bluuebunny/crossref_metadata_2025 huggingface dataset:
Key Success Factors of 3D OBN Survey in a Congested Oil Field in the Caspian Sea
Authors: Belaid Kamel Habib , Rouis Lamia , Khdhaouria Mourad , Rondon Aldrin , Ameish Giamal , Li Xiaoliang , Lyu Xiaolin
Published: March 2023

In this paper, we present and demonstrate that the implementation of an efficient Project Management Strategy has effectively contributed in a safe and successful completion of a very complex 3D OBN Seismic Survey in congested Oil fields. Thus, delivering high quality data on schedule and within the predetermined budget at the full satisfaction of all involved parties and stakeholders.

Strong commitment to HSSE Standards and working as an integrated One-Team with full collaboration and continuous communication between all the Team members are among the main Success Factors of the 3D seismic survey which was carried out during the critical period of COVID-19. Moreover, the deployment of experienced personnel, advanced and reliable Technologies with adequate equipment have also extended the efficiency of this OBN 3D seismic survey.

Preliminary results of 3D seismic data processing, interpretation and reservoir characterization are also briefly presented and discussed as a clear enhancement of data quality was already observed compared to the legacy 3D OBC data set.

A fast track small 3D cube was successfully processed as an utmost and urgent priority for appraisal well selection, design and drilling.
Excelling in Subsurface Unscheduled Deferment: Showcasing Best-In-Class Performance in Field X in the Southern of Oman
Authors: Al Shukaili Ghosin Nasser , Al Ajmi Ahmed Hussain , Al Kindi Said Sailim , Al Riyami Said Nasser , Al Matroushi Saif Mohammed , Al Lawati Mehdi Mohamed , Urdaneta Gerardo Antonio , Morinata Marpaung Billman
Published: March 2023

One of PDO operated field in southern Oman (Field X) was seeing an increase with time in subsurface unscheduled deferment reaching 3.7% of total field potential in 2020. This percentage of subsurface unscheduled deferment was far away from local (2%) and global (1%) top quartile.

Field X considered is one of the oldest fields in southern Oman and currently producing over 90 K bbl/d of net oil from over 2200 oil producers, distributed across 23 fields. The oil is being processed by 5 main stations. Very dynamic operation taking place in Filed X with more than 1600 well interventions yearly. Due to these facts, Subsurface unscheduled deferment management in Field X is a real challenge. And If this business pain not resolved, an average of 3,800 bbl/d unscheduled sub-surface deferment will continue and accumulate.

In a phase-wise approach, a dedicated workshop on subsurface deferment reduction was carried out with all the stakeholders in 2020 to reach the potential solutions to reduce unplanned subsurface deferment in Field X. The four main elements for this pain are Fail Less, Restoration cycle time, resources management and data visualization.

Since 2020 Field X subsurface unscheduled deferment has been decreasing dramatically to 2.9% in 2021 and 2.4% in 2022, approaching local top quartile (2%). A historical record has been achieved in September 2022 by reducing the unscheduled subsurface deferment to only 0.8% beating both local and global (1%) top quartile. This paper will discuss the methodology and best practices that led to achieve such results.
The First Off-Grid Solar Power Plant in Iraq
Authors: Ma Rui , Liu Junxian
Published: March 2023

More and more countries around the world are putting more focus on renewable energies due to the surging price of energy and highly concern about environment issues. Solar energy has significant growth and development in recent years, becoming one of the fastest growing sources of renewable energy worldwide. Countries in Middle East, has shown increasing interest in developing its solar energy sector. Iraqi government has launched several initiatives aimed at increasing the use of solar energy and is committed to developing the country's solar energy sector as a means of reducing its dependence on oil exports and meeting its growing energy demand.

Faihaa Field 2.5 MW Solar Power Plant, which is located in Block 9 approximately 50 km north of Basra City, was invested and commissioned by Kuwait Energy Basra Limited. The power plant is an off-grid 2.5 MW PV solar power plant with 2.5 MWh battery energy storage system. After we put this plant into operation, it has already saved us 1,732 liters diesel per day. Additionally, solar energy is a zero emission energy, so it also help to reduce the emission of greenhouse gases. This is the first off-grid solar power plant in Iraq, which is a notable milestone for solar energy development in this country. The solar energy industry in Iraq will benefit from this project's valuable experience and trained technical team.
Concept of Half-Jacket and Retractable Joints to Restore Offshore Platform's Structural Integrity
Authors: Chatterjee Prabir Kumar , Shah Jinesh
Published: March 2023

