Deepwater Exploration Research Articles

Seismic geomorphology and reservoir conditions of a Middle Miocene submarine channel system in the Taranaki basin, New Zealand

Deepwater channels function as vital deep-sea hydrocarbon reservoirs and as major routes for moving terrestrial clastic sediment to deepwater environments. A high-resolution sequence stratigraphic framework was built for the deepwater area of the Taranaki Basin using high-resolution three-dimensional (3D) seismic data, and various seismic interpretation techniques, including seismic attribute analysis, were applied. The principal controlling factors and petroleum development potential of the Middle-Miocene channel system were investigated with sequence stratigraphy and seismic geomorphology. Four understandings were primarily attained in this study: (1) depending on the different levels of the channel surfaces, the channel system can be divided into five sedimentary units (SU1-SU5), which correspond to the five stages of channel system evolution. These surfaces include one primary draping surface (PDS), five secondary channel erosion surfaces (SCES), and several tertiary channel erosion surfaces (TCES). (2) with the use of seismic facies analysis, six sedimentary elements were identified in the channel system: pelagic deposits (PDs), mass transport deposits (MTDs), outer levee complex (OLC), inner levee and terrace complex (ILTC), and turbidite channel complexes (TCCs). (3) The sedimentary evolution of the channel system was jointly influenced by multiple factors. The sediment supply and submarine geomorphology can directly affect the internal stacking and migration patterns of the channel. In contrast, tectonic activity and relative sea level fluctuations can indirectly affect the sedimentary characteristics of the channel by regulating the components and scale of clastic sediment. (4) SU1, SU2, and SU3 are primarily filled with coarse-grained sediments, which can serve as high-quality hydrocarbon reservoirs. In contrast, SU4 and SU5 can serve as regional cap rocks because they are filled with fine-grained sediments, and the overall channel system can represent a potential hydrocarbon reservoir-cap combination, which can be viewed as a significant research target for upcoming deepwater exploration. Clarifying the sedimentary properties and primary controlling factors at the various evolutionary stages of deepwater channels is vital for predicting the hydrocarbon development potential of the basin and reducing the drilling risk. This also helps with the development of deepwater basins with similar sedimentary environments in New Zealand and elsewhere in the world.

Public policy towards offshore oil projects: Confronting potential deepwater oil spills

There has been a recent surge in global interest in drilling offshore wells in pursuit of new reserves of crude oil, with much of this activity focused on deepwater. One concern related to this uptick in activity is the potential for very large damages that could obtain were a major oil spill to occur. For example, when the Macondo well in the Gulf of Mexico suffered a blowout in 2010 a very large amount of oil flowed from the well into the Gulf causing enormous harm. In response, the United States Government proposed significant regulatory changes related to offshore oil and gas exploration and production. This paper proposes a framework for thinking about the risks associated with deepwater exploration and production, and uses this framework to construct an estimate of society’s necessary willingness to pay to protect ecosystems. Applying this framework to the BP oil spill case study, benefits resulting from a reduction in the risk of a major spill exceeds these costs under a range of potential reductions in risk.

THE STRATEGIC ROLE OF FPSO IN DEEPWATER EXPLORATION: INTEGRATING SOCIAL MANUFACTURING SYSTEMS WITHIN INDUSTRY 5.0

This study analyzes the role of Floating Production, Storage, and Offloading units (FPSO) in deepwater oil and gas exploration within the context of Industry 5.0, focusing on integrating social manufacturing systems. Reviewing common offshore exploration methods, the study identifies FPSOs as key catalysts for innovation, energy efficiency, and sustainability. The research concludes that combining FPSO with Industry 5.0 can optimize horizontal and vertical production processes, enhancing predictive maintenance, advanced safety, and waste management. Continuous innovation is highlighted as vital for addressing future challenges in deepwater exploration.

