Evaluation Method of Pyroclastic Rock Reservoir Based on Gravel Parent Rock Composition
The fault system of a basin is complex and has the characteristics of multiple source,short source and rapid phase transition.T formation develops a set of stable sand conglomerate,which has great exploration potential.Under the influence of volcanism,hydrodynamics,proventology etc.,tuffaceous matter is commonly found in rocks,and pyroclastic rocks are widely developed.According to the experimental analysis of thin sections of rocks,the compositions of gravel parent rocks are diverse,mainly granite,rhyolite,andesite,trachyte,argillaceous siltstone,basalt,tuff,etc.,and the skeleton parameters of different mineral components vary greatly.As a result,the calculation accuracy of reservoir porosity parameters is low,the pore structure is complex,and fluid identification is difficult.Based on the analysis of thin section of rocks and the precise description of drilling core,combined with the logging response characteristics,the conventional log identification methods are established for composition types of different gravel parent rock.On the basis of geological and electrochemical experiments,it is determined that the tuffaceous matrix part(below the muddy level)has similar additional conductivity to that of clay,and almost all logging responses are affected by this part of fine grained material to varying degrees.Therefore,the content of the tuffaceous matrix part is unified with that of the muddy content in sedimentary rocks.For the first time,the content of"mud+tuff"(hereinafter referred to as"mud+ash")is proposed to replace the content of mud,and its content is calculated to eliminate its influence on the electrical conductivity of volcaniclastic sedimentary rock reservoirs.The method provides technical support for reservoir evaluation,geological modeling and the formulation of fracturing programs.
pyroclastic rocksand conglomerateparent rock compositiontuffaceous mattermud contentreservoir evaluation
万方数据
维普
