Workflow Modeling And Application In Drilling Design Based On Petri Net

Drilling design is the guide book to ensure drilling safely and smoothly. It is also the important basis for drilling project budget. However, the traditional design method can't meet the need of increasingly design work and has some problems including non-standard design. This affects the quality of engineering design. The workflow can be used into the automation of drilling engineering design to optimize design work, standardize enterprise management and improve efficiency. The workflow is a core technology to accomplish the modeling, simulation analysis, optimization, management and integration of enterprise business process and achieve the automation of engineering design ultimately.The primary problem is the workflow modeling. How to establish the workflow model of integrated drilling design process is the research emphasis of this paper. Drilling design is a typical discrete event process. Petri net becomes a better choice of the modeling and analysis of the workflow with its strict mathematic definition and systematic analysis and verification methods. It has its unique advantages especially for the modeling of the random and discrete events.The main researches are as follow:1. This paper introduces the thesis such as workflow,modeling and workflow management system, and expounds reasons for the modeling based on Petri nets, Petri nets and relevant theories.2. On the basis of Petri nets theory and requirements of workflow models in drilling design, it defines a stochastic Hierarchy Petri net and presents the mathematical description. It also defines the stochastic Hierarchy workflow net. And it constructs workflow modeling methods upon randomly stratified Petri nets.3. Based on those methods above, it constructs randomly stratified Petri net based workflow models in drilling engineering design, and respectively analyses validity and rationality of main nets and subnets constructed. It discusses methods of optimization and improvement in drilling design, and develops optimized designs. Simulation experiments are conducted by executing an average period of time as index through ExSpect method based on randomly stratified Petri net. The analysis of simulation results can verify the optimized designs'validity, which provides the theories and facts for raising the design efficiency.4. Using Web e Build technology, it implements a workflow management system with basic functions, which is based on optimized models. Oilfield drilling design management and approval integration platform is constructed to cover shortcomings such as non-standard versions,low-efficiency designs in designs of users. And the platform realizes resources sharing of drilling design, inter-operability, and design automatization, therefore improves efficiency in drilling design.