Comments: Celebrating a Legacy: 100 Years of Innovation and 75 Years of JPT at the 2024 ATCE

_ Are you ready to join us for SPE’s Annual Technical Conference and Exhibition (ATCE) in New Orleans, 23–25 September? As SPE celebrates a century of innovation at the 2024 ATCE, we also mark the 75th anniversary of the Journal of Petroleum Technology (JPT). These twin milestones stand as a testament to the achievements that have driven our field forward—innovation, pushing boundaries, setting new standards, and fueling the energy that powers the world. Through the highs of technological breakthroughs and the lows of economic challenges, the oil and gas industry—and ATCE and JPT—have continually evolved, proving their resilience and adaptability. When considering the innovations in our industry, key advancements that often stand out include hydraulic fracturing, horizontal drilling, deepwater exploration, enhanced oil recovery, digitalization and automation, LNG technology, FPSOs, subsea systems, and decarbonization and emissions mitigation. However, the incremental steps that collectively contributed to the broadly defined “wow” factors above are equally notable. To mention only a sampling: enhanced drill-bit designs, advancements in onshore and offshore drilling rigs, real-time data collection, development of 4D seismic technology, integration of multiple data types (e.g., seismic, well logs, production data) for more-comprehensive reservoir characterization, materials-science advancements (polymers, nanocoatings), development of blowout preventers, improved leak-detection systems, and advancements in produced-water treatment and recycling technologies. Less often recognized are the failures that were essential prerequisites for eventual success. The "fail fast, fail often" approach allowed for rapid feedback and necessary adjustments, though it also contributed to the downfall of some startups over the years. As individuals, embracing failure and viewing it as a stepping stone to success is not always our natural response. Presentations at industry events on "lessons learned" vary in transparency, often influenced by differing definitions of failure, stakeholder sensitivities, and legal considerations. As a result, many of the hard knocks that paved the way for the industry's "wow" factors remain largely unknown. ATCE’s theme, “Powering the Future of Energy with a Century of Innovation,” honors the legacy of past breakthroughs while celebrating their ongoing role in shaping a resilient and sustainable future. Olivier Houzé will be named 2025 SPE President with the official passing of the baton from 2024 President Terry Palisch at ATCE. In this issue of JPT, Houzé shares his insights on the challenges facing our Society and its members in his inaugural vodcast and column, “A Roadmap for a Very Busy Year.” Visit the SPE Pavilion (Booth 1449) in the exhibition hall for a variety of SPE Pavilion Talks, including the JPT editors on Tuesday, 24 September, at 1:30 p.m. We’ll highlight the milestones of JPT’s coverage over 75 years and their significance for the future. Visit JPT to learn more about our commemorative features written to date about topics ranging from the Kurdistan Region of Iraq, Azerbaijan, the HSE journey, data science, artificial lift, and a closer look at the past 25 years of innovations in fracturing, drilling, and reservoir engineering. New This Year at ATCE - Strategic Panels will offer a platform for panelists to discuss the current and future challenges and opportunities facing the energy industry. - As an SPE member, you get a complimentary pass to the exhibition hall. If you are not a member yet, you can join now. This pass does not include access to the technical program or conference proceedings. Learn more about the free access pass here. - Non-members registered at the full conference rate will receive a post-show email with a complimentary 1-year SPE membership offer. This offer is valid for new members only, and individuals must meet membership qualifications to join. Whether you’re a seasoned professional or new to the field, ATCE offers an opportunity to connect, learn, and share. Here's to a century of ingenuity and three-quarters of a century of chronicling the journey!

