An adaptive physics-informed deep learning method for pore pressure prediction using seismic data

Accurate prediction of formation pore pressure is essential to predict fluid flow and manage hydrocarbon production in petroleum engineering.Recent deep learning technique has been receiving more interest due to the great potential to deal with pore pressure prediction.However,most of the traditional deep learning models are less efficient to address generalization problems.To fill this technical gap,in this work,we developed a new adaptive physics-informed deep learning model with high generalization capability to predict pore pressure values directly from seismic data.Specifically,the new model,named CGP-NN,consists of a novel parametric features extraction approach(1DCPP),a stacked multilayer gated recurrent model(multilayer GRU),and an adaptive physics-informed loss function.Through machine training,the developed model can automatically select the optimal physical model to constrain the results for each pore pressure prediction.The CGP-NN model has the best generalization when the physicsrelated metricλ=0.5.A hybrid approach combining Eaton and Bowers methods is also proposed to build machine-learnable labels for solving the problem of few labels.To validate the developed model and methodology,a case study on a complex reservoir in Tarim Basin was further performed to demonstrate the high accuracy on the pore pressure prediction of new wells along with the strong generalization ability.The adaptive physics-informed deep learning approach presented here has potential application in the prediction of pore pressures coupled with multiple genesis mechanisms using seismic data.

Prediction of Cuttings-Induced Annular-Pressure Loss in Extended-Reach Wells

Drill cuttings are broken bits of solid material removed from a borehole drilled by rotary,percussion,or auger methods and brought to the surface in the drilling mud.When these cuttings enter the annulus,they have an effect on the drillingfluid rheology and density,which is,in general,quite difficult to evaluate.By introducing an empirical correlation for the rheological properties of cuttings-laden drillingfluids,this study proposes a pres-sure-loss prediction method for an extended-reach well(ERW).After verifying the accuracy of this method,a case study is considered and a sensitivity analysis is conducted assuming a yield-power lawfluid.The results show that an increased concentration of cuttings in the annulus contributes to an increased annular pressure loss.Com-pared to their effect on the drillingfluid density,cuttings have a greater impact on the drillingfluid rheology.A larger rate of penetration contributes to an increased annular pressure loss.For higher drillingfluidflow rates,the annular pressure lossfirst decreases and then it increases.In addition,the annular pressure loss becomes high-er as the cuttings’particle size decreases and the cuttings’concentration grows.

Study on Horizontal Well Layout Boundary Considering Wellbore Pressure Loss

Based on the Dikken analytical calculation method of wellbore pressure loss under single-phase fluid and turbulent flow conditions, the correlation model between horizontal well output and horizontal section length and horizontal section distributed pressure difference is constructed. The influence degree of wellbore pressure loss on daily oil production of horizontal well, horizontal section pressure and production effect of horizontal well under different horizontal well lengths is analyzed, which provides certain reference for the design of horizontal well length and well layout.

EFFECT OF DUMP GAP ON TOTAL PRESSURE LOSS IN DUMP DIFFUSER

The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total pressure loss. Experiments and numerical simulations, keeping the inlet March number of prediffuser constant ( Ma =0 20), are carried out to obtain the regularity of the total pressure loss. It varies with the relative dump gap ( δ =1 2～3 0)by changing the position of prediffuser and combustor liner, respectively. Research shows that there exists the minimum total pressure loss ( σ *=1 6%～1 75%) when relative dump gap δ is about 1 8.

Controlled low central venous pressure reduces blood loss and transfusion requirements in hepatectomy

AIM: To evaluate the effect of low central venous pressure (LCVP) on blood loss and blood transfusion in patients undergoing hepatectomy.