This paper presents a new approach of offshore jacket strengthening with rigidly connected members with minimum number of clamps and bolts. Horizontal and diagonal braces between two successive elevations of a jacket in a plane may be combined to form a prefabricated X-frame which will be able to replace a set of existing damaged members. To facilitate easy installation, X-frame will be assembled along with its connecting half-clamps and one side of the X-frame will be provided with retractable ends. The annulus portion of the movable ends of the X-frame will be grouted to make rigidly joined new braces. Additionally, the concept of half-jacket has been utilized to create additional deck space required for operational purpose. The half-jacket will be integrated to the existing structure by rigid subsea connections. The case study involves an aging offshore platform that undergoes a large amount of horizontal movement due to environmental loads. In spite of earlier upgrade with new piles and clamped braces, the substructure is found to be considerably flexible as a result of loose clamps and construction tolerance provided at the ends of each member. A detailed analytical study has been performed with the proposed strengthening scheme that shows significant improvement of the platform movement due to extreme environmental loads.
Amplitude-Preserving Reconstruction Method for 3D Irregular Data Based on Improved POCS Algorithm
Authors: Ni Yudong , Xu Yinpo , Long Bo , Liu Xinggang , Zhang Chun , Ren Guang , Wang Mingliang
Published: March 2023

In an increasingly complex exploration environment, the acquired seismic data are incomplete and irregular, and field interference often seriously affects the S/N (signal-to-noise ratio) of complex seismic signals. At the same time, weak seismic signals in deep geophysical target are always covered by field noise. How to effectively reconstruct irregular seismic signals and suppress field noise is still a key problem in high-precision seismic exploration. The paper systematically analyzes the inverse problem of sparse optimization for noise suppression of field interferences in irregular seismic data under the framework of 3D curvelet transform, and proposes an amplitude-preserving reconstruction technique for 3D irregular data based on improved POCS algorithm with iterative soft threshold. On the basis of achieving highly sparse representation, the effective seismic signal is inversed iteratively through the change of S/N of adjacent traces to effectively improve the S/N of complex seismic data. At the same time, when solving the sparse optimization problem, the dividing point of noise and effective wave curvelet coefficient is obtained by constructing the ratio formula of curvelet coefficient, which lays the foundation for accurately suppressing noises and reconstructing weak seismic signals. The application of actual data shows that the method can suppress the noises in the complex seismic data, recover the missing data effectively, and improve the fidelity of the reconstructed data.
The Application of Deblending Offshore 3D DAS VSP Data
Authors: Li Fei , Song Jiawen , Zhang Yanbin , Chen Yuanzhong , Yin Tiankui , Han Jianxin , Li Qingfeng , Yu Gang
Published: March 2023

The high productivity blended acquisition technique greatly improves the acquisition efficiency. However, this technology also introduces serious interference noise from adjacent sources. An efficient data deblending method based on sparse inversion is used to separate the simultaneous sources for offshore 3D DAS VSP data. Due to the difference in coherence between main source and blended noise on the time-space common receiver point gathers, which can be expressed by the sparsity in the FKK domain, we can solve the effective signal by imposing additional constraints on the unknown signal model. The signal model with gradually improved signal-to-noise ratio can be obtained by subtracting interference noise from simultaneous sources. The method has been proved to be efficient and useful in separating the main source from the interference noise by using the Offshore 3d DAS VSP data. It should be pointed out that this method is not applicable to the data acquired in the area with irregular spatial distribution of shot points because this method requires 3D FKK transformation of common receiver point data.
A Numerical Study of the Influence of Rock Mineralization on CO2 Storage
Authors: Bello Ayomikun , Dorhjie Desmond Batsa , Ivanova Anastasia , Cheremisin Alexey
Published: March 2023

One of the anthropogenic greenhouse gases that significantly affects the climate is CO2, and it may be possible to lower its emission by sequestering it in an appropriate geological subsurface formation. For secure and effective sequestration, it is necessary to answer questions relating to enhancing the reaction rates of rock minerals to speed up sequestration, understanding the critical reservoir parameters involved with geochemically induced changes and how they affect mineralization, and the affinity of rock minerals for dissolution or precipitation in the presence of CO2 and reservoir brine. Therefore, in this paper, a case study of CO2 sequestration in a saline aquifer was investigated by using a numerical simulator to examine the impacts of injection period, temperature, pressure, and salinity on the CO2 mineralization trapping mechanism during the sequestration process. Nine intra-aqueous and seven mineral reactions were modeled to investigate the dissolution and precipitation of formation minerals. The results of this work can provide the appropriate mineralization temperatures at which each of the simulated minerals can either dissolve or precipitate. Calcite and dolomite mineralize more effectively at medium and lower temperatures, despite the fact that the reaction of other minerals such as illite, kaolinite, K-feldspar, and quartz will be more favored at high temperatures. Porosity and pH showed only slight variations, but they were sufficient to show how the dynamics of mineral reactivity and mineralization trapping efficiency had changed.
An Experimental Study on the Effect of Gas on the Performance of a Multi-parallel Pipe Oil-Water Separator (MPPS)
Authors: Asaadian Hamidreza , Stanko Milan
Published: March 2023

This work presents a comprehensive experimental study on the effect of gas on the performance of oil-water bulk separation in a multi-parallel pipe separator (MPPS). Several flowrates of gas, up to 10% volume fraction were tested and values of separation efficiency and water cut ratio were estimated from measurements. Also, the three-phase flow pattern upstream the separator inlet is reported.

