scholarly journals Experimental Study of Sand Production during Depressurization Exploitation in Hydrate Silty-Clay Sediments

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4268 ◽  
Author(s):  
Jingsheng Lu ◽  
Dongliang Li ◽  
Yong He ◽  
Lingli Shi ◽  
Deqing Liang ◽  
...  
Keyword(s):  
Large Scale ◽  
Silty Clay ◽  
Sand Production ◽  
Fracture Permeability ◽  
Vertical Wells ◽  
Mud Cake ◽  
Water Rates ◽  
Sand Control ◽  
Production Temperature ◽  
Clay Sediment

Silty-clay reservoirs are a weak point in sand production and sand control studies due to their low economy. However, China’s marine natural gas hydrates (NGH) mostly exist in silty-clay sediments, which restrict the sustainable and efficient development of NGH. In order to study the sand production of hydrate silty-clay sediments, hydrate production experiments in vertical wells and horizontal wells were carried out using a self-developed hydrate sand production and sand control simulation device. The results showed a great difference between the hydrate silty-clay sediments and hydrate sand sediments. The significant differences in production pressure and production temperature between the different layers indicated the low permeability and low heterogeneity of the hydrate silty-clay sediments. The sliding settlement of the overall depression in the horizontal well and overall subsidence in the vertical well of the hydrate silty-clay reservoir would easily lead to silty-clay flow and large-scale sand production. When water rates decreased, the property of “silty-clay sediment filtration and wall building” was found, which formed a “mud cake” around the wellbore. The good strength of adhesion and fracture permeability of the “mud cake” provided ideas for reservoir reformation. This study further discusses sand production and sediment reformation in hydrate silty-clay sediments.

scholarly journals Effect of Slot Width and Density on Slotted Liner Performance in SAGD Operations

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 268
Author(s):  
Yujia Guo ◽  
Alireza Nouri ◽  
Siavash Nejadi
Keyword(s):  
Large Scale ◽  
Control Method ◽  
Slot Width ◽  
Control Technique ◽  
Sand Production ◽  
Fines Migration ◽  
Pressure Drops ◽  
Sand Control ◽  
Mechanical Methods ◽  
Triaxial Cell

Sand production from a poorly consolidated reservoir could give rise to some severe problems during production. Holding the load bearing solids in place is the main goal of any sand control technique. The only sand control techniques that have found applications in steam assisted gravity drainage (SAGD) are some of the mechanical methods, including wire wrapped screens, slotted liners and more recently, punched screens. Slotted liner is one of the most effective mechanical sand control methods in the unconsolidated reservoir exploitation, which has proven to be the preferred sand control method in the SAGD operations. The main advantage of the slotted liners that makes them suitable for SAGD operations is their superior mechanical integrity for the completion of long horizontal wells. This study is an attempt to increase the existing understanding of the fines migration, sand production, and plugging tendency for slotted liners by using a novel large-scale scaled completion test (SCT) facility. A triaxial cell assembly was used to load sand-packs with specified and controlled grain size distribution, shape and mineralogy, on multi-slot sand control coupons. Different stress levels were applied parallel and perpendicular to different combinations of slot width and density in multi-slot coupons, while brine was injected from the top of the sand-pack towards the coupon. At each stress level, the mass of produced sand was measured, and the pressure drops along the sand-pack and coupon were recorded. Fines migration was also investigated by measuring fines/clay concentration along the sand-pack. The current study employed multi-slot coupons to investigate flow interactions among slots and its effect on the flow performance of liner under typically encountered stresses in SAGD wells. According to the experimental observations, increasing slot width generally reduces the possibility of pore plugging caused by fines migration. However, there is a limit for slot aperture beyond which the plugging is not reduced any further, and only a higher level of sanding occurs. Test measurements also indicated that besides the slot width, the slot density also influences the level of plugging and sand production and must be included in the design criteria.

Characterization of Sand Production for Clayey-Silt Sediments Conditioned to Openhole Gravel-Packing: Experimental Observations

SPE Journal ◽  
2021 ◽  
pp. 1-18
Author(s):  
Yurong Jin ◽  
Yanlong Li ◽  
Nengyou Wu ◽  
Daoyong Yang
Keyword(s):  
Large Scale ◽  
Early Stage ◽  
Tensile Failure ◽  
Inlet Pressure ◽  
Sand Production ◽  
Failure Patterns ◽  
Sand Control ◽  
Clayey Silt ◽  
Fracture Development ◽  
Gravel Packing