Low central venous pressure reduces blood loss in hepatectomy

AIM： To investigate the effect of low central venous pressure （LCVP） on blood loss during hepatectomy for hepatocellular carcinoma （HCC）. METHODS： By the method of sealed envelope, 50 HCC patients were randomized into LCVP group （n=25） and control group （n=25）. In LCVP group, CVP was maintained at 2-4 mmHg and systolic blood pressure （SBP） above 90 mmHg by manipulation of the patient＇s posture and administration of drugs during hepatectomy, while in control group hepatectomy was performed routinely without lowering CVP. The patients＇ preoperative conditions, volume of blood loss during hepatectomy, volume of blood transfusion, length of hospital stay, changes in hepatic and renal functions were compared between the two groups. RESULTS： There were no significant differences in patients＇ preoperative conditions, maximal tumor dimension, pattern of hepatectomy, duration of vascular occlusion, operation time, weight of resected liver tissues, incidence of post-operative complications, hepatic and renal functions between the two groups. LCVP group had a markedly lower volume of total intraoperative blood loss and blood loss during hepatectomy than the control group, being 903.9 ± 180.8 mL vs 2 329.4 ±2 538.4 （W=495.5, P〈0.01） and 672.4±429.9 mL vs 1 662.6±1 932.1 （W=543.5, P〈0.01）. There were no remarkable differences in the pre-resection and post-resection blood losses between the two groups. The length of hospital stay was significantly shortened in LCVP group as compared with the control group, being 16.3±6.8 d vs 21.5 ± 8.6 d （W= 532.5, P〈0.05）.CONCLUSION： LCVP is easily achievable in technique. Maintenance of CVP ≤4 mmHg can help reduce blood loss during hepatectomy, shorten the length of hospital stay, and has no detrimental effects on hepatic or renal function.

Modified Pressure Loss Model for T-junctions of Engine Exhaust Manifold

The T-junction model of engine exhaust manifolds significantly influences the simulation precision of the pressure wave and mass flow rate in the intake and exhaust manifolds of diesel engines. Current studies have focused on constant pressure models, constant static pressure models and pressure loss models. However, low model precision is a common disadvantage when simulating engine exhaust manifolds, particularly for turbocharged systems. To study the performance of junction flow, a cold wind tunnel experiment with high velocities at the junction of a diesel exhaust manifold is performed, and the variation in the pressure loss in the T-junction under different flow conditions is obtained. Despite the trend of the calculated total pressure loss coefficient, which is obtained by using the original pressure loss model and is the same as that obtained from the experimental results, large differences exist between the calculated and experimental values. Furthermore, the deviation becomes larger as the flow velocity increases. By improving the Vazsonyi formula considering the flow velocity and introducing the distribution function, a modified pressure loss model is established, which is suitable for a higher velocity range. Then, the new model is adopted to solve one-dimensional, unsteady flow in a D6114 turbocharged diesel engine. The calculated values are compared with the measured data, and the result shows that the simulation accuracy of the pressure wave before the turbine is improved by 4.3% with the modified pressure loss model because gas compressibility is considered when the flow velocities are high. The research results provide valuable information for further junction flow research, particularly the correction of the boundary condition in one-dimensional simulation models.

Experimental investigation of particle-induced pressure loss in solid–liquid lifting pipe

In order to investigate the characteristics of particle-induced pressure loss in the solid–liquid lifting pipe,a series of experiments were conducted in 200 mm diameter lifting pipe.Simulation manganese nodules with five different mean diameters of10 mm,20 mm,30 mm,40 mm and 50 mm were used,both in isolation and a combination in equal fraction by mass.The flow velocities in the lifting pipe ranged from 0.12 m/s to 1.61 m/s,and the mass of particles employed was 10 kg for each particle diameter.Three regimes,wavy bed,partly fluidization,and fully fluidization,were observed over the flow velocity.The solid–liquid pressure drop data were measured by differential pressure transmitter,and pressure drop caused by the solid particles was calculated and analyzed.The results show that the evolutions of the pressure loss due to solid particles are relevant to the solid–liquid flow regimes,and they are distinctly influenced by fluid velocity and particle size.

COMPUTATIONAL FLUID DYNAMICS RESEARCH ON PRESSURE LOSS OF CROSS-FLOW PERFORATED MUFFLER

The pressure loss of cross-flow perforated of physical modeling, simulation and data processing. muffler has been computed with the procedure Three-dimensional computational fluid dynamics （CFD） has been used to investigate the relations of porosities, flow velocity and diameter of the holes with the pressure loss. Accordingly, some preliminary results have been obtained that pressure loss increases with porosity descent as nearly a hyperbolic trend, rising flow velocity of the input makes the pressure loss increasing with parabola trend, diameter of holes affects little about pressure loss of the muffler. Otherwise, the holes on the perforated pipes make the air flow gently and meanly, which decreases the air impact to the wall and pipes in the muffler. A practical perforated muffler is used to illustrate the available of this method for pressure loss computation, and the comparison shows that the computation results with the method of CFD has reference value for muffler design.

