bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrocarbon Saturation Determination in Case of Total Losses: Invasion Profile Modelling with Dual Resistivity – A Possible Application in PMCD Drilling
Authors: Ling Kuok Hsu , Zulkiply Hapiz 
Published: March 2022

Abstract

Objectives/Scope
Formation evaluation and appraisal in Central Luconia carbonate reef is challenging when drilling operation change from conventional drilling to pressurised mud cap drilling (PMCD). PMCD drilling has always been the choice to deal with unmanageable losses condition. It is normally applied in carbonate reservoir with karst and vugs. Under this drilling condition, annular pressure and surface pressure is maintained above the formation that is able to take the cuttings and fluids. At the same time, light annular fluid is pumped down the annulus to maintain hole fill and avoid gas migration. Seawater, acts as sacrificial mud is pumped down the drill string to cool the bit and to transport the cuttings to loss zones.
Meanwhile, for an exploration well, the primary objective is to prove hydrocarbon presence and hydrocarbon fluid contact through logging while drilling (LWD) as wireline logging is not favourable from operational perspective. One of the key challenges of interpreting hydrocarbon saturation in PMCD operation is suppression of resistivity value due to sea-water invasion. Indeed, with PMCD, the well is appeared to have high water saturation even though 1 MHz phase shift 36" spacing deep phase resistivity is used in the interpretation. However, this is inconsistent with gas kick occurred at the top of carbonate or gas shows prior to conversion from conventional drilling to PMCD operation. Another observation of resistivity log response in PMCD drilling is that the phase shift resistivity from different sensor spacing (6", 12", 24" and 36", with smaller number indicate shallower depth of investigation, and higher number indicate deeper depth of investigation) appears to have separation, which indicates invasion profile which happens at one time-frame. Although 1D inversion for true resistivity (Rt) can be carried out with multiple sensor spacing phase resistivity and invasion diameter (Di) as inputs, the inversion result does not yield satisfactory result that match pre-PMCD resistivity value. The objective of the paper/ abstract is to highlight the benefits or running dual – resistivity in LWD bottom-hole assembly (BHA) in PMCD well to capture time-lapse resistivity measurement, estimate Rt which is time-dependant and pin-pointing gas-water contact in the exploration/ appraisal wells. This new proposed concept and methodology is still at its early stage, yet designed to make better decision during operational time. Such an approach will provide benefits to petrophysics community in the PMCD well interpretation with minimal incremental cost.
Bringing Huge Core Analysis Legacy Data Into Life Using Machine Learning
Authors: Zulkipli Siti Najmi Farhan , Ralphie Benard , Shah Jamari M , Nordin Taufik , Masoudi Rahim , Razak M Amin Nizar C A , Gazali Ismail Marzuki , Toelke Jonas , Koronfol Safouh , Proctor Jacob , Gonzales David , Vovk Valentyn , Shi Xuebei , Sheng Huiwen 
Published: March 2022

Abstract
Advances in the fields of information technology, computation, and predictive analytics have permeated the energy industry and are reshaping methods for exploration, development, and production. These technologies can be applied to subsurface data to reliably predict a host of properties where only few are available. Among the numerous sources of subsurface data, rock and fluid analysis stand out as the means of directly measuring subsurface properties. The challenge in this work is to maximize information gain from legacy pdf reports and unstructured data tables that represented over 70 years of laboratory work and investment. The implication of modeling this data into an organized data store means better assessment of economic viability and producibility in frontier basins and the capability to identify bypassed pay in old wells that may not have rock material.
This paper presents innovative and agile technologies that integrate data management, data quality assessment, and predictive machine learning to maximize the company asset value using underutilized legacy core data. The developed machine learning algorithms identify potential outliers, benchmark the valuable data against current industry standards, increase the confidence in data quality and avoid amplifying error in predicting reservoir properties.
The workflow presented in the paper is expected to reduce uncertainties in subsurface studies caused by limited core data, improper analog selection, high cost, limited time for acquiring new cores, and long delivery times of core analysis data. The workflow reduces the requirement for subsurface formation evaluation rework as new data becomes available at later project stages resulting in optimized field development. The workflow enhanced by machine learning also improves the prediction and propagation of reservoir properties to uncored borehole sections.
In conclusion, managing legacy core data and transforming it to generate new subsurface insights are critical step to establish a reliable database in support of business excellence and the digitalization journey. Innovative machine learning tools continue to unlock new values from legacy core data that significantly impact the entire reservoir life cycle including reserves booking, production forecasting, well placement, and completion design.
CO2 Leakage Marine Dispersion Modelling for an Offshore Depleted Gas Field for CO2 Storage
Authors: Amir Rashidi M Rashad , Peter Dabbi Edgar , Azahree Ahmad Ismail , Abu Bakar Zainol Affendi , Tan Jen Huang Dylon , Pedersen Claus , K. Tiwari Pankaj , M Sallehud-Din M. Taufik , Shamsudin M. Azim , Hamid M. Khaidhir , Tewari Raj , A. Patil Parimal 
Published: March 2022

