Current experience shows, it is often impossible to fulfill certain functional tasks that are essential in challenging drilling and production environments using conventional macro and micro type fluid additives due to their inadequate physical, mechanical, chemical, thermal and environmental characteristics. Hence, the industry is looking for physically small, chemically and thermally stable, biologically degradable, environmentally benign chemicals, polymers or natural products for designing smart fluids to use virtually in all areas of oil and gas exploration and exploitation. Due to totally different and highly enhanced physio-chemical, electrical, thermal, hydrodynamic properties and interaction potential of nanomaterials compared to their parent materials, the nanos are considered to be the most promising material of choice for smart fluid design for oil and gas field application. This paper describes the formulation and preliminary test results of several nano-based drilling fluids. The recently developed nano-based fluids were formulated using a blend of nanos and nanostabiliser to study the rheological and filtration properties and evaluate its suitability for oil and gas field application. Initial mud formulation indicates that development of a functionally viable, physically stable and homogeneous and also long lasting nano-based drilling mud is difficult using water or salt water as the fluid phase. However, use of a suitable viscosifier at a right concentration and adoption of a special preparation method lead to the formulation of a nano-based drilling mud with desirable rheological and filtration properties along with the gelling behavior and mudcake quality. Initial test results indicate that the newly developed nano-based drilling mud produces suitable high and low end rheological properties including gelling characteristics and thus expected to fulfill its functional task during drilling and after cessation of drilling.

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Drilling a shale formation with no borehole problems can be a challenging task. With high content of clays, shale formations are prone to swelling, dispersion, tight hole and other problems. Those problems are well-documented in literature. Different types of clays give different types of problems. For example, when it is exposed to water, a shale sample with a high percentage of smectite tends to swell while another shale sample with a high percentage of kaolinite tends to disintegrate and disperse. The mechanism that destabilizes reactive shale when it comes in contact with water differs from on shale sample to another. It is important to know which mechanism is taking place in order to be proactive and inhibit the drilling fluid with the appropriate inhibitor. It is also important to characterize the shale sample in terms of its geological structure, mineralogical composition and interaction potential. Shale characterization and testing methods include but not limited to the following: X-ray analysis, degradation and reorientation evaluation using scanning electron microscope (SEM), cation exchange capacity (CEC) determination, swelling test, dispersion test, slake durability test, bulk hardness test, accretion test, shale membrane test, inhibition durability test and uniaxial and triaxial compression tests. Different types of shale inhibitors and stabilizers have been used in the industry such as: potassium chloride, calcium chloride, silicates, polyamines, glycol and lignosulfonate. Each of them has a mechanism by which it can inhibit the hydration, disintegration and dispersion of clays in the presence of water. This paper discusses the physio-chemical and chemico-mechanical effects of shale-drilling fluid interactions and the associated drilling problems that are most frequently encountered while drilling shales formations. It also reviews the most common shale testing methods used to evaluate the interaction potential of various shale-drilling fluid systems. Moreover, the paper describes different mechanisms by which shale can be inhibited and wellbore stability problems can be mitigated.

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His research interest includes advanced wireless communication, image and signal processing.

Achieving successful zonal isolation during well completion is critical to minimize early water production. Currently, cementing is the only method used in Saudi fields to provide zonal isolation. However, in horizontal sections, cementing becomes a challenge and water flows can occur due to channeling. Another method for zonal isolation is to use a rubber elastomer bonded onto a base pipe. The rubber swells in water and provides a seal between the base pipe and the open hole. This paper will outline the step-by-step qualification testing that was carried out in Saudi Aramco facilities in an attempt to improve zonal isolation in horizontal and multilaterals wells. In this study, we present lab evaluation of elastomers at 190ºF using brines of different ionic strengths and pH values. The evaluation involved examining the effect of salinity and pH on the rate of swelling of elastomers. Also, the study investigated the effect of 15 wt% HCl acid on the swelled elastomers. To the best of the authors' knowledge, no previous work was done to examine the impact of these factors on the swelling mechanisms. The elastomer bonded in pipes was tested in autoclaves. The pressure drop across the pipes was measured as a function of time. The influences of fluid density and viscosity were also investigated using elastomer samples. Swelling was related to volume of the samples and fluid characterstics. Water swelling elastomers withstand pressures up to 5,000 psi at 190ºF after placing the elastomers in salinities up to 200,000 mg/l. However, the swelled elastomers shrink in 15 wt% HCl. This paper discusses the advantages and limitations of swelling elastomers and gives recommendations for successful field applications. Introduction Swelling packers can be used for multiple-zone open-hole completions. These packers will swell when they come in contact with wellbore fluids (either crude oil or water). Open-hole completions become attractive because they require fewer trips and no cementing near-wellbore which can cause formation damage. Swelling packers can be used for any of the following reasons:1 Horizontal sections where cementing is difficult, lateral zones with compartmental isolation, and zones with large permeability variations. There are no operational difficulties in running the swelling packers. There are two types of packers; water-swelling and oil-swelling. Contaminations in the wellbore fluids can affect the swelling of the packers. Oil swelling elastomer will swell faster in lighter oils compared to heavier ones. In field applications where acid stimulation is required, the swelling packers will be exposed to acids. Hydrochloric acid is commonly used to matrix acid carbonate formations. Concentrated HCl acids will affect the swelled packers, but not the weak ones.1 Swelling of oil packers depend on thermodynamic absorption process. All liquids have a solubility parameter, which is the energy required to vaporize them. The packers have two components; a polymer and a flexible material. When the polymer is immersed into a liquid with a similar solubility parameter, a strong affinity between the polymer and liquid will cause swelling of the polymer and, as a result, the flexible material will expand and the volume of the packer will increase by several folds. 2 Swelling will continue until equilibrium is reached. The time to reach equilibrium will be reduced at higher temperatures. When swelling reaches equilibrium, the mechanical properties and volume of the packer remain constant. If further expansion is reached, it will be due to thermal chain degradation of the polymer. When expansion is limited by the wall of the hole, the packer will not reach equilibrium and will continue to swell until it does.2