Numerical simulation investigation on pressure loss of diffusion tank of axial main fan

Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tank, numerical simulations of diffusion tank were done. The results of numerical simulations of diffusion tank are shown as follows： ③ In cases of the inlet velocity range from 25.0 m/s to 55.0 m/s, and the angle range of rectifying airflow unit from 2.5° to 7.5°, the average value of pressure losses decreases to the minimum when the angle is 4.5°.② In cases of the inlet velocity of 35.0 m/s, the pressure loss of diffusion tank decreases to the minimum when the angle of rectifying airflow unit is 5.5°. ③ As far as there are different angles of rectifying airflow unit, pressure loss increases gradually along with the addition of inlet velocity.

Evaluation of “C” Values to Head Loss and Water Pressure Due to Pipe Aging: Case Study of Uni-Central Sarawak

Samarahan has transformed from a small village into education hub for the past 2 decades. Rapid development and population growth had led to speedy growth in water demand. The situation is getting worse as the pipes are deteriorating due to pipe aging. Therefore, there is a need to study the adequacy of water supply and relationships among roughness coefficient (C) values in Hazen Williams’ Equation with head loss and water pressure due to pipe aging at Uni-Central, a residential area located at Samarahan Sarawak. Investigations were carried out with Ductile Iron, Abestos Cement and Cast Iron pipes at age categories of 0 - 10 years, 10 - 30 years, 30 - 50 years, 50 - 70 years and >70 years. Six critical nodes named as A, B, C, D, E and F were identified to study the water pressure and head loss. Model was developed with InfoWorks Water Supply (WS) Pro software. The impact of pipe aging and materials to water pressure and head loss was not significant at Nodes A, B, C and F. However, max water pressure at Nodes D and F were only reaching 6.30 m and 7.30 m, respectively for all investigations. Therefore, some improvement works are required. Results also show that Asbestos Cement pipe has the least impact on the head loss and water pressure, followed by Ductile Iron pipe and lastly Cast Iron pipe. Simulation results also revealed that older pipes have higher roughness coefficients, indicated with lower “C” values, thus increase the head loss and reduce the water pressure. In contrast, as “C” values increased, head loss will be reduced and water pressure will be increased.

Experimental study of a simple pressure loss coefficient model for multi-hole orifice

A throttling experiment for the multi-hole orifice （MO） using water was conducted based on the conclusion of key parameters affecting the MO throttling performance. Testing MOs and standard orifice plates （ SO ） were designed for the throttling experiment to compare the throttling effect using the equivalent diameter ratio （RED） and diameter ratio （RD ） as key parameters, respectively. Meanwhile, effective metrical conditions were provided for experimental accuracy. The throttling model form was determined according to the theoretical throttling model of SO. Then the unknown parameters involved were identified by experimental data. A good concordance between the modeling computation and experimental results shows a validation of the MO throtting model.

Association between Tooth Loss and Hypertension: A Systematic Review

Background: An independent relationship between tooth loss and hypertension appears to exist. Objectives: The aim of this study was to systematically review the relationship between tooth loss/number of teeth and hypertension. Materials and Methods: This review was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines. We searched all the relevant studies in international databases of PubMed and Google Scholar search engines from January 2000 to December 2023. Results: Fourteen studies (11 cross sectionals, 2 descriptives and 1 Cohort) met the inclusion criteria for this review. Most cross-sectional studies showed that participants with more tooth loss exhibited a greater proportion of hypertension and higher systolic blood pressure than those with less tooth loss. Cohort study showed that the loss of 8 or more teeth was associated with a higher risk of developing hypertension. Descriptive studies reported that missing teeth were marginally significantly associated with hypertension. Conclusion: This study has revealed a significantly higher SBP in patients with fewer remaining teeth or more tooth loss. In addition, those with more tooth loss showed a higher risk of hypertension than those with less tooth loss.

