对超薄席状砂互层水平井设计的几点认识

UNDERSTANDINGS ABOUT DESIGN OF HORRIZONTAL WELLS WITH EXTRA-THIN SHEET SANDSTONE INTERBEDS

大庆外围油田低丰度薄互层油藏是经济效益低的难采储量，近年来开展了应用水平井方式开发的探索和实践，使得该类油藏得到有效开发。在设计中通过对储层特征分析和水平方向的设计取得了一些研究成果。总结在低丰度薄互层油藏水平井开发实践取得的认识主要有：①采用葡I4底标志层拉平对比方法，更能有效描述砂层的分布情况，为水平井设计和地质导向奠定基础；②认识东西向微裂缝对开发的影响不同，在肇洲油田南部设计与微裂缝东西向夹角30°水平井，在永乐、敖包塔油田南部设计微裂缝方向一致的水平井；③地震-地质结合精细地质描述开展水平井单井设计，现场提前、顺势方法地质导向是有效提高超薄砂层水平井钻遇率的必要手段。为提高薄互层水平井开发效果，还需要不断完善薄互层储层描述方法和深化裂缝对水平井开发影响的认识。

In reservoirs with low-abundance and thin interbeds, the oil is difficult to produce and possesses lower economic benefits. In recent years, the development scheme to use horizontal wells has been tried and practiced and resulted in the effective development of this kind of reservoirs. Through analysis of reservoir characteristics and design of horizontal direction, some study results have been obtained. By summarizing development practice of hori- zontal wells in reservoirs with low-abundance and thin interbeds, the mainly gained understandings are as follows： （1） by adopting flattening correlation method of the marker layer for the bottom of Pu I No. 4 interval, the distribu- tion description of the sandstone layers can be more effectively made , and thus the sound basis can be laid for the design of horizontal wells and geosteering; （2） different influences of micro-fractures with EW directions on develop- ment have been realized, the horizontal wells that form 300 angle with EW directions of micro-fractures have been designed in the south of Zhaozhou Oilfield, but the ones that are concordant with those have been done in the south of Yongle and Aobaota Oilfields ; （3） with the help of fine description by combining seismic technique and geological one , individual horizontal well has been designed, ahead-of-time and track following geosteering on the field site isthe necessary approach to effectively enhance the penetration ratios of horizontal wells in extra-thin sandstone lay- ers. To increase development effects of the horizontal wells in this kind of interbeds, reservoir description methods are still needed to be improved, and understanding of the micro-fracture influence on horizontal wells is necessary to be deepened.