Exxsol D60 spiked with 700 ppm of crude oil, 3.4 wt% NaCl saltwater, and air were used in steady-state and transient tests on a transparent 6.1 m long, 15.24 cm diameter, separator prototype. Preliminary values of separation efficiency and water cut ratio were measured over a variety of total flow rates (300 to 700 L/min), water cuts (WC, 30%, 50%, 70%, and 90%), and water extraction rates (ER, 50% to 90% the rate of inlet water)

It is observed that the gas phase accumulates at higher sections of the separator (i.e. at the inlet section after the splitting and at the exit section where water rich fluid is tapped from the bottom of the pipe). It seems the reduction in separation performance is due to turbulence caused by the gas and reduced cross section for the oil-water mixture to flow. The higher the gas flow rate, the lower the separation efficiency and water cut ratio. The presence of gas impacts more flow conditions with low water cuts including 30 and 50%. The presence of gas has less negative impact on separator performance when the liquid flow rate is high. Results show even small amounts of gas entering the separator have a significant detrimental effect on oil-water separation.

Pipe oil-water separators have several advantages over heavy gravity vessels, including cost, compactness, ease of deployment and enable energy saving by separating close to the source. However, this study shows that the presence of gas can impact dramatically their performance. Thus, the performance of upstream gas separation must be studied closely.
Lower Completion Design for Water Control Inflow Based on Logging While Tripping Data, A Case of Study
Authors: Celma Rafael , Douik Hela , Almarzooqi Maitha , Alawadhi Abdulaziz
Published: March 2023

Oil production nowadays become more challenging worldwide from high depletion and water production. New devices for water control are available in the market, but an integration with borehole data is critical for optimizing the ratio between oil recovery and water constraint. In this case study, the production forecast for the well was of 600 bd with no water, however the initial well test gave a production of 50 bd with 95% water cut. The main reason behind this contrasting result was unexpected structural features connected with lower aquifers.

A lower completion design with water control devices was put in place based on open hole data. To reduce the uncertainty and optimize the design, a logging acquisition of resistivity and caliper was suggested to evaluate the remaining fluids of the reservoir and how much of the water was related to reservoir depletion. Due to a rig restriction (a hoist unit) a pipe convey method to acquire data through logging was not possible. Instead logging while tripping was utilized, and we could successfully acquire a reliable caliper, resistivity, and density neutron readings. These results helped us refining the design, optimizing the amount of control devices, and securing the packer placement in the best zones for proper swelling.

After the flow to clean process, the well tested 250 barrels of oil with 20% water cut which is aligned with the prediction during the design and planning stage.
Experimental Investigation of the Effect of Surface Cleavage and Exposure Time on Rock Wettability
Authors: Aboushanab Mahmoud Sami , Al Naimi Khaloud , Mahmoud Mohamed , Arif Muhammad
Published: March 2023

The wettability behavior of reservoir rocks is recognized as a key factor that influences oil recovery. Several recent studies have investigated factors affecting wettability. However, a thorough understanding of all the elements influencing rock wettability remains elusive. Surface wettability is known to be influenced by a range of operating conditions and the surface-related parameters e.g., surface roughness, surface chemistry etc. While these factors have been rigorously reported before, one key factor that received little or no attention is the surface cleavage. In particular, pure calcite mineral demonstrates multiple cleavage plane, and thus wettability of freshly cleaved calcite can vary depending on the cleavage plane, which can also be very different to the wettability of calcite surface exposed to the atmosphere. Moreover, the traditionally reported macro-scale contact angles lack a bit in terms of the identification of three-phase contact line, and thus the use of high-resolution micro-scale approaches for contact angle measurement becomes essential. Thus, in this study, we investigate the wettability of freshly cleaved and exposed calcite and quartz surfaces and examine the difference in the observed wetting behavior. The contact angles were measured at both micro- and macro-scale using a conventional sessile drop method and environmental scanning electron microscopy (ESEM), respectively to also examine any additional impact of the scale of observation. Advanced image analysis algorithm is then used to process the droplet image and examine the contact angles. Additionally, FTIR spectroscopy is also used to determine the surface chemistry changes in the exposed surfaces that would lead to any wettability alteration. The results of this study indicate that the contact angles observed for both freshly cleaved calcite and freshly fractured quartz are much less than the contact angles of the exposed calcite and quartz – suggesting that freshly cleaved surfaces are more hydrophilic than their exposed versions. Thus, much caution should be considered during dealing with calcite and quartz; as exposure time could be a crucial factor in wettability determination.
A Production Prediction Solution for Tight Gas Formation with Water-Blocking Damage
Authors: Lu Fawei , He Yuchun , Fan Zhaoya , Ren Bonan , Rao Guang , Gao Bei , Chen Jichao
Published: March 2023

With the increase of energu demand of oil and gas and the decrease of conventional oil and gas resources in China, the exploration and development of tight gas reservoirs has becomes the first priority to enlarge gas reserves. The middle-deep sandstone of the Huagang Formation in the Xihu Sag of the East China Sea belongs to the category of tight sandstone reservoirs and is a typical low-permeability, low-porosity reservoir[Xu,G et al. 2012], with strong water-blocking damage, and drill-stem test (DST) results from many wells were showed much lower production than what expected. Conventional productivity evaluation methods are also difficult to accurately evaluated productivity with water-blocking damage condition.

