bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Permian Massive Conglomeratic Reservoir in Karamay Oilfield
Authors: Liu Jingkui 
Published: December 2007

ABSTRACT
This paper gives an analysis of Wuerhe oil reservoir in block-8 and discusses the effectsof Sedimentary facies, reservoir texture, diagenetic compaction and epigenesis on the petrophysical properties and the oil saturation of this low permeable reservoir. The alluvial-flood fan depositional facies and structural elements give controls on the oil and gas distribution; "multi-mixtures" texture makes the petrophysical properties worse; the diagenetic compaction and epigenesis cause authigenic minerals to be vertically distributed zones and horizontally in belts. A low permeability, fine throat and double-porosity reservoirdominated by secondary porosity is formed. Thedata of conventional core analysis, special core analysis, well-testing, and their isopack maps are used to evaluate the reservoir in eachzone and each belt. The development pattern ofthis type of oil reservoir is discussed with these parameters together with those data from the production tests.
The lower Wuerhe oil reservoir of upper Permian in block No. 8 of Karamay oilfield, is located on the monocline of K-W overthrust zone along the N-W margin of Zhunger Basin, it is bounded by No. 202 paleo-uplift in its west andby Mahu depression in its south, being a monocline controlled by "A" type faults formed by an intersection of the K-W fault and No. 202, No. 256 faults. It dips to the southeast at an angle of 3-14° with an average depth of burial of 2900 m, and is a conglomeratic reservoir of alluvial-talus mixed facies with a thickness of 111-815 meters. From the bottom to the top the seven members, U17-U11, are overlapped on Carboniferous-Permian andesite with a mean effective thickness of 58 m, an effective porosity of 9.0% and an effective permeability of 2.15 md.U13,U14,U15, are the major oil-bearing zones and the U16,U12, being the next. The reservoir pressure is 348.5 atm. and saturation pressure is 296 atm. The original GOR is158 m3/m3, and the formation temperature is 67°C. The reservoirviscosity of the oil is low, averaged 0.7 cp. Salinity of formation water is 30 g/l and is in the type of CaCI2, NaHCO3, or Na2SO4(see Tables).
Poor depositional facies, strong diagenic compaction, complicated reservoir matrix texture and intense epigenesis have resulted in the characteristics of a fine throat and low porosity, very low permeability double porosity conglomeratic reservoir which is dominated by secondary porosity.
An Equation of Formation Deviating Force and its Application
Authors: Yang Xunyao 
Published: December 2007

ABSTRACT
An equation of formation deviating force has been developed based on drillability anisotropy of formation. It can be used to simplify the calculation of deviation control by a pendulum drill string, to determine the formation anisotropy index and to analyze quantitatively the total deviation force acting on the bit in combination with drill string mechanics. A sample calculation of deviation control by a pendulum drill string with a specified length is also presented. A number of field tests have demonstrated satisfactory results.
The Black Oil Model for a Heavy Oil Reservoir
Authors: Huan Guanren 
Published: December 2007

ABSTRACT
In a real black oil reservoir, especially in a heavy oil reservoir, the density, viscosity and other fluid properties of the oil vary both horizontally and vertically from point to point in the formation. For example, formation oil viscosity may vary several times and even more from the top of the formation to the water-oil contact. This phenomenon is due to the variation of crude oil composition. In a heavy oil reservoir, due to the gravity segregation and the difference of the oxidation of water to oil, the asphaltine and gel content of the oil varies with depth and the distance to the water-oil contact. The above mentioned phenomenon and the behaviour of that type of reservoir can not be realistically simulated by the conventional black oil model with multipool approach.
This paper suggests a black oil model with four components, which uses a two-pseudo-component-mixture concept to solve the above mentioned simulation problem. In this model, oil is considered as a mixture of two pseudo oil components with the different asphaltine and gel contents. In this case, the properties of the mixture will be dependent on, in addition to the pressure and temperature, the mass fraction of each pseudo component in the mixture.
The paper uses the 'flash' approach in paper(1)to solve this problem. In the model, the pressure and the four components (water, gas and two pseudo oil components) masses per unit formation volume are considered as basic unknowns to be solved. Though more complicated considerations are included, the model still uses the PVT data of conventional black oil, and the computer time would not be increased too much, as the Sequential Implicit method is applied for the numerical solution.
An Improved Model for Interfacial Activity of Acidic Oil/Caustic System for Alkaline Flooding
Authors: Tong Mingzhe , Liu Pu , Zhang Lufang , Zhu Yajie 
Published: December 2007

