Interference Well-test Model And Application For Fractured Well

Low-permeability reservoirs often increase well pattern density to increase oilfield production and inhibit water cut rising.Dense well pattern exacerbates inter-well interference.Existing single-well test analysis methods treat inter-well interference as a boundary effect,and ignore the influence of adjacent well interference.The existing well test interpretation model for fractured well has not considered the influence of the fracture surface flow distribution,nor can it effectively determine the degree of inter-well interference.Considering the mutual interference between vertical well and fractured well or between fractured wells,the finite-element method was introduced to solve the well test model for fractured wells with interference from adjacent well.A typical curve of well test was depicted.The distribution of dimensionless flow rate per unit of fracture length going from the formation into the fracture was analyzed.Due to the presence of interfracture interference,the flow rate across the fracture surface is no longer symmetrical.Considering the high pressure-conductivity ability of fractures,the interference signal will be transmitted to the bottom of the observation well faster,and the pressure derivative curve will appear in the interference transition stage earlier.The effect of the orientation of observation wells and interference wells was studied.When the fractures of observation wells and interference well were on the same line,the high-conductivity of fractures has the most significant influence.Moreover,the effect of the fracture halflength was much greater than the fracture-conductivity.The results of proposed model are highly compatible with the results of numerical model in commercial well test software,which verifies the accuracy and applicability of the model.A field example is interpreted by our model.The interpretation parameters are reasonable,which indicates that our method is an effective tool for judging the connectivity between wells and formulating adjustment treatments for oilfield.