Petroleum exploration and production in Brazil: From onshore to ultra-deepwaters

The Santos Basin in Brazil has witnessed significant oil and gas discoveries in deepwater pre-salt since the 21st century. Currently, the waters in eastern Brazil stand out as a hot area of deepwater exploration and production worldwide. Based on a review of the petroleum exploration and production history in Brazil, the challenges, researches and practices, strategic transformation, significant breakthroughs, and key theories and technologies for exploration from onshore to offshore and from shallow waters to deep–ultra-deep waters and then to pre-salt strata are systematically elaborated. Within 15 years since its establishment in 1953, Petrobras explored onshore Paleozoic cratonic and marginal rift basins, and obtained some small to medium petroleum discoveries in fault-block traps. In the 1970s, Petrobras developed seismic exploration technologies and several hydrocarbon accumulation models, for example, turbidite sandstones, allowing important discoveries in shallow waters, e.g. the Namorado Field and Enchova fields. Guided by these models/technologies, significant discoveries, e.g. the Marlim and Roncador fields, were made in deepwater post-salt in the Campos Basin. In the early 21st century, the advancements in theories and technologies for pre-salt petroleum system, carbonate reservoirs, hydrocarbon accumulation and nuclear magnetic resonance (NMR) logging stimulated a succession of valuable discoveries in the Lower Cretaceous lacustrine carbonates in the Santos Basin, including the world-class ultra-deepwater super giant fields such as Tupi (Lula), Mero and Buzios. Petroleum development in complex deep water environments is extremely challenging. By establishing the Technological Capacitation Program in Deep Waters (PROCAP), Petrobras developed and implemented key technologies including managed pressure drilling (MPD) with narrow pressure window, pressurized mud cap drilling (PMCD), multi-stage intelligent completion, development with Floating Production Storage and Offloading units (FPSO), and flow assurance, which remarkably improved the drilling, completion, field development and transportation efficiency and safety. Additionally, under the limited FPSO capacity, Petrobras promoted the world-largest CCUS-EOR project, which contributed effectively to the reduction of greenhouse gas emissions and the enhancement of oil recovery. Development and application of these technologies provide valuable reference for deep and ultra-deepwater petroleum exploration and production worldwide. The petroleum exploration in Brazil will consistently focus on ultra-deep water pre-salt carbonates and post-salt turbidites, and seek new opportunities in Paleozoic gas. Technical innovation and strategic cooperation will be held to promote the sustainable development of Brazil's oil and gas industry.

Sedimentary build-ups of pre-salt isolated carbonate platforms and formation of deep-water giant oil fields in Santos Basin, Brazil

In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin, based on comprehensive utilization of geological, seismic, and core data, and reconstruction of Early Cretaceous prototype basin and lithofacies paleogeography, it is proposed for the first time that the construction of pre-salt carbonate build-ups was controlled by two types of isolated platforms: inter-depression fault-uplift and intra-depression fault-high. The inter-depression fault-uplift isolated platforms are distributed on the present-day pre-salt uplifted zones between depressions, and are built on half- and fault-horst blocks that were inherited and developed in the early intra-continental and inter-continental rift stages. The late intra-continental rift coquinas of the ITP Formation and the early inter-continental rift microbial limestones of the BVE Formation are continuously constructed; intra-depression fault-high isolated platforms are distributed in the current pre-salt depression zones, built on the uplifted zones formed by volcanic rock build-ups in the early prototype stage of intra-continental rifts, and only the BVE microbial limestones are developed. Both types of limestones formed into mound-shoal bodies, that have the characteristics of large reservoir thickness and good physical properties. Based on the dissection of large pre-salt oil fields discovered in the Santos Basin, it has been found that both types of platforms could form large-scale combined structural-stratigraphic traps, surrounded by high-quality lacustrine and lagoon source rocks at the periphery, and efficiently sealed by thick high-quality evaporite rocks above, forming the optimal combination of source, reservoir and cap in the form of “lower generation, middle storage, and upper cap”, with a high degree of oil and gas enrichment. It has been found that the large oil fields are all bottom water massive oil fields with a unified pressure system, and they are all filled to the spill-point. The future exploration is recommended to focus on the inter-depression fault-uplift isolated platforms in the western uplift zone and the southern section of eastern uplift zones, as well as intra-depression fault-high isolated platforms in the central depression zone. The result not only provides an important basis for the advanced selection of potential play fairways, bidding of new blocks, and deployment of awarded exploration blocks in the Santos Basin, but also provides a reference for the global selection of deep-water exploration blocks in passive continental margin basins.

