Diapir In Yinggehai Basin With Reservoir Space Characteristics

Yinggehai basin, with its rapid subsidence, high geothermal gradient, high formation pressure as the main characteristics. In this study,the study area is located in the central depression belt in Yinggehai basin, with the deep formation mud diapirs,are widespread in the assault on shallow fluid activity frequently. Comprehensive study basin diapir belt of reservoir compaction characteristics through the 20 Wells measured data and the microscopic chips of Yinggehai basin diapir belt,the fluid flow characteristics of reservoir space transformation and control factors of reservoir physical property and high porosity reservoir prediction, the following conclusions:Diapir belt, according to the measured geothermal gradient and the pressure coefficient in the diapir belt exist obvious abnormal high temperature and high pressure, the average geothermal gradient is 4.4 ? /100 m, in diapirs of geothermal gradient is highest, the reasons should be diapir belt tectonic activity and the thermal fluid flow. Overpressure development In the diapir belt, rapid deposition and mudstone undercompaction effect is the main cause of abnormal high pressure.Intense diapir tectonic activities in the upper formation formed in the fault zone,leading to deep overpressure to conduction, and shallow in the shallow strata in the development of high pressure, greatly changed the pattern of distribution of stress in the diapir belt, also provided the impetus and effective channels for assault on deep thermal fluid activities.Reformation of reservoir of the performance of the thermal fluid flow in a series of thermal geological events in the reservoir,the reservoir space formmation and the longitudinal on the distribution of abnormal high pore belt. The deep thermal fluid flow along the fault zone and fracture penetration formation pore, the high temperature accelerated the clay minerals and organic matter thermal evolution process and maturity of organic matter and diagenetic evolution has important role in control. Thermal fluid contamination with CO₂ gas dissolved and in the process of generation of organic acid and organic matter, dissolution feldspar and other particles carbonate cements and foraminifera shells when the fluid go into the pore space, the formation of secondary porosity lead the permeability and porosity of reservoir pore space changed, in the same time on the longitudinal form three zones on the development of abnormally high gap.Sandstone properties of the clastic rock reservoirs are mainly controlled by sedimentary facies and diagenesis, the stronger the hydrodynamic reservoir property,the better, and the compaction and cementation destroy the reservoir property,dissolution of organic acid can improve the reservoir property. Overpressure can inhibit the mechanical compaction, protect the pore; the hot fluid dissolution can effectively improve the reservoir property. Research area is gas reservoir property emplacement and atmospheric water leaching effect, the influence of gas emplacement good for pore protection, atmospheric water leaching effect can increase the shallow reservoir dissolution pore, reservoir on the longitudinal development of abnormal high pore zone is the pass of the hole and geological factors in time and space coupling.According to the vertical heterogeneity is the principle of performance on the plane, the superposition figure of sedimentary facies, diagenetic stage forecast figure,pressure coefficient distribution, can be delineated plane abnormal pore development area. Diapir belt in the middle of the Yinggehai basin and the one yinggehai group of ledong area and the two yinggehai group of eastern area has good reservoir property,in which weak diagenesis, with the overpressure protection of pore, become unusually high hole with the development of favorable horizon.