ABSTRACT
In alkaline flooding, Interfaclal properties of acidic oil/aqueous caustic play an important role. Although lots of experimental results concerning the effect of various parameters upon interfacial tension and surface charge density have been reported, the mechanism is still not well clarified. C. J. Radke, T. F. Yen and D. T. Wasan have already presented their chemical models for interfacial phenomena of this system, but they all ignore the possibility of forming micelles in the aqueous phase.
This article deals with an improved equilibrium chemical model of acidic oil/caustic system. Taking the effect of NaOH-NaCI concentration on the micelles formation into consideration, an expression of interfacial activity is proposed on the basis of Davies theory of the ionic monolayer. Using kerosene containing oleic acid/aqueous solution of hydroxide-sodium containing sodium chloride as the model system, the data of interficial tension (7) and electrophoretic mobility (U) with various concentration of sodium hydroxide and sodium chloride in aqueous phase and acid value of oil phase are presented. The critical micelle concentration of sodium oleate under the various ionic strength is determined and the relation between the micelle concentration and ionic strength is employed in the simulation calculation. γmin and U max thus obtained from the model calculations agree well with the experimental results in regard to the varying trend of parameters used. The mechanisms for the presence of γ min are also suggested. This model may be used in practical numerical simulation for alkline flooding with reasonable option of physicochemical parameters.
Well Testing in the Annulus of Pumping Wells
Authors: Wang Qian , Fu Shenquan , Wang Zhuguo , Sun Yingche 
Published: December 2007

ABSTRACT
Well testing technique in the annulus of a pumping well has been a subject on which great efforts have been made by petroleum scientists and engineers in recent years. Based on the practical situation in our country this paper analyzes and discusses in detail the features of such techniques developed in our country. The paper also describes some testing devices, instruments and equipment used for the well testing in cacing-tubing annulus and puts forward their opinions as to the interpretation of the data obtained from such instruments in the downhole annulus and its application. Thus a valuable basis for the development of well testing techniques in pumping wells in our country is provided.
Variable-Rate Reservoir Limits Testing
Authors: Blasingame T. A. , Lee W. J. 
Published: December 2007

ABSTRACT
This paper presents a new method of estimating drainage area size and shape from production data (bottom-hole pressures and flowrates). The method is a rigorously derived approximation for variable-rate flow in. a closed reservoir. This method requires a graph of Δp/qm vs. the superposition plotting function (which is easily calculated by hand). The slope and intercept of the graph are used to provide the desired estimates of drainage area size and shape.
The method that we propose is an approximation, however it has been proved to be very accurate for the constant rate, constant pressure, exponential rate, logarithmic rate, hyperbolic rate, sinusoidal rate, and discrete rate cases. The method also gives acceptable results for square wave rate and random rate cases.
The new method is derived for the time after the initial pressure transient has reached the outer boundary. The changes in flowrate cause additional transients, but we assume that this effect is negligible when compared to the influence of the outer boundary. Therefore, if the change in flowrate does not dominate the influence of the outer boundary, the new method should give acceptable results. Also, at present, this method is only derived for single-phase flow of a liquid of small and constant compressibility.
Steamflood Surveillance Using Temperature Observation Wells
Authors: Wood S. G. , Dunham D. J. 
Published: December 2007

