Sanhu Biogas Into The Possession Of Research

Quaternary biogenic gas in the Three-lake region of Qiadam basin, its proved and controlled reserves exceed 3000 108m3 at present. Good gas source rock and good combination of reservoir and cover is formed from lacustrine deposition in Pleistocene. Although organic abundance of the quaternary gas source is low, a great deal of gas could be produced, demonstrating with organism simulation testing. The simulation testing data reveals that the microbe bacteria groups are distributed orderly.Four type of microbe bacteria group exists together at the formations 0-200m; bacteria groups thriving at 200-600m; the quantity of bacteria groups decreasing at 600-1000m slightly; the quantity of the groups coming to summit at 1000-1600m; its quantity reducing continuously at 1600-2000m; no methane-pr-oducing bacteria below 1700m.The organic carbon minimum of the quaternary biogas source rock in Three-lake is 0.25%.The quaternary reservoir of Three-Lake is based on the shoreface lake-shoal bar massif. Therefore, they are characterized by a wide distribution, slightly fine lithology, small single layer depth, much developed layers, an unconsolidated texture, a developed primary pore, and a higher shale index. The quaternary covering-strata are consisted mainly of mudstone. The good quaternary unconsolidated cover are attributed to the closed physical difference and hydrocarbon concentration and the wet covering-strata. The quaternary alternating layers with sandstone and mudstone form the good combination with reservoir and cover.The quaternary trap of Three-Lake is the typical syndepositional anticline, with two flank flat. Gas source, reservoir and trap form into the best configuration in time and space. Velocity sag with gas-bearing layers and chaotic reflection can provide some basis for an option of exploration target.The condition of cold climate and the environment of high salinity water body are the external factors of forming the quaternary large-sized biogas field in Three-lake. A sufficient gas source, good combination of the reservoir and cover rock, timely trap and good consequent conservation are the internal factors of forming the quaternary large-sized biogas field. Gas pool scale is relied on trap scale.Favorable zone of biogas prospecting over Quaternary I-type area is distributed into the Tainan-Sebei belt, with an area of 4800km2. There are two favorable zones over II-type area, one is located between Nanlinqiu Mound and Sebei with an area of 3400km2; another is located to the south of Tainan with an area of 3800 km2. Favorable biogas zone in the Upper Tertiary I-type area is distributed between Taijinaier lake and Yikeyawuru region, with an area of 3200km2. The zone in II-type area is distributed between Hongsanhan, Boat-like Mound and Sebei No.1 with an area of 2900km2 roughly.