Summary As one of the geotechnical risks, sanding has been one of the main constraints for safely and sustainably developing marine natural gas hydrate. In this study, a cylindrical vessel that is packed with the clayey-silt sediment collected from the Shenhu area of the northern South China Sea is used to microscopically observe sand detachment, migration within matrix, invasion to gravel packing, and production for openhole gravel packing. More specifically, by injecting water from the vessel boundary, the seepage and stress-strain field for sediment near the wellbore after hydrate dissociation is simulated, and the sand failure characteristics [i.e., the produced sand volume and particle size distributions (PSDs)] are quantified. The sand failure pattern is found to largely differ from that of a sandstone reservoir, whereas fractures, wormholes, and fluidized channels are successively developed along with a large scale of sand production and inlet pressure variation. Followed is a steady flow state with a stable inlet pressure without noticeable sand failure. Correspondingly, the fracture is induced and propagated by the combinational effort of shear and tensile failure, whereas wormholes and fluidized channels are associated with the liquid dragging force. At the end of each test, foraminifera are found to accumulate near the external side of the gravel-packing region, which is beneficial to sand control. In the meantime, a compact mudcake, as an infiltration medium, is observed outside the gravel-packing layer. The 30/50 mesh gravel packing is able to control grain size up to 30.0 µm in diameter with a median of 5.0 µm, whereas the produced grains account for less than 1.0 vol% of the total sediment. By performing sensitivity analysis on sand production, depressurization shall be conducted at a small rate to not only control sand production, but also to induce flow paths at the early stage. Moreover, the sand production rate associated with fracture development is larger than those of wormholes and fluidized channels. This study focuses on the experimental observations on sand failure patterns, and the theoretical formulations and modeling will be presented and explained in a future work.3

scholarly journals Recycling and Reuse of Sediments in Agriculture: Where Is the Problem?

2021 ◽  
Vol 13 (4) ◽  
pp. 1648
Author(s):  
Giancarlo Renella
Keyword(s):  
Scientific Evidence ◽  
Significant Proportion ◽  
Silty Clay ◽  
Fine Sediments ◽  
Sediment Fraction ◽  
Biodegradation Process ◽  
Component Material ◽  
Long Time ◽  
Clay Sediment ◽  
International Conventions

Though suggested by international conventions for a long time, there are still several technical and legislative limitations to a complete reuse and recycling of dredged sediments. In particular, reuse of unpolluted sediments can be practiced, whereas sediment recycling is still affected by several downsides, and a significant proportion of the recycled fine sediments has no practical use and must be landfilled. However, the silty clayey fraction of the recycled sediments is rich in organic matter and macro- and micronutrients useful for plant growth. Nevertheless, sediment recycling in agriculture is not possible, even in non-food agricultural sectors, due to the lack of a permissive legislation and of consolidated supply chains. In addition to plant nutrients, the silty-clay sediment fraction may also accumulate organic and inorganic pollutants, and while the organic pollutants can be effectively biodegraded, metals and metalloids may concentrate at concentrations higher than the limits set by the environmental and agricultural legislations. In this paper, I briefly summarize the scientific evidence on the potential reuse and recycling of sediments in agriculture, and I discuss the main reasons for hindrance of sediment recycling in agriculture. I also present evidence from a real industrial biodegradation process that produces bioremediated fine sediment fractions with suitable properties as a mineral ingredient for plant-growing media. I propose that nutrient-rich recycled sediments could be reconsidered as a component material category in the new EU regulation on fertilizers.

scholarly journals A robust fuzzy logic-based model for predicting the critical total drawdown in sand production in oil and gas wells

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250466
Author(s):  
Fahd Saeed Alakbari ◽  
Mysara Eissa Mohyaldinn ◽  
Mohammed Abdalla Ayoub ◽  
Ali Samer Muhsan ◽  
Ibnelwaleed A. Hussein
Keyword(s):  
Fuzzy Logic ◽  
Correlation Coefficient ◽  
Oil And Gas ◽  
Maximum Error ◽  
Physical Parameters ◽  
Sand Production ◽  
Gas Reservoirs ◽  
The North ◽  
Sand Control ◽  
North Adriatic Sea

