Intensification of gas production from fields with unstable reservoirs

The negative consequences of sand removal from the reservoir and methods of preventing the formation of sand plugs at the bottom of wells are indicated. According to the results of research on the well model, the minimum required gas velocities have been experimentally determined for the removal of sand particles of three different fractions. The optimal concentrations of foaming surface active substances (surfactants) and stabilizers in aqueous solutions have been chosen in order to obtain stable foam for sand plugs flushing on the wells. There has been experimentally set the velocity of the foam with the addition and without the addition of a foam stabilizer for the transfer of solid particles from the well. Two compositions of foaming surfactants and stabilizers have been developed, one of which is proposed for sand plugs flushing at the bottom of the well, and the other – for dosed injection into the annulus of the well to prevent accumulation of the solid phase at the bottom.Theoretical studies have substantiated the choice of the well bore diameter in the gas-bearing formation zone depending on the well productivity and determined the optimal values of the thickness and permeability of the gravel pack in the bottom hole zone of the well with unstable reservoirs, which prevent sand from passing the formation to the well. Theoretical studies have substantiated a rational correlation of diameters of tubing, columns of flexible pipes and the flow rate of the flushing agent for washing the sand plug in the wells with various flushing agents. The composition of the slurry solution has been chosen to create a cement stone with high values of strength and permeability in the bottomhole formation zone. To increase the efficiency and reduce the time and costs there has been proposed a device for the destruction of sand plugs, which consists of a housing with a check valve. A patent-protected design of the device for repairing the lower part of the production casing, damaged as a result of erosion destruction by particles of formation sand, has been proposed. An improved technology for improving the productivity of gas wells with unstable reservoirs has been offered.

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Study of Gas Wells Operation Regimes in Complicated Conditions

Недропользование ◽

10.15593/2712-8008/2021.1.6 ◽

2021 ◽

Vol 21 (1) ◽

pp. 36-41

Author(s):

Maksim A. Popov ◽

◽

Dmitriy G. Petrakov ◽

Keyword(s):

Gas Production ◽

Point Of View ◽

Reservoir Rock ◽

Rock Properties ◽

Internal Stresses ◽

Negative Consequences ◽

Sand Production ◽

Gas Wells ◽

Initial State ◽

Formation Zone

The influence of reservoir rock properties on sand production in wells is considered. It was concluded that the rock should be considered rather not from the point of view of its strength, but from the point of view of the type of cementitious substance and its distribution. When predicting sand production, it is necessary to take into account the internal stresses of the rocks, as well as the change in these stresses during drilling, perforation and operation of the formation due to the violation of their initial state. Within the framework of this work, an analysis of the main causes of sand production during the operation of gas wells and the negative consequences of sand production for gas production equipment is presented. It has been established that water breakthrough, formation depletion, pressure drop at the bottom of the wells due to their frequent shutdown are the main prerequisites for the removal of sand from the bottomhole formation zone. Sand production is associated with such negative consequences as plugging in wells, erosion of underground and surface equipment, collapse of the top of the bottomhole formation zone and production strings. The main technologies for the prevention and elimination of accidents associated with the removal of mechanical particles from the reservoir are considered. Based on the research results, an algorithm was proposed for selecting technological modes of well operation in conditions of water and sand. The parameters for choosing the optimal operating mode of a gas well are substantiated, in which sand is not extracted with the subsequent disabling of downhole and wellhead equipment, the integrity of the bottomhole zone is not violated, and the well is not selfcontained. The results obtained can be applied to improve the efficiency of gas wells operation and predict their trouble-free operation.

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Comparative Study on Compositions of Oil-Water Transition Layer before and after ClO2-Treatment Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.749 ◽

2013 ◽

Vol 652-654 ◽

pp. 749-752

Author(s):

Dan Dan Yuan ◽

Hong Jun Wu ◽

Hai Xia Sheng ◽

Xin Sui ◽

Bao Hui Wang

Keyword(s):