In this paper we integrated core experiment, water-drive gas experiment, gas-drive water experiment, wireline formation test (WFT) results, logging interpretation, formation evaluation results, and numerical simulation analysis and proposed a new production prediction solution for a tight gas formation with strong water-blocking damage. The workflow is following:

First, mobility as a dynamic measurement derived from WFT was studied, which clarified that the near-wellbore zone has experienced water-based mud invasion.

Second, based on WFT, core lab data, well logging interpretation results, and neural network rock typing method, the formation was characterized into different rock types. The characteristics of each rock type and its degree of water-blocking damage were researched.

Then based on dozens of core lab data, the relationship between maximum gas relative permeability (Krg) and absolute permeability was identified. Furthermore, based on the correlation among core lab data, well logging interpreted permeability curve and maximum Krg, the effective permeability profile can be deduced. This profile can help to estimate the approximate maximum productivity of a well, but not accurately enough without irreducible water saturation input.

Third, with calibrated permeability and saturation, a single well model was built with different rock typing results. Each rock type was assigned with the corresponding relative permeability lab data. By this, the process of productivity prediction from the different rock types and the effect of water-blocking damage with the changing of water saturation can be demonstrated.

This solution cannot only simulate gas production with water saturation changing at the initial stage of production, but also simulates the water-blocking damage caused by mud invasion into the formation. It reproduces the generation and release process of "water-blocking."

After verification with multiple wells, this solution can accurately provide production evaluation for a tight gas reservoir with water-blocking damage. It also confirmed the influence of water blocking on tight gas production.
Investigation of Anionic-Nonionic Surfactants for EOR in Carbonate Reservoirs
Authors: Scerbacova Alexandra , Barifcani Ahmed , Phan Chi , Cheremisin Alexey
Published: March 2023

In this work, four linear alkyl ether carboxylates (AECs) C11E5A, C11E11A, C12E4A, and C12E7A were examined as agents for surfactant EOR. Their main properties that have a key effect on surfactants' performance during flooding were investigated: stability, interfacial tension (IFT), wetting ability, and spontaneous imbibition in limestone samples. The thermal stability and salinity tolerance was correlated with the molecular structure of AECs. IFT on the boundary with n-decane and crude oil was evaluated with the spinning drop tensiometry method at five temperatures in the range between 25°C and 70°C and various salinities. The wettability was studied through contact angle measurements of deionized water on the limestone plate surface. The core plates were aged in oil for 14 days to obtain the hydrophobic carbonate surface and then treated with surfactant compositions for 48 hours at 70°C. The wettability alteration mechanism was assessed through the Rock-Eval pyrolysis method, which was not previously applied for this purpose.

The experiments showed that ethylene oxide (EO) chain length influences the stability of AECs. It was found that the temperature rise substantially impacts a surfactant with a longer EO chain C11E11A. In contrast, brine salinity significantly affects the interfacial behavior of AEC with a shorter EO chain. C12E7A strongly hydrophilizes the surface, and the contact angle decreases from 110° to 15÷20°. The Rock-Eval pyrolysis analysis indicated that C12E7A has a better wetting ability due to a combination of "cleaning" (washing of hydrocarbons from the core sample surface) and "coating" (adsorption of surfactant molecules on cleaned spaces) mechanisms.
Investigation of Shale Wettability Alteration upon Exposure to Surfactants
Authors: Alzaabi Ahmed , Adila Ahmed Sami , Rahman Md Motiur , Ali Mujahid , Keshavarz Alireza , Iglauer Stefan , Arif Muhammad
Published: March 2023

The development of unconventional resources such as shales has gained great popularity in the past decade. The objective of this study is to investigate the effect of surfactants on the wettability of shale rocks. In particular, we examine the influence of different concentrations of CTAB and SDBS surfactants on Eagle Ford, Wolf Camp and Mancos shale samples to determine their wettability alteration potential at the macro-scale.

In this work, macro-scale contact angle (CA) measurements of the three studied shale samples were conducted at ambient conditions as a function of surfactant concentration. Additionally, rock surface imaging was conducted via Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) at the nano- and micro-scale respectively. Surface chemistry was also investigated through zeta potential and Fourier-transform infrared spectroscopy (FTIR) analysis to understand the interactions at the surfactant-mineral interface and its associated impact on wettability alteration.

The results indicate that the wettability alteration potential of surfactants on shale surfaces is closely related to rock minerology, while it is a relatively weak function of surfactant concentration. The contact angle results of Eagle Ford and Wolf Camp indicate mixed-wet conditions, while Mancos indicates water-wetness. The contact angle results at high pressure show that the increase in pressure leads to contact angle increase. The results also show that zeta potential results for all shales tends to increase in magnitude as the concentration of both surfactants increase. Additionally, FTIR results indicate the presence of C-O (carboxylate group), Ca-C, and Si-O bonds on the surfactant-treated surfaces at different extent. Finally, surface topography images revealed that Eagles ford and Wolf Camp have a relatively higher surface roughness compared to Mancos.

