Efficiently and accurately understanding the fluid flow behavior in ultra-deep natural gas reservoirs is very challenging due to complex geological environment intricate properties at high pressure. In this study, a fully coupled geomechanical model was developed simulate production phenomena reservoirs. Stress-dependent porosity permeability models were applied, then governing equations of incorporated into COMSOL Multiphysics. Furthermore, verified by reservoir depletion from Keshen field...

Through analyzing the development of large ultra-deep structural gas fields in China, strategies for efficient such are proposed based on their geological characteristics and production performance. According to matrix properties, fracture degree configuration between fractures, reservoirs classified into three types: single porosity permeability system, dual system. These types show remarkable differences different scales permeability, ratio dynamic reserves volumetric water invasion risk....

Seismic, drilling, logging and production performance data were analyzed to study the key geological factors such as reservoir properties gas/water distribution, which influence development of Lower Cambrian Longwangmiao reservoirs in Moxi block, Anyue gas field, Sichuan Basin, strategies are established. The results indicate that: (1) Four stages grain shoals developed longitudinally two main with one trench formed laterally area; (2) Three types identified, millimeter sized dissolved vugs,...

To identify the type of main flow channels complex porous media in oil and gas reservoirs, "main channel index" is defined as ratio comprehensive permeability obtained from well test to matrix core analysis or logging. Meanwhile, a mathematical model established based on equivalent assumption, classification method for put forward, quantitative characterization realized. The has been verified by typical reservoirs. study results show that can quantitatively classify types channels. If index...

In recent years, deep marine carbonate gas reservoirs have become an important field in increasing conventional reserves and production the Sichuan Basin. Due to complex hydrocarbon accumulation conditions, great burial depth complicate gas–water relation, however, this type of faces huge challenges realize efficient development. paper, development history Basin was analyzed. Then, based on such characteristics practices, special technologies were summarized. Finally, research direction for...

Abstract The understanding of water adsorption and desorption behavior in the shale rocks is great significance reserve estimation, wellbore stability hydrocarbon extraction gas reservoirs. However, sorption shales remains unclear. In this study, vapor adsorption/desorption isotherms Longmaxi Sichuan Basin, China were conducted at various temperatures (30 °C, 60 °C) a relative pressure up to 0.97 understand behavior. Then effects temperature properties analyzed, adsorption, hysteresis,...

A gel based on polyacrylamide, exhibiting delayed crosslinking characteristics, emerges as the preferred solution for mitigating degradation under conditions of high temperature and extended shear in ultralong wellbores. High viscosity/viscoelasticity fracturing fluid was required to maintain excellent proppant suspension properties before gelling. Taking into account both cost potential damage reservoirs, polymers with lower concentrations molecular weights are generally preferred. In this...

Natural gas from ultra-deep reservoirs has been a major contributor for reserves boost, deliverability construction, and profits growth in natural industry China. As significant strategic domain the future development of upstream business, high-quality resources great significance economic benefits enhancement sustained regional supply assurance. In this paper, based on appraisal characteristics effectiveness developed large fields, challenges high quality were indicated, which include...

For new manned submersibles to dive deep sea, the conical frustum windows need be designed under external uniform pressure, not only based on rule design method but also verified by numerical or experimental methods. In this paper, contact finite element (FE) model is provided for window and validated accordingly. Based presented FE model, stress deformation characteristics have been accomplished thick then failure reasons criterion of acrylic plastics viewports are thoroughly investigated...

The propagation pattern of pressure drawdown effectively reflects the recoverable reserves range around gas well and serves as a crucial basis for development strategies. However, it is not easy to detect boundary near producing well, especially in low-permeability reservoirs where drainage radius small. Physical simulation experiments can serve method whole profile rate be obtained real time. Using long core plugs with permeabilities 2.300 mD, 0.486 0.046 physical were carried out under...

Capillary pressure was tested on 40 matrix cores (in situ permeability: 0.002×10−3–100 ×10−3 μm2) in the Sulige gas field and pore structure features of different type sands were described finely. Based research features, percolation experiments designed under conditions homogeneous with permeability, heterogeneous water saturation, to laws tight sand. Nanometer throats microscopic capillary are main flow channels for Percolation resistance or gas-water sand is far greater than that...

