improved with CMC (sodium carboxymethyl cellulose). A 13 3/8-in. casing is set and cemented up to the surface.2. A 12 1/4-in. hole is drilled from 750 to 1,800 ft using the same mud. At this depth the mud is converted to a salt-saturated type with a density increasing from 11 to 12 lb/gal. The hole is drilled to 7,500 ft, where an intermediate 95/8-in. casing is set.3. An 8 3/4-in. hole is drilled to 11,000 ft using the same salt-saturated mud weighted with barite up to 18 lb/gal. A 7-in. production casing is set on the top of the pay zone, the Cambrian sandstones.4. The reservoir is cored with 5 15/16-in. diamond core heads using a 12- to 13-lb/gal oil or water base mud.
Why Conventional Cementing Techniques Fail
Difficulties in Drilling the 8 3/4-in. Hole
Three major difficulties are encountered during the drilling of the 8 3/4-in. hole.
High-Pressure CaCl2 Formation Water
At 8,500 ft in the lower Jurassic, a high pressure, 8,500 psi, CaCl2 -saturated water producing formation is encountered. This formation consists of thin beds of porous and locally vesicular dolomite. The water contains 370 ppm of free HCO3 and 430,000 ppm of CaCl2. Mud contamination by this fluid is spectacular. To prevent this water from coming into the hole during drilling, a mud weight of 17 to 18.5 lb/gal is required. The exact amount depends on variations in permeability and the existence of fine fissures in the formation. However, when making trips, some of this water comes into the hole. It varies from 6 to 90 bbl and badly contaminates large amounts of mud which have to be circulated out and separately reconditioned.
Plastic Clays
Located between two massive Triassic salt beds, a clay zone about 15-ft thick is encountered at 9,500 ft. These clays are sufficiently plastic so that they continuously extrude into the wellbore. The only remedy is the use of adequate mud weight (17 to 18.5 lb/gal) to balance the formation. Other methods to control these clays (use of shale control type or extreme low filtration water base muds) have failed.
JPT
P. 146ˆ
Numerical Simulation of Combined Reverse Combustion and Steamflooding for Oil Recovery in a Utah Tar Sand
Authors: Lasaki Gbolahan O. , Martel Richard , Fahy John L. 
Published: December 2007

Abstract
This paper presents the design of the U.S. DOE Laramie Energy Technology Center's (LETC) Project TS-4, which involves numerical simulation of both in-situ reverse combustion and steamflooding. The simulator showed that the combustion could be limited and contained in a middle 10-ft [3-m] interval with a correlatable high-permeability streak within the 65-ft [20-m] pay zone of the upper Rimrock tar sand formation in Northwest Asphalt Ridge, Uintah County, UT. A high-transmissibility path was necessary to obtain adequate injectivity and sustain a stable reverse combustion. Combustion "echoes" developed and the front changed into a forward mode as the formation pressure increased and at very low air-injection rates. Oil recovery by steam injection was accelerated in a formation preheated by a reverse combustion.
An Improved Interpretation Method for Salt Mud Logging
Authors: Towle Guy 
Published: December 2007

Abstract
The increased usage of the FoRxo, Guard and gamma combination of logs in salty muds has led to the development of interpretation techniques which are fast and simple. This is possible because:The effects of bed thickness on both FoRxo and Guard logs are minimal and in moot cases may be neglected.With salt muds, true formation resistivity, Rt, is linearly and directly proportional to recorded Guard log resistivities over a wide range of conditions.Likewise, invaded zone resistivity, Rxo is approximately equal to recorded FoRxo resistivities.
This direct reading of these two vital parameters makes possible a fast but accurate visual location of all zones of interest. The same characteristics of the logs also make possible simplified interpretation curves to calculate both porosity and wager saturation.
Inasmuch as shaly sands are best measured without the disturbing influence of fresh waters, their interpretation is greatly enhanced by this system of logs.
For this technique to be used, the following conditions must be fulfilled:The zones of interest must be invaded by mud filtrate.The ratio of resistivities of mud filtrate to connate water must be known and the ratio must not exceed 10.Mud filtrate resistivity must be known.Mud cake thickness must be small.
Field examples are given which exhibit the inherent features as well as the disadvantages of the proposed techniques. Simplified charts for interpretative procedures are also presented.
In conclusion, the FoRxo, Guard and gamma logs provide a detailed log of the lithology from which porosity and water saturation may be calculated in detail by a simple interpretation method when certain conditions exist. The logging system also provides an improved method of interpreting shaly sands when both formation water and mud filtrate are highly conductive.
A New Nuclear Log for the Determination of Reservoir Salinity
Authors: Stroud Stanley G. , Schaller Herman E. 
Published: December 2007

