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聚类分析方法作为刻画事物之间相似性程度大小的一种数学方法已在石油工业中得到广泛应用，为研究油气井压裂后的效果评价问题提供了依据。利用系统聚类分析方法，将压裂井视为样本点，而将压裂井的地质参数和工程参数视为反映该样本点的欧氏坐标，通过欧氏距离建立反映样本点之间相似性程度大小的距离矩阵，通过最短距离法建立类与类之间的相似性测度，作聚类分析。利用该方法对长庆油田的8口压裂井进行压裂后的效果评价方法研究，并得出如下结论：Kh值高的油气井压后产量也高，但产量也与地层的孔隙体积有关，孔隙度过小，在压后不稳定生产阶段供油气能力低；渗透率(K)高的油气井压裂后效果也好；砂比在35以上的效果较好；每米层厚加砂量高的，油气井压后产量也高；油气井压裂效果不好的另一个原因可能是夹层多且厚。以上结果比较符合现场实际。该方法可以用作油气井压裂后的效果评价分析研究。

SYSTEMATIC CLUSTER ANALYSIS METHOD OF EVALUATING OIL/GAS WELL POSTFRACTURE RESPONSE

According to systematic cluster analysis method,the fractured well is regarded as the sample point but the geological parameters and engineering parameters of the fractured well are regarded as Euclidean coordinate of the sample point.A distance matrix reflecting the degree of likeness among sample points can be set up in light of Euclidean distance,and a likeness measure among classes may be established in accordance with the shortest distance method.So the cluster analysis can be carried out on the basis of those.Through evaluating the postfracture responses of eight fractured wells in Changqing Oil Field by use of such a method,it was concluded that the production of the oil/gas well with great kh value was high after being fractured,but it was also related to the formation pore volume,the oil/gas draining ability being low in the unstable production stage after being fractured because of ultralow formation porosity;the postfracture response of the oil/gas well with high formation permeability was good;the postfracture response was fairly good if the sand content in proppant exceeded 35%;the greater the sand content per meter of formation thickness,the higher the production of oil/gas well after being fractured;and both numerous and thick muddy interbeds may be the other reason of causing the oil/gas well postfracture response bad.The conclusion mentioned above conforms to reality,so that such a method may be used for the evaluation,analysis and research on the oil/gas well postfracture response.