bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Initial Water Saturation Distribution for a Three-Dimensional Model
Authors: Prickett H. D. , Bremer R. E. 
Published: December 2007

ABSTRACT
A new technique was developed for initializing a simulation model to account for areal variation in initial water saturation caused by changes in reservoir quality. The new technique uses permeability and lithology dependent Leverett J-functions with a suite of porosity-permeability transforms to calculate water saturations for finely gridded geologic models of the reservoir. Saturations were then integrated over the larger individual grid-blocks in the 3-D reservoir model.
Laboratory and Simulation Studies of Oil Displacement Behavior Due to Bottomwater Drive
Authors: McCaffery F. G. , Wunderlich R. W. , Cartwright R. P. 
Published: December 2007

Abstract
Laboratory displacement measurements and computer simulations were performed to support field evaluations of residual oil saturation for a high permeability sandstone reservoir exhibiting moderately to weakly water-wet characteristics. Logging and sponge core data had indicated low oil saturations in zones depleted by natural bottom water drive. The laboratory displacement tests were designed to help further verify these results and to provide data most applicable for the prediction of future field performance. Reservoir conditions displacement test data were in reasonable agreement with the field results, but laboratory conditions tests predicted higher residual oil saturations. Water-flood and centrifuge measurements were in agreement under appropriate experimental conditions.
Simple simulations were conducted to evaluate factors affecting the gravity drive process during vertical displacement of oil by water. Particular attention was paid to sensitivity analyses of the effects of the oil relative permeability and viscosity characteristics. The results obtained are useful for reservoir management questions relating to production rates, coning phenomena, and time-lapse monitoring of saturation changes.
Improved Density Log Lithology Identification Using a Borehole-Compensated Photoelectric Factor
Authors: Moake G. L. , Schultz W. E. 
Published: December 2007

Abstract
A photoelectric factor (Pe) measurement is now commonly available with density tools. By aiding in lithology identification, Pe information provides better estimates of matrix densities, thereby improving porosity interpretation from density logs. Pe measurements, however, are adversely affected by borehole rugosity and mudcake. In order to minimize these effects, a borehole compensation method has been developed that yields improved Pe accuracy in non-barite muds.
Prior Pe measurements normally were determined from the density detector farthest from the source (PeL) and were not compensated for borehole effects. However, the Pe obtained from the more tightly collimated short-spaced detector (PeS) is less affected by non-barite mudcake, tool standoff, and borehole diameter than PeL. Thus, unlike the compensation scheme used for density measurements, the primary Pe measurement is obtained from the short-spaced detector.
The densities measured by the short-spaced and long-spaced detectors are both affected by the same borehole factors, although with different sensitivities. It is appropriate, therefore, to derive the density correction term from the difference between the two densities. However, PeL is sensitive to several borehole parameters that do not effect PeS. Thus, a correction based on the difference between PeS and PeL, although partly successful, can lead to inaccuracies. Therefore, a better Pe compensation method was developed.
The primary borehole parameters that affect PeS are the mudcake thickness, mudcake density, and mudcake Pe. (Standoff is included in this analysis by considering the mud between the pad and the formation to be mudcake.) In order to reduce the complexity of the problem, the mudcake Pe is assumed to be small, which means that this model is only appropriate for muds that do not contain barite or hematite. Under this condition, it is shown that the required Pe correction can be determined from the density correction and an estimate of the mud weight.
The correction term is added to PeS to obtain a compensated Pe. A correction term is also obtained for PeL. However, the compensated PeL is less accurate than the compensated PeS, so it is only used in conjunction with PeS to produce a quality curve.
Verification of the Pe compensation is demonstrated with test formation data obtained using various borehole fluids, tool standoffs, and simulated mudcakes. Also, shop calibration procedures and wellsite check tolerances are presented for density and Pe logging. Finally, log examples are presented to illustrate improvements in lithology identification using the compensated Pe.
Applications Using Geochemical Logs
Authors: Colson J. L. , Grau J. A. , Herron M. M. , Herron S. L. , Schweitzer J. S. , Hertzog R. C. , Preeg W. E. , Nurmi R. D. , Johnston J. 
Published: December 2007

