AutoFlow: An automatic debugging tool for AspectJ software

Aspect-oriented programming (AOP) is gaining popu-larity with the wider adoption of languages such as As-pectJ. During AspectJ software evolution, when regression tests fail, it may be tedious for programmers to find out the failure-inducing changes by manually inspecting all code editing. To eliminate the expensive effort spent on debug-ging, we developed AutoFlow, an automatic debugging tool for AspectJ software. AutoFlow integrates the potential of delta debugging algorithm with the benefit of change im-pact analysis to narrow down the search for faulty changes. It first uses change impact analysis to identify a subset of re-sponsible changes for a failed test, then ranks these changes according to our proposed heuristic (indicating the likeli-hood that they may have contributed to the failure), and finally employs an improved delta debugging algorithm to determine a minimal set of faulty changes. The main fea-ture of AutoFlow is that it can automatically reduce a large portion of irrelevant changes in an early phase, and then locate faulty changes effectively.

Simulation of immiscible water-alternating-CO2 flooding in the Liuhua Oilfield Offshore Guangdong, China

In this paper, the immiscible water-alternating-CO2 flooding process at the LH11-1 oilfield, offshore Guangdong Province, was firstly evaluated using full-field reservoir simulation models. Based on a 3D geological model and oil production history, 16 scenarios of water-alternating-CO2 injection operations with different water alternating gas (WAG) ratios and slug sizes, as well as continuous CO2 injection (Con-CO2) and primary depletion production (No-CO2) scenarios, have been simulated spanning 20 years. The results represent a significant improvement in oil recovery by CO2 WAG over both Con-CO2 and No-CO2 scenarios. The WAG ratio and slug size of water affect the efficiency of oil recovery and CO2 injection. The optimum operations are those with WAG ratios lower than 1:2, which have the higher ultimate oil recovery factor of 24%. Although WAG reduced the CO2 injection volume, the CO2 storage efficiency is still high, more than 84% of the injected CO2 was sequestered in the reservoir. Results indicate that the immiscible water-alternating-CO2 processes can be optimized to improve significantly the performance of pressure maintenance and oil recovery in offshore reef heavy-oil reservoirs significantly. The simulation results suggest that the LH11-1 field is a good candidate site for immiscible CO2 enhanced oil recovery and storage for the Guangdong carbon capture, utilization and storage (GDCCUS) project