Multi-Stage Fractured Tight Gas Horizontal Well Test Data Interpretation Study

In recent years, horizontal well technologies are becoming the primary developing means for tight gas reservoirs. In Changqing oil field, 70% -80% of natural gas is tight gas, so multi-stage fracturing is becoming one of the main well stimulation technologies for every gas well. In this area, single well fracturing scale is up to 21 stages, Monolayer maximum plus the amount of sand 127.4m3,and ceramsite into the well is about 1274m3.. In order to evaluate post-frac properties of the horizontal wells, deliverability test and transient pressure test have been conducted for some wells. Fractured Multi-Stage horizontal well test interpretation technology is still at the exploratory stage, For heterogeneity tight gas reservoirs, there are great differences between real formation properties and results interpreted by the conventional horizontal well test interpretation model and multi-stage horizontal wells interpretation model that is being developed currently. In this paper, analytical well test and numerical well test methods are respectively used to analyze the same multi-stage horizontal well test data for acquiring post-frac fracture and reservoir parameters and evaluate fracturing results. From the analysis results, the fracture parameters sensitivity is poor during curve fitting and the results have great limitations if data interpreted by multi-stage horizontal wells analytical well test model, while accurate fracture and reservoir parameters can be obtained if test data is interpreted by the numerical well test model because it just can compensate for the shortcoming of analytical well test.