Carbon Dots Stabilized Foam for Enhanced Oil Recovery

2021 ◽  
Author(s):  
Sivabalan Sakthivel ◽  
Mazen Kanj

Abstract Foams are the divergent fluids that are employed in the upstream oil and gas industry to reduce fluid channeling and fingering in the high permeability region. Foams are usually generated in the high permeability reservoirs (e.g. glass beads) by the alternative injection of surfactant and gas. Conventional foaming systems exhibit stability issues at the high temperature and high salinity reservoir conditions. In this investigation, we study the stability and efficiency (in terms of both enhanced inflow performance and added oil recovery) of foams formed using surfactant solution with and without carbon Nanodots (CND). The study involved using different brine salinities, CND concentrations, temperature and pressure conditions, and types of surfactants. A multifaceted interrelationship of the various influencing mechanisms is demonstrated. Foams are examined using foam analyzer, HP/HT coreflood and microfluidic setup. In trace amounts (5-10 ppm), CND contributed to 60-70% improvement in foam stability in high salinity brine. The improvement is attributed by the reduction of the drainage rate of the lamellae and a delay of the bubble rupturing point. Both microfluidic and core-flood experiments showed noticeable improvement in mobility control with the addition of the CND. This is contributed to an improved foamability, morphology, strength, and stability of the foam.

SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 2243-2259 ◽  
Author(s):  
Pengfei Dong ◽  
Maura Puerto ◽  
Guoqing Jian ◽  
Kun Ma ◽  
Khalid Mateen ◽  
...  

Summary Oil recovery in heterogeneous carbonate reservoirs is typically inefficient because of the presence of high-permeability fracture networks and unfavorable capillary forces within the oil-wet matrix. Foam, as a mobility-control agent, has been proposed to mitigate the effect of reservoir heterogeneity by diverting injected fluids from the high-permeability fractured zones into the low-permeability unswept rock matrix, hence improving the sweep efficiency. This paper describes the use of a low-interfacial-tension (low-IFT) foaming formulation to improve oil recovery in highly heterogeneous/fractured oil-wet carbonate reservoirs. This formulation provides both mobility control and oil/water IFT reduction to overcome the unfavorable capillary forces preventing invading fluids from entering an oil-filled matrix. Thus, as expected, the combination of mobility control and low-IFT significantly improves oil recovery compared with either foam or surfactant flooding. A three-component surfactant formulation was tailored using phase-behavior tests with seawater and crude oil from a targeted reservoir. The optimized formulation simultaneously can generate IFT of 10−2 mN/m and strong foam in porous media when oil is present. Foam flooding was investigated in a representative fractured core system, in which a well-defined fracture was created by splitting the core lengthwise and precisely controlling the fracture aperture by applying a specific confining pressure. The foam-flooding experiments reveal that, in an oil-wet fractured Edward Brown dolomite, our low-IFT foaming formulation recovers approximately 72% original oil in place (OOIP), whereas waterflooding recovers only less than 2% OOIP; moreover, the residual oil saturation in the matrix was lowered by more than 20% compared with a foaming formulation lacking a low-IFT property. Coreflood results also indicate that the low-IFT foam diverts primarily the aqueous surfactant solution into the matrix because of (1) mobility reduction caused by foam in the fracture, (2) significantly lower capillary entry pressure for surfactant solution compared with gas, and (3) increasing the water relative permeability in the matrix by decreasing the residual oil. The selective diversion effect of this low-IFT foaming system effectively recovers the trapped oil, which cannot be recovered with single surfactant or high-IFT foaming formulations applied to highly heterogeneous or fractured reservoirs.


2021 ◽  
Author(s):  
Mohammed T. Al-Murayri ◽  
Dawood Kamal ◽  
Najres Al-Mahmeed ◽  
Anfal Al Kharji ◽  
Hadeel Baroon ◽  
...  

