Alain Pierre TchameniLv-Yan ZhuoLesly Dasilva Wandji DjouonkepRobert Dery Nagre...
1190-1210页
查看更多>>摘要：Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs).However,their inhibitory prop-erties have not been very effective in high-temperature drilling operations.Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials,which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization.This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions.A novel thermo-responsive Janus nanosilica(TRJS)exhibiting zwitterionic character was synthesized,characterized,and assessed as shale stabilizer for WBDFs at high temperatures.Compared to pristine nanosilica(SiNP)and symmetrical thermo-responsive nanosilica(TRS),TRJS exhibited anti-polyelectrolyte behaviour,in which electrolyte ions screened the electrostatic attraction between the charged particles,potentially stabilizing nanomaterial in hostile shaly environments(i.e.,up to saturated brine or API brine).Macro-scopically,TRJS exhibited higher chemical inhibition than SiNP and TRS in brine,prompting a better capability to control pressure penetration.TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding,and the interactions became substantial in brine,according to the results of elec-trophoretic mobility,surface wettability,and X-ray diffraction.Thus,contributing to the firm trapping of TRJS into the nanopore structure of the shale,triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere.The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190 ℃,implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments.
查看更多>>摘要：Sustained casing pressure(SCP)is a crucial issue in the oil and gas production lifecycle.Epoxy resins,exhibiting exceptional compressive strength,ductility,and shear bonding strength,have the potential to form reliable barriers.The injectivity and sealing capacity of the epoxy resin is crucial parameters for the success of shallow remediation operations.This study aimed to develop and assess a novel solid-free resin sealant as an alternative to Portland cement for mitigating fluid leakage.The investigation evalu-ated the viscosity,compressive strength,and brittleness index of the epoxy resin sealant,as well as its tangential and normal shear strengths in conjunction with casing steel.The flow characteristics and sealing abilities of conventional cement and epoxy resin were comparatively analyzed in cracks.The results showed that the application of a viscosity reducer facilitated control over the curing time of the epoxy resin,ranging from 1.5 to 6 h,and reduced the initial viscosity from 865.53 to 118.71 mPa·s.The mechanical properties of the epoxy resin initially increased with a rise in curing agent content before experiencing a minor decrease.The epoxy resin containing 30％curing agent exhibited optimal me-chanical properties.After a 14-day curing period,the epoxy resin's compressive strength reached 81.37 MPa,2.12 times higher than that of cement,whereas the elastic modulus of cement was 2.99 times greater than that of the epoxy resin.The brittleness index of epoxy resin is only 3.42,demonstrating high flexibility and toughness.The tangential and normal shear strengths of the epoxy resin exceeded those of cement by 3.17 and 2.82 times,respectively.In a 0.5 mm-wide crack,the injection pressure of the epoxy resin remained below 0.075 MPa,indicating superior injection and flow capabilities.Conversely,the injection pressure of cement surged dramatically to 2.61 MPa within 5 min.The breakthrough pressure of 0.5 PV epoxy resin reached 7.53 MPa,decreasing the crack's permeability to 0.02 D,a mere 9.49％of the permeability observed following cement plugging.Upon sealing a 2 mm-wide crack using epoxy resin,the maximum breakthrough pressure attained 5.47 MPa,3.48 times of cement.These results suggest that epoxy resin sealant can be employed safely and effectively to seal cracks in the cement.
查看更多>>摘要：The perforating phase leads to complex and diverse hydraulic fracture propagation behaviors in lami-nated shale formations.In this paper,a 2D high-speed imaging scheme which can capture the interaction between perforating phase and natural shale bedding planes was proposed.The phase field method was used to simulate the same conditions as in the experiment for verification and hydraulic fracture propagation mechanism under the competition of perforating phase and bedding planes was discussed.The results indicate that the bedding planes appear to be no influence on fracture propagation while the perforating phase is perpendicular to the bedding planes,and the fracture propagates along the perfo-rating phase without deflection.When the perforating phase algins with the bedding planes,the fracture initiation pressure reserves the lowest value,and no deflection occurs during fracture propagation.When the perforating phase is the angle 45°,60° and 75° of bedding planes,the bedding planes begin to play a key role on the fracture deflection.The maximum deflection degree is reached at the perforating phase of 75°.Numerical simulation provides evidence that the existence of shale bedding planes is not exactly equivalent to anisotropy for fracture propagation and the difference of mechanical properties between different shale layers is the fundamental reason for fracture deflection.The findings help to understand the intrinsic characteristics of shale and provide a theoretical basis for the optimization design of field perforation parameters.
查看更多>>摘要：The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing.In this paper,the fracture mechanism of hollow particles in cement sheath was firstly analyzed by discrete element method,and the effect of hollow particles in cement on casing deformation was investigated by labo-ratory experiment method.Finally,field test was carried out to verify the improvement effect of the casing deformation based on cement slurry modification.The results show that the formation displacement can be absorbed effectively by hollow particles inside the cement transferring the exces-sive deformation away from casing.The particles in the uncemented state provide deformation space during formation slipping.The casing with diameter of 139.7 mm could be passed through by bridge plug with the diameter of 99 mm when the mass ratio of particle/cement reaches 1∶4.According to the field test feedback,the method based on optimization of cement slurry can effectively reduce the risk of casing deformation,and the recommended range of hollow microbeads content in the cement slurry is between 15％and 25％.