ABSTRACT
Elemental logs can be combined with mineral models to provide significant information for geological description and evaluation of downhole formations. Mineral compositions from geochemical logs can be applied to a variety of lithologies, stratigraphie settings, and geological ages including those of the Middle East.
The most abundant element concentrations in the rock-forming minerals are obtained from the Geochemical Logging Tool (GLT*). This tool measures natural, activation, and prompt neutron capture gamma-ray spectra. In addition to the traditional potassium, thorium, and uranium from natural gamma-ray spectrometry, a direct measurement of aluminum concentration is provided. A geochemically-based closure model is used to derive silicon, calcium, iron, sulfur, gadolinium, and titanium concentrations.
The concentration of these elements, expressed in weight percent, significantly improves identification of mineral composition, and allows the estimation of important formation properties -- an excellent basis for a broad range of applications useful to petroleum engineers, geologists, and petrophysicists.
Acoustic Characterization of Permeable Zones From Full Waveform Array Sonic Data
Authors: Poster C. K. 
Published: December 2007

ABSTRACT
Studies of the Stoneley wave in conjunction with log, core and production data have indicated an increase in Stoneley wave slowness and a decrease in amplitude in the vicinity of permeable zones. This case study, in a Middle East carbonate reservoir, compares these Stoneley wave characteristics with open hole Production Logging Tool (spinmeter) measurements which accurately represent variations in the in-situ permeability of formations. The results confirm a qualitative correlation of the Stoneley indicators with both permeable zones and fractures. Examination of the Stoneley waveforms themselves, also indicate events which further suggest the presence of open fractures.
With the Array Sonic Tool* we can carry out routine acquisition and determination of compressional, shear and Stoneley wave slownesses and energies. Stoneley waves are distinguishable in the sonic wavetrain by their large energy, low frequency and late arrival times. The slownesses of all the sonic wave's modes can be estimated from the array's waveforms by a Slowness-Time Coherency (STC) technique.
A Comprehensive Approach To Solve Asphaltene Deposition Problem in Some Deep Wells
Authors: Akbar S. H. , Saleh A. A. 
Published: December 2007

ABSTRACT
Crude oil flowing from deep reservoirs are exhibiting asphalt deposition in the production tubing. In some cases the tubing is getting completely plugged, leading to the loss of production from these wells.
Literature on asphaltene deposition in deep wells with high pressure and high temperature is hardly available. To understand the asphalt precipitation and deposition phenomena and its control, a comprehensive program of work was formulated by the Company as indicated below: 1-Laboratory investigation –asphaltene solubility at various pressures and temperatures–inhibition tests–compositional grading2-Field investigation –effectiveness of plastic coated tubing–down hole chemical injection–effect of PI improvement on deposition behaviour–chemical means of cleaning the tubing–mechanical means of cleaning the tubing
Progress made so far and future continuation of the work is highlighted in this paper.
Field Performance of Submersible Oilwell Pump in Mubarras Field, Offshore Abu Dhabi, U.A.E.
Authors: Miwa M. , Yamamoto Y. 
Published: December 2007

ABSTRACT
Artificial lift with electrical submersible pumps has been applied as a part of oil production in the Mubarras field, offshore Abu Dhabi, U.A.E. since 1975. A trouble analysis is conducted using trouble types experienced in the 13 years to clarify the problems on the electrical submersible pumps. The results show that many problems have been solved by engineering improvements in cable designs, protector systems, etc. Also, transition of pump life time by reservoirs shows that reservoir characteristics are an important factor for the field performances of pumps. The present average pump life time is 774 days and the longest pump life time has reached 1659 days.
Analysis of Pressure Buildup Tests in Naturally Fractured Reservoirs: Field Cases
Authors: Singh B. B. 
Published: December 2007