This study aims to develop scientific understanding of the different shale compositions and surfactant wettability alteration of shale rocks from a micro-scale perspective.
Shale Oil Fracturing Optimization with an Integrated Workflow in Daqing Oilfield, Northeast China
Authors: Xiang Chuangang , Fu Zhiguo , Zhuang Xiangqi , Gao Bei , Chen Yingru
Published: March 2023

In order to improve the production of Gulong shale oil from well stimulation, a Geoengineering integrated model was established through integration of geological modeling, geomechanics modeling, fracturing modeling and reservoir simulation from QH working pad in Daqing oilfield, Northeast China. Based on integrated modeling workflow and study, key stimulation parameters such as stage interval, clusters of stage, frac liquid volume and proppant volume, well spacing were quantitatively optimized. Optimization study indicated 70-80m stage interval, 10m cluster interval (7 clusters per stage), frac volume 1,400 m3 per stage, proppant volume 140 m3 per stage are best parameters in QH pad and 400 m well spacing staggering across zones are best well pattern to QH pad. The study results are of great significance to the realization of large-scale rapid production increase and profitable development for Gulong shale oil reservoirs.
Engineered Bit Design with New Cutter Technology Improved Drilling Efficiency in Abrasive Sandstone in China Ordos Basin
Authors: Liu Yongjun , Li Jinsong , Lin Dong , Sun Jiacai , Luo Lei , Chen Guiyang , Li Peng , Ding Peng , Chen Zhiqiang , Xia Yang , Xiao Rui
Published: March 2023

Dual lateral horizontal wells were drilled for China Changbei tight gas development in Ordos basin. The horizontal 8 ½" hole section is the most challenge part for efficient well construction due to the hardness and abrasiveness of the consolidated sandstone rocks. Optimized drilling performance requires the matching of appropriate drill bit technology to an application for the formation to be drilled, which can be an engineering challenge. Various types of drill bits, including TCI, PDC and Hybrid type bits are used in Changbei for continuous performance improvement.

The 8 ½" hole section consists of hard and abrasive sandstone, interbedded claystone, and conglomerates. Most drill bits suffered short runs due to severe wear in the outer region of the bit including Gauge and Shoulder area, even lost cones for TCI and Hybrid bits.

With collaborations from operators and bit vendors, based on dull review and data analysis, a new type of PDC bit was designed with advanced cutter technology. The new design was developed to increase ROP and run length, avoiding unnecessary trips in the challenging formations and improved the drilling efficiency.

The new designed PDC bit adopted short profile design, reversed circle cutter placement pattern, balanced the aggressiveness and durability with backup cutters and DOC control. PDC cutters was used for passive gauge protection to overcome the wear out due to formation abrasion.

The field trials were very successful. The new designed PDC bit improved 30% on ROP and 10% on footage per bit run than offset Hybrid bits. Moreover, the new designed PDC bit eliminated lost cone risks of TCI and Hybrid bits, which was happened a couple of times in Changbei and caused tremendous NPTs for fishing and sidetracks.

This article will describe the bit performance improvement journey of Changbei tight gas field. Even with a long period of time staying on plateau, step changes still possible with new technology deployment and continuous improvement mindset.
Evaluation of Over-Pressured Gas Reservoirs: Reserves Estimation to Production Performance - A Case Study
Authors: Muneez Iqbal , Saad Mehmood , Muhammad Hasnain , Qazi Munawar , Jahangeer Zafar
Published: March 2023

Geo-pressured reservoirs are challenging in terms of in-place estimation and maintaining sustained production. Estimation of Gas Initially In-place (GIIP) using P/z from early data shows incorrect estimation and resulted in over-predicting GIIP. Typically, over-pressure gas reservoirs show downward curvature in P/z plot early or slightly delayed depending upon the pool limit and the degree of overpressure. A rapid decline in production also observed in the over-pressured gas reservoirs resulted in low hydrocarbon recoveries. This paper aims for correct GIIP estimation in over pressured gas reservoirs and to better manage and maximize recoveries from the Field.

Based on available pressure and production data, two approaches were used in order to estimate the GIIP of the Field. (1) Conventional P/z by using Hammerlindl method (2) Developed analytical model by incorporating rock compressibility value from the Geomechanical SCAL study. The calculation of GIIP from both the methods are somewhat in close agreement as the vital factor of rock compressibility was introduced in GIIP estimation, to cater for the effect of reducing porosity as the pressure drops, resulting in changing storage capacity of the rock. Additionally, consecutive pressure Build-up data history showed reduction in permeability with the time from 9 mD to 0.4 mD. This change in permeability is caused by near wellbore overburden stress increase resulting in rock expansion which in turn reduces/closes pore throats. This manifest as an apparently damaged region causing lower rates and poor recoveries. In this scenario the well would be shut-in at higher abandonment conditions.

Basic geo-mechanical parameter of rock compressibility plays an important role in reserves estimation for over-pressured reservoirs. Previous literature and our evaluation suggest that optimum production strategies for such reservoirs are: (1) To produce at lower rates at which drawdown is less than half of prevailing pore pressures. (2) Drill more wells to sustained production while producing at lower rates. Both strategies under optimum conditions would result in uniform depletion and better recoveries.