Abstract
The salinity log was developed as a means for determining the presence and degree of salinity in formations surrounding the borehole. Being a radiation- or nuclear-type log permits its application in wells that have been cased and in wells where air or other gases may have been the drilling fluid.
Two curves ("chlorine" and "hydrogen") are recorded simultaneously with a single detector, and these curves are compared in the salinity determination. The two curves have been independently calibrated to show their response to changes in salinity and borehole size.
The salinity log has been run successfully in various oil-producing areas of the United States and Canada. Because of changes in the invaded zone with time, the log is most useful when run several days after cementing casing in the well.

Introduction
Everyone familiar with the interpretation of electric logs recognizes that in many cases these logs do not provide positive answers. This is particularly true of the logs that were recorded five or more years ago.
To at least partially satisfy the needs created by these limitations of the electrical jog approach, the salinity log was developed. In addition to not having some of the open-hole limitations of the electric log, the radioactive-type salinity log can be recorded through casing. It is believed that the invaded zone undergoes changes subsequent to the setting of casing in a well. This change may be effected by fluid migration, diffusion of formation fluid and drilling filtrate, gravity segregation, etc., and the rate of change will be influenced by the types of fluids involved, formation permeabilities and pressure differentials. Therefore, the maximum value from the salinity log probably will be realized by running it after sufficient time has elapsed subsequent to setting casing to allow the invaded zone to have effectively dissipated.
Thermodynamic Modeling of Quaternary Systems: Oil/Brine/Surfactant/Alcohol
Authors: Kilpatrick Peter K. , Scriven L. E. , Davis H. T. 
Published: December 2007

AbstractSurfactant flooding for EOR results in multiphase oil/brine/surfactant/alcohol mixtures. Because alcohol and surfactant do not partition among the phases in constant proportion, thermodynamic modeling of quaternary systems is necessary in an accurate treatment of phase equilibria in these systems. We describe here the quaternary version of a free-energy-based equation of state (EOS). The systematic computation of phase equilibria in a quaternary system begins on the binary edges and ternary faces and proceeds by numerical continuation through the higher dimensional composition space. We expedite the computation with knowledge of the limits of thermodynamic stability—the spinodal surfaces—and all critical points that lie on those surfaces. This preliminary calculation indicates those regions in which solution of the nonlinear equations of phase equilibria will suffer from slow numerical convergence. Multiphase equilibria are searched out by both parametric and compositional continuation. The results provide the basis for understanding the trends of three- and four-phase equilibria in oil/brine/surfactant/alcohol mixtures.
Computing Techniques for Water-Drive Reservoirs
Authors: Hicks A.L. , Weber A.G. , Ledbetter R.L. 
Published: December 2007

Abstract
A procedure which makes use of both analog and digital computers has been developed for predicting the pressure-production behavior of water-drive reservoirs. The electric analyzer is used for matching the past pressure and production history of the reservoir and inferring the physical characteristics of the aquifer. When the history has been matched, a set of base curves called "influence functions" are derived and the future behavior of the reservoir is calculated from these curves.

