Variational Disciplinarian Of Development Index And Limit Of Technical Strategy For LSX Oil Field In Extra High Water Cut Stage

Lasaxing oil field has entered extra-high water cut stage, facing difficulties of intractable development and low economic benefits. Herein this article, the author intends to discuss issues like oil field development rules, potentiality estimation and structure adjustment optimization in reference to mechanics of porous flow and reservoir engineering theories.In terms of the situation of approximately the same water cut in various well patterns in Lasaxing oil field, it is proved that the best water control effect could only be achieved when the fluid production ratio and oil production ratio of various wells equal to geologic reserve ratio, taking the restriction of assuring certain amount of oil production as premise. The conclusion could be adopted in the study of sorted injection wells adjustment optimization in Lasaxing oil field. The author figured out that oil field development effect enhancement could be obtained by properly decrease oil production ratio of secondary wells and enhance oil production ratio of fundamental wells.Mathematic model is established based on mechanics of porous flow for inter-layer injection and production structure adjustment, as well as for theoretical analysis on development index tendency. Furthermore a development index forecasting model under the condition of taking stimulation measurements is built using water flooding curve composition and decomposition methods, which greatly raise the prediction accuracy.Geologic factors and factors during development process that may cause the increment of water cut in Lasaxing oilfield have been analyzed applying structural analysis methods, contribution methods and numerical simulation. The analysis results point out problems and obstacles of controlling the increment pace of water cut in Lasaxing oil field and the feasibility of water control, and meanwhile predict water cut variation tendency.Combining the theoretical analysis with practical situation of the oil field, influential factors that attribute to production declination have been studied, and simultaneously the production declination trend has been predicted.Influential factors on pressure system at extra-high water cut stage have been analyzed by numerical simulation combining with practical situations, suggesting adjustment rules for pressure system at extra-high water cut stage and determining pressure system threshold. Based on separate layer prediction, by analyzing the inter-layer water cut differential caused by reservoir anisotropy, well shut in limits could be defined.A new geologic reserve calculation method is proposed based on water flooding curves and relative permeability curves, which has been adopted in Lasaxing oil field for geologic reserve calculation, deciphering the distribution feature of remaining reserves and giving light to future development direction for Lasaxing oil field.