Traditional Agricultural Management of Kam Sweet Rice (Oryza Sativa L.)in Southeast Guizhou Province, China

Background: The Dong people mainly live in Hunan, Guangxi and Guizhou provinces, China, with a long history of glutinous rice cultivation, among which Kam Sweet Rice (KSR) is a group of rice landraces that has been domesticated for thousands of years by the Dong people. The core distribution area of KSR is Liping, Congjiang and Rongjiang County of southeast, Guizhou Province. Paddy fields, forests, livestock and cottages have formed a special artificial wetland ecosystem in local area, and the Dong people have also formed a set of traditional farming systems of KSR for variety breeding, field management, and soil and water conservation. However, this traditional agricultural management has not been reported at multiple levels based on landraces, species and ecosystems.Methods: Fieldwork was conducted in ten villages in southeast Guizhou from 2019-2021. A total of 229 informants were interviewed from the villages. Semi-structured and key informant interviews were administered to collect ethnoecological data on the characteristics and traditional utilization of KSR, traditional farming systems and agricultural management of the Dong people. Results: (1): A total of 57 KSR varieties were recorded as used by the Dong people in southeast Guizhou. We analyzed the cultural importance index (CII) of all KSRs. Varieties with high CII often have a pleasant taste, special biological characteristics of cold resistance, disease and insect resistance and high utilization in the traditional culture of Dong people. (2) There is a clear division of labor between men and women in the breeding, seed retention, field management and grain storage management of different varieties of KSR in Dong communities. In order to resist natural disasters and insect pests, the cultivation of KSR is usually managed by multi-variety mixed planting. These agricultural management modes are the result of Dong people's understanding and adaptation to the local natural geographical environment, as well as the experience and wisdom crystallization of Dong people's long-term practice. (3) The traditional farmland of Dong People is a typical artificial wetland ecosystem that is planted with mixed KSR varieties with rich traditional wisdom. In addition, the economic benefit of the rice-fish-duck symbiotic system was 3.07 times that of hybrid rice alone; therefore, the rice-fish-duck system not only has the function of maintaining soil, water and ecological balance but also improves the income of Dong people.Conclusion: KSR is a special kind of rice that has been domesticated and cultivated by Dong people for thousands of years. Dong people have also formed traditional agriculture dominated by KSR cultivation. The traditional agricultural management of Dong people provides suitable habitats for flora and fauna with biodiversity protection, and convenient conditions for rational utilization and distribution of water resources were also provided. This traditional management mode is of great significance for environmental protection, climate change response, community resource management, sustainable utilization, and agricultural transformation in modern society. Therefore, we call for interdisciplinary research in natural and social sciences, in-depth study of the ecological culture of ethnic areas, and sort out treasures conducive to the development of all mankind.

RESEARCH ON VISUAL NAVIGATION PATH DETECTION METHOD FOR DENSE PLUM GROVE

Aiming at the field management of plum grove in Inner Mongolia of China, taking the dense planting plum groves in Bikeqi town of Hohhot City as the research object, this paper proposed a visual navigation path detection algorithm for plum grove. By processing the video image information of plum grove, comparing RGB and HSV color space model, HSV color model was selected to separate the plant and background in V channel. Homomorphic filtering was used to highlight the region of interest in the image, Otsu was selected to segment the image, the intersection of plum trunk and ground was extracted as feature points, and the least square method was used to fit the navigation path. Through the comparative analysis of detection rate under different detection conditions in one day, the verification test of route accuracy was carried out. The experimental results show that: for dense planting plum grove, the average path detection accuracy of the algorithm is 70% and 73.3% under the condition of front light and weak light, respectively. The detection accuracy and real-time meet the requirements of plum grove field management, and the navigation baseline can be generated more accurately, which provides a preliminary basis for the realization of mechanical vision navigation in plum grove field management.

