Earthquake Constrained Impedance Inversion And Applied Research

Regarding the oil field exploration, the results of seismic inversion play a more and more important role in the fine oil pool description and lateral in reservoir prediction. The technology can actually reflect underground rock layer lothological transitivity mop characteristic and respond indirectly the reservoir containing the fluid nature change characteristic, taking advantage of this can greatly raise the percentage of drilling hits. This article after elaborating several kinds of seismic restrain inversion method (ISIS simulation annealing inversion, constrained sparse spike inversion, multi parameter lothological seismic inversion) principle, key technologies, suitable condition and good and bad points, unifying the actual 3D seismic material of chongxi zone xiangxi group, has carried on the inversion method application, and has carried on the analysis contrast to each kind of inversion method practical application effect, finally has carried on the mop prediction in the impedance inversion foundation to the effective reservoir, get some production and cognition:The method of ISIS simulation annealing inversion is a seismic multi-trace inversion which bases on the fast simulate anneals method. In the progress of impedance inversion, by the seismic material primarily, carries on the inversion by the log information as the constraint condition, because uses the simulation annealing algorithm to seek the overall situation optimal solution, requests lowly to the initial model, suits the exploration degree low area. On the other hand, because this method resolution mainly relies on seismic material itself, Thus in oil-field development stage, if the seismic material itself resolution is not high, and then the inversion result is difficult to satisfy the reservoir fine description.The method of constrained sparse spike inversion supposes that the reflections coefficients of strata are sparse. A rapid trend-constrained pulse inversion calculation is adopted, using the seismic interpretation horizon and logging-constraint to control the trend and scope of wave impedance. The pulse calculation can obtain the wide-band result. The inversion result is faithful to seismic data, simultaneously; the constraint of logging and geology can replenish the component of low and high frequencies. The vertical resolution is heightened comparatively to the conventional seismic data.The method of multi parameter lothological seismic inversion is actually the logging property inversion controlled by seismic horizon data. The method fully uses seismic, logging, geological and other information, and takes log information primarily, by seismic material and geological model as constraint condition, through technologies of major constituent analysis and singular value decomposition, based on seismic data, multiple attributive profiles of acoustic wave, density, resistively, natural gamma, porosity, etc. can be inversed out., can solute impedance and the parameter inversion problem disposable, and carry on the fine reservoir prediction and the description more effectively, The resolution of the method can be heightened for many times comparatively with conventional seismic data. The result of inversion better reflects the lithological and physical change character of reservoirs between wells. But this method mainly embarks from the well, when the well distribution is thin, the inversion result too simulates, change rule distortion.The survey area is 486 km2. The seismic data is pre-stack time migration data which was completed in 2007 characterized by good quality and clear seismic structural reflection. The dominant frequency is up to 65Hz.Log data is relatively few; there are only 9 wells with log datum. The reservoir is featured by medium-high amplitude in seismic data and high porosity, low velocity in the log data. The study area is a new exploration area. Combined with the basic data, seismic acoustic impedance inversion was processed in this area for the first time and good inversion result was achieved. Based on the inversion result, two wells were proposed and both have seen high production industrial oil stream.