Abstract
A depleted gas field situated in offshore Sarawak has been identified by PETRONAS as a potential CO2 storage development site. As part of the monitoring program, CO2 seepage risk and impact on the marine environment needs to be investigated and predicted. This study focuses on understanding the environmental risks associated with the potential seepage of CO2 gas at the depleted field within the 140 m water column through methods of numerical modelling. Leakage scenarios involving existing plugged and abandoned (P&A) wells as CO2 leakage pathways were modelled with leakage rates of 6 tonnes/year, representing a realistic rate and 500 tonnes/year which represents a more improbable and conservative scenario. The modelling period covers three representative climatic periods for the prevailing monsoons in the South China Sea (northwest, southwest and inter-monsoon). Simulation results showed that with the lower rate, changes to the seawater acidity within the far field region were negligible or undetectable. Under the high seepage rate, the pH plume footprint was predicted to extend beyond 200 m distance from the source point. However, the probability was estimated to be less than 1% while the vertical extent of the plume was limited up to 2 m above the seabed. For both scenarios, the CO2 gas were predicted to be fully dissolved within 5 m above the seabed. Therefore, it can be concluded that there is relatively low risk of impact at the storage field in terms of potential increase in seawater acidity if CO2 seepage occurs during the storage period.
Novel Cementing Technology for Deepwater Hydrate Layer
Authors: Chen Yu , Li Yi , Feng Ying tao , Zhang Hao , Wen Da yang , Cui Ce , Wang You wei , Huang Feng , Xiong Min , Zhao Jing fang , Wang Wei , Xiang Xiong , Song Mao lin , Zhao Hu , Fang Enlou , Xiao Wei , Ji Jing 
Published: March 2022

Abstract
Methane Hydrates is an ice-like crystalline substance formed by methane and water under high pressure and low temperature environment. Each 1 unit methane hydrates contains about 170 units (converted in standard conditions) of methane gas. The low temperature and high pressure environment in deep water leads to the existence of hydrate layer in the shallow formation, which poses a significant challenge to cementing. The conventional cement slurry systems have limitations when applied in such well condition, since the heat of hydration during cement setting is high and there is a high risk of gas liberation from methane hydrates, easily causing severe well security issues. The low temperature environment, unconsolidated formation and narrow safety window also increased the complexity of the cementing jobs by a high performance requirement of the cement slurry. A low hydration heat cement slurry and an indoor cementing simulation evaluation method were developed in order to ensure effective isolation of the hydrate layer. This paper will describe in detail about the cement slurry development, performance and evaluation process in the lab with a novel method in the industry. This technology was proven as a solution for deep water hydrate layer well cementing, which is a great reference for cementing industry.
Optimisation of Acid Fracture Design for the Basement Formation in the White Tiger Field
Authors: Nguyen Truong Huu 
Published: March 2022

