Subterranean Formations Research Articles

Sorption of Cs+ and Eu3+ onto coherent and melange-type pre-neogene sedimentary rocks

ABSTRACT Widely present in Japan’s deep subterranean formations, pre-Neogene sedimentary rocks offer an option for high-level radioactive waste (HLW) deep geological disposal due to their favorable properties. However, their barrier properties necessitate further investigation. This research examines the characteristics of pre-Neogene sedimentary rocks, focusing on two rock types: the melange type with a distinct block-in-matrix structure and the sandstone-dominant coherent type. Their ability and mechanism to sorb Cs+ and Eu3+ are assessed, and the differences between the two types are compared. The influence of inorganic carbon in groundwater and the role of clay minerals, such as illite, in the sorption of these metal ions, are highlighted. This investigation lays the groundwork for future studies on migration behaviors of radionuclides, essential for ensuring the long-term safety of HLW geological disposal.

The impact of CO2 saturated brine temperature on wormhole generation and rock geomechanical and petrophysical properties

One solution to attain net zero CO2 emissions is the sequestration of CO2 in subterranean formations. Deep limestone saline aquifers provide excellent storage sites for CO2 due to their high solubility in water and vast aquifer volumes. This study investigates the potential changes in rock petrophysical and geomechanical properties caused by the reaction of carbonated brine (CO2+brine) and limestone rock, as well as the effect of temperature on wormhole generation. Three samples of Indiana limestone (100% calcite) with dimensions of 1.5 inches in diameter and 3 inches in length, 15% average porosity, and 2 mD average permeability were used. The samples were flooded at 1 mL/min and 2000 psi with a carbonated brine consisting of total dissolved salts of 120,000 ppm. To evaluate the effect of temperature on limestone-carbonated brine reaction at CO2 underground storage conditions, the experiments were conducted at three different temperatures (35, 60, and 85 °C). The samples' Young's modulus and Poisson's ratio at different confining pressures were measured before and after carbonated brine coreflooding. Additionally, we used a medical Computed Tomography (CT) scanner to visualize the created wormholes and quantify their volumes. We observed the generation of a wormhole in each of the experiments after 19.7, 26.7, and 46.9 pore volumes (PVs) of CO2-saturated brine were injected at 35 °C, 60 °C, and 85 °C, respectively. Moreover, the lowest temperature treatment created a straight wormhole with less void volume compared to the other temperatures. Wormhole generation at 85 °C showed the largest reduction in rock strength in terms of Young Moduli (YMs) than the other experiments despite showing the lowest reactivity. To the best of our knowledge, this is the first study to reveal the impact of temperature on wormhole generation due to the injection of CO2-saturated brine in limestone. This study also demonstrates that wormhole generation increases CO2 storage capacity; however, CO2 relative permeability increases, implying that CO2 will flow faster and accumulate primarily underneath the caprock. Furthermore, before injecting CO2, the well integrity in hotter carbonate reservoirs should be thoroughly examined. Conversely, this study reveals that CO2 or carbonated water could be utilized for acid stimulation.

Waste cooking oil invert emulsion drilling mud formulation with an effective H2S scavenging performance

Encountering hydrogen sulfide while drilling/stimulating subterranean formations is very common in upstream oil and gas industry. If not effectively scavenged in-situ, this lethal gas will escape to the surface causing serious health and safety problems and potential losses in human lives, in addition to significant economic penalties. Additionally, the release of waste cooking oils to the drainage/sewage systems will lead to some serious operational problems during the treatment of the collected sewage wastewaters. Thus, the key objective of this study is to convert the waste cooking oils from a burden into a valuable commodity via utilizing them for the formulation of invert emulsion drilling fluids. The waste cooking oil invert emulsion drilling mud was stabilized partially by rhamnolipid biosurfactant as a secondary emulsifier. The mud also contained hydrophobic zinc nanoparticles (NPs) as a weighting agent. To provide these waste cooking oil-based drilling muds with an effective H2S scavenging performance, a small quantity (1 wt%) of potassium permanganate was added. Despite the small quantity of the added scavenger, the mud formulation was able to scavenge 99.4 and 237.7 mg H2S/g scavenger at the breakthrough and saturation time, respectively. These H2S scavenged capacities demonstrate the feasibility of incorporating potassium permanganate, which is cheap and abundant material, into waste cooking oil invert emulsion drilling mud formulations. The flow behavior and the viscosity of the waste cooking oil-based mud comprising the H2S scavenger were found to be comparable to those reported in the literature for oil-based muds (OBMs) containing NPs.