Chemical Composition ◽

Transition Layer ◽

Solid Phase ◽

Settling Tank ◽

Physical Structure ◽

Solid Particles ◽

Viscosity Reduction ◽

Insoluble Residue ◽

Before And After ◽

Oil Water

In order to meet the need of separating oil from water in the settling tank of the oilfield, ClO2 treatment for oil-water transition layer in settling tank is introduced. The field test displayed that the technique was achieved by a good performance. For understanding the oxidation and mechanism, compositions of oil-water transition layer were comparatively studied for before/after ClO2-treatment in this paper.The experimental results show that the compositions before and after ClO2-treatment, including physical structure and chemical composition, were varied in the great extension. The physical structure, consisting of water, oil and solid phase, was reduced to less than 5% of water and 0.5% of solid particle and increased to 95% of oil in layer compared with before-treatment, easily leading to clearly separating water from oil. The chemical composition of iron sulfide and acid insoluble substance in solid phase was decreased to more than 90% while the carbonate was reduced more than 70% . After the treatment, the viscosity reduction of the water phase in the layer was reached to 50% after oxidation demulsification with ClO2. The chemistry was discussed based on the principles and experiments. Due to ClO2 destroying (oxidizing) the rigid interface membrane structure which is supported by natural surfactant, polymer and solid particles with interface-active materials, the action accelerates the separating of water and oil and sedimentation of insoluble residue of acid in the layer. By demonstrating the experimental data and discussion, we can effectively control the oxidation performance of chlorine dioxide, which is very meaningful for oilfield on the aspect of stable production of petroleum.

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Effect of 2CaO·SiO2 particles addition on dephosphorization behavior

High Temperature Materials and Processes ◽

10.1515/htmp-2020-0066 ◽

2020 ◽

Vol 39 (1) ◽

pp. 219-227

Author(s):

Aijun Deng ◽

Yunjin Xia ◽

Jie Li ◽

Dingdong Fan

Keyword(s):

Liquid Slag ◽

Solid Phase ◽

Solid Particles ◽

Hot Metal ◽

Liquid Silicate ◽

Phase Complex ◽

Dephosphorization Slag ◽

Stage 1 ◽

Two Stages ◽

Complex Liquid

AbstractThe effect of the addition of 2CaO·SiO2 solid particles on dephosphorization behavior in carbon-saturated hot metal was investigated. The research results showed that the addition of 2CaO·SiO2 particles have little influence on desilication and demanganization, and the removal of [Si] and [Mn] occurred in the first 5 min with different conditions where the contents of 2CaO·SiO2 particles addition for the conditions 1, 2, 3, 4, and 5 are 0, 2.2, 6.4, 8.6, and 13.0 g, respectively. The final dephosphorization ratios for the conditions 1, 2, 3, 4, and 5 are 61.2%, 66.9%, 79.6%, 63.0%, and 78.1%, respectively. The dephosphorization ratio decreases with the increase of 2CaO·SiO2 particles in the first 3 min. The reason for this is that the dephosphorization process between hot metal and slag containing C2S phase consisted of two stages: Stage 1, [P] transfers from hot metal to liquid slag and Stage 2, the dephosphorization production (3CaO·P2O5) in liquid slag reacts with 2CaO·SiO2 to form C2S–C3P solid solution. The increase of 2CaO·SiO2 particles increases the viscosity of slag and weakens the dephosphorization ability of the stage 1. The SEM and XRD analyses show that the phase of dephosphorization slag with the addition of different 2CaO·SiO2 particles is composed of white RO phase, complex liquid silicate phase, and black solid phase (C2S or C2S–C3P). Because the contents of C2S–C3P and 2CaO·SiO2 in slag and the dephosphorization ability of the two stages are different, the dephosphorization ability with different conditions is different.

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The Effect of Opal-Containing Rocks on the Properties of Lightweight Oil-Well Cement

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.325.47 ◽

2021 ◽

Vol 325 ◽

pp. 47-52

Author(s):

Fedor L. Kapustin ◽

N.N. Bashkatov ◽

Rudolf Hela

Keyword(s):

Flexural Strength ◽

Oil And Gas ◽

Gas Production ◽

Cement Stone ◽

Oil Well ◽

Cement Slurry ◽

Water Separation ◽

Oil And Gas Production ◽

Geological Conditions ◽

Cement Grinding

When constructing deep wells for oil and gas production in difficult geological conditions, special lightweight oil-well cements are used. To reduce the density and water separation of the cement slurry as well as to increase the strength, corrosion resistance of cement stone and the quality of well cementing, opal-containing rocks, fly ash, microsphere and other lightening additives are introduced into the cement composition. The influence of sedimentary rocks, such as opoka, tripoli, and diatomite containing from 43 to 81% amorphous silica on the grindability, rheological and physical-mechanical properties of lightweight oil-well Portland cement has been studied. The twelve cement compositions with different content of additives (from 30 to 45%) that meet the requirements of the standard for density, spreadability, water separation, thickening time and flexural strength were selected. The introduction of 45% diatomite or tripoli significantly reduces the duration of cement grinding, provides the cement slurry with water-cement ratio of 0.9 with better density and flexural strength, respectively, 1480 kg/m3 and 1.1–1.5 MPa.

