The Diagenesis Researchs And Favorable Reservoir Predictions In Shuangqing Area, The Liaohe West Depression

As the data collected from all over the world shows, one-third of oil and gas distributes in the reservoir buried deeper than 3500 meters underground approximately . With the burial depth increased , the reservoir characters become worse and worse until there is no commercial value to exploit . Thus it is necessary for geologists urgently to know the diagenesis states in the deep buried reservoirs and the areas where favorable reservoirs developed in the deep horizons exploration . We attempt to predict the areas favorable reservoirs developed in the horizontal orientation in the deep horizons of the west depression of Liaohe, then enrich and perfect the exploration technology of sandstone and conglomerate in the subtle reservoir ulteriorly by studies on diagenesis and evaluating methods of oil and gas reservoirs .As the results of the diagenesis researches show , the reservoirs composed of clastic rock in the Shuangqing area can be divided into the early diagenetic stages and the middle diagenetic stages , aggregately five subphases . It can be divided dominantly into four diagenetic facies , the early compaction and cementation , dissolution , dissolution and partial recementation , strong compaction diagenetic facies . Three high porosity zones develop in the vertical orientation . They mostly occur in fan-delta subsea distributary channels, mouth bars and front sand sheet, braid channel of sublacustrine fan and front-outside fan and so on. We believe that the first high porosity zone formed by eluviation of meteoric waters and dissolution of organic acids to reservoir, the second and the third one mainly formed by dissolution of organic acids dehydration of clay minerals .According to superimposing the map of precipitation facie and diagenetic facies, we have predicted the distribution of favorable reservoir facies, and blocked out the developed favorable and the relatively favorable reservoirs in the area. It's suggested that we should seek the traps that develop in favorable and the relatively favorable reservoirs area and do further explorations and researches in the areas.