Sand management is essential for enhancing the production in oil and gas reservoirs. The critical total drawdown (CTD) is used as a reliable indicator of the onset of sand production; hence, its accurate prediction is very important. There are many published CTD prediction correlations in literature. However, the accuracy of most of these models is questionable. Therefore, further improvement in CTD prediction is needed for more effective and successful sand control. This article presents a robust and accurate fuzzy logic (FL) model for predicting the CTD. Literature on 23 wells of the North Adriatic Sea was used to develop the model. The used data were split into 70% training sets and 30% testing sets. Trend analysis was conducted to verify that the developed model follows the correct physical behavior trends of the input parameters. Some statistical analyses were performed to check the model’s reliability and accuracy as compared to the published correlations. The results demonstrated that the proposed FL model substantially outperforms the current published correlations and shows higher prediction accuracy. These results were verified using the highest correlation coefficient, the lowest average absolute percent relative error (AAPRE), the lowest maximum error (max. AAPRE), the lowest standard deviation (SD), and the lowest root mean square error (RMSE). Results showed that the lowest AAPRE is 8.6%, whereas the highest correlation coefficient is 0.9947. These values of AAPRE (<10%) indicate that the FL model could predicts the CTD more accurately than other published models (>20% AAPRE). Moreover, further analysis indicated the robustness of the FL model, because it follows the trends of all physical parameters affecting the CTD.

Taming the Monster: Arresting Excessive Sand Production Problem in ARAMU037

2021 ◽  
Author(s):  
Emily Ako ◽  
Erasmus Nnanna ◽  
Odumodu Somtochukwu ◽  
Akinmade Moradeke
Keyword(s):  
North Sea ◽  
Niger Delta ◽  
Best Practice ◽  
Integrated Approach ◽  
Sand Production ◽  
Sand Control ◽  
Production Problem ◽  
Normal Production ◽  
The Way

Abstract Chemical Sand Consolidation (SCON) has been used as a means of downhole sand control in Niger Delta since the early 70s. The countries where SCON has been used include Nigeria (Niger Delta), Gabon (Gamba) and UK (North Sea). SCON provides grain-to-grain cementation and locks formation fines in place through the process of adsorption of the sand grains and subsequent polymerization of the resin at elevated well temperatures. The polymerized resin serves to consolidate the surfaces of the sand grain while retaining permeability through the pore spaces. In a typical Niger Delta asset, over 30% of the wells may be completed with SCON. A high percentage are still producing without failure since installation from1970s. Where the original SCON jobs have failed, re-consolidation has also been carried out successfully. Chemical Sand Consolidation development has evolved over the years from: Eposand 112A and B, Eposand 212A and B, Wellfix 2000, Wellfix 3000, Sandstop (resin based), Sandtrap 225, 350 & 500 (resin based) and lately Sandtrap 225,350, 500 (solvent based) and Sandtrap ABC (aqueous based). There have been mixed results experienced with the deployment of either of the latest recipes of SCON. This was due to the fact that the conventional deployment work procedure was followed with the tendency for one-size-fits-all approach to the treatment. This paper details the challenges faced with sand production in ARAMU037, the previous interventions and how an integrated approach to the design and delivery of the most recent intervention restored the way to normal production. The well has now produced for about 2 years with minimal interruption with the activity paying out in less than 6 months. The paper also recommends the best practice for remedial sand control especially for wells in mature assets.

Real-Time Prediction of Choke Health Using Production Data Integrated with AI

2021 ◽  
Author(s):  
Ahmed Alghamdi ◽  
Olakunle Ayoola ◽  
Khalid Mulhem ◽  
Mutlaq Otaibi ◽  
Abdulazeez Abdulraheem
Keyword(s):  
High Pressure ◽  
Real Time ◽  
Large Scale ◽  
Production Systems ◽  
Rate Of Change ◽  
Production Data ◽  
Ann Model ◽  
Sand Production ◽  
Data Set ◽  
Pressure Drops

Abstract Chokes are an integral part of production systems and are crucial surface equipment that faces rough conditions such as high-pressure drops and erosion due to solids. Predicting choke health is usually achieved by analyzing the relationship of choke size, pressure, and flow rate. In large-scale fields, this process requires extensive-time and effort using the conventional techniques. This paper presents a real-time proactive approach to detect choke wear utilizing production data integrated with AI analytics. Flowing parameters data were collected for more than 30 gas wells. These wells are producing gas with slight solids production from a high-pressure high-temperature field. In addition, these wells are equipped with a multi-stage choke system. The approach of determining choke wear relies on training the AI model on a dataset constructed by comparison of the choke valve rate of change with respect to a smoother slope of the production rate. If the rate of change is not within a tolerated range of divergence, an abnormal choke behavior is detected. The data set was divided into 70% for training and 30% for testing. Artificial Neural Network (ANN) was trained on data that has the following inputs: gas specific gravity, upstream & downstream pressure and temperature, and choke size. This ANN model achieved a correlation coefficient above 0.9 with an excellent prediction on the data points exhibiting normal or abnormal choke behaviors. Piloting this application on large fields, where manual analysis is often impractical, saves a substantial man-hour and generates significant cost-avoidance. Areas for improvement in such an application depends on equipping the ANN network with long-term production profile prediction abilities, such as water production, and this analysis relies on having an accurate reading from the venturi meters, which is often the case in single-phase flow. The application of this AI-driven analytics provides tremendous improvement for remote offshore production operations surveillance. The novel approach presented in this paper capitalizes on the AI analytics for estimating proactively detecting choke health conditions. The advantages of such a model are that it harnesses AI analytics to help operators improve asset integrity and production monitoring compliance. In addition, this approach can be expanded to estimate sand production as choke wear is a strong function of sand production.

