Study On Characteristics Of The Formation Pressure Distribution Of Permian-Triassic In Puguang Region

Comprehensively using core, logging, geophysical, geochemical and drilling data, based on the analysis of the geological background of Permian-Triassic formation of PuGuang region, the paper systematically researched the basic geological character, distribution of measured abnormal pressure, pressure simulation and the factors that impacted distribution of the abnormal pressure. Achievements are shown as following.By analyzing, the measured pressure distribution in the study area is characterized by the distribution of multi-layers, several pressure systems in vertical. Formation with normal pressure in Puguang area has good physical properties and developed pores; Formation with abnormal high-pressure in Maoba area has good physical properties and the types of pores are mainly crack-type. Fractures are widely developed.Using known lithological and drilling data, combined with the boundary conditions of the study area, the paper used PetroMod simulating the pressure distribution of some wells and profiles in the study area .With a certain deviation in numerical value, the simulation results have the same trend as the measured pressure from drilling.Based on the analysis of the pressure from measure and simulation, this paper researched the factors that impacting the deposition background and the abnormal pressure. Account that the compaction in the area makes a certain contribution to the formation of abnormal pressure; The distribution of abnormal pressure has certain relevance to the distribution of gypsum-salt layer, and the areas with thick and wildly distributed gypsum-salt layers has abnormal pressure; The thickness of the erosion formation has a certain impact on the distribution of abnormal pressure. It is proved that smaller abnormal pressure always develops in the area with thicker erosion formation; Hydrocarbon generation proffers a great contribution to the formation and distribution of abnormal pressure; Using finite element analysis software, this paper conducts a preliminary simulation on the distribution of the stress .The results show that tectonism plays a great role on the formation of abnormal pressure and the area with larger stress has greater abnormal pressure.