查看更多>>摘要：Due to the complexity and variability of carbonate formation leakage zones,lost circulation prediction and control is one of the major challenges of carbonate drilling.It raises well-control risks and pro-duction expenses.This research utilizes the H oilfield as an example,employs seismic features to analyze mud loss prediction,and produces a complete set of pre-drilling mud loss prediction solutions.Firstly,16 seismic attributes are calculated based on the post-stack seismic data,and the mud loss rate per unit footage is specified.The sample set is constructed by extracting each attribute from the seismic trace surrounding 15 typical wells,with a ratio of 8:2 between the training set and the test set.With the calibration results for mud loss rate per unit footage,the nonlinear mapping relationship between seismic attributes and mud loss rate per unit size is established using the mixed density network model.Then,the influence of the number of sub-Gausses and the uncertainty coefficient on the model's pre-diction is evaluated.Finally,the model is used in conjunction with downhole drilling conditions to assess the risk of mud loss in various layers and along the wellbore trajectory.The study demonstrates that the mean relative errors of the model for training data and test data are 6.9％and 7.5％,respectively,and that R2 is 90％and 88％,respectively,for training data and test data.The accuracy and efficacy of mud loss prediction may be greatly enhanced by combining 16 seismic attributes with the mud loss rate per unit footage and applying machine learning methods.The mud loss prediction model based on the MDN model can not only predict the mud loss rate but also objectively evaluate the prediction based on the quality of the data and the model.
查看更多>>摘要：During the production period of shale gas,proppant particles and rock debris are produced together,which will seriously erode the elbows of gathering pipelines.In response to this problem,this paper takes the elbow of the gathering pipeline in the Changning Shale Gas Field as an example to test the erosion rate and material removal mechanism of the test piece at different angles of the elbow through experiments and compares the four erosion models with the experimental results.Through analysis,it is found that the best prediction model for quartz sand-carbon steel erosion is the Oka model.Based on the Oka model,FLUENT software was used to simulate and analyze the law of erosion of the elbow of the gas gathering pipeline under different gas flow velocities,gas gathering pressure,particle size,length of L1,and bending directions of the elbow.And a spiral pipeline structure is proposed to reduce the erosion rate of the elbow under the same working conditions.The results show that this structure can reduce erosion by 34％.
查看更多>>摘要：The printed circuit heat exchanger(PCHE)is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process.In this paper,a PCHE straight channel in the length of 500 mm is established,with a semicircular cross section in a diameter of 1.2 mm.Numerical simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel.The pseudo-boiling theory is adopted and the liquid-like,two-phase-like,and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow features.The results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop.It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point.The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleate-boiling-like state and heat transfer deterioration related to a film-boiling-like state.The effects of pa-rameters,including mass flow rate,pressure,and wall heat flux on flow and heat transfer were analyzed.In calculating of the averaged heat transfer coefficient of the whole channel,the traditional method shows significant deviation and the micro segment weighted average method is adopted.The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux.The peak of the convective heat transfer coefficient can only form at high mass flux,low wall heat flux,and near critical pressure,in which condition the nucleate-boiling-like state is easier to appear.Moreover,heat transfer deterioration will always appear,since the supercritical flow will finally develop into a film-boiling-like state.So heat transfer deterioration should be taken seriously in the design and safe oper-ation of vaporizer PCHE.The study of this work clarified the local heat transfer and flow feature of su-percritical methane in microchannel and contributed to the deep understanding of supercritical methane flow of the vaporization process in PCHE.
查看更多>>摘要：Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir.By water coning,we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore.Autonomous inflow control device(AICD)is an important instru-ment maintain normal production after bottom water coning,however,the resistance increasing ability of the swirl type AICD is insufficient at present,which seriously affects the water control effect.Aiming this problem,this paper designs a multi-stage resistance-increasing and composite type AICD.The separation mechanism of oil-water two phases in this structure,the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed.Establishing the dual-phase multi-stage separation and resistance-increasing model,and verified by measuring the throttling pres-sure drop and oil-water volume fraction of the AICD,it is found that the composite type AICD has the effect of ICD and AICD at the same time,which can balance the production rate of each well section at the initial stage of production,delay the occurrence of bottom water coning.In the middle and later stages of production,water-blocking can be effectively increased to achieve water control and stable production.After structural sensitivity analysis,the influence law of various structural parameters on the water control performance of composite AICD was obtained.The simulation calculation results show that,compared with the existing swirl type AICD,composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average.The composite AICD is suitable for the entire stage of horizontal well production.
查看更多>>摘要：Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline.The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from.In the present study,a comprehensive evaluation of 24 prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser.Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2° to-5° to investigated the effect of the elbow on the frictional pressure drop in the riser.The inlet gas velocity ranges from 0.03 to 6.2 m/s,and liquid velocity varies from 0.02 to 1.3 m/s.A total of 885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations.Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging.The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.
查看更多>>摘要：Magnetic field and microorganisms are important factors influencing the stress corrosion cracking(SCC)of buried oil and gas pipelines.Once SCC occurs in buried pipelines,it will cause serious hazards to the soil environment.The SCC behavior of X80 pipeline steel under the magnetic field and sulfate-reducing bacteria(SRB)environment was investigated by immersion tests,electrochemical tests,and slow strain rate tensile(SSRT)tests.The results showed that the corrosion and SCC sensitivity of X80 steel decreased with increasing the magnetic field strength in the sterile environment.The SCC sensitivity was higher in the biotic environment inoculated with SRB,but it also decreased with increasing magnetic field strength,which was due to the magnetic field reduces microbial activity and promotes the formation of dense film layer.This work provided theoretical guidance on the prevention of SCC in pipeline steel under magnetic field and SRB coexistence.
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