Production performance with time, rapidly decreases as permeabilities reduce due to near wellbore stress sensitive region caused by larger drawdown so a controlled drawdown is recommended.
A Look Ahead to the Future of Surfactant Flooding EOR in Carbonate Reservoirs under Harsh Conditions of High Temperature and High Salinity
Authors: Adel Imad A. , Hassan Anas Mohammed , Al-Shalabi Emad W. , AlAmeri Waleed
Published: March 2023

Carbonate reservoirs under harsh conditions of high temperature and high salinity (HTHS) have been exploited through primary and secondary recovery methods. This leaves substantial untapped reserves that require the use of enhanced oil recovery (EOR) techniques. Chemical EOR (CEOR) applications, particularly surfactants, in improving recovery under these HTHS conditions are challenging. Developing suitable surfactants that withstand these conditions can improve water imbibition into the low permeability rock matrix, alter the rock wettability, and significantly lower the interfacial tension. The assessment and evaluation of potential surfactants as EOR agents is of great interest and has a strategic role in unlocking further reserves from the vast accumulations of light oil in low permeability carbonates. However, the implementation of surfactants under these conditions faces various challenges, such as stability, compatibility, and high retention values, which need to be overcome for successful applications. This paper provides comparative review analyses and critical discussions on the recent developments to overcome these obstacles and the promising potential for successful surfactant flooding implementations in carbonates.

Surfactant selection is a complicated process, where the surfactant formulation needs to pass several screening techniques. In this paper, limitations, requirements, and aspects affecting the IFT, microemulsion phase behavior, and retention were thoroughly reviewed. Surfactant retention remains the primary factor limiting the implementation of surfactants in carbonate reservoirs under harsh conditions. Nevertheless, recent laboratory studies (screening and corefloods) showed that chemical formulations, including new classes of surfactants with suitable solvents and alkalis, showed excellent performance with minimal retention values under these conditions. Field studies and pilots of surfactant EOR in carbonate reservoirs were also reviewed, highlighting procedures, achievements, challenges, and the way forward to successful applications. A list of recommendations and conclusions is provided at the end of the study based on the literature and our expertise in this area. Surfactant EOR has long been considered impractical in the high temperature and high salinity conditions present in carbonate reservoirs. This study reviews the latest developments and positive outcomes that change this perception and aid in unlocking these reserves. The study is also considered a guide to starting surfactant flooding projects in carbonates under harsh conditions in the Middle East region and elsewhere.
Reservoir Modelling of Nanoparticle-Assisted Foam to Optimize Gas Injection in an Unconsolidated Heavy Oilfield
Authors: Bello Ayomikun , Dorhjie Desmond Batsa , Ivanova Anastasia , Cheremisin Alexander , Cheremisin Alexey
Published: March 2023

Foam can be used as an enhanced oil recovery (EOR) technique because it can reduce gas channeling and gravity override during gas EOR operations by lowering gas mobility, which will bring about an increase in oil recovery factor. An integrated method for numerically simulating foam assisted by nanoparticles for EOR in a heavy oilfield is presented in this paper. The extent to which the gas EOR optimization techniques can lower gas breakthrough while boosting oil recovery was investigated through a series of numerical simulations. The aim of this study is to model foam flooding with nanofoams as an EOR technique that combines the oil recovery mechanism of foam flooding with that of nanoparticles. The interfacial properties contributed to the injection fluid served as a representation of the modeling of nanoparticles in the foam liquid. Our findings demonstrated that the recovery factor is higher during the injection of nanofoams than in water and gas flooding. In fact, for both nitrogen and CO2, the recovery factor of foam enhanced by nanoparticles was nearly twice as high as that of gas injection. Foam injection is more effective and productive than WAG and gas injection, which shows that it is the best EOR technique for the model utilized in this study. The simulation of the optimization techniques carried out will aid in the development of future development processes in this field.
IFT Reduction Negatively Impacts Oil Recovery When Wettability Alteration Happens
Authors: Deng Xiao , Patil Shirish , Al Shehri Dhafer , Kamal Muhammad Shahzad , Shakil Syed Muhammad , Zhou Xianmin , Mahmoud Mohamed , Al Shalabi Emad Walid , Hassan Anas
Published: March 2023

Interfacial tension (IFT) reduction and wettability alteration (WA) are the two most important mechanisms for chemical EOR. When two mechanisms are combined, however, the relative contribution of each mechanism is hard to determine. Researchers have obtained different, sometimes conflicting, conclusions. Numerical simulation studies usually suggest that, when WA happens, IFT should not be reduced. In this work, we investigated experimentally how IFT reduction impacts oil recovery when wettability alteration happens. To answer this question, this study tests the oil recovery potential of novel zwitterionic surfactants (ZS) and Gemini surfactants (GS) for oil-wet carbonate rock. A chelating agent was added to alter the properties of the surfactants to get comparable WA performance but different IFT.