Pemex’s Deepwater Ambitions Return

Pemex, Mexico’s state oil company, is laying the groundwork for a new round of deepwater exploration in the Gulf of Mexico in hopes to land a new elephant or two that could play a meaningful role in reversing the country’s downward production trajectory in the coming years. The company has seen its crude oil production cut in half since 2004 when production peaked at around 3.8 million B/D. By 2019, that number had fallen to nearly 1.8 million B/D. Levels have stabilized in recent years with the current estimate being just over 1.9 million B/D. Since taking office in 2018, Mexico President Andrés Manuel López Obrador has directed the operator to concentrate its drilling activity on less costly areas such as shallow water and onshore. Pemex is the world’s most indebted oil company with a debt load in excess of $100 billion. “We haven’t heard of any really large discovery recently,” said Diego Becerril, research manager, global analyst upstream team with Wood Mackenzie. “It’s been a couple of years since they last announced a giant discovery. They used to do it every year. “They were able to kind of control the production decline for a few years—2022 and 2023—I think by continuing to explore near areas that they already know, which in the end, doesn’t have that much prospectivity, but they can bring it online in a relatively short term and add volumes into the production portfolio. But moving forward they still need more resources. That is probably part of the reason we’re seeing a change of strategy going into deep water,” he said. The operator’s early deepwater exploration campaign in the mid-2000s was greeted with mixed results. The program yielded one known commercial gas discovery at Lakach. Other wells—Nab-1 (oil), Lalail-1 (gas), and Noxal-1 (gas)—all yielded hydrocarbons, but none of those finds were thought to be standalone development candidates. The debt burden has not prevented Pemex from planning more than $1 billion in investment in deepwater drilling to be conducted over the next several years. In February, hydrocarbons regulator CNH approved an updated plan for drilling in the Holok-Han area. The $400 million-plus investment plan follows 20 years of drilling in the area, during which 14 wells were drilled over that time—13 exploration wells and one delineation well—but no development plans emerged as a result of the program. The revised plan has Pemex drilling up to seven additional exploration wells in Holok-Han targeting Lower Eocene, Lower Pliocene, and Lower Miocene-aged reservoirs. CNH also approved plans for fresh drilling in the Perdido area. The $680 million program would see Pemex drill exploration wells in seven blocks near the US/Mexico maritime border and on trend with large finds on the US side. The bulk of the drilling would take place in 2026, likely utilizing Transocean drillship Deepwater Invictus, which will be under contract with Pemex for a 1,080-day period starting in late 2025. Pemex has identified more than 2 billion BOE in Perdido, according to CNH. The operator drilled 28 exploration wells from 2012 to 2019 in the area.

Characteristics of geothermal field and tectono-thermal evolution in Baiyun Sag, Pearl River Mouth Basin, China

Baiyun Sag has become the primary focus of deepwater exploration in the Pearl River Mouth Basin. However, its complex and high-variate geothermal characteristics have severely constrained further oil and gas exploration and resource evaluation. In this study, the present-day geothermal field and tectono-thermal evolution histories of Baiyun Sag were systematically studied based on measured rock thermal conductivity and heat generation data, borehole temperatures, low-temperature thermochronometer analyses, and geodynamic methodologies. The thermal conductivity of 251 core samples ranges from 1.131 to 4.478 W/(m·K), with an average of 2.258 W/(m·K), while the heat generation rate of 106 samples ranges from 0.868 to 1.735 μW/m³, averaging 1.499 μW/m³. The thermal conductivity in Baiyun Sag exhibits a gradual decrease from the Wenchang Formation to the Hanjiang Formation, whereas the heat generation rate decreases with depth. The present-day heat flow in Baiyun Sag ranges from 66.6 to 139.1 mW/m2, with an average of 89.7 ± 14.7 mW/m2, showing a gradual increasing trend from northwest to southeast. Formation temperature at depths of 1–5 km increases proportionally with depth. Thermal inversion, as inferred from low-temperature thermochronological data of six basement samples, reveals distinct temperature paths for each tectonic unit in Baiyun Sag. These paths are primarily linked to regional tectonic uplift-subsidence and basement heat flow variation. Geodynamic simulations further indicate two extensional events in Baiyun Sag during the Eocene and Middle Miocene, leading to a rapid increase in basement heat flow. This study systematically elucidates the present-day geothermal field characteristics and tectono-thermal evolution history of Baiyun Sag, bearing significant implications for regional tectonic evolution and future deepwater oil and gas explorations.

Characteristics of resistivity variation in deep granite and in-situ detection applications

During the construction of deep vertical shafts, water inrush and flooding accidents are prone to occur, which seriously affect construction safety. Accurately determining the groundwater conditions is a prerequisite for effectively controlling water hazards and conducting risk management. In order to ensure the accuracy of the resistivity method in deep vertical well water exploration construction, a combination of indoor rock physics, mechanical testing, and on-site engineering measurements was used to analyze the influencing factors of granite resistivity. The corresponding relationship between resistivity and formation integrity was revealed, and water exploration experiments were conducted in the working face of deep underground mines. The results show that: (1) Rock resistivity is influenced by metallic minerals, saturation, temperature, ion content of fracture water, and joints. Regarding deep subsurface detection issues, the main factors affecting the detection results are water content and rock integrity. (2) During the loading process, rock resistivity exhibits significant stage response characteristics, which are closely related to rock integrity and damage accumulation. (3) A degradation model for aquifer zoning based on resistivity benchmark line was established. When the formation resistivity is higher than the benchmark line, it indicates a well-integrated formation with low water content. (4) Resistivity cloud maps and zoning degradation models can be used to visually determine and evaluate the occurrence status of formations and the effectiveness of grouting.

