储层质量钻前预测方法探讨——以松辽盆地汪家屯地区为例

STUDY ON PREDRILLING RESERVOIR QUALITY PREDICTION —TAKING WANGJIATUN REGION, THE SONGLIAO BASIN AS AN EXAMPLE

储层质量钻前预测包括储层孔隙度预测和渗透率预测。碎屑岩储层的孔隙度主要与沉积相和成岩作用有关,但在沉积相相同或岩性相近的条件下,储层孔隙度则主要受成岩作用的控制。据此,该文建立了应用成岩指数ID 预测储层孔隙度的模型,预测误差小于2%,并以松辽盆地汪家屯地区登三段为例说明了这一模型的应用。汪家屯地区登三段属于浅水河道沉积,储层岩性主要为岩屑长石砂岩和长石岩屑砂岩。在东北部登三段储层处于晚成岩阶段 B期,孔隙度最高值可达 14%~16%;西部地区登三段处于晚成岩阶段C期,储层物性较差,孔隙度最高值为10%~12%。

Predrilling reservoir quality prediction includes porosity prediction and permeability prediction. The porosity of clastic rock reservoirs is determined by both sedimentary facies and diagenesis. But for the same sedimentary facies or the similar lithology, the porosity of reservoirs is mainly controlled by diagenesis. According to this, a model of porosity prediction for clastic rock reservoirs using diagenetic index I_D was established, with the predicting error of less than 2%. The Deng-3 Member (K_1d^3) in Wangjiatun region, the Songliao Basin was taken as an example to illustrate the application of this model. The reservoirs were composed of lithic arkose and feldspathic litharenite, and were deposited in shallow river facies. At present, the reservoirs in northeastern Wangjiatun region are in the late diagene-tic stage B, with the maxi-mum porosity of 14%-16%; and the reservoirs in western Wangjiatun region are in the late diagenetic stage C, with poorer reservoir petrophysical properties and the maximum porosity of 10%-12%.