To understand the interactions between shale rocks and aqueous drilling fluids, the spontaneous imbibition of water phase into shale pore systemsneeds to be investigated. It is important to study the shale-fluid interactions to mitigate problems associated with drilling shale formations using water-based drilling fluids. Spontaneous imbibition experiments have been frequently conducted to assess the flowback and recovery for reservoir engineering applications. In this paper, the literature has been reviewed in an attempt to link the work that has been carried out in that area to study the water filtrate invasion of drilling fluids into shale rocks while drilling. Over the years, different techniques and instruments have been used to study the spontaneous imbibition into shale rocks including: spontaneous imbibition device, which is basically analytical balance to measure the weight changes as imbibition progresses, pulse decay permeameter, scanning electron microscopy, X-ray tomography and nuclear magnetic resonance. To aid in analyzing and interpreting the results, the rocks are characterized in terms of: surface area, porosity, permeability and wettability. Fluids that have been used as the imbibing medium included: water, oil, brines, and surfactants. Three imbibition mechanisms have been revealed by literature: capillarity, osmotic diffusion, and water adsorption. These mechanisms can be distinguished when imbibed water volume is plotted against time where the imbibition rate differs for three distinct regions. Factors that were found to have impact on imbibition process include: capillary pressure, porosity, pore size distribution, pore connectivity, effective permeability, presence of fractures, bedding, mineral composition and clay content, fluid type, and properties and depositional environment (marine or continental).

More adaptable and user-independent techniques are required for multi-sensors based daily locomotion detection (MS-DLD). This research study proposes a couple of locomotion detection methods using body-worn multi-sensors to successfully categorize several locomotion transitions, including falling, walking, jogging, and jumping, along with bodyspecific sensors based on the modified hidden Markov models (HMMs) approach. This research presents both standard and state-of-the-art methods for MS-DLD. Conventionally, to improve MS-DLD process, the proposed methodology consists of a wavelet transformed Quaternion-based filter for the inertial signals, patterns recognition in the form of kinematic-static energies, and state-of-the-art multi-features extraction. These features include entropy, spectral, and cepstral coefficients domains. Then, fuzzy logic-based optimization has been introduced in order to achieve the selective features by converting them into codewords. This paper also introduces another state-of-the-art way to model daily locomotion detection and derives body-specific modified HMMs. The model divides the sensor data into three active body-specific parts including head sensors, mid-body sensors, and lower body sensors. Body-specific modified HMMs have been provided with raw data for the three active body-specific sensors and gave better results with less computational complexities when compared to the conventional methods. The proposed systems have been experimentally assessed and trialed over three diverse publicly available datasets: the UP-Fall dataset consisting of falling and other daily life activities, the IM-WSHA dataset comprising everyday locomotion actions, and the ENABL3S gait and locomotion dataset consisting of multiple gait movements. Experimental outcomes indicate that the proposed conventional technique achieved improved results and outperformed existing systems based on detection accuracies of 90.0% and 87.5% over UP-Fall, 86.0% and 88.3% over IM-WSHA, and 86.7% and 90.0% over ENABL3S datasets for kinematic and static energy patterns, respectively. Further, the results show that the state-of-the-art body-specific modified HMMs method achieved 94.3% and 95.0% over UP-Fall, 92.0% and 93.3% over IM-WSHA, and 90.0% and 95.0% over ENABL3S datasets for kinematic and static patterned signals, respectively. The results of state-of-theart efficient system show a significant increase in detection accuracy when compared to standard systems.