Hydrate Control in Subsea Natural Gas Production

One of the most significant technological challenges that this industry faces today is securing the production flow in deep water exploration. Intense conditions of high pressure and low temperatures will favor the formation of the hydrates which could restrict or block the pathway to the extent that there can be a humungous financial loss.
 This research was devoted to hydrate control in subsea natural gas production using results from water concentration estimation for reservoir, wellhead and onshore receiving terminal conditions. For illustration, a natural gas stream from the Niger Delta was selected where the transportation medium is a pipeline. Further implementation as part of the hydrate formation assessment input was done on the temperature and pressure profile along this pipeline.
 A hydrate inhibition strategy based on monoethylene glycol (MEG) is under consideration. It is revealed that in the case if a temperature falls below 20°C and pressure will increase above 100 bar, then it would be met with a flow configuration in a region where hydrates are formed. Estimation of water concentration thus suffices to give useful information as possible prevention methods to hydrate formation while the gas flow is going on in the pipeline. The actual thermodynamic conditions required for the hydrate formation can also be deduced from the temperature and pressure data.

Analysis of the world deepwater oil and gas exploration situation

The global trends in deepwater oil and gas exploration, characteristics of deepwater oil and gas discovery, and layout of deepwater oil and gas exploration business by seven major international oil companies are systematically analyzed using commercial databases (e.g. S&P Global and Rystad) and public information of oil companies. The deepwater area is currently the most important domain for global oil and gas exploration and discovery, with the most discoveries and reserves in passive continental margin basins. The deepwater discoveries have the greatest contribution to the total newly discovered oil and gas reserves in the sea areas, with an increasing number of lithological reservoirs discovered, and oil and gas discoveries mainly distributed in the Mesozoic–Cenozoic. The seven major international oil companies are widely active in various aspects of deepwater oil and gas exploration and development, and play a leading role. Based on years of theoretical understanding of global oil and gas geology and resource evaluation, it is proposed that favorable deepwater exploration areas in the future will mainly focus on three major areas: the Atlantic coast, the Indian Ocean periphery, and the Arctic Ocean periphery. Six suggestions are put forward for expanding overseas deepwater oil and gas exploration business: first, expand the sources for obtaining multi-user seismic data and improve the scientific selection of deepwater exploration areas; second, increase efforts to obtain deepwater exploration projects in key areas; third, adopt various methods to access into/exit from resource licenses flexibly; fourth, acquire licenses with large equity and operate in “dual-exploration” model; fifth, strengthen cooperation with leading international oil companies in deepwater technology; and sixth, improve business operation capabilities and gradually transform from “non-operators” to “operators”.

Paleoenvironmental reconstruction of the Eocene sediments in the Baiyun sag of the Pearl River Mouth Basin

The Baiyun sag of the Pearl River Mouth Basin has become a focus for deepwater exploration with the highest hydrocarbon potential in northern South China Sea. The Eocene organic-rich mudstones are the main source rocks in the Baiyun sag, and the evolution of their depositional environment remains unclear. Based on the core and geochemical data, we investigated the depositional environments of the Eocene Wenchang and Enping sediments in the Baiyuan sag and revealed the sedimentary environment influences on the formation of the source rocks in the study area. The results indicate that the sediments of the Wenchang and Enping formations were deposited in dysoxic to oxic environments. Moreover, according to the concentrations of salinity-sensitive trace elements, and δ13C (-10.9‰ to -7.2‰, average -8.58‰) and δ18O (-18.4‰ to -14.5‰, average -17.1‰) values of carbonate cement in the sandstone samples, the Wenchang and Enping formations were in fresh water to brackish water conditions during their deposition, with increasing salinity from bottom to top, which suggests that the two formations were mainly deposited in lacustrine environment and the Enping formation experienced a relatively extensive lake transgression. The vertical variations of geochemical characteristics suggest that the Wenchang and Enping formations were deposited under a semi-arid/warm condition and all Eocene sediments experienced mild to moderate chemical weathering, relatively large detrital input and stable paleowater depth. Both primary productivity and preservation conditions played essential roles in controlling the enrichment of organic matters in the Baiyun sag, and the preservation conditions resulted from the restricted water setting. The present work provide a comprehensive analysis of depositional environments based on the abundance of high-resolution geochemical data. The results obtained reveal the dominated factors controlling organic matter enrichment in the Baiyun Sag of the Pearl River Mouth Basin. Those findings are not only significant for understanding the region’s paleogeography, but also provide guidance for future profitable oil and gas exploration in the northern South China Sea and other similar areas.

