Study On Hydrocarbon Accumulation And Prediction Technology In Dongpu Salt-lake Basin

The author studied the Dongpu depression thoroughly using the sequence stratigraphy,formation correlation, hydrocarbon accumulation evaluation and seismic reservoir prediction,etc. and a set of comprehensive technology of hydrocarbon exploration has been summarizedwhich includes seismic and geology in salt-lake basin.The salt formation has been put into the sequence frame through the research of highaccuracy sequence stratigraphy. This partition method is not only more reasonable and moreadvantageous to attach the salt rhythm to every grade sequence unit but also assured highunification of sequence and salt rhythm. The partition result is very helpful to the next workin the whole depression. The distribution regularity of the salt rock has been indicated that itis cyclic and rhythmical vertically and divisional and migratory breadthwise. According tothis regularity, the author put forward the migratory model of salt-sand eat and flow and theconcept of salt-sand interlaced zone. It has been also indicated that the incessant migration ofsalt-sand eat and flow zone is the main reason of hydrocarbon enrichment in Dongpudepression. The direction of subtle reservoir exploration in salt lake basin has also been pointout in the study results.After the study of hydrocarbon accumulation, the author indicates that the salt rock isfavorable to hydrocarbon accumulation. The salt rock not only enriched the organic matter,enhanced the quality of source rock but also preserved them from damage. The thermalevolution process of the source rock buried deeply is be stifled by the abnormal highpressure which induced by salt rock and the stage of hydrocarbon generation has beenlengthened. The salt rock is a good boundary of different petroleum systems andhydrocarbon accumulation dynamic systems. There are 7 types of reservoirs, which relatedto salt rock and many hydrocarbon bearing system of beds have been formed in the middleof the salt rock and below the salt rock. These results guided the oil and gas exploration wellin Dongpu salt lake basin.Through the study of seismic and geology and the analysis also of forward simulation,the author indicates that the salt rock has low natural Gamma, low density and middle-highvelocity in logging data and has strong amplitude, high continuity and middle-low frequencyin seismic data. So the salt rock has a more obvious seismic and geologic characteristic andis easy distinguish from the other lithology. A horizon calibration technology ofdisplacement method of seismic and geology has been formed according to the obviouscharacteristic of salt rock. This method solved the problem that it is very difficult to calibratethe horizon using the old well, which has no logging density. According to eat and flow andmoving model of salt and sand, a two-way reservoir prediction technology has been formedwhich based on reverse thinking and sequence stratigraphy and has been already used to thehydrocarbon exploration well.It is a rare work in the similar basin at home and abroad to make the systemic researchon the rich oil and gas area in Dongpu salt bearing depression using seismic combinedgeology theory. The salt-sand eat and flow and moving model and two-way reservoirprediction technology, etc., are promethean results and have obvious pertinence to salt lakebasin. These results have been used to the hydrocarbon exploration and development andhelped to add the reserves and increase the yield. These results will still guide the practice ofhydrocarbon exploration and development in the future in Dongpu depression.