Application Of Thin Interbeds Inversion On Gaoyou Sag

The major geologic target of Gaoyou Sag is“thin interbeds”with mid-high velocity and mid-high P-impedance,and distribution varies quickly in lateral.Due to the limitation of rock physics and seismic resolution,the high P-impedance of the sand actually shows lithology,physical property,fluid,depth and high-velocity shale.The ambiguity of inversion result can not satisfy the quantification requirement of practical production.Based on basic data in Yongan,Lianmengzhuang and Majiazui,sand distribution rules and sedimentary micro-facies were summarized.Through geologic modeling,rock physics modeling and seismic forward modeling,relation of reservoir parameter,rock physics and seismic was analyzed,and geophysics models and attribute models in different areas were built up.Aiming at different geologic and seismic data condition of Yongan,Lianmengzhuang and Majiazui,technology of seismic attribute analysis,constrained sparse spike inversion,geostatistics inversion and effective sand interpretation were applied.10 subtle traps were discovered and verified,with the predicted resource of 2589×10~4t.Three objects were optimized,and YongX48 was successfully drilled with an increased reserves of about 5million tons.Innovation was also made:According to different geologic and seismic condition,seismic attribute analysis,constrained sparse spike inversion,facies controlled log-constrained inversion,geostatistics inversion were compositely applied.Consequently,the prediction result is in accordance with drilled wells,and sand within 5 meters could be predicted.