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INFLUENCE OF MECHANOMAGNETIC ACTIVATION OF SOLUTIONS CaCl2 AND Na2S2O3 ON PHASE STRUCTURE OF CEMENT STONE

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20196212.6114 ◽

2019 ◽

Vol 62 (12) ◽

pp. 101-107

Author(s):

Tatyana E. Slizneva ◽

Marina V. Akulova ◽

Pavel B. Razgovorov

Keyword(s):

Solid Phase ◽

Tap Water ◽

Pore Space ◽

Control Sample ◽

Hydrodynamic Cavitation ◽

Cement Stone ◽

Cement Pastes ◽

Carbonate Ion ◽

Joint Influence ◽

Reactive Oxygen Forms

The mechanism of the joint influence of the magnetic field and hydrodynamic cavitation on the properties of CaCl2 and Na2S2O3 solutions used for mixing cement pastes is considered. Hydrodynamic cavitation leads to the formation of reactive oxygen forms, HCO3– anions, carbon dioxide nanobubbles, and initiates the interaction of new forms with impurity metal cations dissolved in water. After mechanomagnetic treatment of the solutions, particles of a solid phase with sizes of 5...10 and 10...100 nm were found in them. The observed increase in the ξ- potential indicates the stabilization of such dispersed systems with the preservation of nanoscale fractions in them (up to 3 days). At the same time, the progress of reactions under the conditions of tightness that occur after cement paste has been mixed. The effect of activating factors in tap water is more pronounced than in distilled water, which is explained by the process of hydration of the carbonate ion and the formation of fine nucleation centers. Using X-ray phase analysis, it was found that, along with calcite, aragonite crystallizes in the resulting cement stone, which is practically absent in the control sample. In addition, the analysis of diffraction patterns taken on the modified samples reveals the inclusion of a carbonate ion. Obviously, optimization of the pore space in the cement stone is achieved both by clogging the pores with fine calcium carbonate, and by forming small pores during crystallization of ettringite-like phases. It is established that the resulting cement stone is characterized by increased strength (by 9-30%) and frost resistance (up to 55%) compared to that obtained by the traditional method.

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Comparative Assessment of Turbulence Models for Prediction of Flow-Induced Corrosion Damages

ASME 2011 Pressure Vessels and Piping Conference: Volume 3 ◽

10.1115/pvp2011-57817 ◽

2011 ◽

Author(s):

Kaushik Das ◽

Debashis Basu ◽

Todd Mintz

Keyword(s):

Corrosion Rate ◽

Cross Sections ◽

Volume Fraction ◽

Solid Phase ◽

Turbulence Models ◽

Reynolds Stress Model ◽

Continuous Phase ◽

Comparative Assessment ◽

Solid Particles ◽

Protective Film

The present study makes a comparative assessment of different turbulence models in simulating the flow-assisted corrosion (FAC) process for pipes with noncircular cross sections and bends, features regularly encountered in heat exchangers and other pipeline networks. The case study investigates material damage due to corrosion caused by dissolved oxygen (O2) in a stainless steel pipe carrying an aqueous solution. A discrete solid phase is also present in the solution, but the transport of the solid particles is not explicitly modeled. It is assumed that the volume fraction of the solid phase is low, so it does not affect the continuous phase. Traditional two-equation models are compared, such as isotropic eddy viscosity, standard k-ε and k-ω models, shear stress transport (SST) k-ω models, and the anisotropic Reynolds Stress Model (RSM). Computed axial and radial velocities, and turbulent kinetic energy profiles predicted by the turbulence models are compared with available experimental data. Results show that all the turbulence models provide comparable results, though the RSM model provided better predictions in certain locations. The convective and diffusive motion of dissolved O2 is calculated by solving the species transport equations. The study assumes that solid particle impingement on the pipe wall will completely remove the protective film formed by corrosion products. It is also assumed that the rate of corrosion is controlled by diffusion of O2 through the mass transfer boundary layer. Based on these assumptions, corrosion rate is calculated at the internal pipe walls. Results indicate that the predicted O2 corrosion rate along the walls varies for different turbulence models but show the same general trend and pattern.