Abstract The Sabriyah Upper Burgan is a major oil reservoir in North Kuwait with high oil saturation and is currently considered for mobility control via polymer flooding. Although there is high confidence in the selected technology, there are technological and geologic challenges that must be understood to transition towards phased commercial field development. Engineering and geologic screening suggested that chemical flood technologies were superior to either miscible gas or waterflood technologies. Of the chemical flood technologies, mobility control flooding was considered the best choice due to available water ion composition and total dissolved solids (TDS). Evaluation of operational and economic considerations were instrumental in recommending mobility control polymer flooding for pilot testing. Laboratory selected acceptable polymer for use with coreflood incremental oil recovery being up to 9% OOIP. Numerical simulation recommended two commercial size pilots, a 3-pattern and a 5-pattern of irregular five spots, with forecast incremental oil recovery factors of 5.6% OOIP over waterflood. Geologic uncertainty is the greatest challenge in the oil and gas industry, which is exacerbated with any EOR project. Screening of the Upper Burgan reservoirs indicates that UB4 channel sands are the best candidates for EOR technologies. Reservoir quality is excellent and there is sufficient reservoir volume in the northwest quadrant of the field to justify not only a pilot but also future expansion. There is a limited edge water drive of unknown strength that will need to be assessed. The channel facies sandstones have porosities of +25%, permeabilities in the Darcy range, and initial oil saturations of +90%. Pore volume (PV) of the two recommended pilot varies from 29 to 45 million barrels. A total of 0.7 PV of polymer is expected to be injected in 5.6 and 7.9 years for the 3-pattern pilot and the 5-pattern pilot, respectively, with a water drive flush to follow for an additional 5 to 7 years. Incremental cost per incremental barrel of oil of a mobility control polymer flood which includes OPEX and CAPEX costs is $20 (USD). This paper evaluates the (commercial size) pilot design and addresses field development uncertainties.


2021 ◽  
Author(s):  
Chengdong Yuan ◽  
Wanfen Pu ◽  
Mikhail Alekseevich Varfolomeev ◽  
Aidar Zamilevich Mustafin ◽  
Tao Tan ◽  
...  

Abstract How to control excessive water production in high-temperature and high-salinity reservoirs has always been a challenge, which has been facing many oil reservoirs in Tarim Basin (China), such as Y2 reservoir with an average temperature of 107 ℃, salinity of 213900 mg/L (Ca2++Mg2+>11300mg/L), and permeability from 2 to 2048 mD. In this work, we present experimental studies to determine the potential EOR process for Y2 reservoir from foam flooding, polymer gel/foam flooding, and microgel/surfactant flooding. To simulate the permeability heterogeneity of Y2 reservoir, a 2-D sand-pack model was used for flooding experiments. Vertically, three layers (first 0.6cm, second 0.8cm and third 1.6cm from top to bottom, respectively) were packed with different size sand to simulate permeability heterogeneity (permeability increases from first to third layer). A 0.3 cm higher permeability zone was also filled inside third layer. Horizontally, permeability gradually decreases from middle to two sides. In this model, injection well was vertical, and production well was horizontal. The effect of impermeable interlayer was also studied by isolating the second and third layer. The results show that conformance treatments using in-situ crosslinked gel or micro-gel are necessary before foam or surfactant injection under a high permeability heterogeneity. When an impermeable interlayer existed between the second and third layer, the additional oil recovery of N2 foam flooding, in-situ crosslinked gel/N2 foam flooding, and microgel/surfactant flooding was 16.34%, 20.37%, 17.50%, respectively, which was much higher than that without impermeable interlayer (9.84%, 13.62%, 12.07%). This implies that when multiple layers exist, crossflow between layers is unfavorable for improving oil recovery, which should be paid extra attention in EOR process. Foam flooding has not only a good mobility control capacity but also a good oil displacement ability (verified by visual observations of washed sand after experiments), which, together with the strong conformance control ability of crosslinked gel, makes in-situ crosslinked gel/N2 foam flooding yield the highest displacement efficiency. Generally, for high-temperature and ultra-high-salinity reservoirs with strong heterogeneity like Y2 reservoir, in-situ crosslinked gel/foam flooding can be a good candidate for EOR. This work provides a potential EOR method with high efficiency, i.e. in-situ crosslinked gel assisted N2 foam flooding, for the development of similar reservoirs like Y2 with high temperature, ultra-high salinity, high heterogeneity and multiple layers. Moreover, this work also highlights that, despite that foam has the ability of mobility and profile control, a conformance treatment is necessary to block high permeability zone before foam injection when the reservoirs has a strong heterogeneity.