ABSTRACT
Field cases of pressure build-up tests are presented for two reservoirs which showed existence of fractures on cores. The nature of the pressure build-up data on these tests have shown the importance of preparing various cross-plots to diagnose the existence of fractures in the reservoir. In many cases presented, 2 parallel straight lines with transition in between were noticed on Horner plot. In some cases, the pressure build-up tests conducted in the early life of the well were typical of a homogeneous system with afterflow and skin, although linearity of data points was obvious on Δ p vs square root of shut-in time plot. Subsequent pressure build-up tests of the well, however, showed 2 parallel lines with transition in between on Horner plot. The tests with 2 parallel slopes, showed unique trend on Pollard plot since it yielded two intersecting straight lines after early period, not reported earlier.
The storativity ratios are estimated to be rather high in spite of the large matrix block height estimated, perhaps due to high matrix permeability. These facts underscores the importance of using all available evidences to derive physically consistent parameters for analysis of naturally fractured reservoirs.
Time-Lapse Saturation Monitoring and Its Applications to Time-Lapse Mapping
Authors: Nutt R. L. , Watfa M. 
Published: December 2007

Abstract
Oil production and water injection involve extensive fluid movement through a reservoir. Monitoring of these fluid movements, and in particular water flooding of the hydrocarbon zone, is essential to optimization of reservoir performance. Fluid movements in carbonate reservoirs are complicated by their heterogeneous pore systems, which result in wide variations in permeability and cause uneven sweep and non-uniform depletion. High permeability streaks can promote fingering and channelling within the reservoir. Development of these irregular flow patterns is a function of porosity and permeability distribution, proximity to the original oil/water contact, activity of the underlying aquifer, vertical and lateral distance from injection points, and production and injection rates and distribution. The combined effects of all these parameters cannot be reliably modelled and predicted: their inter-relationship can only be determined by measurement of fluid saturations field-wide throughout the production life of the field.
The normal technique for monitoring water saturation changes behind casing, when water salinity is high, is to survey using neutron decay time logs. These measure the neutron capture cross-section (Σfor) of the formation, which can be interpreted - together with open hole logs - to obtain values for water saturation.
This paper illustrates an application of this technique on a field-wide basis over an extended period. Open and cased hole log data are combined into a data base of long term variations in water saturation. All the interpreted data are represented on maps which show the changes of water saturation with time. Maps of permeability distribution provide additional information which can explain anomalies and irregularities in the saturation maps. Such a field-wide study of reservoir behaviour enhances understanding of fluid movements, identifies high permeability intervals, and indicates zones of undisplaced hydrocarbon. The final objective is to use the derived model and understanding in simulations which will optimize and accurately forecast reservoir performance.
Study of a Complex Carbonate Reservoir Using the Formation MicroScanner (FMS) Tool
Authors: Badr A. R. , Ayoub M. R. 
Published: December 2007

Abstract
The Simsima reservoir is a complex carbonate reservoir exhibiting a high degree of heterogeneity, both vertically and laterally. The reservoir subunit log correlation has always been a difficult task due to its intricate nature, further complicated by high and sometimes erractic levels of radioactive content which affect the GR log response. Hence, correlation of lithology variation within the reservoir has been stressed and has only been possible with the study of cores.
Since it is envisaged not to core this reservoir in each future development well and since core recovery is not always good, the study of these lithology variations and their impact on the reservoir characteristics by use of the Formation MicroScanner (FMS) log, developed recently by Schlumberger, has been applied with encouraging results.
A Field Study and Mapping of Permeability in Gulf of Suez Sandstone Reservoirs
Authors: Khafagi M. R. 
Published: December 2007