The surfactants used in this study were a zwitterionic surfactant Erucamidopropyl Sulfobetaine, and a locally synthesized amino-amine-based cationic Gemini surfactant. Diethylenetriamene pentaacetate (DTPA) chelating agent was used. Indiana limestone was selected to represent carbonate rocks. The spinning drop method was applied in IFT measurements. Static contact angle under room conditions and reservoir conditions was conducted to evaluate the WA performance of studied materials. Spontaneous imbibition tests were conducted using oil-aged limestone core plugs. By comparing the IFT reduction, WA, and oil recovery, the relative importance of the mechanism was reflected.

Results show that investigated zwitterionic surfactant reduces IFT more than Gemini surfactant. However, Gemini surfactant showed much better WA performance than zwitterionic surfactant. When DTPA was added to zwitterionic surfactant, the wettability alteration performance of zwitterionic surfactant was improved. The mixture of DTPA and zwitterionic surfactant (DTPA/ZS) showed comparable wettability performance compared to DTPA and Gemini surfactant (DTPA/GS). However, the IFT value of DTPA/ZS is much lower compared to DTPA/GS. In spontaneous imbibition tests, the mixture of DTPA/ZS recovered oil much slower than the mixture of DTPA/GS. This shows that when wettability alteration happens, reducing IFT to the ultralow condition has a negative effect on oil recovery. This is because when wettability is altered to water-wet conditions, the capillary force becomes a driving force that helps oil production. Reducing IFT will reduce the magnitude of capillary force, thus negatively impacting the oil recovery rate.

This study shows that for the spontaneous imbibition process in low permeability carbonate rock, IFT reduction negatively impacts the oil recovery when the rock wettability is altered from oil-wet to water-wet.
A High Molecular Polymer LCM to Cure Severe Losses While Drilling Shallow Aquifers in UAE
Authors: Hamdan Tariq , Saraji Raymond , Yang Tao , Al-Rahma Rahma , Abdullah Dalia , Al Nuaimi Mouza , Zhou Changjiang , Hu Xuezhi , Cheng Yi , Guo Yongjun , Zhang Xinmin
Published: March 2023

Today, well durations are relatively longer due to several factors. Some of these include but not limited to intermediate section down hole losses. Therefore, there is an opportunity to explore possible ways to reduce well duration and cost while meeting all business objectives with 100% HSE. Dammam, U.E.R, and Simsima are karsts-prone carbonate aquifers widely developed across UAE. As formation pressures are depleted, severe to total losses is increasingly occurred during drilling through these shallow aquifers. Conventional loss curing agents are often failed, especially in Simsima, because of their inability to set in such complex and large fractures and caverns.

ZND gel is a water-soluble high molecular polymer, which will automatically set and seal the space after being pumped into loss channels. As hardly be diluted by any formation fluid, a gel slug is formed to isolate drilling fluids and consolidate agent from being washed away into loss zones. In this study, we present a composite solution of ZND gel and Cement applied in onshore Abu Dhabi, which effectively mitigated the total losses encountered in Simsima.
Innovative Management Reporting for Real Time Dynamic Decision Making
Authors: Samsuddin Khairul Nazri
Published: March 2023

This manuscript will be consisting of 2 main sections. 1st section which directly addresses the title of this article i.e. innovative management reporting for real time dynamic decision making. The 2nd section of the manuscript will touch 4 frequently asked questions which will support the concept and understanding of the title.
Meta Learning Using Deep N-BEATS Model for Production Forecasting with Limited History
Authors: Al-Ali Zainab Al-Ali Hussain , Horne Roland
Published: March 2023

Fluid rate quantification is important for field development and well planning. Existing physical and data-driven models require a copious amount of reservoir information and history to improve the capability of prediction. In this paper, we introduce a new approach of using a deep meta learning approach using Neural Basis Expansion Analysis for Interpretable Time Series Forecasting (N-BEATS) model to forecast the oil rate, eliminating the need of large historical training datasets to overcome the limitation of conventional models.

Two deep learning models, the Long- Short-Term Memory (LSTM) and N-BEATS, were used to forecast the oil rate data of two wells from Norne Field in Norway. The historical bottom hole pressure data with only 500 data points were used as input in the LSTM model. To overcome the dataset limitation, we developed and tested a pretrained N-BEATS transfer model. The N-BEATS model was initially trained on a large and heterogeneous dataset, widely known as the M4 series, with an excess of 100,000 time series. This pretrained model was then used to forecast the oil rates using a meta learning approach.

It was challenging to fit the LSTM model, as it demanded complex hyperparameter tuning and grid search to solve this nonlinear multivariate time-series forecasting problem. Even after we tuned the model's parameters, the model could not generalize the testing data attributed to the limited and small dataset available during training. Our work showed that the newly proposed N-BEATS meta learning model was better able to capture the dynamic time series features from the M4 dataset and transfer the learned knowledge. The N-BEATS approach was able to forecast oil rates in Norne field for both wells without supplying the model with any features or input variables, such as the reservoir pressure. The Mean Squared Error (MSE) was used as an evaluation metric to benchmark the prediction results from both models. The results clearly demonstrated that the N-BEATS meta learning approach outperformed the LSTM model performance when comparing the difference between the model forecast and actual data. We concluded that using the pretrained N-BEATS model overcomes the previous disadvantages in LSTMs model requiring feature selection and abundant training history.