The Effect of Ice Floe on the Strength, Stability, and Fatigue of Hybrid Flexible Risers in the Arctic Sea

Flexible risers have proven to be a popular choice for deepwater exploration due to their ability to withstand functional and environmental stress while maintaining system integrity. In the challenging arctic conditions, lightweight hybrid composite flexible risers are likely to be employed to mitigate the increase in effective tension. This study investigates the strength and stability performance of production hybrid composite flexible risers with composite pressure armour in the harsh environmental conditions of the Arctic seas. At a water depth of 340 m, the flexible riser was analysed in various global configurations to evaluate the static, dynamic, and lamina-scale performance of its carbon fibre-reinforced thermoplastic polymer composite layer. The drifting ice in the region generated additional load on the riser system, and the effects of this ice on the riser design and its dynamic and lamina-level performances were also analysed. The results indicate that the current riser design incorporating the composite layer is insufficient to ensure system integrity without mitigating the effects of ice loading. The carbon fibre direction in each lamina must be optimised for excess axial stress emanating from the combined action of hoop, axial, and bending stresses. Finally, recommendations on how to improve the life of the lightweight hybrid composite riser in arctic conditions are provided.

Salt reconstruction in full-waveform inversion using topology optimization techniques

SUMMARY With the increasing advances in the oil and gas industry, seismic imaging near or under salt structures has become an important point in deep-water exploration. Detailed velocity models of these areas are particularly interesting not only to characterize hydrocarbon reservoirs but also to identify potential sites for hydrogen and carbon dioxide storage in offshore salt caverns. Thus, we study the full-waveform inversion for the salt reconstruction in acoustic media with constant density considering the time-harmonic wave propagation in a finite element formulation using the topology optimization (TO) method. This problem is challenging due to the strong velocity contrast between salt bodies and the sedimentary background, in addition to the lack of low-frequency data and the inherent ill-posedness of the inverse problem. In this context, we incorporate techniques from the TO field, usually used in design applications, to overcome or reduce these known problems. We initially defined the squared slowness as a combination of two fields, one related to the salt shape and the other to the background. An interpolation rule based on the solid isotropic material with penalization method, combined with filtering and projection schemes, is used to find the shape of the salt bodies with increased sharpness interfaces. A Helmholtz-type filter is applied to modify the gradient aimed to regularize the problem and provide a more stable way for the salt shape to evolve during the inversion process. In particular, we demonstrate that the proposed approach may be relevant for reconstructing media with salt bodies when a suitable starting model is unavailable, and sharp interfaces are required. In addition, we present inversion results from synthetic data generated by a variable density model to demonstrate the approach capability when subjected to a reconstruction application.

Light Penetrating the Seawater Column as the Indicator of Oil Suspension-Monte Carlo Modelling for the Case of the Southern Baltic Sea.

The strong need to control investments related to oil extraction and the growing demand for offshore deep-water exploration are the reasons for looking for tools to make up a global underwater monitoring system. Therefore, the current study analyses the possibility of revealing the existence of oil-in-water emulsions in the water column, based on the modelling of the downwelling radiance detected by a virtual underwater sensor. Based on the Monte Carlo simulation for the large numbers of solar photons in the water, the analyses were carried out for eight wavelengths ranging from 412 to 676 nm using dispersed oil with a concentration of 10 ppm. The optical properties of the seawater were defined as typical for the southern Baltic Sea, while the oil emulsion model was based on the optical properties of crude oil extracted in this area. Based on the above-mentioned assumptions and modelling, a spectral index was obtained, with the most favourable combination of 555/412 nm, whose value is indicative of the presence of an oil emulsion in the water.