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A numerical study of the nucleation, growth and settling of crystals from a turbulent convecting fluid

10.5194/egusphere-egu21-14371 ◽

2021 ◽

Author(s):

Vojtech Patocka ◽

Nicola Tosi ◽

Enrico Calzavarini

Keyword(s):

Magma Chamber ◽

Solid Fraction ◽

Large Scale ◽

Solid Phase ◽

Numerical Study ◽

Equilibrium Concentration ◽

Solid Particles ◽

Settling Rate ◽

Carrier Fluid ◽

Nucleation Growth

We evaluate the equilibrium concentration of a thermally convecting suspension that is cooled from above and in which solid crystals are self-consistently generated in the thermal boundary layer near the top. In a previous study (Patoc&#780;ka et al., 2020), we investigated the settling rate of solid particles suspended in a highly vigorous (Ra = 108 , 1010, and 1012 ), finite Prandtl number (Pr = 10, 50) convection. In this follow-up study we additionally employ the model of crystal generation and growth of Jarvis and Woods (1994), instead of using particles with a predefined size and density that are uniformly injected into the carrier fluid.We perform a series of numerical experiments of particle-laden thermal convection in 2D and 3D Cartesian geometry using the freely available code CH4 (Calzavarini, 2019). Starting from a purely liquid phase, the solid fraction gradually grows until an equilibrium is reached in which the generation of the solid phase balances the loss of crystals due to sedimentation at the bottom of the fluid. For a range of predefined density contrasts of the solid phase with respect to the density of the fluid (&#961;p /&#961;f = [0, 2]), we measure the time it takes to reach such equilibrium. Both this time and the equilibrium concentration depend on the average settling rate of the particles and are thus non-trival to compute for particle types that interact with the large-scale circulation of the fluid (see Patoc&#780;ka et al., 2020).We apply our results to the cooling of a large volume of magma, spanning from a large magma chamber up to a global magma ocean. Preliminary results indicate that, as long as particle re-entrainment is not a dominant process, the separation of crystals from the fluid is an efficient process. Fractional crystallization is thus expected and the suspended solid fraction is typically small, prohibiting phenomena in which the feedback of crystals on the fluid begins to govern the physics of the system (e.g. Sparks et al, 1993).References Patoc&#780;ka V., Calzavarini E., and Tosi N.(2020). Settling of inertial particles in turbulent Rayleigh-Be&#769;nard convection. Physical Review Fluids, 26(4) 883-889.Jarvis, R. A. and Woods, A. W.(1994). The nucleation, growth and settling of crystals from a turbulently convecting fluid. J. Fluid. Mech, 273 83-107.Sparks, R., Huppert, H., Koyaguchi, T. et al (1993). Origin of modal and rhythmic igneous layering by sedimentation in a convecting magma chamber. Nature, 361, 246-249.Calzavarini, E (2019). Eulerian&#8211;Lagrangian fluid dynamics platform: The ch4-project. Software Impacts, 1, 100002.

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Whistling of Pipes With Narrow Corrugations: Scale Model Tests and Consequences for Carcass Design

Volume 4B: Pipeline and Riser Technology ◽

10.1115/omae2013-10813 ◽

2013 ◽

Author(s):

Joachim Golliard ◽

Stefan Belfroid ◽

Erik Bendiksen ◽

Casper Frimodt

Keyword(s):

