重构反演在断陷盆地致密储层预测的应用——以海拉尔盆地贝中油田为例

Application of reconstruction inversion in prediction of tight reservoir in faulted basin:take Beizhong oilfield in Hailar basin as an example

为了最大限度提高断陷盆地致密砂砾岩储层预测精度,从5个方面详细阐述了地震重构反演关键技术流程——测井曲线预处理、地震合成记录制作、基于频率补偿曲线重构技术、基于模型地震反演和随机地震反演方法,以贝中油田南二段为例,完成致密砂砾岩储层预测研究.研究表明,该重构反演方法分辨率和预测精度显著提高,该方法达到了致密砂砾岩储层预测的要求.并在重构反演在油田实际应用主要体现以下两点:(1)指导沉积微相划分.采用井点定相、反演切片组形的思路,综合录井、测井岩电等资料,完成南二段主力小层沉积微相的绘制;(2)有效指导高效水平井位部署.为了降低钻井失利风险,提高砂岩钻遇率,最大限度优化井网,综合构造和储层预测结果,采用探评井转注优化方式,实行"四注一采"井网方式,在区内部署了阶梯式水平井X2-P1.并通过数值模拟方法,当注采井井距300 m,且采用压裂求产方法时,预测至含水98%时,该井初期最高日产17.9 m^3,累产油6.59×10^4 m^3,采出程度22.13%.为此,提出的重构反演方法可以作为致密砂砾岩刻画的有效技术手段,这对后续断陷盆地致密砂砾岩储层含油潜力挖潜提供了有利技术支撑.

In order to maximize the downfaulted basin dense conglomerate reservoir prediction accuracy,from five aspects in detail elaborated the seismic reconstruction inversion key technology processes:log pretreatment,seismic synthetic record made,based on the frequency compensation curve reconstruction technology,seismic inversion and stochastic seismic inversion method based on the model,to Beizhong oilfield in the N2 section as an example,the complete dense conglomerate reservoir prediction research.The results show that the resolution and prediction accuracy of this reconstruction inversion method are significantly improved,and the method meets the requirements of tight conglomerate reservoir prediction.And in the reconstruction inversion in the actual application of the oilfield mainly reflects the following two points:(1)By using the idea of well point phasing and inversion section configuration,and integrating logging and log electric data,the main small layer sedimentary microfacies of the N2 section was drawn.(2)Effectively guide the deployment of efficient horizontal Wells.In order to reduce the risk of drilling failure,improve the rate of drilling in sandstone,optimize the well pattern to the maximum extent,and integrate the structure and reservoir prediction results,adopt the exploration evaluation well diversion optimization method,implement the"four injection and one production"well pattern,and deploy the stepped horizontal well X2-P1 in the area.And through numerical simulation method,when the injection and production Wells are 300 m apart and the fracturing method is adopted for production,it is predicted that when the water cut reaches 98%,the highest daily output of the Wells in the initial stage is 17.9 m^3,the accumulative oil production is 6.5910^4 m^3,and the recovery degree is 22.13%.Therefore,the proposed reconstruction inversion method can be used as an effective technical means for the characterization of dense conglomerate reservoirs,which provides a favorable technical support for the exploration of oil-bearing potential of tight conglomerate reservoirs in subsequent fault basins.