| With the sustainable quick development of Chinese economy, the Earthserves us with food, water, and energy sources. However, it bringsdisaster, such as volcano, earthquake, Tsunami as well. Problems we faced,of environment, resource and energy, they are not only the process ofseeking the secrecy of nature, but also the effort of obtaining theresource and energy. Therefore, we need solve them by developing deepexploration technology.Geologists and geophysics are making every effort in recent100years.Scientists in China realized that to solve the problems we have to carryout the program of deep exploration, to achieve the innovation anddevelopment of geosciences. However, geoscientists from all over theworld have to face the fact that we know little about the inner structureof the world. The deepest drilling until now is12km, which is just thesurface layer of the Earth comparing with the whole geological system.During the researches, scientists realized that it was much more difficultfor getting into the earth than into the sky. By getting into the earth,we mean to get to know the inner structure of the earth. The most efficientway of doing this is Deep Continental Scientific Drilling Program, whichis a necessary tool of modern geosciences. It can provide the directinformation with the increase of the depth, and also the most reliableway to prove the result of geophysics research. Chinese super deepdrilling is designed to drill10km, which will face a series of challenges.With the increase of the depth, temperature, pressure and the probabilityof the accident will increase as well, that makes the forecast of the riskbecome more importation. The implement of the Deep Continental ScientificDrilling Program could be a verification mean in the lab, and also it plays the important role in the secret seeking and research improvement. Andthe launch of dynamic real-time quantitative risk assessment can decrease theloss in manpower, physics, the financial resource, and reduce the riskof program, which is really meaningful.However, the methods exist cannot satisfy the need of deep continentalscientific drilling, for the following reasons.(1) The informationresources of risk analyze are the experience of experts andsingle-resource data. In some situation, those could be criterion. Butin others, the experience could make mistakes for the subjective judgments.(2) In the general evaluation of risk analyze, we used to multiply theprobability by the influence, which is too general to make every necessaryrisks into consideration.(3) The exist risk analyze methods are static.Even though some are already applied to the management of oil exploration,most of them are about the budget and time evaluation. Those methods arenot really competent for a program like this. We need to put more effortin dynamic risk analyze. Therefore, it is necessary to make a solution.How to get mass data and make effective use of them is the premiseof the result of risk analyze, which involves data fusion of multi-scalemulti-source information, with the improvement of drilling technology andmeasures to get data.These data comes from gravity prospecting, magnetic prospecting,electrical prospecting, seismic prospecting and LWD information, whichare multi-type, multi-scale, multi-temporal, large-scale andcomplex-structure. However, if we use them properly, those data canconcert with and make up for each other. Besides, we developed an expertsystem, which is a huge resource of information. The problems that broughtwith the changing objective condition could be solved by a real time riskassessment. For example, pressure, temperature and the geologicalstructure could change the risk factor, thus the probability that the risk happens could be changed also. We need to keep indentifying and updatingthe factors, monitoring the probability of the risk during the drillingprocess, to take prevention measures in time. As the result, it needs todevelop a series of methods which are interdisciplinary and specific.In summary, the data from deep exploration are uncertainty. To solvethose problems, we need to combine the data with the risk assessmentmathematical models based on statistics. Therefore, it is reallymeaningful to do a study on a real time risk assessment while drilling.The research objects are to forecast and prevent risks, to build a riskassessment system of multi-index, by making use of data updating andassessment method improvement. This article is aimed to analyze how totake all the necessary characteristics into consideration in deepcontinental scientific drilling program, especially in super deepdrilling, for the shortage of method and technology of a real time riskassessment while drilling. The article will study on dynamic parameter fusionmethod of risk assessment to prevent random risk and to improve the assessmentbased on multi-scale, multi-source, real time and recursion data. Thusthis article studies some related issues that forms a logical framework,which can divided as following7sections.The first chapter is the abstract, which mainly introduces thebackground, purpose and significance of the study.The second chapter is the literature review, obtained by acomprehensive analysis based on literature research, which primarilydefines two important concepts involved in this dissertation anddescribes their nature.The third chapter is the first part of the three core chapters in thedissertation. It is the research on the static risk assessment methods,mainly in which risk sequencing is done according to the risk evaluationsof all the factors. Furthermore, based on the conclusions of pastexperiences and implications, a new set of four-dimensional evaluation standards is created, which includes the risk probability, the riskconsequence severity, the unpredictability and the consequencesseriousness of deterioration. For the risk assessment of this project,the new set is much more appropriate than the standards used before, sinceit can more precisely offer a forecast of risk probability closer to thefact. More intuitively and clearly it provides the project implementationparty with a quantitative standard to determine the upcoming projects,including the list of which aspects the risk occur in firstly and thecalculation of the possible risk.The fourth chapter is the second part of the core. The same as thelast, it also belongs to the research on the static risk assessment methods.But it mainly does the whole risk assessment of the project, with theapplication of integrated ISM and ANP.The fifth chapter is another part of the core. It is about the dynamicrisk assessment methods. The aim of this part research is raisedprincipally according to specific characteristics of the projectimplementation, which are presented as followings. Many factors maychange during the drilling, but it is impossible to get enough accurateinformation of changing