Abstract
Permeability is one of the most difficult parameters to determine downhole. The normal procedure is to obtain values of permeability thickness (kh) for a zone from pressure drawdown or buildup tests. Core data for permeability are used extensively for calibrations, and to obtain permeability profiles. Generally, the applications of permeability data can be divided into two categories: To evaluate the performance of zones and sub-zones in each well and predict producibility or injectivity.To map and grid permeability thickness (kh) on a field basis to simulate and optimize field performance.
To obtain a continuous permeability profile as a function of depth, a large number of core analyses are needed over the zones of interest for each well. For economical reasons, however, most of the wells in a field have neither test data nor adequate permeability core analysis. With this limited permeability data for a field, a complete picture cannot be constructed. Thus, additional permeability data is needed. This is achieved by acquiring additional data, or by estimating permeability, using the existing core data as calibration standards.
This paper discusses a statistical technique in which core, test and log data are integrated to estimate permeability values in a Nubia sandstone reservoir. A statistical data-bank of information is constructed from a selected number of key wells where complete data (such as porosity, permeability, and so on) are available. This data-bank is then used to estimate missing permeability values for wells where all the data in the data-bank is available with the exception of permeability. A greater abundance of scattered data is thus obtained, and this allows individual well and field performances to be evaluated. The logic behind using a data-bank is that some of the log parameters, such as porosity, irreducible water saturation (Swirr), Archie Factor (m), etc., are also sensitive to the factors which affect permeability, including pore and grain distribution, and the number of pores and channels. Hence, a multi-dimensional correlation can be established. The results obtained from statistical data-bank analysis were compared with core, production and test data. The results of the correlation gave a reasonable degree of certainty.
Geochemistry and Hydrodynamics of the Partitioned Neutral Zone: Their Impact on Shallow Reservoir Performance
Authors: Ghoniem S. A. , Al-Zenki F. H. 
Published: December 2007

Abstract
This paper presents a hydrodynamic model for the Partitioned-Neutral Zone (PNZ) situated between the State of Kuwait and the Kingdom of Saudi Arabia. Geological and petrophysical data, Potentiometric surface measurements and salinity data were used to split Cretaceous and younger formations of PHZ into nine hydrodynamic layers. Based on these data, it was concluded that 4 layers are hydrodynamically active and at least 3 layers are substatic while the remaining 2 layers do not include enough data to reach conclusion. The geochemistry of the produced water further confirm the hydrodynamic model of PNZ area. The impact of activity of the shallow layers on the respective oil reservoirs is discussed. Results of managing shallow reservoirs in light of the proposed model are presented. Salinities recommended for the estimation of original oil-in-place (OOIP) of the shallow reservoirs are also given in this paper.
Drilling and Completion of Dual Gas Injection Wells in Multilayered Reservoirs
Authors: Farid E. A. , AI Khaffaji N. H. J. , Rayan M. A. 
Published: December 2007

Abstract
In Bab field, one of the major oil fields of the onshore area of Abu Dhabi, U.A.E., there are two limestone saturated oil reservoirs with large gas caps, laying in sequence, called Bab Thamama B and Bab Thamama C reservoirs, which will be referred to as zone B and zone C throughout this paper.
Reservoir studies revealed that the upper zone B which contains the most oil accumulation in Bab structure is divided into two main pseudo reservoirs, B Upper and B Lower. All wells drilled for zone B were completed dually in these two pseudo reservoirs. Consequently, complete separation behind the casing between B Upper and B Lower is mandatory before running the final dual completion. Today, 73 dual oil producers and 90 dual peripheral water injectors were drilled and completed in zone B. It is worth mentioning that zone B was put on production since 1960.
The lower zone C, which is also divided into two main subzones CI and CII, is a saturated oil reservoir with a larger gas cap and an oil rim above the oil water contact. Subzone CI is a short interval with unfavourable reservoir characteristics and is presently not considered for development. Zone C is developed to supply gas for domestic use, and today, 19 gas producers were drilled and completed singly in CII subzone.
3-D Seismic Ihsan/Jameel Area (Oman) Results and Implications
Authors: Gardham R. , Moeshart W. W. 
Published: December 2007

