Research On The Characteristics And Damage Mechanism Of The Cambrian Dolomite Reservoir In Yaha

The 25%of oil and gas around world is contain in dolomite.After many years of exploration and research,the Yaha,Tarim Cambrian dolomite reservoir has been proved to have great potential for exploration and development.The dolomite reservoir has strong heterogeneity and cracks are generally developed.Reservoirs are vulnerable to pollution damage and affect oil and gas production,which seriously restricts the efficient exploration and development of dolomite reservoirs.This essay will argue that the Geological Characteristics of the Cambrian Dolomite Reservoir in Yaha,to clarify the potential damage mechanism of the reservoir,focus on the experiment of reservoir damage assessment and evaluation of the degree of reservoir damage and mechanisms.The results show that:(1)By means of thin section identification,X-ray diffraction,scanning electron microscopy and other techniques and combined with drill data,By means of thin section identification,X-ray diffraction,scanning electron microscopy and other techniques and combined with drill data,to clear that the rock types of dolostones of Cambrian in the Yaha are putty crystal dolomite and powder crystal dolomite primarily,with low content of clay minerals;(2)The reservoir physical properties are extremely heterogeneous,and properties are gradually improved from the bottom up.Correlation of porosity and permeability is poor;(3)The reservoir space is mainly composed by intergranular pores,intergranular pores,cracks and caves.Specially,cracks occurrence are dominated by high angles,and reservoir can be divided into fractured reservoir,porous reservoir and fractured-porosity reservoir.(4)Based on the geological characteristics of Cambrian reservoirs in the Yaha,an experimental evaluation method for the reservoir stress sensitivity under simulated in-situ conditions was established.The evaluation results show that the stress sensitivity damage degree of the pore reservoirs is less than 50%,and the stress sensitivity damage degree of the horizontal cracks is reach up to 80%,and the high-angle seam stress-sensitive damage degree is greater than 65%;(5)According to relevant industry standard,the damage degree and mechanism evaluation experiment of different types of reservoir were carried out.Using the technique of NMR T2 distribution and NMR imaging combining characterization of liquid solid mud invasion depth and mechanism,combined with the core wells mud invasion occurrence anatomy,clear porous dolomite reservoir drilling open the liquid on the damage degree is low,the solid particle invasion depth;fractured reservoir in the width of>100 ?m,solid invasion damage;width of<100 ?m,can take temporary plugging technology to prevent liquid solid invasion.In view of the above research results,this paper confirms the reservoir characteristics and damage mechanism of the Cambrian dolomite reservoir,and provides technical support for the efficient development of the Yaha Cambrian dolomite oil and gas reservoir.