Matrix Acidizing Optimization for Screened Sandstone Formation at High-Rate Gas Well of Deepwater GWK-8

Deepwater GWK-8 is a gas well in deep sea with 1500 meters water depth and a deviated well with a sandstone formation that has good permeability, potentially high-rate gas well, high reservoir pressures, and large reservoir size. This well is expected to immediately ramp up production at optimal productivity through Floating Production Storage and Offloading (FPSO) in Makassar Strait. For a gas well at deep-water exploration must be commercially viable, it needs to achieve optimal production rate. Gas production initially was not meet the expectations, so it needed to be optimized by one of stimulation method that suitable for this well is matrix acidizing. Sandstone formation is screened by Shape Memory Polymer (SMP) sand control system and matrix acidizing is carried out to optimize the deliverability of gas well by dissolving formation impurities and normalize damage in the wellbore. Methodology of this study begins with collecting data on reservoir data, formation lithology, completion, and well-testing. The optimization of matrix acidizing process is based on initial well-testing results where skin (s) of pre-acidizing is 46 with a permeability (k) is 51.4 mD. The matrix acidizing process uses mud acid (HCl-HF) for upper zone of deepwater GWK-8 that has been installed Shape Memory Polymer (SMP) sand control at the pay zone area. Based on well-testing of post-matrix acidizing, successfully proven in reducing the skin number (s) from 46 to 10, increasing permeability (k) from 51.4 mD to 120 mD, and increasing productivity from 30 MMSCFD to 44 MMSCFD.

Niger Delta Indigenes’ Perception of Community Participation in The Development Communication Strategies and Practices of Oil Companies in Nigeria

This study adopts the principles that underpin participatory development communication in order to highlight the ideology that guides oil corporations’ development communication practices and strategies in Nigeria. The study specifically examines the usage of Global Memorandums of Understanding (GMoUs) by oil firms to engage people in community-based development initiatives. Given Shell and Chevron's stranglehold in onshore, shallow, and deep-water exploration and development in Nigeria, 16 oil-producing localities in their operational zones were chosen at random for the study. The study's design was cross-sectional and drew from survey procedures. 400 respondents were selected through a multistage selection approach from the study’s population for the purposes of data collection and analysis. The study found that although indigenes of the Niger Delta are aware of the GMoUs programmes, they lack the knowledge to take part in them. Thus, the Niger Delta indigenous people claim that the GMoUs programmes are self-serving and need to be carefully adapted to satisfy the desire of the people for bottom-up induced development. The study suggests that development communication experts be involved in the conception and implementation of the ideas because the GMoU model, which oil companies adopted, was flawed in its conception due to a potential lack of sufficient literature review for development agents to gain the understanding needed to guide implementation.

Analysis of the world oil and gas exploration situation in 2021

The global exploration investment, new oil and gas discoveries, exploration business adjustment strategies of oil companies in 2021, and future favorable exploration domains are systematically analyzed using commercial databases such as IHS and public information of oil companies. It has been found that the world oil and gas exploration situation in 2021 has continued the downturn since the outbreak of COVID-19. The investment and drilling workload decreased slightly, but the success rate of exploration wells, especially deepwater exploration wells, increased significantly, and the newly discovered reserves increased slightly compared with last year. Deep waters of the passive continental margin basins are still the leading sites for discovering conventional large and medium-sized oil and gas fields. The conventional oil and gas exploration in deep formations of onshore petroliferous basins has been keeping a good state, with tight/shale oil and gas discoveries made in Saudi Arabia, Russia, and other countries. While strengthening the exploration and development of local resources, national, international, and independent oil companies have been focusing on major overseas frontiers using their advantages, including risk exploration in deep waters and natural gas. Future favorable exploration directions in the three major frontiers, the global deep waters, deep onshore formations, and unconventional resources, have been clarified. Four suggestions are put forward for the global exploration business of Chinese oil companies: first, a farm in global deepwater frontier basins in advance through bidding at a low cost and adopt the “dual exploration model” after making large-scale discoveries; second, enter new blocks of emerging hot basins in the world through farm-in and other ways, to find large oil and gas fields quickly; third, cooperate with national oil companies of the resource host countries in the form of joint research and actively participate exploration of deep onshore formations of petroliferous basins; fourth, track tight/shale oil and gas cooperation opportunities in a few countries such as Saudi Arabia and Russia, and take advantage of mature domestic theories and technologies to farm in at an appropriate time.

