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[en] In this paper it is proposed a method of acoustic pulses generation in a wellbore by means a plasma gun which located at the well mouth. Acoustic measurements results are presented. It is shown that the wellhead pressure affects on the amplitude and hydrodynamic pulse shape, on its attenuation and the impact intensity at the well bottom zone. It was determined the range of wellhead pressures at which a impulse force of wave reaches the highest values at the well bottom zone. It is shown that this method can favorably affect on the oil well productivity.
[en] In his recent comment on our previously published paper (Zhao et al 2013 J. Geophys. Eng. 10 035014), which outlined a mathematical model for the analysis of the pressure behavior of a horizontal well in naturally fractured low permeability reservoirs with a TPG (Lu 2014 J. Geophys. Eng. 11 038001) suggested that there were several errors in it. We thank the author for his careful review, and here we address his concerns. (reply)
[en] In a recent paper, we developed a physics-based data-driven model referred to as INSIM-FT and showed that it can be used for history matching and future reservoir performance predictions even when no prior geological model is available. The model requires no prior knowledge of petrophysical properties. In this work, we explore the possibility of using INSIM-FT in place of a reservoir simulation model when estimating the well controls that optimize water flooding performance where we use the net present value (NPV) of life-cycle production as our cost (objective) function. The well controls are either the flowing bottom-hole pressure (BHP) or total liquid rates at injectors and producers on the time intervals which represent the prescribed control steps. The optimal well controls that maximize NPV are estimated with an ensemble-based optimization algorithm using the history-matched INSIM-FT model as the forward model. We compare the optimal NPV obtained using INSIM-FT as the forward model with the estimate of the optimal NPV obtained using the correct full-scale reservoir simulation model when performing waterflooding optimization.
[en] Investigation of high-pressure extraneous gas on contour comb. band, spreading trichloroethylene steams are in given article. Increasing of extraneous gas pressure brings to decreasing free molecule circling time is shown
[en] Highlights: • Depressurization and thermal co-stimulation using horizontal well were proposed. • 3D stimulation showed that gas release rate was 3 × 105 m3 per day within 450 days. • 2D stimulation showed that Class 3 hydrates could be dissociated within 8500 days. • 2D Simulation showed that heat flow was 1620 W lasting 1500 days, and decreased fast. • 1.1× 105 kg water was collected within 2000 days and then no more water was produced. - Abstract: Class 3 hydrate reservoirs exploiting using horizontal well by depressurization and thermal co-stimulation was simulated using the HydarteResSim code. Results showed that more than 20% of hydrates in the reservoirs had been dissociated within 450 days at the well temperature of 42 °C and well pressure of 0.1P0, 0.2P0 (P0 is the initial pressure of the reservoirs, simplifying 42 °C and 0.1P0, 42 °C and 0.2P0). While the production behavior of 42 °C and 0.5P0, 42 °C and 0.8P0 were not so exciting. In order to understand the production character of the well in long term, the cross section of 1 m length reservoirs was simulated. Simulation results showed that 4.5 × 105 m3 gas would be collected within 4500 days and 1.1 × 106 kg water could be produced within 1500 days in the well at 42 °C and 0.1P0. 3.5 × 105 m3 gas would be collected within 8500 days and 1.1 × 106 kg water could be produced within 1500 days in the well at 42 °C and 0.2P0. The heat flow was 1620 W at the beginning and then decreased rapidly in the two cases. For reservoirs of 1495.2 m in length, about 6.7 × 108 m3 and 5.3 × 108 m3 gas would be collected in the well corresponding to conditions of 42 °C and 0.1P0, and 42 °C and 0.2P0
[en] This paper presents a mathematical model for the analysis of the transient pressure behaviour of a horizontal well in naturally fractured low permeability reservoirs, which takes the threshold pressure gradient (TPG) into consideration. Then, the solution of this model is obtained by using the method of Laplace transform and Fourier cosine transform, and the type curves are plotted by the Stehfest numerical inversion method. Pressure behaviour is analysed by examining the pressure drawdown curves, the derivative plots and the effect of the characteristic parameters. The typical pressure response of this reservoir is presented by the following five flow regimes: (1) wellbore storage and transition flow; (2) early radial flow in the vertical plane; (3) line flow in the horizontal plane; (4) matrix-fracture system transition flow; and (5) later pseudo-radial flow affected by the TPG. At the end, a field application manifests the correctness of the solutions derived in this paper, and the results have both theoretical and practical significance in predicting the production behaviour of carbonate reservoirs and evaluating fluid flow and transport in such a formation. (paper)
[en] Carbon dioxide (CO2) has been injected in the subsurface permeable formations as a means to cut atmospheric CO2 emissions and/or enhance oil recovery (EOR). It is important to constrain the boundaries of the CO2 plume in the target formation and/or other formations hosting the CO2 migrated from the target formation. Monitoring methods and technologies to assess the CO2 plume boundaries over time within a reservoir of interest are required. Previously introduced methods and technologies on pressure monitoring to detect the extent of the CO2 plume require at least two wells, i.e. pulser and observation wells. We introduce pressure transient technique requiring single well only. Single well pressure transient testing (drawdown/buildup/injection/falloff) is widely used to determine reservoir properties and wellbore conditions. Pressure diagnostic plots are used to identify different flow regimes and determine the reservoir/well characteristics. We propose a method to determine the plume extent for a constant rate pressure transient test at a single well outside the CO2 plume. Due to the significant contrast between mobility and storativity of the CO2 and native fluids (oil or brine), the CO2 boundary causes deviation in the pressure diagnostic response from that corresponding to previously identified heterogeneities. Using the superposition principle, we develop a relationship between the deviation time and the plume boundary. We demonstrate the applicability of the proposed method using numerically generated synthetic data corresponding to homogeneous, heterogeneous, and anisotropic cases to evaluate its potential and limitations. We discuss ways to identify and overcome the potential limitations for application of the method in the field.
[en] Natural gas production from the dissociation of methane hydrate in a confined reservoir by a depressurizing downhole well was studied. The case that the well pressure was kept constant was treated, and two different linearization schemes in an axisymmetric configuration were used in the analysis. For different fixed well pressures and reservoir temperatures, approximate self similar solutions were obtained. Distributions of temperature, pressure and gas velocity field across the reservoir were evaluated. The distance of the decomposition front from the well and the natural gas production rate as functions of time were also computed. Time evolutions of the resulting profiles were presented in graphical forms, and their differences with the constant well output results were studied. It was shown that the gas production rate was a sensitive function of well pressure and reservoir temperature. The sensitivity of the results to the linearization scheme used was also studied
[en] The article 6 of the Law no. 2017-1839 from December 30, 2017 putting an end to the search for and to the exploitation of hydrocarbons, foresees that any mining stock owner concerned by liquid or gaseous hydrocarbons has to provide to the administrative authorities a report demonstrating the absence of utilization of forbidden well stimulation techniques (like hydraulic fracturing) in their activity. This document is a compilation of the 85 reports produced by the mining stock owners regarding the different areas concerned by a valid exploration permit or a production concession in continental France and its overseas territories