Integrating Laboratory Testing and Numerical Modelling for a Giant Maturing Carbonate Field in UAE — II. Coupled Geomechanical Modelling of Stacked Reservoir Intervals

A mature field located in a gently dipping structure onshore Abu Dhabi has multiple stacked oil and gas reservoirs experiencing different levels of depletion. The average reservoir pressure in some of these intervals had declined from the early production years to the present day by more than 2000 psi. Coupled geomechanical modelling is, therefore, of the greatest value to predict the stress paths in producing reservoir units, using the concept of effective stress. This paper examines the implications for long-term field management—focusing primarily on estimating the potential for reservoir compaction and predicting field subsidence. This paper takes the work reported in Noufal et al. (2020) one step further by integrating the results of a comprehensive geomechanical laboratory characterization study designed to assess the potential geomechanical changes in the stacked reservoirs from pre-production conditions to abandonment. This paper adopts a geomechanical modelling approach integrating a wide array of data—including prestack seismic inversion outputs and dynamic reservoir simulation results. This study comprised four phases. After the completion of rock mechanics testing, the first modelling phase examined geomechanics on a fine scale around individual wells. The goal of the second phase was to build 4D mechanical earth models (4D MEMs) by incorporating 14 reservoir models—resulting in one of the largest 4D MEMs ever built worldwide. The third phase involved determining the present-day stress state—matching calibrated post-production 1D MEMs and interpreted stress features. Lastly, the resulting model was used for field management and formation stimulation applications. The 4D geomechanical modelling results indicated stress changes in the order of several MPa in magnitude compared with the pre-production stress state, and some changes in stress orientations, especially in the vicinity of faults. This was validated using well images and direct stress measurements, indicating the ability of the 4D MEM to capture the changes in stress magnitudes and orientations caused by depletion. In the computed results, the 4D MEM captures the onset of pore collapse and its accelerating response as observed in the laboratory tests conducted on cores taken from different reservoir units. Pore collapse is predicted in later production years in areas with high porosity, and it is localized. The model highlights the influence of stress changes on porosity and permeability changes over time, thus providing insights into the planning of infill drilling and water injection. Qualitatively, the results provide invaluable insights into delineating potential sweet spots for stimulation by hydraulic fracturing.

Integrated Subsurface Study for Gas-Oil Communicating Reservoirs: From Structural Synthesis to Optimum Co-FDP

This paper presents an integrated subsurface study that focuses on delivering field development planning of two reservoirs via comprehensive reservoir characterization workflows. The upper gas reservoir and lower oil reservoir are in communication across a major fault in the crest area of the structure. Gas from the upper reservoir, which is not under development, is being produced along with some oil producers from the oil reservoir as per acquired surveillance data. Pressure depletion is observed in observer wells of the upper reservoir, which substantiate both reservoirs communication. The oil reservoir is on production since 1994, under miscible hydrocarbon water alternating gas injection (HCWAG) and carbon dioxide (CO2) injection. The currently implemented development plan has been facing several complexities and challenges including, but not limited to, maintaining miscibility conditions, sustainability of production and injection in view of reservoirs communication, reservoir modeling challenges, suitability of monitoring strategy, associated operating costs and expansion of field development in newly appraised areas. In this study, an assessment of multiple alternative field development scenarios was conducted; with an aim to tackle field management and reservoir challenges. It commenced by a comprehensive synthesis of seismic, petrophysical (including extensive core characterizations), geological, production and reservoir engineering data to ensure data adequacy and effectiveness for development planning. The process was followed by evaluation of the historical reservoir management, HCWAG and CO2 injection practices using advanced analytics to identify areas for improvement and accelerate decision making process. The identified areas of improvement were incorporated into a dynamic model via diverse set of field management logics to screen wide range of scenarios. In the final step, the optimal scenarios were selected, in line of having strong economic indicators, honoring operational constraints, corporate business plan and strategic objectives. The comprehensive and flexible field management logic was set up to target different challenges and was used to extensively screen hundreds of different field development scenarios varying several parameters. Examples of such parameters are WAG ratio, injection pressures for both water/gas and CO2, cycle duration, well placement, reservoir production and injection guidelines, different co-development production schemes coupled with static and dynamic uncertainty properties against incremental oil production and discounted cash flow. The simulation results were analyzed using standardized approach where a number of key indicators was cross-referenced to produce optimal field development scenarios with regards to co-development effect of both reservoirs, miscibility conditions, balanced pressure depletion, harmonized sweep as well as robust discounted cash flow. Strong management support, multi-disciplinary data integration, agility of decision making and revisions in a controlled timeframe are considered as the key pillars for success of this study. The adopted workflow covers subsurface modeling aspects from A-Z and following reservoir characterization and modeling best practices. The methodology applied in this study uses an integrated subsurface structured approach to tackle reservoirs challenges and co-development, generate alternative development options leveraging on data analytics techniques and advanced field management strategies.

