The Sensibility To Stress Path Of Carbonate Formation Research:an Example From Under Paleozoic Formation Of Changing Gas Field

Based on core and geological data in Changing gas field, by the technique of experimental analysis and combined with the theory of rock pore compressing , some research experiments of the cores of this area are designed as follows: the research experiment of core porosity under the condition that normal pressure and normal temperature; the research experiment of core porosity sensibility to stress path under the condition that simulate formation; the research experiment of core permeability under the condition that normal pressure and normal temperature; the research experiment of core permeability sensibility to stress path under the condition that high pressure and high temperature; the research experiment of core permeability sensibility to stress path under the condition that simulate formation; the research experiment of simulating gas production curve under the condition that simulate formation. Finally, the reservoir sensibility to stress path are evaluated by combining the research results as above mentioned with the petrology features, the physical properties, and the pore structure of this area The results are indicated:1. The Changing under Paleozoic reservoir is carbonate reservoir with tight basis and highly heterogeneous and comprehensive void for penetrating and contain.2. The research experiment of porosity and permeability under normal pressure and temperature condition indicates that the full diameter cores should be used to study porosity and permeability in the studied area when the reservoir is carbonate formation with highly heterogeneous.3. The experiment research of core porosity sensibility to stress path under the condition that simulate formation indicates that the rock porosity is reducing with the overlay pressure increasing. The amplitude of porosity reducing is relation with rock' pore structure.4. Under the higher pressure and higher temperature, the permeability is reducing with the overburden pressure increasing,. The amplitude of reducing permeability is relation with rock' pore structure.5. The simulating experiment of higher producing pressure drop under fully simulatingformation condition shows that the formation permeability residual is decreasing with the increasing of experiment pressure drop6. The simulating experiment research of higher producing pressure drop under fully simulating formation condition shows that the gas well's reasonable pressure drop is relation with the formation's producing ability. The reasonable producing pressure drop of reservoir type I should be under 2.5 MPa; The reservoir type II should be under 3.5 MPa, just a little higher than reservoir type I; as for the type reservoir III, the experiment shows there has no co relation between producing pressure drop and penetrate velocity.7. The sensibility model to stress path of carbonate formation reservoir is set up, comprehensively the reservoir formation sensibility to stress path is evaluated in this area.