Mohammed Haroun

The Application of Direct Current Potential to Enhancing Waterflood Recovery Efficiency

Abstract Advantages of direct current (DC) application, concurrently with waterflooding, in mobilizing trapped oil is investigated. Application of DC on completely water swept core recovered 3–9% additional oil, which is slightly less when DC is applied from the beginning of waterflooding process. Reduced water requirement (15–22%) and permeability enhancement up to 40% are found to be added benefits. The effect is more pronounced in higher permeability core and higher density oil. These phenomena are attributed to formation of clay colloids and mobilization of trapped oil along with connate water due to the added dynamics of electrokinetic and electrochemical processes.

The Stimulation of Sandstone Reservoirs Using DC Potential

Abstract The authors describe the effect of direct current application in conjunction with waterflood on improving flow properties of Berea sandstone cores. Single- and two-phase flow experiments are conducted on a specially designed coreflood setup, under constant electrode potential. The results showed that core permeability may increase up to 223% when hydraulic gradient and electroosmotic flow are applied in the same direction. The effect is insignificant when they work in opposite direction. It is verified from experimental results that dislodgement of clay in colloidal form, resulting increase of effective pore throat diameter improved hydraulic permeability.

The Effect of DC Electrical Potential on Enhancing Sandstone Reservoir Permeability and Oil Recovery

Abstract The merits of using electrokinetic phenomena to improve reservoir permeability on sandstone reservoir core plugs are investigated with detail clay mineralogy studies. Normal and reverse DC configuration is applied along with waterflood and studies are conducted on single-phase and two-phase fluid saturation conditions. The produced brines are acid digested and analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). In single-phase flow experiments, permeability enhanced 180% with the normal electrode configuration but negligible change is observed in reverse configuration. In two-phase flow 59% and 10% permeability enhancement is observed in normal and reverse configurations, respectively. In addition, 11.6% additional oil is recovered from normal configuration. The results are examined in terms of electrolyte movement and resulting changes within the clay microstructure. In normal electrode configuration, formation of colloidal clay suspension and flowing out along with produced brine is evident. This has resulted in increased pore passage and core permeability, whereas in the reverse configuration, clay structures remained unchanged. The given explanations are supported by ICP-MS and X-ray diffraction results.

A novel improved oil recovery approach for increasing capillary number by enhancing depth of penetration in abu dhabi carbonate reservoirs

During the last few decades, there has been a globa l increase in oil demand by 35%. Besides, the petroleum industry is faced with a number of challe nges when considering the reservoir such as low swe ep efficiency, formation damage and implementing costl y techniques to enhance and improve the oil recover y. Electrokinetic Low-concentration acid IOR (EK LCA-I OR) is one of the emerging IOR technologies, which involves the application of the Low-concentration a cidizing integrated with electrically enhanced oil recovery (EK-EOR). This research focusses on analyzing the e ffectiveness of the EK LCA-IOR process in Abu Dhabi carbonates, improving the capillary number and enha ncing depth of penetration. Core-flood tests were conducted by saturating Abu D habi carbonate core-plugs with medium crude oil in a specially designed core-flood setup at Abu Dhabi re se voir conditions. After the water flooding stage, EK LCAIOR was applied using varying voltage gradients and ci concentrations upto 1.2% HCl injected at the anode and transported by EK to the target producer (catho de). Moreover, the capillary number change, and Sin gle Energy CT Scan (SECTS) results were analyzed in ord er to observe the effect on rock-fluid interaction t control rock adsorption capacity through interfacial tensio and depth of penetration. Several correlations at reservoir conditions relate d o acid concentration, displacement efficiency an d permeability enhancement have shown that the applic ation of water flooding on the carbonate cores yiel ds an average oil recovery of 58%. An additional 17-28% o il recovery was enhanced by the application of EK L CAIOR recording a maximum oil displacement of 88%. In addition, EK LCA-IOR was shown to enhance the reservoir’s permeability by 53% on average across t he tested core-plugs. EK LCA-IOR also improves the capillary number by 500% in Water-wet core plugs an d 1500% in Oil-wet core plugs, mainly due to a decr ease in interfacial tension. This indicates the decrease in acid adsorption as acid is precisely transporte d to the targeted production well through the tortuous path with an increased depth of penetration as proven by the SECTS results where EK LCA-IOR has penetrated 60% o f core-length that revealed minor fractures, precis ely delivering the acid front throughout the core-plug. Finally, EK LCA-IOR enhances capillary number along with an increased depth of penetration while allow ing us to save on the OPEX by maintaining decreased power consumption while reducing the acid/water requireme nt upto 10 times. This study takes one step forward to wards the development of EK Low-concentration acid IOR method feasible for Abu Dhabi oil fields in order t o make smart water floods applicable for complex fr actured reservoirs of UAE.

Improving MMP by Co-Injection of Miscible CO2 With Abu Dhabi Crude Oil

Miscible CO2 injection is a method to increase oil production. Combinations of Carbon dioxide with other gases as miscible solvents are emphasized in this paper to improve CO2 miscible injection process. Emphasis is on identifying CO2 solvent mixtures with reduced MMP to achieve miscibility at reasonable injection pressures in Abu Dhabi fields. Two targeted crude oils (Oil 1 and Oil 2) from Abu Dhabi carbonate reservoirs are utilized. The minimum miscibility pressure (MMP) of targeted oils with mixtures of N2, CH4, C2H6, and HC rich gas of varying composition with CO2 injection gas are evaluated through simulation. Cell to Cell and Semi-analytical (key tie lines) methods are applied using CMG simulator. Results show that miscibility is predicted to occur with multiple contact miscibility (MCM): vaporization and/or condensation mechanisms. The increase of C2H6 concentration in the CO2 injected gas reduced MMPs for targeted Oil 1 by 100 psi/10 mol%. However, N2, CH4 and HC rich gas increments in CO2 injected gas increased the MMPs for targeted Oil 1. MMP was observed to be 2300 psi for pure ethane with Oil 1. In addition, MMPs for targeted oils with N2/ C2H6 and N2/ CH4 injected gas mixtures are assessed. This study can open possibilities for future enriching of CO2 and N2 miscible injection to improve miscibility and recovery of oil.Copyright

A Biodegradable Scale Inhibitor for Oil Well Application

Abstract Ascorbic acid, an easily biodegradable natural product with an excellent environmental profile, was studied in an oil well downhole condition for inhibiting calcium carbonate scale deposition. Scale inhibition efficiency studied in artificial seawater and formation water mixtures of various proportions through static jar test and dynamic tube blocking tests show its calcite scale inhibition potential at high-temperature wellbore conditions. Investigation made through scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectrometry revealed severe structural anomalies of CaCO3 crystals and explain the scale prevention mechanism. Its biodegradation rate studied using a UV-visible method in a marine environment is excellent and meets environment requirements. In a sensitive marine environment, ascorbic acid could be deployed as an excellent green chemical for continuous injection into the wellbore to prevent carbonate scale deposition.