ABSTRACT
Much has been written about screening criteria and design methods for steamflooding. However, equally important is surveillance of existing projects. Fields undergoing expensive supplemental recovery processes cannot be installed and then left unattended. Careful monitoring of a steamflood is needed to ensure that the operator is producing the most oil for the least steam, or in other words, is maximizing the project's profitability.
This paper describes one of the current surveillance programs for the Tulare formation steamflood in the South Belridge field, in Kern County, California. The progress of this steamflood is difficult to determine from volumetrics because of simultaneously flooding multiple sands with commingled injection and production wells. A primary tool was therefore needed to directly measure areal and vertical sweep efficiencies in order to optimize drainage and injection.
This has been accomplished by the use of temperature observation wells in about one per every three five-acre patterns. The observers consist of wells converted to observation and newly drilled observation wells. Several logging techniques were evaluated to ensure accurate, economical and timely data.
These observation wells are logged semiannually to determine the temperature of each of seven producing sands. This information is then used to construct computerized temperature isotherm maps for each sand over the entire field. These maps show which areas are being adequately heated and which are either too hot or not hot enough. Steam injection profiles and rates can then be adjusted accordingly using analytical heat balance calculations or temperature based injection guidelines from thermal reservoir simulations. The maps also show where additional steam injection wells or producers may be required.
Conductivity Testing of Proppants at High Temperature and Stress
Authors: McDaniel B. W. 
Published: December 2007

ABSTRACT
A non-commercial approach to measure fracture conductivity in the laboratory has been developed to assist operators in selection of proppants for high temperature and high stress hydraulic fracturing applications. Simple laboratory tests that would dictate proppant choice are no longer considered sufficient since test parameter choices affect the outcome so drastically. For example, extending the stress period from 1 hour to 18 hours can decrease the measured conductivity value by a factor of three. The added effects of brine flow at elevated temperature for extended time periods have been seen to result in even greater conductivity decreases.
Much conflicting conductivity data has been presented in our industry. Often, the choice of test parameters or the test cell design have been responsible for these discrepancies. Sometimes such data are used to select a certain product and may significantly disagree with other published test results which indicate the superiority of a different proppant.
In this work, several variables that can affect measured proppant conductivity were evaluated using five proppants of different composition.
The variables studied were: (1) Effects of extended time at different test conditions; (2) Variation between ambient and elevated temperature testing; and (3) Effects of brine flow at high, temperature and closure stress.
Subzero Hydraulic Fracturing: A Field Case Study, Lisburne Carbonate Reservoir, Prudhoe Bay Unit, North Slope, Alaska
Authors: Schumacher J. P. , Dickerman R. P. 
Published: December 2007

ABSTRACT
A successful hydraulic fracture treatment was performed on a delineation well in the Lisburne naturally fractured reservoir, North Slope, Alaska during extremely severe weather conditions. The well performance information from this delineation well was of critical importance to the development and subsequent funding of the $2 billion Lisburne project. Logistical problems which developed prior to the fracture treatment required special design considerations usually taken for granted in many North American locations. Special considerations for economy, the environment and safety were integrated into a straightforward hydraulic fracture treatment performed at a wind chill temperature of −85°F (−51°F ambient).
This paper discusses the fracture design and February 11, 1984 field treatment which led to the successful stimulation of the South Bay State No. 1 delineation well. Also included is a discussion of the results obtained from the subzero hydraulic fracture treatment. A better understanding of equipment performance, fluid rheology, proppant mixing, logistic limitations and human elements under severe weather conditions was gained from the treatment.
In addition, this paper addresses the following cold weather concerns that arose prior to the implementation of the fracture treatment:
○ Use available equipment, successfully perform hydraulic fracture treatment. ○ Mix proppants and additives "on the fly". ○ Proper function of electronic, pneumatic and hydraulic systems as well as rubber conveyor belts. ○ Safe and proper seal of surface tubulars. ○ Rheological properties of gelled diesel. ○ Effects of the elements on human beings. ○ Pre-frac breakdown to gain more data. ○ Uncomplicated pump schedule.
A Study of Crude Oil Composition During CO2 Extraction Process
Authors: Wang G. C. 
Published: December 2007