Abstract
After the period of exploitation at the basement formation of the White Tiger field, the production rates of producer wells had been declining due to near-wellbore formation damaged from drilled cutting and lost circulation materials of drilling activity, leading to natural permeability of the basement reservoir to be decreased. In fact, the effective permeability of the basement was varied between 0.004D 10 464D, with an average permeability of 135mD, the reservoir temperature was ranged between 1300C and 135°C and reservoir pressure was varied 200atm to 320atm. There were a wide variety of stimulating technologies methods applied to the near-wellbore treatment basement formation such as acid salt, mud acid, oil acid emulsion, Gas-Oil-Acid emulsion, and explosion treatment. However, these methods had been brought a low successful stimulation after treatment when the production rates were rapidly decreased after a short time because the near-wellbore basement was re-damaged of producer wells. To eliminate the above problems, this study has presented the optimal acid fracture treatment design with an acid HCl concentration of 15%. The program of acid fracture treatment comprises a fracture propagation model, the acid volume 50400gals, the acid fracture length 119ft, etched acid width 0.344in, and acid fracture conductivity 3350mD.ft, and NODAL tubing evaluation production rate and bottom hole flowing pressure of 3500psi, and comparison between production the rate at pre-treatment and post-acid fracture treatment. The result showing the oil productivity index has been increased with folds of 2.6.
Case Study: The Importance of Integrated Flow Assurance Modelling for Carbon Capture and Storage CCS Project
Authors: Zakaria Mohd Uzair , Wan Hashim Wan Mahsuri , Nik Omar Nik Fauziah , M. Norpiah Rohaizad , Abu Bakar M Azuan , Wan Mohamad Wan Amni 
Published: March 2022

Abstract
A gas field located offshore Malaysia will be developed with carbon capture technology which will recover the remaining amount of hydrocarbon from CO2 rich permeate stream and subsequently concentrate the amount of CO2 to higher purity. The separated high concentration CO2 will be compressed, transported to storage site and injected to store the CO2 safely in a sub-surface geological formation which is a depleted gas field.
One of the key success criteria for the CCS development is to be able to inject the CO2 to the reservoir for permanent storage from early to end of injection life. Typically, the battery limit of interface between the subsurface and surface engineer is the surface ITHP whereby the initial prediction was based on stand-alone sub-surface well modelling. A validation exercise was conducted using surface well modelling, including a sensitivity of three main Equation of State (EOS) being considered i.e., GERG-2008, PR 1978 and Advanced PR 1978, to allow the range of pressure drop to be translated to the ITHP number to be quantified. It is acknowledged that impurities within the CO2 stream have strong effect on phase behaviour and physical property predictions. The CO2 composition under study is &gt;95mol% with a mixture of impurities. In addition, ambient temperature has also been found to influence pressure drop prediction. A similar approach is extended for pipeline study. Subsequently, the result provides a clear picture to develop a basis for facility design pressure.
The integrated approach of flow assurance between wells and pipeline is important as this was found to affect the CO2 source pressure and design of the surface facility. This paper explains how the study was conducted during conceptual engineering stage and can serve as a reference to other CCS projects.
Use of Surface Desander to Bring Back Subsea Production. How to Overcome Reservoir, Well and Facilities Challenges
Authors: Guzman Manuel , Krishnan Thanushya , Gwee Yong Chin , Wu Yvonne 
Published: March 2022

Abstract
A subsea well in Deepwater field in Malaysia observed high sand production during the first half of 2019, this well had been on production for around 7 years. Further evaluation during the second half of 2019 determined that the downhole sand control had been compromised and the well would require intervention to bring back its locked in potential. Technical and Economical evaluations were conducted to determine the most feasible well restoration activity. This paper covers the aspects from technology selection to operation challenges and identified solutions.
Riserless well intervention was initially identified to restore production from this well and compared with other alternatives. After technical and economical evaluations, the use of a surface desander was identified as the best solution to unlock production from this well while a more permanent solution was evaluated. A surface desander was installed upstream of first stage separation. Well and facilities operating envelopes were updated to determine the operating window for the well as per last observed conditions before the well was shut in. However, once the well was back online a much higher than anticipated watercut was observed and different solutions, in term of surface settings, were tested to determine a new operation window.
The use of surface desander to handle subsea sand control failure requires a steady flow against a significant choke to the flowline at the end of the riser. Changes in reservoir watercut provided a significant challenge to flow the well at steady conditions and limited the efficacy of surface desander.
Flow assurance is a key parameter to avoid sand deposition along the subsea flowline to the platform. Use of a neighbor well proved to allow continuous steady production and a new logic was designed to maximize production from both wells while keeping sand from reaching the production facilities.
Guidance for Design and Operation of Pump Rooms Following the Explosion on the FPSO Cidade de São Mateus
Authors: Duddy Michael , Ronza Andrea , Zakariah Noorhafizal 
Published: March 2022