Introduction
Electric analog methods are particularly well-suited for complex water-drive problems. Like all other methods of analyzing water-drive reservoirs, however, analog methods are subject to certain limitations. One of the more obvious and serious of these results from inaccurate or insufficient knowledge about physical characteristics of the reservoir and aquifer. However, it is not insurmountable because the unknown characteristics can usually be inferred from the reservoir's previous behavior. Simons and Spain have shown that even with scant reservoir data and limited production history, electric analyzer studies can provide useful and reliable results.
Aside from this limitation on analyzer predictions, the main disadvantage has been lack of a technique for keeping predictions abreast of latest production forecasts. Pressure behavior of a reservoir depends on the rate at which fluid is withdrawn; it is therefore necessary to specify the future withdrawal schedule before the future pressure behavior can be calculated. Conventionally, the electric analyzer predicts pressure behavior for a specific production schedule. If this schedule is abandoned in favor of some new one, as is frequently the case, either the study must be rerun or results adjusted in some manner. The usual procedure is to predict pressures for several different forecasts covering a wide range of production rates. Pressures for specific rates other than those studied can then be approximated by interpolating between the analyzer predicted curves. However, reliability of this type of prediction is doubtful.
This paper describes a technique for predicting future behavior of water-drive reservoirs that retains all advantages of electric analyzer analysis and eliminates the main disadvantage. That is, the analyzer is used conventionally to infer unknown reservoir parameters from the pressure history, but not to predict the future behavior directly. Instead, a derived set of base curves, called influence functions, can be used to calculate future behavior for any production schedule.
Automatic Data Readout Cuts Equipment and Labor Costs In Oklahoma Waterflood Project
Authors: Verseman C.S. 
Published: December 2007

Abstract
Automatic data readout is being utilized at seven LACT batteries in the North Burbank Unit to determine BS AND W, temperature and gravity. This results in a more efficient operation by increasing the accuracy of determining the three required functions for selling crude oil and by reducing operating labor. The paper covers the type of equipment utilized and the operating characteristics of the system.

Introduction
The North Burbank Unit, a waterflood project, is located in the northwestern portion of Osage County, Okla., Phillips Petroleum Co. is the operator. The unit was started in 1951 and presently has nine LACT systems, two manual tank batteries and 13 water-injection stations. The present average daily production is 24,500 bbl of oil and 175,000 bbl of water. Water is injected into the Burbank sand and recovered through a completely closed system. Fig. 2 is a typical LACT system and water- station installation. A basic dump-tank type system is used for the North Burbank LACT. Vessels comprising a system (see Fig. 2) are the 95-bbl meter tank, the 61-bbl pipeline sump and one 545-bbl surge tank. Four other stock tanks in series furnish the emergency storage for both water and oil. Flow of merchantable oil is from the heater treater to the surge tank, through the transfer pump to the meter tank, into the pipeline sump and then to the pipeline pump-quite conventional for LACT systems throughout the industry. Maximum capacity is approximately 7,000 B/D. This delivery volume depends upon the capacity of the transfer and pipeline pumps. An automatic-data-readout system is used at 7 of the 10 LACT installations. This equipment eliminates the need for storing and analyzing crude-oil samples. BS AND W, temperature and API gravity are measured electronically each time the meter tank fills. Measured values are stored on electrical-impulse counters for readout as required by the Production Dept. to determine daily oil production and by the various pipeline companies to write their weekly run tickets.

Typical Fill and Dump Cycle
Following is a description of one fill and dump cycle starting with the meter tank empty (see Figs. 1 and 2 -- a block diagram of the data- readout system and an LACT flow sheet, respectively). When the transfer pump starts, oil flows through the BS AND W cell to the meter tank. The BS AND W monitor continuously measures the volume per cent of BS AND W in the stream. This value is digitized by the averager and pulses are stored on a counter. Since this is a rate function (pulses/minute/per cent BS AND W), the time (minutes) required to fill the meter tank is also digitized and accumulated on a counter. When the tank is full, the transfer pump stops and BS AND W data are no longer digitized. However, the monitor continues to analyze the sample of oil in the monitor pump-bypass stream from the surge tank and will shut down the system if excess BS AND W is detected.
JPT
P. 473^
Flow Through a Porous Medium With Periodic Barriers or Fractures
Authors: Chirlin Gary R. 
Published: December 2007

Abstract
Apparent permeability of a reservoir may be affected by local variations in permeability whose extent and location are not known in detail. One way to approximate this condition is to postulate a regular pattern of typically shaped and oriented inclusions.
An example is the presence of a large number of very thin, relatively impermeable shale streaks distributed throughout an otherwise homogeneous reservoir. If these barriers to flow generally are oriented alike, then at a scale that is large compared to the individual barriers, apparent permeability will be anisotropic, being higher parallel to the barriers than perpendicular to them. Discontinuous horizontal shale streaks can be responsible for reduced vertical oil drainage to the pumping well1; therefore, a reasonable prediction of vertical permeability in such settings can be of value.
This paper examines the special case of a periodic array of infinitely thin, impermeable barriers opposed to single-phase, two-dimensional (2D) flow. Results provide a quantitative picture of the importance of barrier geometry and arrangement to the apparent anisotropy of permeability. The problem setting, formulated previously,2,3 allows a closed-form analytical expression to be obtained for anisotropy as a function of barrier geometry. However, a previously published solution3 is incorrect.2,4 The purpose of this paper is to present a correct solution and to discuss some of its consequences. Analytical results for this and other geometries, in two and three dimensions, have been developed previously.2 Numerical results for this problem are also available for both single-phase5 and two-phase (gas/oil)1 flow.
Some Possible Applications of Thermal Recovery in Utah
Authors: Covington R.E. 
Published: December 2007

