Research On The Prediction Of Efficient Wells In Carbonate Fractured-cavity Reservoirs In Tahe Oilfield

The actual development of Ordovician carbonate fractured-cavity reservoirs in Tahe Oilfield shows that the effectiveness of fractured-cavity reservoirs is affected by many factors,and it is difficult to accurately predict the effective fractured-cavity reservoirs during development,resulting in a low success rate of efficient wells prediction in the work area.In view of this problem,this paper starts with a variety of data on the geology,logging,earthquake,and production dynamics of efficient and inefficient wells in the work area.Analyzing the geological-geophysical characteristics of efficient wells and inefficient wells,summarizing the factors affecting the effectiveness of reservoirs,and establishing a seismic identification model for efficient wells.Based on the above,efficient wells prediction study was carried out to predict effective fractured-cavity reservoirs,and the principle of selecting favorable targets for efficient wells is summarized to improve the success rate of efficient well prediction,and the favorable drilling targets for efficient wells were selected.The types of spaces and the fillings of fractured-cavity reservoirs are classified,and the influence of sand and mud filling on the effectiveness of the reservoir is summarized.The identification mark of the sand and mud filling section are summarized.Through fine reservoir calibration,combing with logging interpretation,seismic section,and typical phenomenon in efficient wells and inefficient wells production.The factors affecting the effectiveness of the reservoir except sand and mud filling are summarized,and the main control factors of efficient well production are summarized.Based on forward simulation results,the size of beaded reflections,tectonic location and trough amplitude were selected to statistically analyze the seismic reflection characteristics of efficient wells in the work area,and the seismic identification mode of efficient wells was established.The colored inversion method is selected to predict the fractured-cavity reservoirs,and the frequency division inversion method is combined with the BP neural network to predict the sand and mud filling in the reservoirs.Both inversion results have good consistency with the existing wells in the work area.Combining two kinds of inversion results to characterize the effective fractured-cavity reservoirs in the work area,the characterization results have good consistency with the existing efficient wells in the work area,and good prediction results have been obtained.Based on the above research,the principles for selecting favorable targets for efficient wells are summarized: the reservoirs with large scale,large number,high tectonic location,and low sand and mud filling are preferred.Based on this principle,combined with the results of colored inversion and frequency division inversion,the favorable drilling targets for efficient wells were selected.