摘要：The aim of this dissertation is to estimate the structural analysis and hydrocarbon potentialof Miano area, Central Indus Basin, Pakistan.Study area hosts a number of gas fields withstructural and stratigraphic traps.Area is situated in Middle Indus Basin which is a part ofan extensional regime showing normal faulting due to the split of the Indian Plate firstly
from Africa and then from Madagascar and Seychelles.Miano area recognized as a provenpetroleum province which has complex tectonic history.Inversion is carried out forCretaceous extensional and overprints of Tertiary strike-slip tectonics.
The area has prospect with accumulation of hydrocarbons in structural and stratigraphictraps including pinchouts.NW-SE oriented Khairpur and Mari highs are main structuralfeatures with impact on the fault system.Sands of Lower Goru of Lower Cretaceous ageare performing as a reservoir in the region.Miano has great potential of hydrocarbons forwhich more exploratory wells are required to be drilled with better insight of structural andstratigraphic traps.Miano prospect area is surrounded by a number of gas fields with thegreat Mari amongst them.At the time when OMV led joint venture entered the block allfields produced from relatively shallow Tertiary reservoirs.Similar types of structural trapswere also expected in Miano area.
For the interpretation of the seismic data reflectors were marked based on stratigraphicstudies.These reflectors named as Sirki Shale, Habib Rahi, Sui Main Limestone, Ranikot,Upper Goru, Lower Goru, Lower Goru Sand, Chiltan formation initially time sections wereprepared, which were converted to depth section to give true subsurface picture.Straightreflectors representing strike line with lacking structures.Dimensional visualization of theprominent reflectors was done, which showed how formations are stratified in thesubsurface.In addition, rock properties were also calculated using this data, specialconcentration was on the porosity of the rockswhich further confirmed the reservoirpotential.
The area is of high interest tectonically which has made it a good prospect area andaccumulation of hydrocarbons is due to structural, lithological variation and pinching ofstrata.Khairpur High and Mari High are providing suitable environment to hydrocarbons.The sands of Lower Goru of Lower Cretaceous are acting as a reservoir in the area.Mianoprospect area has a great potential of hydrocarbons and more exploratory wells may be
drilled in the future targeting the Lower Goru Sands.
Inversion technique is used to calculate impedance from seismic data.In seismic inversionthere is an ambiguity seen in transforming impedance values into rock properties likeporosity.A good indication of reservoir is when there is a sharp increase in porosity andlow impedance detected.This phenomenon also represents the occurrence of shale becauseshale has anexcellent porosity and low impedance like reservoir rock.The study isrevolving around to separate those two different features means to identify reservoir andnon-reservoir rocks by cross plot analysis.The technique is used to resolve this ambiguityin which gamma ray values are imbedded during porosity prediction from impedance.Thistechnique prevents from misleading and helps a lot in isolating the points which come fromthe shale.To achieve target in the first attempt require high exploration costs.Optimizationtechnology innovate higher-value solutions.Exploration risk is mitigated by reservoirprediction through Inversion technique.It involves the transformation of impedance intoquantitative rock properties like porosity,saturation and pore pressure.
3D mapping is also done on desired wells including Kadanwar-10, Maino-02, Mian-05,Miano-07, and Miano-09.The technique is established in this research to resolve artefactsin the interpretation for the exploration ofhydrocarbon.
Keywords: Seismic; Well; Base map; Synthetic Seismogram; Tectonic; Time-and-depthInterpretation; Contours; Structure; 3D view; Inversion; Impedance; Petrophysics; Gammaray log; Cross plot; Reservoir characterization