Sand Production in Ultra-Weak Sandstones: Is Sand Control Absolutely Necessary?

1997 ◽  
Author(s):  
J. Tronvoll ◽  
E. Papamichos ◽  
A. Skjaerstein ◽  
F. Sanfilippo
Keyword(s):  
Sand Production ◽  
Sand Control

A geomechanical approach for sanding risk assessment applied to three field cases for completion optimisation

2010 ◽  
Vol 50 (1) ◽  
pp. 623 ◽  
Author(s):  
Khalil Rahman ◽  
Abbas Khaksar ◽  
Toby Kayes
Keyword(s):  
Decision Making ◽  
Petroleum Industry ◽  
Cost Effective ◽  
Development Planning ◽  
Control Measures ◽  
Sand Production ◽  
Field Development ◽  
Well Completion ◽  
Sand Control ◽  
Production Prediction

Mitigation of sand production is increasingly becoming an important and challenging issue in the petroleum industry. This is because the increasing demand for oil and gas resources is forcing the industry to expand its production operations in more challenging unconsolidated reservoir rocks and depleted sandstones with more complex well completion architecture. A sand production prediction study is now often an integral part of an overall field development planning study to see if and when sand production will be an issue over the life of the field. The appropriate type of sand control measures and a cost-effective sand management strategy are adopted for the field depending on timing and the severity of predicted sand production. This paper presents a geomechanical modelling approach that integrates production or flow tests history with information from drilling data, well logs and rock mechanics tests. The approach has been applied to three fields in the Australasia region, all with different geological settings. The studies resulted in recommendations for three different well completion and sand control approaches. This highlights that there is no unique solution for sand production problems, and that a robust geomechanical model is capable of finding a field-specific solution considering in-situ stresses, rock strength, well trajectory, reservoir depletion, drawdown and perforation strategy. The approach results in cost-effective decision making for appropriate well/perforation trajectory, completion type (e.g. cased hole, openhole or liner completion), drawdown control or delayed sand control installation. This type of timely decision making often turns what may be perceived as an economically marginal field development scenario into a profitable project. This paper presents three case studies to provide well engineers with guidelines to understanding the principles and overall workflow involved in sand production prediction and minimisation of sand production risk by optimising completion type.

Implications of accurate geomechanical modelling and systematic core testing for sanding evaluation and sand control decisions – a case study from Perth Basin

2020 ◽  
Vol 60 (1) ◽  
pp. 267
Author(s):  
Sadegh Asadi ◽  
Abbas Khaksar ◽  
Mark Fabian ◽  
Roger Xiang ◽  
David N. Dewhurst ◽  
...  
Keyword(s):  
Management Strategies ◽  
Mechanical Tests ◽  
Well Test ◽  
Sand Production ◽  
Gas Field ◽  
Stress Regime ◽  
Full Field ◽  
Field Development ◽  
Sand Control ◽  
Rock Mechanical Properties

Accurate knowledge of in-situ stresses and rock mechanical properties are required for a reliable sanding risk evaluation. This paper shows an example, from the Waitsia Gas Field in the northern Perth Basin, where a robust well centric geomechanical model is calibrated with field data and laboratory rock mechanical tests. The analysis revealed subtle variations from the regional stress regime for the target reservoir with significant implications for sanding tendency and sand management strategies. An initial evaluation using a non-calibrated stress model indicated low sanding risks under both initial and depleted pressure conditions. However, the revised sanding evaluation calibrated with well test observations indicated considerable sanding risk after 500 psi of pressure depletion. The sanding rate is expected to increase with further depletion, requiring well intervention for existing producers and active sand control for newly drilled wells that are cased and perforated. This analysis indicated negligible field life sanding risk for vertical and low-angle wells if completed open hole. The results are used for sand management in existing wells and completion decisions for future wells. A combination of passive surface handling and downhole sand control methods are considered on a well-by-well basis. Existing producers are currently monitored for sand production using acoustic detectors. For full field development, sand catchers will also be installed as required to ensure sand production is quantified and managed.

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