Minimise Risks Through a Comprehensive Validation of the Existing Production Operation and Planning Strategy for the Largest Oilfield in Poland

Integrated field management is a key initiative recognised by many operators that helps delivering the promise of digital to meet their business strategic objectives of increased hydrocarbon production, reduced exploration and appraisal costs, and sustained development and operation costs. This paper presents how an integrated asset model has been developed for the largest oilfield in Poland to enable a comprehensive validation of its current development plan and operating strategy to ensure safe operation; assessment of other feasible development scenarios to fully realise its potential and paving the path to digital oilfield. A proven integrated asset modeling approach has been adopted to bring a complex reservoir, multiple interdependent wells, pipelines networks, process models together into one single platform. The integrated modeling platform included both gas and water reinjection network models to provide a pore to process closed loop solution. Development of this integrated reservoir-wells-pipelines-network-process facility-water and gas reinjection network models focused to provide all the vital valuable inputs to better field management, fast and accurate decision-making, optimal safe operation in meeting the set seasonal sales contract. Assessments of production operation strategy and field development scenarios were conducted at full field level from reservoir to process plant, accounting wells, pipelines, process handling capacities, the complete system constraints and back pressure effects of all involved components. The availability of fully integrated asset model with pore to process solution enables engineers to better understand the current well performance and production potentials; to ensure a safe and optimal process plant operation. The model helped to identify bottlenecks imposed by the existing pipelines network and process facility; it also enabled the asset team to confirm the existing development plan was not optimal. Other feasible planning scenarios which could further enhance the overall asset productivity were identified, i.e. via determining location of infill wells and which unused idle producers to be converted to gas or water injectors. The study demonstrated a comprehensive validation of the existing development and operation strategy was achievable with the approach. The paper describes how the developed integrated asset model enables the asset team to validate the existing operating strategy and field development scenario of the studied onshore brownfield; to further enhance asset productivity and to achieve efficient field management by adjusting the operating condition in meeting the seasonal sales contract. The integrated asset model also helps to evaluate and to analyse forecasts of different development scenarios including infill drilling and adding new wells and other enhanced oil recovery (EOR) techniques to achieve an ultimate recovery and asset economics.

Peer Irrigators and the Choice of Field Management and Water Control Practices for Irrigation in Arkansas

We examined how irrigation techniques in use by family and friends influence the use and share of land utilizing different irrigation techniques by Arkansas producers. A bivariate sample selection model simultaneously estimated how farm characteristics determine the use and explain the share of a farm that utilizes an irrigation technique. We found that the irrigation techniques in use by family and friends do affect the irrigation techniques a producer uses and the share of acres utilizing different irrigation techniques. A producer with a family or friend that uses end-blocking irrigation is 41% more likely to use end-blocking themselves. Having a family or friend who uses pivot irrigation technology tends to decrease the share of irrigated acres that utilizes end block irrigation by 0.211. We also found that when the irrigation techniques in use by family and friends interact with variables such as location and participation in a regional conservation partnership program, the effects on the producer’s decision vary. The share of irrigated acres that use cutback irrigation decreases by 0.21 for a producer who has a peer that uses irrigation scheduling. However, if the producer lives along Crowley’s Ridge and has a peer that uses irrigation scheduling, the share of irrigated acres that use cutback irrigation decreases by an additional 0.54.