Increasing the Environmental Friendly of Process Fluids Used for Well Drilling

An important aspect of hydrocarbon drilling is the use of drilling fluids that remove cuttings and stabilize the wellbore, providing better filtration. The properties of drilling fluids are essential to the success of any drilling operation. Fluids were originally developed to enable and cost effectively rotary drilling in subterranean formations. In addition, drilling fluids were designed to form a filter cake, which was primarily designed to reduce filtrate loss to the formation, was thin, and retained the drilling fluid in the wellbore. One of the most important functions of drilling fluids is to minimize the amount of drilling fluid filtrate entering a hydrocarbon containing formation, which can cause damage to the formation due to changes in rock wettability, fines migration, mud plugging with solids, and formation water incompatibility. To stabilize these properties, a number of additives are used in drilling fluids to ensure satisfactory rheological and filtration properties of the fluid. However, the commonly used additives are hazardous to the environment: when drilling fluids are disposed of after drilling operations, they, together with drill cuttings and additives, are discharged into water bodies and cause unwanted pollution. Therefore, these additives should be replaced with additives that are environmentally friendly and provide superior performance. In this regard, biodegradable additives are needed for future research. The review article presents an investigation into the role of various biowastes as potential additives for use in water-based drilling fluids. The use of waste-derived nanomaterial was considered, and rheological and filtration studies of water-based drilling fluids were carried out to evaluate the effect of waste additives on the performance of drilling fluids.

Persisting Effects in Daphnia magna Following an Acute Exposure to Flowback and Produced Waters from the Montney Formation.

Hydraulic fracturing extracts oil and gas through the injection of water and proppants into subterranean formations. These injected fluids mix with the host rock formation and return to the surface as a complex wastewater containing salts, metals, and organic compounds, termed flowback and produced water (FPW). Previous research indicates that FPW is toxic to Daphnia magna (D. magna), impairing reproduction, molting, and maturation time; however, recovery from FPW has not been extensively studied. Species unable to recover have drastic impacts on populations on the ecological scale; thus, this study sought to understand if recovery from an acute 48 h FPW exposure was possible in the freshwater invertebrate, D. magna by using a combination of physiological and molecular analyses. FPW (0.75%) reduced reproduction by 30% and survivorship to 32% compared to controls. System-level quantitative proteomic analyses demonstrate extensive perturbation of metabolism and protein transport in both 0.25 and 0.75% FPW treatments after a 48 h FPW exposure. Collectively, our data indicate that D. magna are unable to recover from acute 48 h exposures to ≥0.25% FPW, as evidence of toxicity persists for at least 19 days post-exposure. This study highlights the importance of considering persisting effects following FPW remediation when modeling potential spill scenarios.

Improvement of Hydrogen Sulfide Scavenging via the Addition of Monoethanolamine to Water-Based Drilling Fluids.

