Experimental study on the degree and damage-control mechanisms of fuzzy-ball-induced damage in single and multi-layer commingled tight reservoirs

Fuzzy-ball working fluids(FBWFs)have been successfully applied in different development phases of tight reservoirs.Field reports revealed that FBWFs satisfactorily met all the operational and reservoir damage control requirements during their application.However,the damage-control mechanisms and degree of formation damage caused by fuzzy-ball fluids have not been investigated in lab-scale studies so far.In this study,the degree of fuzzy-ball-induced damage in single-and double-layer reservoirs was evaluated through core flooding experiments that were based on permeability and flow rate indexes.Additionally,its damage mechanisms were observed via scanning electron microscope and energy-dispersive spectroscopy tests.The results show that:(1)For single-layer reservoirs,the FBWF induced weak damage on coals and medium-to-weak damage on sandstones,and the difference of the damage in permeability or flow rate index on coals and sandstones is below 1%.Moreover,the minimum permeability recovery rate was above 66%.(2)For double-layer commingled reservoirs,the flow rate index revealed weak damage and the overall damage in double-layer was lower than the single-layer reservoirs.(3)There is no significant alteration in the microscopic structure of fuzzy-ball saturated cores with no evidence of fines migration.The dissolution of lead and sulfur occurred in coal samples,while tellurium in sandstone,aluminum,and magnesium in carbonate.However,the precipitation of aluminum,magnesium,and sodium occurred in sandstone but no precipitates found in coal and carbonate.The temporal plugging and dispersion characteristics of the FBWFs enable the generation of reservoir protection layers that will minimize formation damage due to solid and fluid invasion.

Improved clonal selection algorithm optimizing Neural Network for solving terminal anti-missile collaborative intercepting assistant decision-making model

Programming terminal high-low collaborative intercepting strategy scientifically and constructing assistant decision-making model with self-determination and intellectualization is onekey problem to enhance operational efficiency.Assistant decision-making model has been constructed after analysis on collaborative intercepting principle;then Improved Clonal Selection Algorithm Optimizing Neural Network(ICLONALGNN)is designed to solve the terminal anti-missile collaborative intercepting assistant decision-making model through introducing crossover operator to increase population diversity,introducing modified combination operator to make use of the information before crossover and mutation,introducing population update operator into traditional CLONALG to optimize Neural Network parameters.Experimental simulation confirms the superiority and practicability of the assistant decision-making model solved by ICLONALG-NN.

Functionality evaluation of system of systems architecture based on extended influence diagrams

System of systems architecture（SoSA） has received increasing emphasis by scholars since Zachman ignited its flame in 1987. Given its complexity and abstractness, it is critical to validate and evaluate SoSA to ensure requirements have been met.Multiple qualities are discussed in the literature of SoSA evaluation, while research on functionality is scarce. In order to assess SoSA functionality, an extended influence diagram（EID） is developed in this paper. Meanwhile, a simulation method is proposed to elicit the conditional probabilities in EID through designing and executing SoSA. An illustrative anti-missile architecture case is introduced for EID development, architecture design, and simulation.

Direct Structural Evidences of Epitaxial Growth Ge<SUB>1-X</SUB>Mn<SUB>X</SUB>Nanocolumn Bi-Layers on Ge(001)

Molecular Beam Epitaxy (MBE) system equipped with in-situ Reflection High-Energy Electron Diffraction (RHEED) has been used for (Ge, Mn) thin film growth and monitoring the surface morphology and crystal structure of thin films. Based on the observation of changes in RHEED patterns during nanocolumn growth, we used a real-time control approach to realize multilayer structures that consist of two nanocolumn layers separated by a Ge barrier layer. Transmission Electron Microscopy (TEM) has been used to investigate the structural properties of the GeMn nanocolumns and GeMn/Ge nanocolumns bi-layers samples.