Abstract
On the 11th of February 2015 a pump room explosion on the Floating Production Storage and Offloading (FPSO) Cidade de São Mateus killed nine persons, injured twenty-six more and crippled the unit, requiring that it be removed to a yard to effect repairs. In 2020 the FPSO Owner confirmed that the FPSO Charter and the Services Agreements with the respective Oil and Gas Company had reached their final terms and the unit remained in lay-up in Singapore.
Seven years on from this event, although the causes leading up to the incident are well understood within some sections of the oil and gas industry, along with the availability of various high-quality publications on the subject, there remains no consolidated guidance from Classification Societies, regulatory authorities, insurers nor industry advisory groups on how to prevent a reoccurrence of a similar event. Indeed, some FSO/FPSO operators have not implemented the required changes within their existing fleet or within their subsequently developed facilities.
This paper provides a synopsis of the incident onboard the FPSO Cidade de São Mateus (CdSM) and the root causes of the accident. From those findings, it describes the design and operational measures some Floating Storage and Offloading (FSO)/FPSO owner/operators and oil and gas companies have implemented to further reduce the potential risks associated with the use of pump rooms. These measures are subsequently visualised by way of a bow-tie diagram. An overview of current Classification Society rules and regulatory authority requirements relating to pump rooms are shown and discussed. Furthermore, the paper demonstrates some of the flaws that still exist in the engineering and operation of contemporary FSO/FPSO pump rooms. As a continuation from those defects, several FPSO pump room incidents that have occurred after 2015, which could have led to a similar catastrophic pump room explosion to that of CdSM, are explained. Finally, the paper contains a recommended basis for design and operational guidance to owners and operators of FSO/FPSOs with pump rooms.
A Permeability Evolution Model of Double-Porosity Media with Consideration of Temperature and Pressure Variations
Authors: Zhang Yi , Li Gao , Leng Guangchun , Wang Keda , Wang Rui , Li Pingxian 
Published: March 2022

Abstract
Reservoir heat treatment (RHT) can improve rock seepage capacity. Recently, it has been considered as a potential technology to enhance unconventional oil and gas recovery. This work presents a permeability evolution model to describe the thermal cracking effects of double-porosity media under temperature change and certain formation pressure. Moreover, to verify the accuracy of the model, a typical double-porosity media (tight sandstone) is selected as the sample, and the permeability of the sample is tested using a simulated formation heating device. Firstly, according to the observation results under SEM, 400°C is regarded as the transition temperature of porous and fractured media. The two-parameter exponential function and the improved "cubic law" are used to characterize the permeability of the pore part and the fracture part respectively. Secondly, rock is comprised of matrix grains and pore space. In the model hypothesis, the volume of the matrix grains is just a function of temperature, and the pore space is compressed or released under the action of effective stress, considering the difference of deformation between the matrix grains and the pore space, the Hooke's law based on engineering strain and natural strain is adopted for them respectively. Thirdly, the influence of temperature on crack spacing and opening is analyzed based on the energy principle and Weibull distribution. Finally, a permeability evolution model is established for the whole process of thermal expansion and cracking. The model describes two phases. In the first phase, the matrix grains expand under confining pressure, and at the same time accumulate thermal stress. In the second phase, after the thermal stress overcomes the confining pressure, the porosity recovers and cracks are gradually damaged and formed. The interaction between thermal stress and confining pressure is controlled by introducing a modulation factor. Due to the difference of component properties, the rock has obvious non-uniform thermal fracture phenomenon. Therefore, in this model, three parameters are introduced to ensure the robustness of the model: the contribution of deformation behavior of the matrix grains and pore space to crack opening, the influence of effective stress on crack opening, and the crack proportion of effective seepage. The results indicate that the model can describe the permeability evolution behavior of double-porosity media under certain confining pressure and temperature changes, it provides theoretical guidance for RHT to enhance oil and gas recovery.
Understanding the Interactions at Rock-Water and Oil-Water Interfaces during Controlled-Salinity Water Flooding
Authors: Belhaj Ahmed Fatih , Singh Navpreet , Sarma Hemanta Kumar 
Published: March 2022