The release of the lethal hydrogen sulfide (H2S) gas during the drilling of sour subterranean formations is of huge health and safety concern. Additionally, the contact of this corrosive gas with handling equipment might result in severe damages and significant economic losses. Accordingly, effective in situ scavenging of H2S while drilling is very crucial. Thus, we report herein the addition of monoethanolamine (MEA) to water-based mud with the objective of improving the H2S-scavenging efficacy of the mud. The H2S-scavenging capacity was evaluated for the MEA-containing mud and compared with the base mud and fluids containing the commercial scavengers, SourScav and triazine. Also, the key mud characteristics including rheology, filtration properties, alkalinity, and corrosion rate were investigated in the presence and the absence of MEA, and the obtained results were compared to those of SourScav and triazine. The obtained experimental results revealed that the addition of MEA to the base mud significantly improved the H2S adsorption capacity of the base mud by 117%, compared to 50 and 74% with the SourScav and triazine. Additionally, the pH value of the MEA-containing mud complied with the practical recommendations for drilling in a sour environment. Moreover, the plastic viscosity was increased by 13% to 37 cP with the MEA-containing mud with an insignificant impact on the yield point. Furthermore, the MEA-containing mud showed a favorable zero corrosion rate, as was the case for SourScav and triazine muds. However, unlike SourScav and triazine, MEA did not substantially enhance the filtration performance. Nonetheless, the filtration characteristics of the MEA-containing mud were still better than the base mud and within the recommended practical range for water-based muds. Overall, the results presented in this study reveal that the addition of monoethanolamine to water-based muds improves the mud characteristics and, more importantly, provides a superior H2S-scavenging performance relative to SourScav and triazine scavengers, suggesting the commercial relevance of MEA for drilling applications.

Exact Solutions for Gravity-Segregated Flows in Porous Media

The review is devoted to exact analytical solutions for quasi-2D gravity segregated flows or gravity currents in subterranean porous formations. The problems under consideration are quasi-linear. The driving forces are two components of the buoyancy—one exerting the bulk of the light fluid and one due to the curvilinearity of the interface between the fluids. In the case of homogeneous formation or where the seal slope is negligible, the transport equation is parabolic and allows for a wide set of self-similar solutions. In a large-scale approximation of the buoyancy domination, the governing equation is hyperbolic; the method of characteristics allows for a detailed analytical description of gravity current propagation with final accumulation in the geological trap. Analytical models for leakage via the caprock seal are also discussed. The work was completed by formulating some unsolved problems in segregated flows in porous media.

A New Scale for Global History

A New Scale for Global History

Analysis of mathematical modeling methods in the processes of underground injection, storage, and conversion of carbon dioxide

The problem of carbon dioxide utilization is of increasing concern to the public, since measures to reduce greenhouse gas emissions are no longer sufficient to prevent a global increase in temperature on the planet. Most modeling scenarios show that a significant deployment of negative emission technologies is required. Carbon dioxide is often used as an agent for enhancing hydrocarbon production in the development of oil and gas fields, which is technologically consistent with projects for its utilization and underground storage in depleted reservoirs, saline aquifers, and shale rocks. For the successful implementation of such sequestration projects, it is necessary to conduct a complex of experimental, modeling, and field studies. It is necessary to understand the characteristic physical and chemical changes that occur in a subterranean formation during sequestration processes, such as dissolution, chemical reactions, convective mixing, advective processes, and dispersion. Computer modeling of ongoing processes is seen as a very important task for the correct functioning of such projects. The article deals with topical problems of computer modeling of processes associated with underground injection and storage of carbon dioxide, and also presents the results of laboratory studies on the utilization of carbon dioxide through its catalytic conversion into useful energy resources—hydrogen and hydrocarbons. The findings of this study can help to better understand physicochemical mechanisms that can occur in subterranean formations when carbon dioxide is injected. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Analysis of depleted gas reservoir underground gas storage wellbore integrity change during gas injection and production processes

Depleted gas reservoir type underground gas storage is the most widely distributed gas storage in the world. Due to the complex geological conditions and frequent gas injection and production operations, it is prone to the wellbore integrity failures leading to hazards such as annular pressure. To protect the wellbore integrity and contain the escape of gas to subterranean formations or surface, a finite element model is developed to study the wellbore integrity change. This model simulates the typical gas injection and production processes of gas storage with complex geological conditions and non-uniform ground stress. A new comprehensive method considering complex well conditions was developed to simulate the wellbore integrity failure process more realistically. This model can predict the wellbore integrity failure and high-risk areas during the gas injection and production processes. The simulation results indicate that the cement shear failure sections are mainly concentrated near the upper and lower boundaries of the formation interlayer during the gas injection process, and the distribution area and trend of the shear failure areas are the same as the gas production process. The most common cement tensile failure sections during the gas injection process all occur on the inner side of the cement in the direction of maximum ground stress during the gas injection process. The highest effective (Von Mises) stress area of the casing is mainly concentrated in the upper and lower boundary zone of the formation interlayer during the gas injection process. And the highest Von Mises stress sections are mainly distributed in the direction of the minimum ground stress near the formation interlayer lower boundary inside the casing, which is similar to the distribution in gas production process. The first cohesive failure position and final failure distribution result of cement inner interface both appear in the depth range of the formation interlayer. The cement outer interface's first and final failure areas are all concentrated on the lower boundary of the formation interlayer and consistent with the direction of the maximum ground stress. The cement inner interface failure occurred earlier but not as significant as the outer interface failure, which occurred later but the failure range was large in this case. Practical guidelines and solutions derived from the simulation results can be useful for improved wellbore integrity protection in field applications.