Prediction Model ◽

Gas Production ◽

Scale Model ◽

Small Scale ◽

Operational Conditions ◽

Flexible Pipes ◽

Cavity Opening ◽

Flexible Risers ◽

Onset Velocity ◽

Operational Envelope

Pipes for gas production and transport with a corrugated inner surface, as used in flexible pipes, can be subject to Flow-Induced Pulsations when the flow velocity is larger than a certain velocity. This onset velocity is dependent on the geometry of the corrugations, the operational conditions and the geometry of the topside and subsea piping. In this paper, small-scale tests performed on corrugated tubes are reported. The tested geometries include both “classical” profiles, similar to the inner profile of agraff flexible risers, and profiles with less typical variations, such as narrower and/or deeper cavities, or irregular pitch. These tests were performed in order to evaluate the validity of a prediction model developed earlier for the onset of pulsations, for corrugated pipes with these kinds of atypical variations, which are found on a new type of carcass designs. The mechanism of Flow-Induced Pulsations in corrugated pipes is discussed, as well as the principle of the prediction model. The experimental results show that the validity of the model remains reasonable in most cases, except when the cavities are very narrow. In this case, the model becomes overly conservative. This limitation can be attributed to the fact that, for very narrow cavities, the cavity opening becomes too small compared to the boundary-layer momentum thickness, effectively destroying any instability of the shear layer. Furthermore, the shift towards higher frequencies of the acoustic source term due to narrower cavities, and the possible coupling with higher acoustic modes, is considered. The results of the analysis are used to evaluate the onset velocity and whistling behavior of a newly developed carcass design of flexible risers. A previous analysis has indicated that the particular geometry profile of the new design improves the whistling behavior by pushing the onset velocity outside the typical operational envelope of flexible risers. The analysis confirms that the new design will be less prone to whistling than flexible risers with classical agraff carcasses.

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Scale-Up of Solid-Liquid Mixing Based on Constant Power/Volume and Equal Blend Time Using VisiMix Simulation

MATEC Web of Conferences ◽

10.1051/matecconf/201818704002 ◽

2018 ◽

Vol 187 ◽

pp. 04002

Author(s):

Megawati ◽

Bayu Triwibowo ◽

Karwono ◽

Waliyuddin Sammadikun ◽

Rofiatun Musfiroh

Keyword(s):

Solid Phase ◽

Scale Up ◽

Solid Particles ◽

Liquid Mixing ◽

Liquid Suspension ◽

Two Parameters ◽

Solid Liquid ◽

Tank Geometry ◽

Impeller Geometry

Mixing is one of the important process in many areas of chemical industries, for instance pharmaceutical, drug, ink, paint and other industries. Solid-liquid suspension is produced for 80% of all mixing industries such as leaching process, crystallization process, catalytic reactions, precipitation, coagulation, dissolution and other applications. Two main objectives in solid-liquid mixing namely, avoid settling of solid particles on the tank bottom and ensure the solid particles are uniformly distributed. Many factors that can affect the quality of solid-liquid mixing, they are tank geometry, impeller geometry and speed, baffles, viscosity and density of media. Scale-up of the process is important to conduct before produce it on commercial scale. Two parameters for scale-up solid-liquid mixing are equal blend time and power per volume. Before scaling up the process to industrial scale, an engineer must know the condition of the mixture between both of two. VisiMix can simulating scale-up of solid-liquid mixing in order to know the phenomena inside the tank without conducting a large number of experiments and cheaper. The simulation start from keep the ratio of impeller to tank diameter remains constant, then change the condition operation of mixing. In this paper, power per volume parameter is more recommended as a result of the degree of uniformity of solid phase in liquid.

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Enskog kinetic theory for monodisperse gas–solid flows

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.404 ◽

2012 ◽

Vol 712 ◽

pp. 129-168 ◽

Cited By ~ 68

Author(s):

V. Garzó ◽

S. Tenneti ◽

S. Subramaniam ◽

C. M. Hrenya

Keyword(s):

Reynolds Number ◽

Kinetic Theory ◽

Gas Phase ◽

Parameter Space ◽

Shear Viscosity ◽

Solid Phase ◽

Constitutive Relations ◽

Solid Particles ◽

Analytical Treatment ◽

Starting Point

AbstractThe Enskog kinetic theory is used as a starting point to model a suspension of solid particles in a viscous gas. Unlike previous efforts for similar suspensions, the gas-phase contribution to the instantaneous particle acceleration appearing in the Enskog equation is modelled using a Langevin equation, which can be applied to a wide parameter space (e.g. high Reynolds number). Attention here is limited to low Reynolds number flow, however, in order to assess the influence of the gas phase on the constitutive relations, which was assumed to be negligible in a previous analytical treatment. The Chapman–Enskog method is used to derive the constitutive relations needed for the conservation of mass, momentum and granular energy. The results indicate that the Langevin model for instantaneous gas–solid force matches the form of the previous analytical treatment, indicating the promise of this method for regions of the parameter space outside of those attainable by analytical methods (e.g. higher Reynolds number). The results also indicate that the effect of the gas phase on the constitutive relations for the solid-phase shear viscosity and Dufour coefficient is non-negligible, particularly in relatively dilute systems. Moreover, unlike their granular (no gas phase) counterparts, the shear viscosity in gas–solid systems is found to be zero in the dilute limit and the Dufour coefficient is found to be non-zero in the elastic limit.

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