Abstract
During the period July 1983 - August 1985, four wells (Rawnaq-1, Jameel-1 Ihsan-1 and Mawhoob-1) were drilled in the Ihsan and Jameel area of South Oman. Of these four wells, the latter three tested hydrocarbons at commercial rates from the Gharif Formation.
As the seismic coverage over the fields was not sufficient to allow delineation of further appraisal and development wells, a new seismic survey had to be recorded over the area. In view of the obvious migration problems in an area with several small, high relief structures, it was decided to acquire a 3-D seismic survey. This survey was carried out during March and April 1986 and processed in the autumn of that same year.
After intepretation, a new depth map of the top of the Gharif Formation was constructed, which showed significant changes compared to the previous map, based on 2-D seismic data. Subsequent drilling results during 1987 demonstrated the considerable improvement in the accuracy of the 3-D seismic interpretation and also confirmed the presence of a field which was unrecognized on the earlier map. The new information resulted in a four fold increase in Expected Ultimate Recovery for the area.
The acquisition of a 3-D seismic survey in this poor seismic data area has resulted in an early, more accurate estimation of Expected Ultimate Recovery for Field Development Planning which would not have been obtained with a detailed 2-D seismic grid.
Downhole Seismic Array Applications for Reservoir Delineation in Pakistan
Authors: Zaman A. S. H. , Yousaf M. , Ahmed S. 
Published: December 2007

ABSTRACT
The key oil producing formations in northern Pakistan are significantly affected by extensive and complex faulting. The detection of these faults has been an objective of offset Vertical Seismic Profiles (VSPs) for the past several years.
Recently, two land walkaway VSP surveys were undertaken in a cased development well 2750m deep. The objective was to delineate the fault pattern in the Cambrian sandstone and Eocene limestone reservoir formations. A single setting of the eight-receiver Downhole Seismic Array (DSA*) tool enabled the data to be acquired in a single run per line, using two vibrators operating at a regular shot point spacing of 75m, with a maximum offset of 3km from the well. The shot points were located on two orthogonal lines centered at the well. An important factor of the acquisition, affecting the interpretation, was the correct determination of static corrections which were obtained by running refraction spreads. These were then applied to the VSP data prior to velocity filtering.
The final interpretation involved the integration of surface seismic, VSP, walkaway VSP and well logs, including the Formation MicroScanner (FMS*) log. The walkaway VSP results appeared to be superior in resolution when compared to the surface seismic section. In addition, they delineated the fault pattern around the well, thus giving a better understanding of the complex tectonic framework of the area. The major reverse fault crossing the wellbore and causing an abnormal thickness of the Cambrian sandstone was clearly identified on the zero-offset VSP, and its lateral extension away from the well in all the directions was imaged by the walkaway VSPs.
An Experimental Investigation of First and Multiple Contact Miscible Displacement in Arabian Carbonate Cores
Authors: Asar H. K. , Okaygun H. , Arshad A. 
Published: December 2007

ABSTRACT
The application of enhanced oil recovery (BOR) for a Saudi Arabian carbonate reservoir was the subject of this study. Initial process screening revealed that miscible displacement was the only viable EOR process for recovering the relatively heavy oil (28° API). The use of separator gas, separator gas enriched with liquefied petroleum gas (LPG), pure LPG, CO2, and CO2 enriched with LPG as displacing fluids was explored. Some of the experimental results were presented in the 1987 Middle East Oil Technical Conference (see ref. 1). Further results obtained from a continuation of the study are described in this paper.
The minimum miscible pressure of pure CO2 with oil was found to be higher than the reservoir pressure. CO2 enriched with 15 percent LPG gave optimal multiple-contact miscibility conditions. An unconventional apparatus consisting of a slim tube and a core holder joined in series was designed to study multiple-contact displacement. It was found to be very useful for investigating the effectiveness of enriched CO2 as a displacing fluid.
The conclusions of this experimental study for the carbonate cores were: (1)Oil displacement efficiencies by LPG and enriched CO2 were comparable, although the displacement mechanisms were different.(2)The optimal size of LPG and enriched CO2 was 5 and 25 percent, respectively.(3)Water alternating with gas (WAG) gave similar results when used in place of continuous CO2 as driving fluid.(4)CO2 acted as an excellent buffer for separating the displacing fluid from the driving fluid.(5)The amount of oil recovered by the miscible process was twice as much as that recovered by waterflooding.