Numerical Characterization of the Annular Flow Behavior and Pressure Loss in Deepwater Drilling Riser

In drilling a deepwater well,the mud density window is narrow,which needs a precise pressure control to drill the well to its designed depth.Therefore,an accurate characterization of annular flow between the drilling riser and drilling string is critical in well control and drilling safety.Many other factors influencing the change of drilling pressure that should be but have not been studied sufficiently.We used numerical method to simulate the process of drill string rotation and vibration in the riser to show that the rotation and transverse vibration of drill string can increase the axial velocity in the annulus,which results in the improvement of the flow field in the annulus,and the effect on pressure loss and its fluctuation amplitude.In addition,there are also multiple secondary flow vortices in the riser annulus under certain eccentricity conditions,which is different from the phenomenon in an ordinary wellbore.The findings of this research are critical in safely controlling well drilling operation in the deepwater environment.

Effect of autologous blood donation on the central venous pressure, blood loss and blood transfusion during living donor left hepatectomy

AIM： Autologous blood donation （ABD） is mainly used to reduce the use of banked blood. In fact, ABD can be regarded as acute blood loss. Would ABD 2-3 d before operation affect the CVP level and subsequently result in less blood loss during liver resection was to be determined.METHODS： Eighty-four patients undergoing living donor left hepatectomy were retrospectively divided as group Ⅰ （GⅠ） and group Ⅱ （GⅡ） according to have donated 250-300 mL blood 2-3 d before living donor hepatectomy or not. The changes of the intraoperative CVP, surgical blood loss,blood products used and the changes of perioperative hemoglobin （Hb） between groups were analyzed and compared by using Mann-Whitney Utest.RESULTS： The results show that the intraoperative CVP changes between GⅠ （n = 35） and GⅡ （n = 49） up to graft procurement were the same, subsequently the blood loss,but ABD resulted in significantly lower perioperative Hb levels in GI.CONCLUSION： Since none of the patients required any blood products perioperatively, all the predonated bloods were discarded after the patients were discharged from the hospital. It indicates that ABD in current series had no any beneficial effects, in term of cost, lowering the CVP, blood loss and reduce the use of banked blood products, but resulted in significant lower Hb in perioperative period.

Analysis of Gas Flow Rate and Pressure Loss of Medical Mask Differential Pressure Tester

The objective of this study is to find a suitable method to overcome the pressure loss problem in the gas pipe during the gas exchange detection of medical masks.Based on the European Standards EN 14683,the parameters of a medical mask differential pressure tester were selected,subsequently two schemes of gas pipe layouts were designed,including four kinds of pipe diameter which are 4,5,6.5,and 8mm respectively.Lastly,the models of each scheme were established and imported into Fluent,and the relevant parameters were set for simulation.After data analysis,the results showed that among the four different pipe diameters,the pressure loss of 8mm diameter of the pipe was lower in both the schemes,additionally the pressure loss of the second scheme(the gas pipe was short and smooth)was lower under the same pipe diameter.At the flow rate of v=8L/min,the pressure loss from the inlet to the measurement point is less than 200Pa,and the estimated measurement error is less than 1.5%.In conclusion,shortening the length of the pipe,and increasing the diameter of the pipe can reduce the gas pressure loss,subsequently improve the measurement accuracy of the medical mask differential pressure tester.

Optimal central venous pressure during partial hepatectomy for hepatocellular carcinoma

