In view of reservoirs with low pressure, medium porosity, and permeability in Changqing Oilfield, along the "double high stage" middle late development featuring a sharp rise water cut comprehensive flooding recovery rate, study composite surfactant system was conducted. It is found that there synergistic effect between dodecyl hydroxypropyl sulfobetaine (HPSB) naphthenic petroleum sulfonate (NPS). When ratio HPSB to NPS 8:2, best interfacial activity exhibited formation target block, which...

In order to investigate energy supply capacity and oil production contribution of near-fracture fracture-free zone in fractured tight reservoirs, a series CO2 huff-and-puff tests were designed carried out different experimental conditions. A fracture-matrix long-core system was established simulate the matrix reservoirs. The NMR technique utilized identify microscopic remaining certain core samples. effects fracture length, soaking time, depressurization method, asphaltene precipitation on...

Aiming at the low efficiency of heavy-oil thermal recovery, a downhole multi-thermal fluid generator (DMTFG) can improve viscosity reduction effect by reducing heat loss in process wellbore transportation. The steam generated MDTFG causes damage to packer and casing, owing return upwards along annular space passage oil casing. To mitigate this damage, transfer model for multi-channel coiled tubing wells prediction upward temperature field annulus were established with basic laws...

Abstract One of the important research directions shale gas is its adsorption mechanism. The focus current work to describe micro-storage state and select accurate model. Micro-storage under different thermal maturity described from perspective accumulation. In organic pores, methane molecules behave as competitive with water molecules. Inorganic pores are surrounded by or movable water, in which only a few amounts dissolved. Based on simplified local-density (SLD) model, mechanism pore size...

Abstract To evaluate the exploration potential of tight oil reservoirs in Upper Triassic Yanchang Formation, a combined research was done to investigate source rock distribution, diagensis, pore systems, petrophysical parameters. begin with, horizontal distribution and vertical thickness reservoir were clarified with data from well drilling regional geological background. After that, X-ray diffraction scanning electron microscopy experiments conducted study types morphologies. Then size...

The effective displacement of the shale oil from organic nanopores plays a significant role in development reservoirs. In order to deeply understand microscopic mechanism alkane by CO2 nanopores, pore model matter and molecular n-dodecane were established investigate influences key parameters on process using Monte Carlo dynamics simulation method. instantaneous adsorption molecules demonstrates that are proportional increase injection pressure as well size. addition, results also show...

The stress and adsorption motivation deformation during shale oil production directly affect its development dynamics. First, a mathematical simulation of pore in under is established. We analyzed the impact factors including reservoir pressure, Biot coefficient, bulk modulus, tortuosity on characteristics nanopores. Second, model multifactor synergistic effect derived by combining molecular dynamics, which takes into account influence total reservoir. Finally, obtained. results show that...

Abstract Due to the confinement effect of nanopores, fluid-phase behavior shale oil reservoirs is much different from that conventional reservoirs. The accurate description phase change characteristics fluid in nanopores basis design development plan, production system, and EOR methods In this study, molecular dynamics simulation was employed analyze single-component system hydrocarbon–CO 2 mixture organic nanopores. results show on pressure influenced by distribution electron cloud....

CO2 injection has been proven to be an effective method improve oil recovery of tight reservoirs. soaking and flooding are common processes used constitute some patterns. To investigate the difference performance asphaltene precipitation distribution between processes, tests under immiscible miscible conditions were carried out with core samples. Then NMR technique was utilized analyze microscopic remaining after each test. The results indicated that in small pores less than 0.6 μm more...

Abstract The dynamic kill process is divided into two stages: “dynamic pressure stability” and “static stage in this paper. In stability stage, sea water fluid was pumped the well initial killing fluid; Then pump weight liquid by quantified displacement based on that can achieve complete effect, control kick effectively to drill efficiency. paper, multiphase multicomponent staged equation established considering effect of shallow flow gas influx, meanwhile, it adopts auxiliary equations such...

Coring experiments show that nanopores are extensively distributed in shale oil reservoirs and tend to be deformed when a significant pressure variation exists, thus the dynamic capillary force phenomenon flow mechanisms can significantly changed. To characterize two-phase influenced by synergistic effect of microcosmic pore deformation force, models based on Gassmann’s theory established describe variations radius roughness field. And then, innovative methods quantify under comprehensive...

Refracturing treatment is widely used to enhance the well productivity in shale gas reservoirs, particularly for initially fractured wells with low productivity. The principal of this work based on transient behavior pressure and rate a vertically refractured reservoir, considering fracture reorientation adsorption desorption property. Based point-source theory Laplace transform, semi-analytical solution obtained by coupling reservoir artificial fractures. validation new carried out smoothly...

In the process of long-term water flooding in Gaoqian Southern Area with an average porosity 30% and permeability <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"><mn>1333.5</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></math> μm2, fluid-solid interaction among oil, water, rock has a great influence on pore structure. It resulted changes reservoir parameters extension time. This paper used electron microscopy scanning, mercury injection, X-ray...

Multi-component thermal luid technology optimizes development effects and has a strong adaptability, providing new choice for the efficient of heavy oil reservoirs. However, due to significant differences between phase behavior multi-component thermal-fluid-heavy systems conventional systems, lack targeted large-scale research, key issues such as these are unclear. This research studies influencing factors emulsions foamy in system through high-temperature high-pressure PVT experiments,...

Summary Due to the low porosity and permeability of shale matrix, multi-fractured horizontal well (MFHW) is one most well-known technologies promote withdrawal oil. It a great challenge characterize flow behavior by coupling pre-Darcy in pores matrix Darcy inside fractures, particularly radial composite reservoir with stimulated volume (SRV). Because semi-analytical method can contribute revealing mechanism MFHW, approach efficiently obtain suitable exact solution becomes key issue. In this...

Refracturing treatment is an economical way to improve the productivity of poorly or damaged fractured horizontal wells in tight reservoirs. Fracture reorientation and fracture face damage may occur during refracturing treatment. At present, there still no report on rate decline solution for refractured In this work, by taking a semi-analytical method, traditional Blasingame-type solutions were derived well intercepted multiple fractures with anisotropic reservoir. The accuracy reliability...

The adsorption properties of shale oil are great significance to the development resources. This study is aimed at understanding microscopic mechanism in organic nanopores. Thus, a molecular model micropore walls and multicomponent fluids CO2, C4H10, C8H18, C12H26 constructed investigate pattern nanopores under different temperature pore size conditions. quantity heat simulated with Monte Carlo method, which has been used previous studies for single-or two-component fluids. results...