Study Of High Quality Reservoir Prediction Techniques In Low Porosity/permeability Sandstone In TMB Area Of Erdos Basin

Combination of the seismic data resulted from wide-azimuth acquisition and perfect fidelity processing with drilling and well logs, the study explores the method of predicating high quality reservoir rock from the reservoir rock with low permeability and porosity so as to provide a better predication method and research thinking for the similar reservoir, and to reduce the exploration risk.The reservoir rock developed in Tabarmiao region of Ordos basin is typically of low permeability and porosity. Research of predicating high quality reservoir rock from the reservoir rock with low permeability and porosity was carried out through the analysis of multiple information and multiple methods suitable to the geological feature of study area, and the follow major results and innovation are achieved.1) Carried out the research for the method of making synthetic seismogram considering offset information based on Zoeppritz Equation, and the waveform of synthetic seismogram resulted from this method is perfectly similar to the true seismic data. Calibrated reflection firstly with the synthetic seismogram considering offset information, and the accuracy of reflection calibration has been improved which lays down a solid foundation for correct structural interpretation, seismic inversion, seismic attributes extraction and analysis.2) Found out firstly the relationship between the thickness of pay zone and the maximum thickness of individual bed within sandstone set; proposed firstly the relationship between maximum thickness of individual sandstone bed and the reflection energy; predicated the distribution of high quality reservoir rock (the thickness of gas-producing zone) based on the reflection energy.3) Proposed clearly the working procedure of distinguishing firstly sandstone from mudstone with natural Gamma inversion data, then predicating the high quality reservoir rock from the reservoir rock with low permeability and porosity in the case of acoustic impedance data can not be used to distinguish high quality reservoir rock (or gas-bearing sandstone) from mudstone. 4) The result of the research showed that 3rd member of lower Shihezi Fm (He-3) and 1st member of Shanxi Fm (Shan-1) developed in Permian are the major gas producing zones in the area; high quality reservoir rock within He-3 distributes in the block of well DK13–to well Shan208 in the northwest of the area, and the block of well Shan207 to well D3 in the southeast of the area; the block of well Shan207 to D3 with an area of 12 km2 is the high quality reservoir rock area discovered in this research and has been confirmed by the well D52 drilled according to the research result. The result of the research pointed out that there is a high quality reservoir rock area with an area of 45 km2 within Shan-1 in the southwest of the area, and the high quality reservoir rock area has been confirmed by well DK28 drilled according the research result. It is considered that the high quality reservoir area is one of the major prospects for future reserve.Four wells designed according the result of this research have gained good effect which illustrate that the accuracy of high quality reservoir rock predication is high, and the research thinking used is right.