Tailored highly porous, templated polyurethane for sand consolidation

AbstractA novel polymeric resin formulation is developed to mitigate sand production from subterranean formations composed of unconsolidated or weakly consolidated sands via a chemical sand consolidation approach. The developed formulation aims to minimize the formation permeability loss commonly observed in a chemical sand consolidation treatment. The new formulation is a water‐in‐oil high internal phase emulsion with poly(ε‐caprolactone) polyol and isophorone diisocyanate monomer incorporated in the external oil phase. Highly porous, emulsion templated polyurethane forms through the reaction between polyol and isocyanate under elevated temperature. Additionally, CO2 generated through the reaction between excess isocyanate monomer and water leads to the formation of more pores in the cross‐linked polymeric network. When the developed formulation is applied for sand consolidation treatment, the interconnected pores formed after resin curing act as “channels” in the consolidated products and allow the produced fluid such as oil, water, or gas to easily flow through, thereby limiting permeability reduction. The effectiveness of using porous polyurethane material for sand consolidation is evaluated through a compressive strength and permeability study of the consolidated sandpacks prepared with this chemistry.

The Utilization of Steelmaking Industrial Waste of Silicomanganese Fume as Filtration Loss Control in Drilling Fluid Application

Abstract Drilling fluid is considered the backbone of drilling operations in the oil and gas industry to unlock hydrocarbon from subterranean formations. Maintaining the drilling fluid properties, for example, flow properties such as rheology, plastic viscosity (PV), yield point (YP), gel strength (GS), and circulation loss, is the challenge for fluid/mud engineers to carry out successful drilling operations. A variety of chemicals have been added to improve the drilling fluid properties by introducing new chemicals or optimizing the existing chemicals without affecting the other essential fluid properties. The present study for the first time employs the eco-innovation concept to explore the utilization of steelmaking industry waste, i.e., silicomanganese fume (SMF), as a bridging material. The objective of this article is to design an eco-friendly framework that comprehensively explains and utilizes SMF as a bridging material in water-based fluid (WBF). The eco-innovation/eco-friendly framework includes the steps required for processing and understanding the new material and evaluating its effects on flow and the bridging properties of WBF. A scanning electron microscope (SEM), X-ray fluorescence (XRF), and particle size distribution (PSD) were used to understand the physicochemical properties of SMF. The flow properties were studied using a Fann rheometer before and after hot rolling at 120 °F. A high-pressure high-temperature (HPHT) filter press equipment was used to investigate the bridging capability of seepage losses following conditions of 190 °F and 300 psi differential pressure. Minimal cleaning and disintegration with a mortar and pestle are enough to prepare SMF to be incorporated in drilling fluid. The SEM and XRF results showed that SMF contains oxides of manganese, silicon, potassium, calcium, and magnesium, while the PSD revealed a natural bimodal distribution with an average grain size of D50 of around 29 μm. SMF showed a noticeable and measurable enhancement of flow properties and bridging capability in WBF. The SMF-based WBF showed improved rheological properties, plastic viscosity, and yield point compared with marble-based WBF. Adding SMF to WBF with and without marble showed a ten-fold superior plugging performance compared with marble-based WBF using 20-μm ceramic discs. The findings revealed the successful utilization of SMF in WBF by improving the rheology, plastic viscosity, yield point, and bridging capability.

