Prediction Model of Drilling Costs for Ultra-Deep Wells Based on GA-BP Neural Network

Drilling costs of ultra-deepwell is the significant part of development investment,and accurate prediction of drilling costs plays an important role in reasonable budgeting and overall control of development cost.In order to improve the prediction accuracy of ultra-deep well drilling costs,the item and the dominant factors of drilling costs in Tarim oilfield are analyzed.Then,those factors of drilling costs are separated into categorical variables and numerous variables.Finally,a BP neural networkmodel with drilling costs as the output is established,and hyper-parameters(initial weights and bias)of the BP neural network is optimized by genetic algorithm(GA).Through training and validation of themodel,a reliable prediction model of ultra-deep well drilling costs is achieved.The average relative error between prediction and actual values is 3.26%.Compared with other models,the root mean square error is reduced by 25.38%.The prediction results of the proposed model are reliable,and the model is efficient,which can provide supporting for the drilling costs control and budget planning of ultra-deep wells.

Neoadjuvant camrelizumab(an anti-PD-1 antibody)plus chemotherapy or apatinib(a VEGFR-2 inhibitor)for initially unresectable stage II–III non-small-cell lung cancer:a multicentre,two-arm,phase 2 exploratory study

This multicentre,two-arm,phase 2 study aimed to explore the efficacy and safety of neoadjuvant camrelizumab plus chemotherapy or apatinib in patients with initially unresectable stage II–III non-small-cell lung cancer(NSCLC).Eligible patients regardless of PD-L1 expression received neoadjuvant camrelizumab 200 mg and platinum-doublet chemotherapy every 3 weeks(arm A)or those with PD-L1-positive tumors received neoadjuvant camrelizumab and apatinib 250 mg once daily(arm B),for 2–4 cycles,followed by surgery.The primary endpoint was major pathological response(MPR)rate.Thirty patients in arm A and 21 in arm B were enrolled.Surgery rates were 50.0%(15/30)in arm A and 42.9%(9/21)in arm B,with all patients achieving R0 resections.Of these patients,the MPR and pathological complete response rates were both 20.0%(95%CI 4.3–48.1)in arm A and were 55.6%(95%CI 21.2–86.3)and 11.1%(95%CI 0.3–48.2)in arm B,respectively.The corresponding objective response rates were 33.3%(95%CI 11.8–61.6)and 55.6%(95%CI 21.2–86.3).With a median follow-up of 22.4 months(95%CI 19.0–26.0),the median event-free survival was not reached(NR;95%CI 13.6-NR)in arm A and 16.8 months(95%CI 8.6-NR)in arm B.Grade 3 or above treatment-related adverse events occurred in eight(26.7%)patients in arm A and three(14.3%)in arm B.Biomarker analysis showed baseline TYROBP expression was predictive of treatment response in arm B.Neoadjuvant camrelizumab plus chemotherapy or apatinib exhibits preliminary efficacy and manageable toxicity in patients with initially unresectable stage II–III NSCLC.

Seismic effects on reinforcement load and lateral deformation of geosynthetic-reinforced soil walls

Current design methods for the internal stability of geosynthetic-reinforced soil(GRS)walls postulate seismic forces as inertial forces,leading to pseudo-static analyses based on active earth pressure theory,which yields unconservative reinforcement loads required for seismic stability.Most seismic analyses are limited to the determination of maximum reinforcement strength.This study aimed to calculate the distribution of the reinforcement load and connection strength required for each layer of the seismic GRS wall.Using the top-down procedure involves all of the possible failure surfaces for the seismic analyses of the GRS wall and then obtains the reinforcement load distribution for the limit state.The distributions are used to determine the required connection strength and to approximately assess the facing lateral deformation.For sufficient pullout resistance to be provided by each reinforcement,the maximum required tensile resistance is identical to the results based on the Mononobe-Okabe method.However,short reinforcement results in greater tensile resistances in the mid and lower layers as evinced by compound failure frequently occurring in GRS walls during an earthquake.Parametric studies involving backfill friction angle,reinforcement length,vertical seismic acceleration,and secondary reinforcement are conducted to investigate seismic impacts on the stability and lateral deformation of GRS walls.