2021 ◽  
Vol 73 (01) ◽  
pp. 12-13
Author(s):  
Manas Pathak ◽  
Tonya Cosby ◽  
Robert K. Perrons

Artificial intelligence (AI) has captivated the imagination of science-fiction movie audiences for many years and has been used in the upstream oil and gas industry for more than a decade (Mohaghegh 2005, 2011). But few industries evolve more quickly than those from Silicon Valley, and it accordingly follows that the technology has grown and changed considerably since this discussion began. The oil and gas industry, therefore, is at a point where it would be prudent to take stock of what has been achieved with AI in the sector, to provide a sober assessment of what has delivered value and what has not among the myriad implementations made so far, and to figure out how best to leverage this technology in the future in light of these learnings. When one looks at the long arc of AI in the oil and gas industry, a few important truths emerge. First among these is the fact that not all AI is the same. There is a spectrum of technological sophistication. Hollywood and the media have always been fascinated by the idea of artificial superintelligence and general intelligence systems capable of mimicking the actions and behaviors of real people. Those kinds of systems would have the ability to learn, perceive, understand, and function in human-like ways (Joshi 2019). As alluring as these types of AI are, however, they bear little resemblance to what actually has been delivered to the upstream industry. Instead, we mostly have seen much less ambitious “narrow AI” applications that very capably handle a specific task, such as quickly digesting thousands of pages of historical reports (Kimbleton and Matson 2018), detecting potential failures in progressive cavity pumps (Jacobs 2018), predicting oil and gas exports (Windarto et al. 2017), offering improvements for reservoir models (Mohaghegh 2011), or estimating oil-recovery factors (Mahmoud et al. 2019). But let’s face it: As impressive and commendable as these applications have been, they fall far short of the ambitious vision of highly autonomous systems that are capable of thinking about things outside of the narrow range of tasks explicitly handed to them. What is more, many of these narrow AI applications have tended to be modified versions of fairly generic solutions that were originally designed for other industries and that were then usefully extended to the oil and gas industry with a modest amount of tailoring. In other words, relatively little AI has been occurring in a way that had the oil and gas sector in mind from the outset. The second important truth is that human judgment still matters. What some technology vendors have referred to as “augmented intelligence” (Kimbleton and Matson 2018), whereby AI supplements human judgment rather than sup-plants it, is not merely an alternative way of approaching AI; rather, it is coming into focus that this is probably the most sensible way forward for this technology.


2021 ◽  
Author(s):  
Xia Yin ◽  
Tianyi Zhao ◽  
Jie Yi

Abstract The water channeling and excess water production led to the decreasing formation energy in the oilfield. Therefore, the combined flooding with dispersed particle gel (DPG) and surfactant was conducted for conformance control and enhanced oil recovery in a high temperature (100-110°C) high salinity (>2.1×105mg/L) channel reservoir of block X in Tahe oilfield. This paper reports the experimental results and pilot test for the combined flooding in a well group of Block X. In the experiment part, the interfacial tension, emulsifying capacity of the surfactant and the particle size during aging of DPG were measured, then, the conformance control and enhanced oil recovery performance of the combined flooding was evaluated by core flooding experiment. In the pilot test, the geological backgrounds and developing history of the block was introduced. Then, an integrated study of EOR and conformance control performance in the block X are analyzed by real-time monitoring and performance after treatment. In addition, the well selection criteria and flooding optimization were clarified. In this combined flooding, DPG is applied as in-depth conformance control agent to increase the sweep efficiency, and surfactant solution slug following is used for improve the displacement efficiency. The long term stability of DPG for 15 days ensures the efficiency of in-depth conformance control and its size can increase from its original 0.543μm to 35.5μm after aging for 7 days in the 2.17×105mg/L reservoir water and at 110°C. In the optimization, it is found that 0.35% NAC-1+ 0.25% NAC-2 surfactant solution with interfacial tension 3.2×10-2mN/m can form a relatively stable emulsion easily with the dehydrated crude oil. In the double core flooding, the conformance control performance is confirmed by the diversion of fluid after combined flooding and EOR increases by 21.3%. After exploitation of Block X for 14 years, the fast decreasing formation energy due to lack of large bottom water and water fingering resulted in a decreasing production rate and increasing watercut. After combined flooding in Y well group with 1 injector and 3 producers, the average dynamic liquid level, daily production, and tracing agent breakthrough time increased, while the watercut and infectivity index decreased. The distribution rate of injected fluid and real-time monitoring also assured the conformance control performance. The oil production of this well group was increased by over 3000 tons. Upon this throughout study of combined flooding from experiment to case study, adjusting the heterogeneity by DPG combined with increasing displacement efficiency of surfactant enhanced the oil recovery synergistically in this high salinity high temperature reservoir. The criteria for the selection and performance of combined flooding also provides practical experiences and principles for combined flooding.