Gas content and flow characteristics are closely related to shale lithofacies, significant differences exist in the pore structure fractal among lithofacies. In this study, X-ray diffractometer (XRD), field-emission scanning electron microscopy (FE-SEM), gas adsorption (N2 CO2), theory were employed systematically characterize attributes of marine Wufeng-Longmaxi formation shales. The information various pores microfractures lithofacies was extracted quantified via high-resolution FE-SEM...

The natural pesticide phenazine-1-carboxylic acid (PCA) is known to lack phloem mobility, whereas Metalaxyl a representative systemic fungicide. In order endow PCA with mobility and also enhance its antifungal activity, thirty-two acid-N-phenylalanine esters conjugates were designed synthesized by conjugating the active structure N-acylalanine methyl ester of Metalaxyl. All target compounds characterized 1H NMR, 13C NMR HRMS. evaluation results revealed that several exhibited moderate potent...

When reservoir heterogeneity is strong, there a great error between the calculated oil saturation based on J-function and actual interpreted by logging. Aimed at this problem, quality index proposed to classify average mercury curves, model original are established, experimental measurement numerical simulation with an illustration of oilfield in Pearl River Mouth Basin. The method accords closely that logging, it reliable show properties strongly heterogeneous reservoirs. In addition, paper...

Abstract The development of water drive gas reservoirs (WDGRs) with fractures or strong heterogeneity is severely influenced by invasion. Accurately simulating the rules invasion and drainage recovery countermeasures in fractured WDGRs, thereby revealing mechanism an appropriate strategy, important for formulating management measures enhancing reservoirs. In this work, physical simulation methods were proposed to gain a better understanding optimize control WDGRs. Five groups experiments...

Aiming at the separation of mud and sand in natural gas hydrate, for designed built-in twisted tape hydrocyclone, numerical simulation method was used to study effects different types operating conditions on internal flow field efficiency, influence hydrate particle size distribution. The research results show that has same swirling direction as which is beneficial improving intensity, ability carry separate solid particles obviously enhanced. hydrocyclone with a length 300 mm better...

Abstract Traditional porous media imbibition models deviate from the actual process in oil and gas reservoirs. Experimental studies on gas–water reservoirs were carried out to describe dynamic profile variation of wet phase saturation further reveal front amount. Optimization correction methods established, experimental verifications performed. Studies have shown following: (1) Unlike homogeneous media, water is more complicated, it impossible for maximum reach 100%. (2) Contrary theoretical...

The relationship between fracture calcite veins and shale gas enrichment in the deep Ordovician Wufeng Formation–Silurian Longmaxi Formation (Wufeng–Longmaxi) shales southern Sichuan Basin was investigated through core thin section observations, cathodoluminescence analysis, isotopic geochemistry fluid inclusion testing, basin simulation. Tectonic mainly undulating part of structure non-tectonic are formed gentle structure. latter, induced by hydrocarbon generation, occurred at stage peak...

Abstract The remoteness and isolation of hadal zone environments make this region inner space a particularly fertile field for scientific inquiry. After the successful development 7,000-m class deep manned submersible Jiaolong, Chinese government scientists have recognized necessity to develop submergence vehicles up 11,000 m depth. In paper, unique journey Challenger Deep is described. whole project construct movable laboratory that includes mothership, three full ocean depth landers,...

The varying law of on-way water saturation in the depletion-drive development (the formation pressure: 20 MPa depleting to abandonment pressure) water-bearing gas reservoirs was studied through four groups cores whose physical properties represent rocks Sichuan Xujiahe reservoirs, and permeability are 1.630×10−3 μm2, 0.580×10−3 0.175×10−3 0.063×10−3 respectively. Combined with rock characteristics microscopic pore structure capillary pressure, interaction mechanism between different...

Seasonal delta is a sandy fan-shaped sedimentary system formed by seasonal river flooding in continental basins. Modern finds that deltas mainly develop an arid-semi-arid climate environment with gentle terrain. However, the study of ancient rock records still insufficient, leading to misinterpretations as other systems, which poses challenges correct understanding origin and spatial distribution sand body deposits. In this study, red bed deposits Cretaceous Baxigai Formation west Tabei...

For fractured gas reservoirs with strong water drive, phase trapping affects the recovery significantly. The may be less than 50% for some while it is only 12% Beaver River field. mechanism has been revealed by results of depletion experimental test. residual pressure trapped as high 11.75 MPa a 12.8 cm imbibition layer resulting in deceased 49.5% compared that without layer. A mathematical model built to calculate thickness based on capillary and relative permeability matrix. are analyzed...