The Method Of Fault Lateral Sealing Shale Content And Analysis Of Problems In Its Application

According to the mechanism of lateral fault sealing,.Whether the fault can laterally seal oil and gas,it depends mainly on the shale content of fault rock.Up to now,the quantitative evaluation method of lateral sealing ability of fault is mainly the method of shale gouge ratio(SGR),the algorithm takes into account all kinds of geological factors,which can reflect the shale content of fault rock more accurately.In the use of clay content of fault rock(SGR)evaluate the fault lateral sealing,according to the different geological conditions in the study area,the method of lateral sealing capacity of the corresponding faults can be adopted,which can be divided into three main categories :(1)in the study area,there is no known oil water interface of fault trap,the establishment of the fault rock shale content limit method,to evaluate the ability of lateral fault sealing of oil and gas;(2)in the study area,there is one or a small amount of oil water interface of fault trap,the improved Yielding fault rock shale content prediction method for oil column height is used to evaluate the ability of the fault to seal oil and gas;(3)In the study area,there are many or a lot of known oil water interface fracture ring geological conditions,a statistical method of fault rock shale content ~ oil column height is established to evaluate the ability of faults to seal oil and gas.In the use of the above three kinds of fault rock clay content method to evaluate the west slope of Shulu,Wen'an slope,Bozhong 34-1/N and Bozhong area 28-2S/N lateral sealing of faults,The prediction results are in close agreement with the actual distribution of oil and gas,which proves the reliability of the three evaluation methods.However,there is also the ability of individual faults to seal oil and gas laterally,which is not consistent with th e actual distribution of oil and gas.There are mainly two kinds of factors causing this kind of phenomenon:(1)the fault sealing ability of the fault is weak,resulting in the failure of fault trap: in this case,,through the accumulation of the ancient stratigraphic thickness,ancient fault throw,and ancient clay content in the faulted strata,combined SGR algorithm the present faulted prediction method of oil column height,can establish a set of ancient fault lateral sealing ability recovery method in the period of oil and gas accumulation.And the method is used to quantitatively evaluate the lateral sealing capacity of Wen 13 fault trap,the predicted results are in good agreement with the distribution of oil and gas in Wen 13 well,It is proved that this method is feasible for quantitative evaluation of the lateral sealing of faults;(2)late fault activity resulting in drilling failure in the fault trap:in the case,through the recovery of oil and gas accumulation period,the fault activity rate reflects the failure of the late fault activity to the early formation of closed fault.And through the comparison of controlled trap fault activity rate of Jin 24 fault-trap Jin and 33 fault-trap after faulted period of oil and gas accumulation in the Qijia-Yuanyanggou area.Results show that the activity intensity of Jin 24 fault-trap is significantly greater than the activity intensity of Jin 33 fault-trap after the accumulation period,the actual sealing ability range small,resulting in Jin 24 fault trap drilling failure.