Microanchored borehole fiber optics allows strain profiling of the shallow subsurface

Vertical deformation profiles of subterranean geological formations are conventionally measured by borehole extensometry. Distributed strain sensing (DSS) paired with fiber-optic cables installed in the ground opens up possibilities for acquiring high-resolution static and quasistatic strain profiles of deforming strata, but it is currently limited by reduced data quality due to complicated patterns of interaction between the buried cables and their surroundings, especially in upper soil layers under low confining pressures. Extending recent DSS studies, we present an improved approach using microanchored fiber-optic cables—designed to optimize ground-to-cable coupling at the near surface—for strain determination along entire lengths of vertical boreholes. We proposed a novel criterion for soil–cable coupling evaluation based on the geotechnical bearing capacity theory. We applied this enhanced methodology to monitor groundwater-related vertical motions in both laboratory and field experiments. Corroborating extensometer recordings, acquired simultaneously, validated fiber optically determined displacements, suggesting microanchored DSS as an improved means for detecting and monitoring shallow subsurface strain profiles.

Technology Focus: CO2 (July 2020)

During the past 12 months, CO2 has taken center stage in global political debates and climate-change dialogues. Countries and companies are coming under intense pressure to find sustainable solutions to address the issue of carbon footprint by reducing CO2 emissions. In May of last year, 2019 SPE President Sami Alnuaim wrote a JPT article on the circular economy. The essence was on sustainability through efficiency, conservation, recycling, and reusing to minimize our impacts. While he was addressing the broader picture, I want to focus this article on the circular carbon economy. The circular carbon economy, which is not new, is a framework in which emissions of carbon from all sectors of the economy (including oil and gas) can be addressed through the four R pillars: reduce, recycle, reuse, and remove. We in the oil and gas industry can work collaboratively with governments, companies, academia, and other organizations on these four pillars. For example, energy efficiency can be improved across the entire chain of operations, flaring can be reduced to near zero, and investments can be made into high-efficiency technologies that reduce the carbon footprint. For the recycle and reduce pillars, CO2 can be converted into useful products such as methanol or used for well stimulation or conformance control, for example. And the biggest impact can be made with the removal of CO2 permanently from the atmosphere by capturing and storing it. Two examples are storage in subterranean formations and mineralization in cements, rocks, or other materials. We need to look for (or create) appropriate business opportunities that will reduce our impact on the environment and reduce our carbon footprint and intensity. The papers that follow are examples of these four R pillars. One describes some promising pathways to lower atmospheric carbon through a practical and holistic approach. Another is the harvesting of energy from waste heat (improving efficiency) during oil and gas operations using supercritical CO2. The third is an example of using CO2 in place of water for fracturing operations. Many other opportunities can be adopted, and a business case can be made for them. What the industry needs at this stage is a willingness to work together, share best practices, conduct innovative research, and focus on technologies that lower cost of capture and make our operations more sustainable.

Two-phase bitumen/water relative permeability at different temperatures and SAGD pressure: Experimental study

The heavy oil or bitumen trapped in subterranean formations in Canada and North America can be effectively produced and recovered using thermal enhanced oil recovery (TEOR) techniques, especially steam assisted gravity drainage (SAGD) processes. Heating the formation to a high temperature greatly reduces the oil viscosity, which increases the oil mobility in the reservoir. In the SAGD process, the steam injected through a long horizontal well creates a steam saturated zone, called steam chamber, around the well that gradually expands laterally and vertically within the reservoir. The edge of the growing steam chamber is where the oil is displaced by the steam. There is a large temperature gradient in the oil drainage zone with steam temperature at the edge of the steam chamber and close to the original reservoir temperature on the other side of the drainage zone. The fluid flow behavior, which is controlled by relative permeability, can be sensitive to the temperature in this transition zone. The objective of this study was to investigate the impact of temperature on two-phase bitumen/water relative permeability of sand over a wide range of temperature from 70 to 220 °C.In the present study, isothermal displacement experiments were conducted with an advanced experimental rig under the confining pressure of 1400 psi using Athabasca bitumen, deionized water, and clean silica sand at six different temperatures. All experiments were repeated to ensure that the results are repeatable and reliable. The JBN (Johnson, Bossler and Neumann) method was used to obtain the two-phase relative permeability. The effect of temperature on relative permeability for the bitumen system was found to be substantial and should be accounted for in simulation of SAGD processes. The endpoint water relative permeability can increase by two orders of magnitude in going from the reservoir temperature to the steam temperature. The endpoint oil relative permeability also increases, albeit more modestly and the residual oil saturation decreases. Besides the relative permeability tests, contact angle and IFT measurements at high-temperature, high-pressure conditions were conducted to evaluate the fluid-fluid and rock-fluid interactions and examine any changes in wettability. According to the contact angle results, the wettability of system was water-wet and shifted toward strongly water-wet at higher temperatures. In addition, the IFT displayed a decreasing trend with temperature and reached the minimum value of 18 mN/m in the temperature range of 125–155 °C.

