Recognition And Evaluation Of Thin Reservoir And Its Application In H Oilfield

The prediction of thin reservoirs is always a difficulty for researching, correspondingly developed a variety of methods and techniques. In numerous reservoir prediction methods, only suitable for this area, can be effective and solve the evaluation of lithologic reservoirs. In this study the key technology be used is the curve reconstruction and seimic inversion.The target stratum of H oilfield in Iraq have the characteristics of thin thickness, multi-layer development and rapid lateral variation, resulting in the recognition and prediction of the reservoir is becoming much more difficult. The unsuccessful well well-7 is in the high position of the strctural map, make people begin to realize the underground geological condition is more complex than originally thought. The study area be badly in need of using geophysical methods to take reasonable prediction and evaluation of the underground reservoirs.In this thesis, by using the high resolution seismic data of H oilfield in Iraq, the integrated application of drilling, seismic, well logging, testing and analysis data in the study area, to carry out horizon interpretation and precise structure mapping, reservoir prediction, sand body thickness of each small layer and sedimentary facies, finally found out lots of favorable targets for well location determination, we take the following techniques:first of all, the collected logging curves in the area were standardized, To eliminate the error caused by different acquisition time and different instrument units; the pseudo log of acoustic curve improve the ability to identify the lithology. Secondly, by the known well data, the stratum model as constraint condition, the impedance generated by sparse spike inversion, construct a reasonable distribution of impedance trend area. To solve the problem of the conventional inversion cannot recognize the thin sand, using stochastic simulation, geostatistical inversion technique, making full use of logging data, widen the seismic bandwidth, finally reach the target of recognition and prediction of the reservoir. Based on the geological inversion results, establishing sand body thickness of each small layer and sedimentary facies, we not only have a deep understanding of the distribution of the underground reservoirs, but also laid a solid foundation for the final well location determination.We recognize that H oilfield is a structural and lithologic reservoir under the background of anticline structure. The main reservoir is beach bar in tidal-flat environment, the lithology is medium to post sandstone. Analysis the distribution of sand body, we find that the favorable reservoir mainly distributed in the northwest and southwest slope area of the structure. The NA layer reservoirs have the characteristic of "one sand for a reservoir", high position of the structure and southwest slope area is favour of hydrocarbon accumulation, also suitable for well site deployment. On the basis of structural interpretation, combined with analysis method for curve reconstruction and seismic inversion, predicting sand body distribution and carried out the sedimentary facies analysis work, searching for favorable reservoir belt, finally analysis the distribution of oil and gas reservoirs in the area, This can be regarded as a approprite method for recognition and evaluation of Thin Reservoir, the results become advantageous basis of optimization target for drilling.