Osamah Alomair

Planning Miscibility Tests And Gas Injection Projects For Four Major Kuwaiti Reservoirs

The escalating oil demand and maturity of most of the giant oil fields in the world, especially in the Middle East, the techniques for improving oil recovery have became more feasible and essential. Kuwait long term strategy is to increase oil production to meet marked demand. Currently, miscible gas injection is considered for enhancing oil production from Kuwaiti oil reservoirs. A key parameter for assessing the applicability of gas injection for a given reservoir is the minimum miscibility pressure (MMP). In this paper various miscibility experiments for planning gas injection projects in major producing fields in Kuwait are discussed. These experiments include swelling tests, slim-tube tests, and core flooding studies. These tests are useful tool for screening of the potential reservoirs for improving their future oil production and for developing suitable EOS for planning gas injection projects of the chosen fields. INTRODUCTION Many definitions of miscible displacement have been widely discussed in the literature (Benham et. al., 1965, Stalkup, 1983, Holm, 1987, and Lake, 1989). These definitions clearly convey a consensus that miscibility refers to the absence of an interface between the injected fluids and the reservoir crude oil. The absence of an interface means, in terms of a measurable variable, the value of the interfacial tension between the displacing and displaced fluids is zero. Miscible displacement is only achieved at pressures greater than a certain minimum. This minimum is called the Minimum Miscibility Pressure (MMP). The MMP of a gas/oil pair is traditionally determined by flooding an oil-saturated slim-tube with a gas at four or five different pressures; the MMP is defined as the lowest pressure at which essentially all oil available for recovery can be displaced by 1.2 of the pore volume of solvent injected. This pressure can be located graphically by the intersection of two lines that define both an immiscible and miscible performance regimes on a plot of recovery versus pressure, or recovery versus composition. The methods for estimating MMM are classified into experimental and calculation methods. The experimental methods for measuring MMP are; slim tube apparatus, rising bubble apparatus, PVT Cell, variable interfacial tension, and other methods. Slim-tube method is the most common and has been accepted as the standard method to determine MMP. The MMP calculation methods are divided into; correlation, numerical (simulation), and analytical (EOS) methods. Because of their improved speed, analytical methods offer significant promise for developing improved fluid correlations and for use in compositional streamline simulations. Minimum Miscibility Pressure Experimental Methods Slim-Tube Test In this method, the miscibility conditions are determined by conducting the displacements at various pressures or gas enrichment levels in the oil-saturated Slim-tube and monitoring the oil recovery. Then, the oil recovery is plotted against the pressure (Stalkup, 1983). The minimum miscibility pressure is defined as the pressure at which the oil recovery versus pressure curve shows a sharp change in slope. The MMP is traditionally defined as the lowest pressure at which essentially all oil available for recovery can be displaced by 1.2 PV solvent injected. The disadvantages of this method are; it is very time consuming, expensive, does not account for third fluid water, and several points are required to establish the MMP (a minimum of five points are recommended). Furthermore, Slimtube may give a lower MMP that it actually is because the way the porous medium is packed. On the other hand, Slim-tube test can mimic porous medium and hence are capable of representing multicontact fluid dispersions mechanism due to mixing in the porous medium. Rising Bubble Apparatus (RBA) In the rising bubble experiments, the MMP is inferred from the pressure dependent behavior of rising bubbles. The MMP is determined from the observations of changes in shape and appearance of bubbles of the injected gas as they rise through a thin column of crude oil. The pressure at which a rising gas bubble vanishes in a column of oil is termed as the MMP (Christianson and Haines, 1984). This method is considerably faster with low cost and requires smaller quantities of fluids, compared

Assessment of Ambient Air Quality in the State of Kuwait: Al Jahra City Study

The main objective of this study is to present an assessment of ambient air quality of Al Jahra city (32 kilometers/20 miles northwest Kuwait City). Measurements of ambient sulfur dioxide (SO2), nitrogen oxides (NO2) carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM10), ozone (O3), methane (CH4) and Non-methane hydrocarbons (NCH4) along with metrological factors (winds speed, wind direction, and solar radiation) were taken over the period of the year 2008. Most regional and worldwide studies considered these pollutants for the assessment due to its vital effects on both health and environmental. The study present a descriptive statistics of the data, calculation of the Air Quality Index (AQI) based on the reading average, along with the hazard quotient. Result shows that the AQI was in the green (good) region except for PM10 it was in the yellow (moderate) region. The calculated Hazard Index of all the components separately and the overall Health Index, did not exceed its ambient air quality standard (AAQS) which is reported by the USEPA. This paper also studies any possible relation between the presented factors using the correlation matrix technique. It was found that there is a relation between the NOx and both carbon monoxide and carbon dioxide. A simple analysis of variance using ANOVA test was made on the data to identify the variance (quality) of the data. A temporal study was made using the average concentrations of the data during the hours of the day for the whole year to study the trend of these pollutants during that covered year. This part enables us to predict the sources of the pollutants according to its peak times.

Classifying rock lithofacies using petrophysical data

This study automates a type-curve technique for estimating the rock pore-geometric factor (λ) from capillary pressure measurements. The pore-geometric factor is determined by matching the actual rock capillary pressure versus wetting-phase saturation (Pc–Sw) profile with that obtained from the Brooks and Corey model (1966 J. Irrigation Drainage Proc. Am. Soc. Civ. Eng. 61–88). The pore-geometric factor values are validated by comparing the actual measured rock permeability to the permeability values estimated using the Wyllie and Gardner model (1958 World Oil (April issue) 210–28). Petrophysical data for both carbonate and sandstone rocks, along with the pore-geometric factor derived from the type-curve matching, are used in a discriminant analysis for the purpose of developing a model for rock typing. The petrophysical parameters include rock porosity (), irreducible water saturation (Swi), permeability (k), the threshold capillary-entry-pressure (Pd), a pore-shape factor (β), and a flow-impedance parameter (n) which is a property that reflects the flow impedance caused by the irreducible wetting-phase saturation. The results of the discriminant analysis indicate that five of the parameters (, k, Pd, λ and n) are sufficient for classifying rocks according to two broad lithology classes: sandstones and carbonates. The analysis reveals the existence of a significant discriminant function that is mostly sensitive to the pore-geometric factor values (λ). A discriminant-analysis classification model that honours both static and dynamic petrophysical rock properties is, therefore, introduced. When tested on two distinct data sets, the discriminant-analysis model was able to predict the correct lithofacies for approximately 95% of the tested samples. A comprehensive database of the experimentally collected petrophysical properties of 215 carbonate and sandstone rocks is provided with this study.