Wan Rosli Wan Sulaiman

Fault Interpretation Using Image Logs

In oil and gas reservoirs, having the faults attributes such as dip inclination degree, dip azimuth, strike, location of the faults and the type of the faults is essential due to their effect on production rate. Therefore, in this work a new method will be introduced to provide this geological information. By using the Formation Micro Imager (FMI) tool, the fault interpretation job will be done in one of the Iranian production wells, located in Gachsaran field.

Monitoring Foam Stability in Foam Assisted Water Alternate Gas (FAWAG) Processes Using Electrokinetic Signals

The natural pressure in hydrocarbon reservoirs is only sufficient in producing small amount of hydrocarbon at the end of the depletion stage. Therefore, in order to enhance or increase the hydrocarbon recovery, water or other fluids are injected into the formation to extract the hydrocarbon from the pore space. This common practice is known as Improved or Enhanced Oil Recovery (IOR or EOR). Foam is purposely used in some of the EOR displacement processes in order to control the mobility ratio, hence improving the volumetric sweep efficiency. The efficiency of a foam displacement process in EOR depends largely on the stability of the foam films. In laboratory, foam stability is usually measured through physical observation of the foam bubble in a glass tube. Unfortunately, this direct observation is not possible in the reservoir. Therefore, indirect measurement such as the measurement of electrokinetic signal would be a better alternative. This study aims to determine the correlation between the foam stability and the associated streaming potential signals which resulted from the flowing fluid in foam assisted water alternate gas (FAWAG) process. The experimental work will be conducted at the Reservoir and Drilling Engineering Laboratories at the Faculty of Petroleum and Renewable Energy Engineering (FPREE), UTM. The investigation includes sample preparation, sample analysis, displacing fluid formation, rheological properties test and electrokinetic signal measurement by using NI Data Acquisition System (NIDAS). It is expected that the burst of the foam bubble will change the pattern of the electrokinetic signals. The research findings could lead to a new approach in monitoring a FAWAG process. Application in the real field could benefit the oil and gas industry in term of making the EOR process more efficient and more economic.

Simulation of Surfactant Based Enhanced Oil Recovery

Surfactant flooding is an important process for enhanced oil recovery. A substantial amount of remaining oil resides in reservoirs especially in carbonate oil reservoirs that have low primary and water-flood oil recovery. Most of the surfactant flooding studies to date has been performed in water-wet sandstone reservoirs. As a result, the effects of heterogeneity and wettability of carbonates on surfactant flooding efficiency are fairly unknown. The purpose of this simulation study was to determine the effects of wettability and wettability alteration on Dodecylbenzene Sulfonate surfactant flooding in carbonate reservoirs. This study used the multi-phase, multi-component, surfactant flooding simulator called UTCHEM. The base case results showed that additional 27.8% of oil recovered after water-flooding process. Sensitivity analyses of key parameters such as chemical slug size and concentrations, salinity, reservoir heterogeneity and surfactant adsorption were performed to optimize a surfactant design for a mixed-wet dolomite reservoir. The study was then extended to simulating wettability alteration during the field scale surfactant flood. The results of modeling the wettability alteration showed that significant differences in injectivity and oil recovery are caused by the changes in the mobility of the injected fluid. As the use of surfactant flooding spreads into the reservoir especially oil-wet and mixed-wet reservoirs, the importance of surfactant-based wettability alteration will become important.