Abstract
The bituminous sandstones of the Rocky Mountain region have significant reserves of oil. Production costs of the reserves must be reduced to be equal to or lower than the cost of crude oil produced by conventional methods. Three Utah deposits alone, Sunnyside, Vernal (Asphalt Ridge) and Whiterocks contain proved reserves of 875 million bbl of oil and "possible" reserves in excess of one billion bbl. In addition, there are at least six more deposits of asphaltic sands which contain substantial reserves within the state.
The most important deposits in Utah from the standpoint of thermal recovery are those of the Sunnyside area, Carbon County, Utah and the Asphalt Ridge-Vernal deposits, Uintah County, Utah. Two other areas which have thermal recovery potential are the bituminous sandstones of the Whiterocks area, Uintah County, Utah and the San Rafael Swell-Nequoia Arch area in Emery, Wayne and Garfield counties, Utah.
A preliminary evaluation of these four areas is discussed from the standpoint of geology, reservoir engineering, costs, markets and future development possibilities. These four, and perhaps three of the six areas of lesser importance, compare favorably with areas now being developed by thermal methods in California, Oklahoma, Texas and Kansas.

Introduction
The threat of large-volume, low-cost imported oil moving into the United States, combined with ever increasing exploration, drilling, completion and production costs, makes it imperative that the American oil industry take a long, hard look at the tremendous amount of oil in the bituminous sandstone deposits, in oil shale reserves and in shallow-to-moderate-depth depleted or semidepleted fields where production has declined beyond the point of profitable return on production costs.
For example, prior to 1950 the only method considered at all feasible for producing the bituminous sandstones of the Rocky Mountain region was by either conventional or strip mining and extracting the bitumen through various types of separation processes.
A New General Model of Fluid Loss in Hydraulic Fracturing
Authors: Settari A. 
Published: December 2007

Abstract
This paper gives a new formulation of fluid loss in hydraulic fracturing that is much more general than the classical theory while retaining its simplicity. The model allows many parameters to vary during filtration and can, therefore, simulate nonlinear effects.
The model has been validated against laboratory data for Newtonian fluids and crosslinked gels. The results show that the finite length of the core, viscosity screenout, and shear sensitivity are important parameters that can be represented by the model. The standard analysis gives values of leakoff coefficients that will give incorrect, considerably higher leakoff when applied to field conditions.
Fracture Conductivity Comparison of Ceramic Proppants
Authors: Cutler R. A. , Enniss D. O. , Jones A. H. , Swanson S. R. 
Published: December 2007

AbstractLightweight, intermediate-strength proppants have been developed that are intermediate in cost between sand and bauxite. A wide variety of proppant materials is characterized and compared in a laboratory fracture conductivity study. Consistent sample preparation, test, and data reduction procedures were practiced, which allow a relative comparison of the conductivity of various proppants at intermediate and high stresses. Specific gravity, corrosion resistance, and crush resistance of each proppant also were determined.Fracture conductivity was measured to a laminar flow of deaerated, deionized water over a closure stress range of 6.9 to 96.5 MPa [1,000 to 14,000 psi] in 6.9-MPa [1,000-psi] increments. Testing was performed at a constant 50°C [122°F] temperature.Results of the testing are compared with values from the literature and analyzed to determine proppant acceptability in the intermediate and high closure stress regions. Fracture strengths for porous and solid proppants agree well with calculated values.Several oxide ceramics were found to have acceptable conductivity at closure stresses to 96.5 MPa [14,000 psi]. Resin-coated proppants have lower conductivities than uncoated, intermediate-strength oxide proppants when similar size distributions are tested. Recommendations are made for obtaining valid conductivity data for use in proppant selection and economic analyses.