ABSTRACT
The extraction process of hydrocarbon from crude oil by CO2 and the development of miscibility were simulated in a high pressure visual cell. Samples of the extracted crude oil as well as the enriched CO2 vapor were withdrawn successively from the cell for composition analysis using a gas chromatograph.
Three natural crude oils with gravities ranging from 17° to 45° API (sp. gr. 0.80 to 0.90) were chosen for the study. The results indicate that the CO2-crude oil interactions can be divided into three stages: (a) CO2 condensation, (b) extraction-condensation and (c) extraction. It was found that the amount of hydrocarbon being extracted was proportional to pressure or CO2 density. Lighter components from C5 to C20 were comparably easy to be extracted, however, heavier components up to C36 may also be extracted though in a relatively smallquantity. For heavy crude oil containing low intermediates of C5 to C20, the extraction was inefficient at all conditions. Active and deep extraction may cause permeability damage due to excessive asphaltine deposition.
Temperature has a great effect on CO2 extraction. The extraction efficiency could be improved with reduced temperature. Best extraction was obtained when CO2 was in liquid state.
Evaluation of the Performance of 13% Cr/4130 Bimetallic Tubing in CO2 Environment
Authors: Dávila A. , Newski M. , Zerpa G. 
Published: December 2007

ABSTRACT
The corrosion behavior of 13%Cr/4130 bimetallic tubing produced by hot forging was evaluated under extreme CO2environment, i.e. well conditions. This investigation involves corrosion testing in static autoclaves and an additional full scale test, in order to evaluate the corrosion behavior of the pipe and its connection under different Venezuelan well-operational conditions. Furthermore chemical composition, mechanical testing and metallographic characterization were also carried out.
The study is relevant to the oil industry since it implies a cost reduction of about 30% compared with the use of conventional 13%Cr OCTG tubulars. Excellent resistance was achieved with mechanical properties of the pipe similar to the 4130 carbon steel and a corrosion resistance to the CO2 environment equivalent to that of the 13%Cr conventional pipe. However, the interfase shows depleted chrome regions, as a result of carbon diffusion for adequate metallurgical bonding during manufacture of the pipe, which makes it susceptible to galvanic corrosion. As a result of this investigation the bimetallic tubing will be tested under different field conditions.
A Color Borehole Television System for Developing Gas Production From Devonian Shales
Authors: Darilek G. T. 
Published: December 2007

ABSTRACT
A specialized borehole television system has been developed to aid in the development of gas production from eastern Devonian gas shales and other tight formations. The borehole television has advanced capabilities that are useful for visually diagnosing geological and reservoir factors associated with gas production. These features include high resolution color video, compass for orientation determination, control of borehole debris to maintain an unobstructed view, and simultaneous forward and upright side view. The side view is provided by positioning a mirror in front of the camera lens. Upright orientation of the side view image is maintained by rotating the camera and mirror assembly as a unit within the camera housing. The forward view provides rapid reconnaissance and the side view is used for detailed inspection of features in the borehole. A compass placed beneath the side view mirror is used to determine the orientation of the viewed image.
Field applications in the Appalachian basin demonstrated the usefulness of the color borehole television system. Geologists visually examined the depths of the gas wells to identify the factors affecting gas production. Of particular utility was the ability to definitively identify areas of gas and oil entry. Gas condensate was observed to bubble and vaporize as it entered the boreholes. The locations of side wall core samples were verified and the orientation of these samples was determined. Geological strata, crude oil stains, condensate and crude oil in the bottom of the well, cavities, porous zones, fractures, and casing were inspected. The camera was also used to locate a stuck logging probe lodged between the casing and a washout behind the casing The system has been installed in a borehole television logging truck for use in Gas Research Institute Devonian shale research programs and other commercial applications in the Appalachian Basin.
Pressure Transient Analysis of Methane Production From Coal Beds: An Analytical Approach
Authors: Bayles G. A. , Reznik A. A. 
Published: December 2007