Polymeric microsphere injection in large pore-size porous media

High water-cut has become a worldwide challenge for oil production. It requires extensive efforts to process and dispose. This entails expanding water handling facilities and incurring high power consumption costs. Polymeric microsphere injection is a cost-effective way to deal with excessive water production from subterranean formations. This study reports a laboratory investigation on polymeric microsphere injection in a large volume to identify its in-depth fluid diversion capacity in a porous media with large pore/particle size ratio. The performance of polymeric microsphere injection was evaluated using etched glass micromodels based on the pore network of a natural carbonate rock, which were treated as water-wet or oil-wet micromodels. Waterflooding was conducted to displace oil at reservoir temperature of 95 °C, followed by one pore volume of polymeric microsphere injection. Three polymeric microsphere samples with median particle size of 0.05, 0.3, and 20 μm were used to investigate the impact of particle size of the polymeric microspheres on incremental oil production capacity. Although the polymeric microspheres were much smaller than the pores, additional oil production was observed. The incremental oil production increased with increasing polymeric microsphere concentration and particle size. As a comparison, polymeric microsphere solutions were injected into oil-wet and water-wet micromodels after waterflooding. It was observed that the oil production in oil-wet micromodel was much higher than that in water-wet micromodel. The wettability of micromodels affected the distribution patterns of the remaining oil after waterflooding and further dominated the performance of the microsphere injection. The study supports the applicability of microsphere injection in oil-wet heterogeneous carbonates.

Estimating transition time from deep filtration of particles to external cake during produced water re-injection and disposal

Water production management from oil and gas fields is a big challenge for petroleum industry. Re-injection and disposal of produced water into subterranean formations/oil reservoirs is considered as an environmentally-friendly solution for managing massive water production in petroleum industry. Formation damage resulted from plugging by dispersed particles in the injected water is one of the main concerns in waterflood/disposal projects that causes rapid permeability impairment. Main mechanisms for permeability decline due to injection of low-quality water are deep filtration of dispersed particles into the porous rocks and external filter cake formation on the injection surface. In this article, an empirical correlation is developed for prediction of transition time from deep bed filtration to external cake formation based on available experimental data points from the literature. The proposed correlation includes measurable parameters such as solid particle size to pore size ratio (jamming ratio) and injection concentration of suspended particles which was ignored in previous studies. The proposed correlation is evaluated with water injection data of 15 wells with good agreement. The developed correlation can be used for design and planning of operations with solid in liquid dispersion including drilling fluid, low-quality water flooding, and waste water disposal into subterranean formations.

Condition Assessment of Building Foundation in Karst Terrain Using both Electrical Resistivity Tomography and Multi-channel Analysis Surface Wave Techniques