Abstract
Over the years, laboratory studies and a limited number of field trials have demonstrated the potential of enhancing oil recovery using controlled-salinity water flooding. The injected brine composition is one of the promising techniques that could alter the wettability of carbonate rocks by changing the concentration of the potential determining ions (PDIs), specifically Ca2+, Mg2+, and SO42− ions. In this study, a comprehensive experimental study was conducted to investigate the rock-fluid and fluid-fluid interactions at rock-water and oil-water interfaces. The first step of the study was to measure the interfacial tension (IFT) using the spinning-drop tensiometer and study the dynamic behavior of the oil-water interactions. The zeta potential of carbonate rock samples was then measured using a specially-designed zeta potentiometer capable of utilizing the whole core plug, rather than the pulverized samples. The streaming potential technique was used for the zeta potential measurements and the experiments were conducted under different modified brine composition and rock saturation conditions. Subsequently, wettability alteration experiments were conducted using a specially designed high-pressure high-temperature (HP/HT) cell. The IFT measurements showed an increasing trend as salinity decreases, clarifying that rock-water interactions are more dominant over oil-water interactions. Results of the zeta potential experiments showed a clear trend of yielding more negative values as the seawater gradually diluted down to 1%dSW, due to the expansion of the electrical double layer. On the other hand, when the brine composition was modified, the increase of the PDIs (Ca2+ and Mg2+) did not have as much impact on zeta potential as the SO42− ions. In the wettability alteration experiments, both diluted and composition-modified brine generated a higher imbibition rate, resulting in a higher total oil production when compared with the experiments using the seawater. Furthermore, the wettability alteration of the rock surface trended more towards water-wetness conditions, as inferred from the contact angle measurements. The measurement of zeta potential before and after wettability alteration tests showed that the zeta potential value became less negative after the experiment, which suggested the expulsion of oil from the rock. This was further verified by the measurements of zeta potential for the unsaturated rock and saturated rock with brine and oil. The findings from this study would provide a better understanding of the rock-fluid and fluid-fluid interactions during controlled-salinity water flooding, which will benefit future studies in this area.
Study on Riser System in Hang-Off Configuration for Deep-Sea Mining
Authors: Yamamoto Marcio , Yamamoto Joji , Masanobu Sotaro 
Published: March 2022

Abstract
For Deep Sea Mining (DSM), the current concept for the Vertical Transport System (VTS) has multiple lines for the return of water to the sea bottom. Such VTS resembles a drilling riser, which is a field-proven technology. Our objective is to compare a drilling riser with different boundary conditions, including hang-off configuration.
Numerical simulation was calculated using commercial software for dynamic analysis of riser systems. The simulation included a 1, 500m long riser, sea current, irregular waves, and the platform motion calculated using Response Amplitude Operator.
For the top tensioned configuration, the tensioning system is required to avoid the riser pipe's buckling and the Mathieu Instability at the bottom portion of the riser. On the other hand, the same phenomenon did not occur in the hang-off configuration. The LMRP and BOP attached to the bottom end kept the riser pipe tensioned during the whole simulation. Therefore, the hang-off configuration is an important alternative for DSM riser. Besides, a tensioning system shall be mandatory for VTS when supported or attached to the seafloor.