Structural Characteristics Of The Baikouquan Formation In The Mahu Sag, Junggar Basin And Its Effects On Hydrocarbon Accumulation And Sedimentation

The Mahu lake depression of Triassic in Junggar basin is a large sedimentary depression, the relationships of source-reservoir-cap in the Baikouquan group are good, the configuration between time and space has created massive accumulation of geological foundation. Exploration in recent years proved that the Baikouquan group of the Mahu lake area exploration potential is big, the Baikouquan group has formed the scale of reservoir geological conditions, with the profound of exploration, there are two problems in terms of structure. First of all, the Baikouquan group evolution of sedimentary structure formation and accumulation of the control effect is unclear; Second, the Baikouquan group developed much more groups of faults, but its control effect on reservoir is unclear yet.To solve the above problems, this study defined the strata distribution, sedimentary thickness, structure characteristics of the Baikouquan formation of the Mahu lake depression by means of the comprehensive using of drilling, logging, geology, seismic data for joint interpretation, mapping, and has carried out tectonic stages, palaeostructure control action on today's oil and gas analysis of the Baikouquan group of Mahu lake depression, palaeostructure control action on today's oil and gas analysis, preliminary identified clear control function of paleostructure, present tectonic on the reservoir forming of Baikouquan group. Baikouquan formation of the Mahu lake depression in vertical has three sets of normal cycle deposition, mostly with fan delta deposition, early distribution limit, after the expiration of the concave distribution, depositional paleogeomorphology overall performance for the ancient convex multistage slope and slope break control; Experienced multiphase tectonic movement, two properties of compresso-shear and strike-slip fault are roughly divided into three groups on plane. Northeastward compresso-shear faults control the accumulation period of ancient nose and local fan sedimentary (e.g. Mabei\Mlaxi); northeastward strike-slip faults control the movements of the bridge of the nose and the source, local segmentation reservoir (e.g. Manan). The reservoiring background is complicated by multiphase tectonic movement, but now the nose still controls the oil and gas enrichment; In the sedimentary period, The valley mouth and paleo-uplift control the fan controls the fan in main distribution. And the front end and flank is advantage with development area; Along the source direction, there are two levels of slope break; downhill fold flat area is relatively developed area of favorable reservoir.