In foundation survey projects for hotel buildings in Kentucky, assisted by drilling data, an integrated geophysical survey was undertaken. The main goal of the project was to investigate the depth of the top rock and the void locations, if any present. The project used shallow non-invasive geophysical survey methods, including electrical resistivity tomography (ERT) and multi-channel analysis of surface wave (MASW). A shallow subsurface survey was performed using the MASW equipped with a 24-geophone array, equipped with 4.5 Hz geophones to estimate the clay/soil thickness. The 22 2-d ERT profiles for imaging resistivity changes in subterranean formations were used to survey the top rock and delineate possible karst areas in the area. These methods successfully reflect the top of the rock at an average depth of about 60 ft. Additionally, several relatively large karst feature zones in the study area were mapped with the use of the ERT data. Finally, the 2-d ERT profiles were used to study the geological properties of the foundation structure. Using the established geophysical model, the internal structure of the foundation was revealed. The results are in good agreement with the actual situation in the study area as evinced by available borehole data, and can guide engineers when solving foundation problems and reveal the weakness of the karst lava development area that may appear under a foundation during its construction.

Touching with Light, or, How Texture Recasts the Sensing of Underground Water

This paper is an ethnographic examination of the early social life of a project to map Costa Rica’s aquifers using LandSat imagery and a specialized algorithm. The project aims to make subterranean formations accessible for public agencies mediating recent environmental conflicts over underground water, which have been diagnosed as the country’s first “water war.” I analyze the presentation to the public of this project and the technology it uses to show how vision and touch are conceptual resources that people use to describe the technicalities of satellite imagery. Attending to the semiotic and technical power of vision and touch requires a nonessentialist understanding of the senses. It requires moving away from a narrow understanding of sensing as embodied, phenomenological practice. Focusing on the role of texture as that which operates in the interstices of vision and touch, I propose going beyond panoptic imaginaries in order to grasp the diverse social lives that technologies such as satellite imaging have.

Nanoparticle-Enhanced Hydraulic-Fracturing Fluids: A Review

Summary Hydraulic-fracturing fluids are used to break down subterranean formations where oil and gas are trapped. Pad or prepad fluids are first pumped into the formation to generate the fracture geometry. Once the fracture geometry is created, additional fluid containing proppant is used to transport these solid particles into the fractures. Then, the hydraulic pressure is released and the fracture will tend to close. At that stage, the proppant prevents fracture closure and provides a conductive channel for hydrocarbons to flow into the wellbore. Biopolymers, synthetic polymers, foams, viscoelastic surfactant (VES) fluids, and slickwater are all used as fracturing fluids, each with properties that are beneficial under certain conditions. Today, their formulations are well-developed, and more recently, may incorporate small-sized particles in the nanometer size range. Such nanoparticles have addressed certain technological limitations of fracturing fluids. For example, VES fluids were reported to suffer high leakoff rates in moderate permeability reservoirs (200 md) and were limited in temperature (beyond approximately 220°F, viscosity was diminished significantly). Another challenge is the pressure-dependent behavior of borate-crosslinked gels, where the viscosity was found to drop significantly under high pressures. Also, in high-temperature reservoirs (>350°F), it is very challenging to design a fluid that can sustain enough viscosity for a required period of time. Synthetic polymers (mainly acrylamide-based polymers) are commonly used and have been reported to be used at high concentrations. These high-concentration requirements are imposed by the need for a stable viscosity under high-temperature conditions. High polymer loading increases the potential of formation damage caused by the fluid residue. These challenges, which can be addressed by nanotechnology, could have a major impact on hydraulic-fracturing applications. For instance, the working temperature limit of VES-based fluids was improved from 200 to 250°F (93 to 121°C) by adding zinc oxide (ZnO) and magnesium oxide (MgO) nanoparticles. The borate-crosslinked gels were found to maintain their viscosity at pressures up to 20,000 psi when using boronic acid-functionalized nanolatex silica particles as crosslinkers, while under such high pressures, conventional borate crosslinkers showed more than 80% reduction in viscosity. Moreover, the rheological properties of mixed VES/polymer fluids were enhanced when using nanoparticles. Use of foams can reduce the amount of water consumed in hydraulic fracturing. Alfa olefin sulfonate (AOS) surfactant can be foamed by use of carbon dioxide (CO2). Aluminum oxide nanoparticles were found to stabilize the foams created by AOS, VES, and CO2. This has a potential application in waterless fracturing. This review paper will capture all of these aspects and summarize the most recent experience of nanoparticle usage in hydraulic-fracturing fluids design.