Influence of Hydrophilic Polymer on Pure Water Permeation, Permeability Coefficient, and Porosity of Polysulfone Blend Membranes

It is well known that membrane with hydrophobic property is a fouling membrane. Polysulfone (PSf) membrane has hydrophobic characteristic was blended with a hydrophilic polymer, cellulose acetate phthalate (CAP) in order to increase hydrophilicity property of pure PSf membrane. In this study, membrane casting solutions containing 17 wt% of polymer was prepared via wet phase inversion process. The pure PSf membrane was coded as PC-0. PSf/CAP blend membranes with blend composition of 95/5, 90/10, 85/15 and 80/20 wt% of total polymer concentration in the membrane casting solutions were marked as PC-5, PC-10, PC-15 and PC-20 respectively. All of the membranes were characterized in terms of pure water flux and permeability coefficient in order to study their hydrophilicity properties. The investigated results shows that increased of CAP composition in PSf blend membranes has increased pure water flux, permeability coefficient and porosity of the blend membrane which in turn formed membrane with anti-fouling property.

Transient pressure analysis for vertical oil exploration wells: a case of Moga field

Reservoir engineers use the transient pressure analyses to get certain parameters and variable factors on the reservoir’s physical properties, such as permeability thickness, which need highly sophisticated equipments, methods and procedures. The problem facing the exploration and production teams, with the discoveries of new fields, is the insufficiency of accurate and appropriate data to work with due to different sources of errors. The well-test analyst does the work without reliable set of data from the field, thus, resulting in many errors, which may consequently cause damage and unnecessary financial losses, as well as opportunity losses to the project. This paper analyzes and interprets the noisy production rate and pressure data with problematic mechanical damage using a deconvolution method. Deconvolution showed improvement in simulation results in detecting the boundaries. Also, high-risk area analysis with different methods being applied to get the best set of results needed for subsequent operations.

Adsorption of aerosol-OT on sand and shale at high sodium salt concentration

Surfactant flooding is a method for additional recovery of oil from partially depleted reservoirs by changing the interfacial tension. During the application of surfactant into a reservoir, a certain loss in the high equivalent weight fraction occurs. These surfactant molecules are the most efficient in lowering the interfacial tension between reservoir brine and crude oil. Introducing the surfactant to rock sediment may result in these losses and increase the partition or adsorption of hydrocarbon organic compounds (HOCs) in the rock-water system. The adsorptive behaviour of Aerosol-OT was studied under high salt concentration at room temperature in the presence of sandstone and shale. This study detected the adsorption based on the monitored changes in the initial concentration of the surfactant. The adsorption of the surfactant Aerosol-OT has been investigated using batch adsorption isotherms and the technique of UV-Vis spectroscopy. The objective of the study was to gain further insight into the surfactant adsorption for these adsorbents and to determine the appropriate isotherm model. The equilibrium results showed that the value of concentration changed from 0.03 g/L to the lowest value of 0.0124 g/L, which is lower than half. The batch adsorption isotherms that Aerosol-OT adsorption behaviour followed was found to fit Langmuir-Frandluich model.

Wettability Alteration of Dolomite Rock Using Nanofluids for Enhanced Oil Recovery

Wettability alteration of rock by surfactant has been considered as feasible method for recovery of oil reservoirs by modifying the wettability of rock surface from oil-wet to water-wet condition. The impact of surfactant can be enhanced by adding nanoparticles. Cationic surfactant performed well in carbonate rock by forming ion pairs between cationic head and acidic component of the crude. Meanwhile, nanoparticles will form continuous wedge film between the liquid and solid surface. In this paper, Al2O3 and ZrO2 nanoparticles were used as enhanced oil recovery (EOR) agents. The impact of these two nanoparticles on contact angle and interfacial tension was studied. Besides that, adsorption Cetyltrimethylammonium Bromide (CTAB) surfactant on rock surface was also investigated. The results show a significant change in water-oil contact angle after application of surfactant and nanoparticles. Initial water-oil contact angle for 6 dolomites demonstrate oil-wet condition. Then, the dolomites were submerged in prepared solution for 48 hours. The result shows that, dolomites 2, 5 and 6 changes drastically to more water-wet condition with contact angle 56°, 40° and 47° respectively. For surfactant adsorption, the adsorption is very fast at the beginning. The adsorption rate after 5 minutes was 50 mg/g and after 60 minutes the adsorption rate was 310 mg/g. The adsorption rate slowed down after 60 minutes and after 180 minutes the adsorption rate was 315 mg/g in which the rate of adsorption achieve equilibrium. Nanoparticles retention test and Zeta potential shows that Al2O3 is more stable than ZrO2. The results for interfacial tension (IFT) also show a significant reduction. The IFT value reduces from 8.46 mN/m to 1.65 mN/m and 1.85 mN/m after the application of Al2O3 and ZrO2 nanofluids respectively

