Research And Application Of Automatic Correlation Of Base-level Cycle

Stratigraphic correlation establishes their right relationship in space with the physical characteristics of rock stratum. In practice, the traditional contrastive process by geologists is not clear. The result of contrast is not the only. This uncertainty is very important for the accuracy and efficiency of stratigraphic correlation. Expert's manual contrast is not only complicated, and it carries a very strong empirical.Many experts, who study the automatic stratigraphic correlation with computer, hope that the computer technology can solve this problem of stratigraphic correlation. To the present, they have developed a lot of stratification.This paper based on the results of their predecessors, raised the contrastive strategy which is after stratification, and use dynamic waveform matching as a major contrast. Well first wavelet transform, the separation of base-level cycles, a short-term cycle of semi-cycle as the basic unit matching coefficients were compared. New Method retained test results contrast reasonable means of CORRELATOR expert system and redesign the knowledge base by the basic knowledge and principle of the base-level cycle. It ensures the reasonability and practicability of contrastive results.1.Wavelet transform and its application in dividing the base-level Turnaround point of base-level cycles is the change location of both the increase and decrease of up to a downward, the position of the limit of accommodate increased to the maximum or minimum value reduced to a single-way changes. It is the boundary of dimidiate time quantum of the base-level Setting different parameters through wavelet transform can gain different levels of the division cycle results, but in practical applications, as the cycle changes to the complexity, scale of the problem is very elusive. The purpose of this study which use wavelet transform to divide the base-level cycles is provide accurate stratigraphic correlation and comparative cycle unit.2. The dynamic waveform match and the application in stratigraphic correlationThe dynamic waveform match is using the substitution, deletion and insertion three operations to translate one string into another string, based on the difficulty degree of the operation requirement can calculate the similarity of these two strings.Make the curves of each sequences fitted in two wells then extract the characteristic parameters of the well logging curves after fitting. Using these characteristic parameters can according to the dynamic waveform match method can realize the contrast between the strata. In the process of contraction, demand to adopt a"Matching Cost"when contrasting between two strata, if the collective matching cost achieve the minimum value, the opposite strata matching relations of the two well is the best relation under this condition.3. The expert system and the application in the comparison of Base-level CycleThe expert system is the computer program systems which using the knowledge of the humankind experts in a certain special domain was memorized in the computer to simulate the humankind experts solve the domain problem. According to the characteristic of base-level cycle comparison, this study revised the rule of comparison in the original knowledge base, mainly to delete the contrastive rule based on the lithology contras of the knowledge base, add to the rule which need to followed to contrast take the base-level cycle as the units. And according to the importance degree of contrast principles defined by the rules to perform the classification and ordination of the knowledge base, this method make the expert system has higher efficiency and better test results.The work of expert system should combine the contrast system introduced in the previous chapter. because if there is have the abandoned contrast relation, well then need to recalculate various matching coefficients in the new condition, looking for a new matching program.Finally, the above-mentioned method is using to carry out the automatic contrast experiments about the well drilling in the Kongnan area of Dagang Oilfield, achieving better results. It is show this above-mentioned method is feasible.