ABSTRACT
Transient and semi-steady-state solutions of the radial diffusivity equation are presented for the case of well tests on coalbed-methane reservoirs.
An inverse diffusion term, which characterizes coupled matrix-fracture gas. transport, is defined from a Langmuir desorption term and the inverse hydraulic diffusivity. The ratio of this total or coupled diffusivity to the hydraulic diffusivity is identified as the time delay of the bottom-hole flowing pressure response of the coalbed vis-a-vis that of a conventional gas reservoir during a constant-rate pressure drawdown test.
The modified transient and semi-steady-state equations for pressure drawdown as functions of time are completely analogous to those for conventional gas reservoirs when the inverse hydraulic diffusivity of the latter is replaced by the inverse coupled diffusivity of the coalbed.
A numerical simulator is employed to solve the open forms of both the conventional and coalbed radial diffusivity equations. The usual straight-line trends for the transient and semi-steady-state periods are manifest from simulation of both cases. These were parallel for the transient time period and divergent for the semi-steady-state period.
Values of permeability, net skin factor, area of drainage and shape factor are obtained directly from the pressure-versus-time plots of the two time periods.
The present analysis is limited to the extreme matrix-to-fracture transport rates, namely, instantaneous and zero. Actual pressure-response data, however, can be analyzed for any implicit transport rate.
The present work is limited to single-phase gas flow without wellbore storage and to a single net skin effect.
Designing Hydraulic Fractures for Efficient Reserve Recovery
Authors: Elbel J. L. 
Published: December 2007

ABSTRACT
In designing hydraulic fracturing treatments, the designed fracture length is often limited to a percent of the drainage distance. If the well spacing is based on a square pattern, the results may be that the designed fracture length is too small to achieve adequate production at an early time. If the fracture length is increased to provide adequate early-time production rates and the spacing is increased accordingly but still in a square pattern, the result may be that a large portion of the reserves will remain in place after a normal 20- or 30-year well life. A number of papers have been written concerning fracture optimization and well spacing indicating the need for a rectangular drainage shape. This paper shows how cumulative production type curves for hydraulically fractured wells can be used as guidelines in determining the combinations of fracture length, fracture conductivity, spacing and spacing geometry to provide an adequate early production (one to two years) and efficient reserve recovery (±90% in 20 to 30 years). The method presented can be performed in a matter of minutes. It can also provide a basis for a more thorough reservoir simulation if more detail or accuracy is required to overcome the limitations imposed by the use of type curves.
Effective Production Strategies for Coalbed Methane in the Warrior Basin
Authors: Wicks D. E. , Schwerer F. C. , Militzer M. R. , Zuber M. D. 
Published: December 2007

ABSTRACT
This paper discusses the economics of coal-bed methane production in the Warrior Basin under a variety of production strategies. Traditional development practices in the basin have used such techniques as hydraulic fracture stimulation in the single major coal seam, with wells spaced relatively close together on a square shaped pattern. This paper examines the enhancement of production using larger stimulations along with the corresponding economic impacts. Also examined are the effects of using multiple completions on several coal seams in the Pratt, Mary Lee, and Black Creek coal groups to further increase production from a single well. Finally, the impacts on production of drilling on various sized spacings and drilling on elongated pattern shapes to take advantage of permeability anisotropy are simulated. The production streams are then utilized in a detailed cost and economics model to determine the minimum gas price required for various rates of return on investment.
The effects of technology and production strategies for coalbed methane are forecast using a detailed two-phase, dual-porosity finite-difference simulator to predict both gas and water production rates. These rates are then used in the cost and economics model to determine equipment size and compression costs as well as generating revenue streams on which to calculate discounted cash flow. Costs are also determined by the depth of the seams, and in the case of stimulation, the thickness of the treated interval. The majority of the detailed reservoir data required to run the simulator were determined through field and labora tory tests at the Gas Research Institute's Rock Creek Multi-Seam site.