To the best of our knowledge, our work presents a novel approach of using N-BEATS meta learning model for oil rate forecasting without any prior knowledge of the field. Most previous machine and deep learning attempts were based mainly on deriving predictions from an abundant historical field data. This research showed promising results using meta learning and N-BEATS model in the petroleum industry, especially for new or green fields with limited historical data.
Radial and Huff-n-Puff Gas Injection on Microfluidic Chips
Authors: Pereponov Dmitrii , Tarkhov Michael , Rykov Alexander , Filipov Ivan , Zenova Elena , Cheremisin Alexey , Shilov Evgeny
Published: March 2023

Most of the reservoirs today are mature, and traditional waterflooding is not enough for the effective development of oil formations. One of the ways to significantly increase production efficiency for deep, low permeable reservoirs is gas EOR (enhanced oil recovery) methods. This paper presents a method for screening and increasing efficiency of gas EOR methods based on microfluidic studies and for studying the influence of various factors on the oil displacement process. Such technology can be used on par with traditional core flooding tests, reducing time, cost, and the amount of needed fluid. The porous structure was realized as a silicon-glass microchip that can withstand high pressure and temperature close to the reservoir conditions. For the tests, n-decane was chosen as a model oil phase, while nitrogen was used along with carbon dioxide for screening. On the microchips, several tests were done that proved the approach's effectiveness for screening gases before field application. The most effective for carbon dioxide occurred miscible displacement, resulting in the almost complete displacement of n-decane. Additionally, when comparing tests with the same system pressure but a different pressure drop, a more considerable drop led to a higher oil recovery coefficient. Since the conventional nitrogen injection resulted in an insignificant displacement coefficient even after an increase in differential pressure, it was decided to use this agent for the huff-n-puff injection experiment. The test led to the raising of the sweep efficiency coefficient by two times. Thus, an experimental procedure and a unique microchip geometry with the radial homogenous porous structure were developed, allowing tests to be performed for both conventional gas flooding imitating a five-spot pattern and huff-n-puff gas injection.
Two Phase Relative Permeability Curve Upscaling of Naturally Fractured Reservoirs Under Poro-Elastic Environment
Authors: Abdel Azim Reda Rabiee , Hamada Ghareb , Al Jehani Abdurrahman
Published: March 2023

The target of upscaling is to replace the very fine and detailed models with coarse models, including much less data. These coarse models are more feasible for running simulations than the fine models. However, upscaling does not aim to speed up reservoir simulations at the cost of simulation results. This study presents an innovative approach to upscale the two-phase core relative permeability to reservoir grid block scale under poro-elastic framework for fractured basement reservoirs using glass bead laboratory measurements and finite element technique. This approach uses a hybrid methodology to calculate grid block equivalent permeability tensors by combining the discrete fracture network and single permeability approaches. The first step in the workflow of upscaling the core relative permeability curve is dividing the reservoir into a number of grid blocks (20 m × 20 m × 30 m) and then the individual grid block is divided into laboratory glass bead model scale of (20 cm × 10 m × 2 cm) to enhance the upscaling process. Next, the new generated kr curves ( Fahad et al. 2013) correlation bas ed on glass bead scale is is used to upscale the laboratory relative permeability curve to each fine-scale grid. The Levenberg-Marquardt inversion algorithm is used during the simulation process of the relative permeability upscaling to match produced oil recovery before and after upscaling. The results illustrate that the upscaling kr curves process is strongly affected applied stresses, fracture orientation and connectivity.
New Dissolvable Isolation Tool Eliminating Plug and Perf Operation Challenges and Reduce Completion Costs
Authors: Wang Jinlu , He Xusheng , Wang Junyuan , Xiao Fengfeng , Liu Qi , Zhang Longlong , Chen Haili
Published: March 2023

In recent years, operators have reported that dissolvable frac plugs have made completions more time-consuming and costly in many cases. Poorly designed dissolvable frac plugs can cause problems such as early failure and skidding under pressure when they dissolve too early.

On the other hand, if dissolvable frac plugs do not dissolve completely, it can lead to extended post-intervention time. Drilling out a composite frac plug typically takes 2-15 minutes, while removing a dissolvable frac plug that hasn't dissolved fully can take up to an hour or even longer due to the material structure not being designed for quick drilling.

Additionally, when undissolved frac plugs are pushed towards the bottom of the well, they can create a pack-off on the way, which increases drill-out time. This is a common issue in low temperature and low salinity environments because temperature and salinity are two key factors that influence the dissolving process of dissolvable frac plugs.

Based on our experiences, dissolvable technology can be both beneficial and challenging. To customize products that are suitable for different conditions, expertise and a thorough understanding of both application and engineering are necessary. The tool supplier must consider all operational details, including the conditions and requirements, to design, simulate, validate, and optimize the product in order to achieve optimal performance and results for end users. This requires a careful balance between tool performance and dissolvability.