BACKGROUND:Low central venous pressure(CVP) affects hemodynamic stability and tissue perfusion.This prospective study aimed to evaluate the optimal CVP during partial hepatectomy for hepatocellular carcinoma(HCC).METHODS:Ninety-seven patients who underwent partial hepatectomy for HCC had their CVP controlled at a level of 0 to 5 mmHg during hepatic parenchymal transection.The systolic blood pressure(SBP) was maintained,if possible,at 90 mmHg or higher.Hepatitis B surface antigen was positive in 90 patients(92.8%) and cirrhosis in 84 patients(86.6%).Pringle maneuver was used routinely in these patients with clamp/unclamp cycles of 15/5 minutes.The average clamp time was 21.4±8.0 minutes.These patients were divided into 5 groups based on the CVP:group A:0-1 mmHg;B:1.1-2 mmHg;C:2.1-3 mmHg;D:3.1-4 mmHg and E:4.1-5 mmHg.The blood loss per transection area during hepatic parenchymal transection and the arterial blood gas before and after liver transection were analyzed.RESULTS:With active fluid load,a constant SBP ≥90 mmHg which was considered as optimal was maintained in 18.6% in group A(95% CI:10.8%-26.3%);39.2% in group B(95% CI:29.5%-48.9%);72.2% in group C(95% CI:63.2%-81.1%);89.7% in group D(95% CI:83.6%-95.7%);and 100% in group E(95% CI:100%-100%).The blood loss per transection area during hepatic parenchymal transection decreased with a decrease in CVP.Compared to groups D and E,blood loss in groups A,B and C was significantly less(analysis of variance test,P【0.05).Compared with the baseline,the blood oxygenation decreased significantly when the CVP was reduced.Base excess and HCO 3-in groups A and B were significantly decreased compared with those in groups C,D and E(P【0.05).CONCLUSION:In consideration of blood loss,SBP,base excess and HCO 3-,a CVP of 2.1-3 mmHg was optimal in patients undergoing partial hepatectomy for HCC.

Mudcake effects on wellbore stress and fracture initiation pressure and implications for wellbore strengthening

Although a large volume of mudcake filtration test data is available in the literature, effects of mudcake on wellbore strengthening cannot be quantified without incorporating the data into a stress-analysis model. Traditional models for determining fracture initiation pressure （FIP） either consider a wellbore with an impermeable mudcake or with no mudcake at all. An analytical model considering permeable mudcake is proposed in this paper. The model can predict pore pressure and stress profiles around the wellbore, and consequently the FIP, for different mudcake thickness, permeability, and strength. Numerical examples are provided to illustrate the effects of these mudcake parameters. The results show that a low-permeability mudcake enhances FIP, mainly through restricting fluid seepage and pore pressure increase in the near- wellbore region, rather than by mudcake strength. Fluid loss pressure （FLP） should be distinguished from FIP when a mudcake is present on the wellbore wall. Fracture may occur behind the mudcake at FIP without mudcake rupture. The small effect of mudcake strength on FIP does not mean its effect on FLP is small too. Mudcake strength may play an important role in maintaining integrity of the wellbore once a fracture has initiated behind the mudcake.

AN INVISCID MODEL FOR THE BASE PRESSURE OF TRANSONIC TURBINE CASCADE

An inviscid base pressure model for transonic turbine blade has been presented. It has been shown that for a given back pressure the base pressure at the trailing edge, and the profile loss of a turbine blade are fixed according to the model and the base pressure can be calculated with the help of an inviscid numerical scheme. A parameteric study on the model shows that a blade profile with positive curvature downstream of the throat is advantageous for generating less loss, whilst the worst situation is when the exit flow reaches the sonic condition.

Influence of bluff body shape on wall pressure distribution in vortex flowmeter

To investigate the influence of bluff body shape on wall pressure distribution in a vortex flowmeter,experiments were conducted on a specially designed test section in a closed water rig at Reynolds numbers of 6.2×10 4-9.3×10 4.The cross sections of the bluff bodies were semicircular,square,and triangular shaped,and there were totally 21 pressure tappings along the conduit to acquire the wall pressures.It is found that the variation trends of wall pressures are basically identical regardless of the bluff body shapes.The wall pressures begin to diverge from 0.3D(D is the inner diameter of the vortex flowmeter) in front of the bluff body due to the diversity in shape,and all reach the minimum values at 0.3D behind the bluff body.A discrepancy between the triangular or square cylinder and the semicircular cylinder in wall pressure change is observed at 0-0.1D behind the bluff body.It is also found that the wall pressures and irrecoverable pressure loss coefficients increase with flow rates,and the triangular cylinder causes the smallest irrecoverable pressure loss at a fixed flow rate.