Author(s):  
Mohamed Saeed Shamlooh1 ◽  
Ahmed Hamza ◽  
Ibnelwaleed Hussein ◽  
Mustafa Nasser ◽  
Saeed Salehi

High water production in oil and gas wells reduces significantly the recovery factor. Mechanical as well as chemical methods are applied to shut off water productive zones. Crosslinked polymers showed high efficiency to seal off water zones in high permeability sandstone and fractured carbonate reservoirs. Moreover, emulsified polymeric formulations have been introduced for deep profile modification by changing the wettability of the rock and hence allowing selective plugging of water. This poster provides an overview of the polymeric formulations used for such application.


Author(s):  
L.S. Leontieva ◽  
◽  
E.B. Makarova ◽  

The oil and gas sector of the economy in many states remains the main source of foreign exchange and tax revenues to the budget. Moreover, its share, for example, in Russia, accounts for about 12 % of all industrial production. However, this sector, as the practice of world oil prices shows, is experiencing not only a rise, but also a decline. Consequently, the problem of forming a balanced portfolio of oil and gas assets is an object of close attention on the part of national oil and gas companies. The issues of choosing the optimal combination of oil and gas assets in the portfolio are no less urgent, especially among the tasks that all oil and gas companies face, both in Russia and abroad. An investment portfolio or a portfolio of oil and gas assets, which includes new projects for the commissioning of fields, as well as measures to enhance oil recovery, and exploration are objects of real investment. The high volatility of the oil and gas industry is influenced by various factors, including: macroeconomic, innovation risks and a number of others. These circumstances stimulate the sector to increase the resilience of its project portfolios in order to respond flexibly to changes. In an increasingly challenging and uncertain environment, oil and gas companies around the world face constant pressures as difficult strategic decisions and building long-term plans lead to a sustainable portfolio. In order to achieve their goals and maximize profitability, companies should apply certain algorithms in their practice. The article substantiates the role and importance of project portfolio management in achieving the goals of the state and companies in the oil and gas sector. The main goal of the article is to build an algorithm that is aimed both at determining the stability of the portfolio and the ability to flexibly respond to changes in the environment. The scientific novelty of the research lies in the determination of an algorithm for assessing the sustainability of a portfolio of projects of oil and gas companies. Application of this algorithm will allow oil and gas companies to take into account the influence of external factors. The research methodology is based on such methods as analysis of internal regulations and reporting of companies for project portfolio management, risk analysis, project ranking; grouping and classification method.


2015 ◽  
Vol 799-800 ◽  
pp. 196-200
Author(s):  
Abhilash M. Bharadwaj ◽  
Sonny Irawan ◽  
Saravanan Karuppanan ◽  
Mohamad Zaki bin Abdullah ◽  
Ismail bin Mohd Saaid

Casing design is one of the most important parts of the well planning in the oil and gas industry. Various factors affecting the casing material needs to be considered by the drilling engineers. Wells partaking in thermal oil recovery processes undergo extreme temperature variation and this induces high thermal stresses in the casings. Therefore, forecasting the material behavior and checking for failure mechanisms becomes highly important. This paper uses Finite Element Methods to analyze the behavior two of the frequently used materials for casing - J55 and L80 steels. Modeling the casing and application of boundary conditions are performed through Ansys Workbench. Effect of steam injection pressure and temperature on the materials is presented in this work, indicating the possibilities of failure during heating cycle. The change in diameter of the casing body due to axial restriction is also presented. This paper aims to draw special attention towards the casing design in high temperature conditions of the well.


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