Coral Reef Identification, Evaluation And Exploration Targets Selection From 3D Seismic Block On Right Bank Of Armu River, Turkimanistan

The 3D seismic block with area 3400 km2 is located on the middle-west part of Chaerju tectonic zone of Armu basin,Turkimanistan.The carbonate of Carluofu-Oxford formation is the major exploration target.This article has developed studying on tectonic evolving,sedimentary environment of target reservoir,structures and faults analysis on the basis of the result of seismic data interpretation,geology,drilled wells and well logs.The results of study could reveal that the work area has three historic tectonic events: the period of valley basin on P-early J era,the period of stable basin on late J-early Tertiary era and the period of foreland basin on late Tertiary -Quaternary era.The sedimentary environment for the carbonate of Carluofu-Oxford formation may be the platform margin,the wide platform or slope close to margin. There are two types faults happened during two periodic eras:the normal faults formed on the period of valley basin and the reverse faults or shift faults formed on the period of foreland basin.On the basis of results by integrated study,according to the special sediment, geo-frame and abnormal seismic response,we could identify,predict and evaluate biogenic reefs through sedimentary analysis,tracking seismic attribute,sonic log, abnormal thickness of biogenic reef and the different deformation of salt overlay on the biogenic reefs.The main sediment environment for biogenic reefs is plat margin or slope close to margin.The seismic response for biogenic reefs display special reflections such as flat bottom,arch top and scatter or blank reflection inside.The thickness is much larger for biogenic reefs than that of normal carbonate strata just because biogenic reefs grew up very quickly with died biology bodies piled up heavily.Moreover,the salt overlay on the coral reef could form thick salt pillow on the tails for the character of flowing of coral reef and become thin on the main body of biogenic reef on the contrast.As a result,we have found,predicted and identified biogenic reefs zone with area 631 km~2.Base on the above,we have concluded a series of methods to identify,predict and evaluate biogenic reefs.There are two types of biogenic reefs according to study: one is barrier reef zone located on the plat margin such as Samandepe reservoir, Yashyldepe reservoir.The second is dot reef or reef-shoal zone located on the front margin or slope to deep water such as Tangygui reservoir,Pirgui reservoir and Yangui reservoir.On the basis of analysis the rule of oil or gas assembled and different reservoir model for coral reef on A,B block,we have provided many exploration targets to drill,which have been applied into exploration effectively.