Nanoparticles Performance as Fluid Loss Additives in Water Based Drilling Fluids

Nanoparticles are used to study the rheological characteristics of drilling fluids. Nanoparticles have high surface to volume ratio, therefore only small quantity is required to blend in the drilling fluid. This research evaluates the performance of nanosilica and multi walled carbon nanotubes (MWCNT) as fluid loss additives in water based drilling fluid with various nanoparticles concentration and temperature. The results show that plastic viscosity, yield point and gel strength of drilling fluid increases as the concentration of nanoparticles increased. Drilling fluid with nanosilica gives the highest filtrate loss of 12 ml and mudcake thickness of 10 inch at 1 g concentration at 300°F. However, drilling fluid with MWCNT shows a decreasing trend in fluid loss and mudcake thickness. The results also show that xanthan gum containing 1 g of MWCNT gives 4.9 ml fluid loss and mudcake thickness of 4 inch at 200°F. After aging, plastic viscosity, yield point and gel strength of mud containing nanoparticles decrease significantly especially for 1 g of nanosilica and 0.01 g MWCNT. Fluid loss and mudcake thickness increased when the mud is exposed to temperature above 250°F. The results showed that xanthan gum with MWCNT gives a better rheological performance.

Reservoir Monitoring Using Streaming Potential; Is the Thermoelectric Correction Necessary?

Wellbore streaming current and their applicability in the location of subsurface sand bodies were discovered in 1931 and the usefulness of this measurement has persisted to the present day. Through the endeavor of many researchers, knowledge and understanding of streaming potential (SP) have slowly evolved from the original mere recognition of its existence to its present-day quantitative use in many applications such as Enhanced Oil Recovery (EOR), water flooding, intelligent wells, etc. The spontaneous potential acts to maintain overall electroneutrality when a separation of electrical charge occurs in response to gradients in pressure (Electrokinetic), chemical composition (Electrochemical), or temperature (Thermoelectric). In spite of it being discovered 70 years ago, unfortunately little work has been done to find measurable value especially for thermoelectric coupling coefficient. Many researchers attempt to generate a universal model for SP. They attributes the limitations (if any) of their model to the scarce availability of accurate estimation for coupling coefficient. This study measures the value of thermoelectric coupling coefficient for five rock samples saturated with 0.01M (NaCl) saline brine. The study takes account of temperature dependant electrode effect. The result shows value of 0.2 mV/K, which is in a good match with most of the published data. It was also found that there is no strong correlation between the thermoelectric coupling coefficient and porosity. The measured thermoelectric values are considered insignificantly small compared to the electrokinetic effect in the system.

Dielectric relaxation process and microwave heating mechanism in ε- Caprolactone as a function of frequency and temperature

Dielectric properties of materials play a significant role in design of microwave assisted processing system. This paper is focused on the dielectric properties of ε-caprolactone (ε-cap) which is the monomer for the biodegradable polymer, Poly (ε-caprolactone) (PCL). The dielectric properties of ε-cap were measured across a wide range of frequencies (0.1 GHz5.0 GHz) and temperatures (20-150oC). Then the measured dielectric properties data was modelled using Debye model in order to relate quantitatively the dielectric properties to microwave heating mechanisms. The analysis carried out gives a clear picture of interaction of ε-cap with microwave energy and its heating mechanism in microwave assisted polymerisation process. This study concluded that microwave heating mechanism of the ε-cap in the measured range may be dominated by the dipole reorientation.