Geological and Development Features of Marine Deep Gas-Condensate Fields in Azerbayjan

摘要

The paper deals with geological and development features ofrnmarine deep gascondensate fields in the South Caspian Basin.rnThe Bulla-deniz Field is taken as an example. Specific featuresrnof the above field are as follows: its complicated geologicalrnstructure; steep angles of formation dip (12°-22°); large heightrnof the reservoir (about 1.500 m); large occurrence depth ofrnproducting horizons (5,500 m – 6,500 m); non-uniformrnstructure of producing horizons; abnormal initial formationrnpressure (71.4 MPa); rather low formation temperaturern(110°C); abnormal pore pressure in clays; high clayiness ofrnreservoir-rocks (up to 30%); inner water drive andrndeformation of reservoir- rocks in the process of development;rndissipated hydrocarbon fluid in the pore space of reservoirrocks;rnhigh condensate content (412 g/m3); oil slugs. Inrnaddition, the initial phase state of the formation system was inrnkeeping with the conditions below critical pressure andrntemperature, and therefore since the very beginning ofrnreservoir exploitation the system had a two-phase state.rnThe Institute of Deep Oil and Gas Deposits, AzerbaijanrnAcademy of Sciences, has carried out works concerningrnestimation of reserves, planning and analysis of the above fieldrndevelopment.rnThus, a complicated geological structure of the field and alsorntroubles while drilling resulted in the creation of methods forrninterpretation of geological-geophysical data to provide arnreliable hydrocarbon reserves estimation and to chooserneffective systems of development.rnThe hydrodynamic calculation methods to calculaterntechnological indices of the above type gascondensate fieldsrndevelopment at various drives have been worked out.rnTo enhance the output of producing wells a new approachrnand calculation algorithm of condensate recovery with ?dry?rnhydrocarbon gas out of a near-bottomhole area have beenrndeveloped. Calculations and experimental tests performedrnhave proved a high efficiency of the method suggested.