Benthic community zonation from mesophotic to deep sea: Description of first deep-water kelp forest and coral gardens in the Madeira archipelago (central NE Atlantic)

The Madeira archipelago has a unique underwater landscape that is characterised by narrow shelves, steep slopes and a large submarine tributary system that boosts primary productivity in oligotrophic waters and thus offers a potential for hotspots of biodiversity. Despite this, there have been limited deep-water exploration activities with less than five expeditions since the 1960s. Here, we investigated the seabed on the southern side of the Madeira-Desertas Ridge using a manned submersible along a 3.8 km long transect starting at 366 m depth up the ridge shelf until its top at 73 m. Benthic habitats and community composition were documented with video along a depth gradient from mesophotic to deep sea. Six distinct biotopes were recognised (three deeper, and three shallower than 115 m depth). Our results showed a rich biodiversity with deep biotopes characterised by sponges and non-reef-building corals (e.g., Pachastrella monilifera, Viminella flagellum, Eunicella verrucosa) and shallow biotopes comprising macroalgae and the gorgonian Paramuricea cf. grayi. The pronounced benthic zonation reflects the steep environmental gradient that includes high topographic variation, heterogeneous substrates, and bidirectional regular wave-motion at the shallow mesophotic part. Together with biotic factors, such as low density of sea urchins and presence of predatory fish, this environment with unusual deep light penetration, a mesoscale cyclonic eddy, and deep wave-motion, has allowed the establishment of a mature deep-water kelp population of Laminaria ochroleuca in the plateau (max. >100 individuals p/100 m2). At the same time, a conspicuous coral fauna was observed on a wide range of soft to hard bottoms with several species taking advantage of the favourable hydrodynamic regime and seawater properties together with substratum availability to create coral gardens. These habitats were previously not known from Madeira, and their newfound discovery in the archipelago merit further investigation and protection.

The influence of the inter-tropical convergence zone on the Orinoco River and Late Quaternary tropical planktonic foraminiferal assemblages

Although deep-water oil and gas exploration offshore eastern Trinidad is becoming prevalent, the use of ecostratigraphy around eastern Trinidad are limited mostly to neritic water depths. Changes in planktonic foraminiferal assemblages of Core BGT086, offshore eastern Trinidad, are used here to indicate biozonal events useful for deep-water (>1000 m water depth) exploration. Decreased proportional abundances of Globigerinella obesa and Globigerina bulloides mark the southward migration of the inter-tropical convergence zone (ITCZ) during the Younger Dryas (YD). A decrease in species richness and Globigerinoides ruberwhite proportional abundance is consistent with rising temperature during the YD. During Biozone Z2, nutrient-preferring species (G. bulloides, Neogloboquadrina dutertrei) declined in proportional abundance, while G. ruberpink increased in proportional abundance, reflecting the arrival of the ITCZ in the area. Decreases in mean diversity (measured using the Shannon Function, H) and evenness (equitability index, E), and an increase in mean dominance (max pi) support the claim that the ITCZ arrived in the area after the YD. A sudden increase in Globorotalia menardii proportional abundance marked the start of Biozone Z1, at which time there was a change from a stressed community to a less stressed one. Boundaries of SHE abundance biozones coincided with noticeably enhanced assemblage changes, being consistent with the southward migration of the ITCZ and the onset of Biozone Z1. The mean value of the pairwise assemblage turnover index (ATIs) is here used as a proxy for what we term 'assemblage stability'. Comparisons of mean planktonic foraminiferal ATIs from Core BGT086 and six other nearby tropical piston cores (Cores 1, 2 and 3 off NW Tobago, and En20-2, En20-10 and En20-16 from the Leeward Islands, Lesser Antilles) showed no statistical difference in assemblage stabilities within similar planktonic foraminiferal biozones. Kruskal-Wallis tests determined a significant difference in median ATIs values when all seven cores' ATIs were used, but the difference was not significant when data above the YD boundary (i.e., Biozone Z) were used. The lowered nutrient influx from the Orinoco River due to the arrival of the ITCZ in the area after the YD would have triggered a stable environment for planktonic foraminiferal assemblages. This implies that caution must be used to ensure data from the same biozone is used when analyzing assemblage stabilities of planktonic foraminifera.