Condensate Gas Reservoir Failure Of The Development Process Condensate Contamination Mechanism And Lift Method

The gas condensate reservoirs are very different from dry gas reservoirs and oil reservoirs. The basic issue of the gas condensate reservoirs is the prevention of condensate loss due to reservoir depletion in addition to the gas recovery. This study mainly focuses on the complicated phase behavior, the condensate accumulation and the recovery-specific phenomena of gas condensate reservoirs in the field life. The mechanisms and effects of gas soak, water injection and electromagnetic heating are systematically investigated to re-stimulate the abandoned well by use of some typical gas condensate reservoirs. These exploring studies break a new path for further advancement of development techniques. The main achievements and innovative results are as follows:1. It is experimentally found that the dew point pressure of the remaining new mixtures may decrease due to the retrograde condensation of heavier components left in the reservoirs during the natural depletion. This finding implies that it isn't necessary to keep the pressure over the initial dew point pressure. It is of important significance to choose the gas injection pressure.2.The microscopic visual flow instrument is developed. The condensate distribution, accumulation and flow in porous media are featured via this visual device. The results provide further insights into condensate flow in porous media.3. The long core equipment is employed to quantitatively evaluate the passive effects of condensate on the gas flow. Also found are the evident effects of restoring the effective gas permeability by gas injection. The field experiments show that dry gas soak can effectively eliminate /alleviate the condensate accumulation and improve the gas mobility near wellbore, implying as a potentially promising technique4. The exploring studies of in-house and field water injection pilot tests demonstrate that the pressure maintenance by water injection is promising solution for the abandoned gas condensate well.5. The new method of eliminating the near-well bore condensate blockage stimulated by electromagnetic heating is proposed for the first time. The mathematical simulation model is established for a gas-condensate well electromagnetic heating stimulation to eliminate blocking near wellbore region. The computer software was coded to evaluate the electromagnetic heating efficiency. This software is used to study the effects of gas reservoir parameter, production system, and heating mode on several important factors such as temperature, pressure, condensate saturation and relative permeability. These results of Banqiao gas condensate field is taken as case example prove that it is feasible to eliminate the near wellbore blockage by electromagnetic heating. This work provides theoretical guidance for choosing the stimulation well and optimizing the heating technique.The above studies will considerably contribute to the further improvements of stimulation technology of condensate recovery during the late development phase.