Exploration

摘要： 2021 is the year with the least amount of oil and gas exploration and discoveries in the past 75 years.The world’s new proven oil and gas reserves were 6.6×10^(9) barrels of oil equivalent,compared with 19×10^(9) barrels of oil equivalent in 2020,with a significant decline in new proven oil and gas reserves.

摘要： Throughout its century-long history,the Communist Party of China(CPC)has been striving to explore and implement an ownership system of the means of production.Upon its founding in 1921,the Party envisioned to create a sole ownership system after the victory of the National Revolution.In war times,land issues dominated the agenda of the Party’s work on the ownership structure since most of its bases and liberated areas were in the countryside.After the founding of the People’s Republic of China in 1949,China established a basic socialist economic system through“one industrialization and three transformations,”i.e.socialist industrialization and the transformations of agriculture,artisanal production,and capitalist industry and commerce.This nascent socialist economic system was characterized by the sole public ownership of the means of production and a highly centralized planned economy.Since the reform and opening up in 1978,the Party took bold steps to explore and reform the socialist ownership system under the principle to keep public ownership as the mainstay and allow diverse forms of ownership to develop side by side.In the new era,the Party has redefined China’s basic socialist economic system by creating a mixed ownership structure at two levels with public ownership as the mainstay.China’s increasing economic vitality and dynamism have witnessed the exploration and growth of this mixed ownership system.

摘要： Background:Unresectable disease is sometimes diagnosed during surgery in patients with pancreatic ductal adenocarcinoma(PDAC).This study aimed to identify preoperative risk factors for metastatic disease diagnosed at surgical exploration and to investigate and compare survival in resected and nonresected patients.Methods:Patients were identified from the Swedish National Pancreatic and Periampullary Cancer Registry 2010-2018.Predictors of metastatic disease were evaluated with a multivariable logistic regression model,and survival was evaluated with Kaplan-Meier estimates and log-rank tests.Results:In total,1938 patients with PDAC were scheduled for surgery.An unresectable situation was diagnosed intraoperatively in 399 patients(20.6%),including 234(12.1%)with metastasized disease.Independent risk factors for metastasis were involuntary weight loss(OR=1.72;95%CI:1.27-2.33)and elevated carbohydrate antigen 19-9(CA19-9)(35-599 U/m L,OR=1.79,95%CI:1.11-2.89;≥600 U/m L,OR=3.24,95%CI:2.04-5.17).Overall survival was lower among patients with metastasized disease than that among patients with a resectable tumor(P<0.001).Conclusions:Involuntary weight loss and an elevation of CA19-9 are preoperative risk factors for diagnosing metastasized disease during surgical exploration.

摘要： Time flies, Petroleum Exploration and Development has gone through 10 years of hard work and international development since it was included in SCI in 2012. With the help and support of the journal editorial committee members, experts, authors and readers, Petroleum Exploration and Development has kept growing fast. As we bid farewell to the unforgettable year 2021 and welcome the Spring Festival of the Year of Tiger in 2022.

摘要： Distribution characteristics,organic matter development characteristics,gas-bearing characteristics,reservoir characteristics,and preservation conditions of the Shahezi Formation shale of Lower Cretaceous in the Lishu fault depression,Songliao Basin,NE China,are analyzed using organic geochemical,whole rock,and SEM analysis data,and CO_(2)and N_(2) adsorption and high-pressure mercury injection experiment data in combination with the tectonic and sedimentation evolution of the region to reveal the geological conditions for enrichment and resource potential of continental shale gas.The organic-rich shale in the Lower Cretaceous of the Lishu fault depression is mainly developed in the lower submember of the second member of the Shahezi Formation(K_(1)sh_(2)^(1) Fm.)and is thick and stable in distribution.The shale has high TOC,mainly types II_(1) and II_(2) organic matter,and is in the mature to the over-mature stage.The volcanic activity,salinization,and reduction of the water environment are conducive to the formation of the organic-rich shale.The shale reservoirs have mainly clay mineral intergranular pores,organic matter pores,carbonate mineral dissolution pores,and foliated microfractures as storage space.The pores are in the mesopore range of 10–50 nm,and the microfractures are mostly 5–10μm wide.Massive argillaceous rocks of lowland and highstand domains are deposited above and below the gas-bearing shale separately in the lower submember of the K_(1)sh_(2)^(1) Fm.,act as the natural roof and floor in the process of shale gas accumulation and preservation,and control the shale gas enrichment.Based on the above understandings,the first shale gas exploration well in Shahezi Formation was drilled in the Lishu fault depression of Songliao Basin.After fracturing,the well tested a daily gas production of 7.6×10^(4) m^(3),marking a breakthrough in continental shale gas exploration in the Shahezi Formation(K1 sh Fm.)of the Lishu fault depression in Songliao Basin.The exploration practice has reference significance for the exploration of continental shale gas in the Lower Cretaceous of Songliao Basin and its periphery.

摘要： 2018年9月,美国国防高级研究计划局(DARPA)启动了被称为“加速第三波”的人工智能探索(Artificial Intelligence Exploration,AIE)项目,探索人工智能类人水平的交流和推理能力,以实现人工智能对新环境的自适应。自此之后,人工智能的可解释性成为人工智能领域的一个研究热点。

摘要： The national and international progress in deep space exploration has greatly promoted the development of planetary science in China.Substantial progress in different areas of planetary science has been achieved in 2020-2022.In this report,we summarize the research achievements obtained in China in the last three years.The achievements include the research on geology,geochemistry,and space physics of the Moon,Mars,Mercury,Venus,giant planets,asteroids,and comets.The recent work on science objectives,mission payloads,and analytical capabilities that supports the lunar and deep space exploration program of China has also been introduced in this report.Finally,we report the progress on developments of discipline and research team of planetary science in China.

摘要： On June 28,2022,Clarivate Analytics released the 2021 SCI Journal Citation Reports(JCR).The SCI impact factor of Petroleum Exploration and Development was 5.194,ranked Ist in all the journals of Petroleum Engineering;and ranked 32nd among the 201 journals in the JCR category of Multidisciplinary Geosciences.

摘要： There’s a conversation you’re avoiding.It feels important and you are putting it off.But delaying doesn’t solve anything.Getting started might involve some awkward moments,but,after that,the situation is open for discussion and exploration.Tried and tested approaches can help to smooth the way.Here are some useful tips from my experience as a psychotherapist(精神治疗医生).

摘要： Determining scale and variable effects have critical importance in developing an energy resource policy.This study aims to explore the relationships in heterogeneous lignite sites using different scale models,spatial weighting as well as error-based pair-wise identification.From a statistical learning framework,the relationships among the quality variables such as geochemical variables and the contributions of the coordinates to quality measures have been exhibited by generalized additive models.In this way,the critical roles of spatial weights provided by the coordinates have been specified at a global scale.The experimental studies reveal that incorporating the geological weighting in the models as the additional information improves both accuracy and transparency.Because relationships among lignite quality variables and sampling locations are spatially non-stationary,the local structure and interdependencies among the variables were analyzed by geographically weighting regression.The local analyses including spatial patterns of bandwidths,search domains as well as residual-based areal dependencies provided not only the critical zones but also availability of pair-wise model alternatives by calibrating a model at each point for location-specific parameter learning.The results completely show that the weighting models applied at different scales can take spatial heterogeneity into consideration and these abilities provide some meta-data and specific information using in sustainable energy planning.