during its initial work process. It means thatthe risk of project execution increases without obtaining sufficientaccurate information during the pre-construction. Also some factors arechanging while it is drilling deeper, but there is only a general forecastof trend in the preliminary stage. That increases the danger, too.Meanwhile it is obvious that because of the specificity of this project,there do be very serious consequences if the risk mentioned in thisdissertation occurs. So it is necessary to increase the predictabilityof risk continuously, in order to provide the executive staff with earlywarning for preparing in advance. The sixth chapter is a case study, which applies the methods mentionedin the three core chapters above to the continental scientific deepdrilling project. The results of the project in the case offer averification of the methods. It surely draws an integrated picture ofquantitative description of the project risk on one hand, and on the otherhand confirms the feasibility and correctness of the methods used.The seventh chapter is the conclusion of the whole dissertation andperspective, which contains some recommendations about the lack of thestudy done here and its direction for further research.Based on a large number of domestic and foreign literature readingand research, there raised are7specific questions of risk assessment.This dissertation does the research on the risk evaluation methods oflarge projects and discusses the problems discovered as follows:(1)How to determine the rationality of each weight in the comment set?(2)How to determine the relative importance of each risk?(3)How to achieve the perfection of the existing deficient evaluationmethods in order to get more reasonable evaluation results but withoutmissing or increasing the risk?(4)How to sort various risk factors more accurately?(5)How to evaluate the whole risk index of the project objectively?(6)How to effectively filter mass data obtained from the dynamic riskassessment?(7)How to effectively monitor the dynamic process?In view of the questions above, a solution is put forward to solvethe problem that the existing dynamic risk assessment methods are rarelyinvolved in the study, and also the evaluation dimensions of each riskfactor are improved in the process of static risk assessing.Thisdissertation deals with the improved measures, the adjustment scheme,integrated processing methods, ideas of handling process, processing technique and so on.These innovations and improvements are listed asfollows:(1)The rationality of every weight is confirmed by using analytichierarchy process and network analysis.(2)The relative importance of each risk is determined by using ANP.(3)An approach of application of a new four-dimensional assessmentmethod is presented in the method of fuzzy-synthetic evaluation.(4)The interdependence between risks is identified by using ISM andthe factor assessment method of project risk is studied on the base offuzzy-synthetic evaluation method. How to do it? Firstly identify riskfactors in the preliminary phase; and then establish the comment set andevaluation standards; thirdly determine the weight of each risk index andestablish fuzzy evaluation matrix; finally calculate the risk index ofrisk factors.(5)In order to rank the importance of risk, a method is proposed byintegrating the ISM and ANP. Based on this integration method of the wholeproject risk assessment, ISM and ANP are effectively integrated, and usedto calculate the project overall risk index.(6)Based on Kalman filter, this dissertation puts forward a kind ofextended method for filtering multi-scale data.(7)In the research of dynamic risk assessment method, combined withthe actual characteristics, this dissertation presents dynamic riskassessment model based on multi-scale information fusion.(8)This dissertation applies the creative method in SinoProbecontinental scientific deep drilling project in order to verify itsfeasibility.The research thinking and technical route of static method of riskassessment includes the following aspects: (1)The fuzzy comprehensive evaluation method is used to assessproject risk factors.Firstly identify risk factors in the preliminary phase; and thenestablish the comment set and evaluation standards; thirdly determine theweight of each risk index and establish fuzzy evaluation matrix; finallycalculate the risk index of risk factors.(2)The method of the whole project risk assessment, which integratesISM and ANP, is applied in the whole project risk assessment.ISM and ANP are effectively integrated in order to calculate theproject overall risk index. First, determine the degree ofinterdependence between each risk and build a reachable matrix; then,establish a directed graph and an interpretive structural model; thirdly,with the application of ANP, build net structure in order to set up supermatrix; next, on the basis of the super matrix, design clustering matrixand weighted super matrix; finally, get the result of the whole projectrisk assessment.The research thinking and technical route of dynamic method of riskassessment includes the following aspects:(1)The problem about filtering multi-source informationThe data of this project is gained in diversified ways, includinggravity measuring, magnetic density surveying, resistivity checking,seismic surveying, well logging and mud logging in the process of drillingand so on. For a certain risk factors, not all data can be used. Sometimesseveral measurements are able to refer to the same geologicalcharacteristics, but the accuracy of their precision and characterizationare different from each other. To deal with this, the dissertation focuseson how to efficiently use these data without redundant information. inThe referred concept of multi-sensor here is not completely the same aspast, but a generalized one, regarding various means of obtaining data as a multi-sensor target. Partly the research focuses on introducing theconcept of multi-scale Kalman filtering and establishing multi-sensormulti-scale algorithm.(2)The expressing method and the modeling approach of Multi-scaleinformation fusion used in the dynamic processThe expressing method and the modeling approach of Multi-scaleinformation fusion used in the dynamic process are established, andapplied in monitoring the dynamic process in order to assess the risk ofprocess.Chapter3-6are core in the dissertation.The research results include the static risk assessment methodresearch and the research of dynamic risk assessment method. One of theshortages of this article is that it has not verified the risks by dynamicrisk assessment for the reason that dynamic risk assessment needs largeamount of workload. In the future study, we need to improve the dataprocessing to deal with the multi-scale and large amount data based onthis program. |
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