强水敏储层洗井过程的储层伤害及保护  

Reservoir Damage and Protection During Well Flushing Operation for a Strong Water Sensitivity Reservoir

作　　者：叶禹 宁坤 穆凌雨 左琴[2] 马莉娜 梁佳莹 王秀宇[4] 温远国 张雅 YE Yu;NING Kun;MU Lingyu;ZUO Qin;MA Lina;LIANG Jiaying;WANG Xiuyu;WEN Yuanguo;ZHANG Ya(CNPC Engineering Technology R&D Company Limited,Beijing,China;No.5 Oil Production Plant of PetroChina Changqing Oilfield Branch,Xi′an,Shaanxi 710000,China;Laojunmiao Oil Production Plant of PetroChina Yumen Oilfield Branch,Gansu,Jiuquan 735000,China;College of Petroleum Engineering,China University of Petroleum,Beijing 102249,China;Petroleum Development Center of Shengli Oilfield,Sinopec,Dongying,Shandong 257000,China)

机构地区：[1]中国石油集团工程技术研究院有限公司 [2]中国石油长庆油田分公司第五采油厂 [3]中国石油玉门油田分公司老君庙采油厂 [4]中国石油大学(北京)石油工程学院 [5]中国石化胜利油田分公司石油开发中心有限公司

出　　处：《钻采工艺》2023年第6期120-125,共6页Drilling & Production Technology

基　　金：中国石油横向项目“储层敏感性分析及岩心驱替实验测试”(编号:HX20200340)。

摘　　要：G储层在油井热洗清蜡后滞留的洗井液易与原油乳化堵塞地层。该储层含有35%的伊/蒙混层,易发生膨胀导致强水敏。针对该现象利用水化膨胀实验定量分析黏土矿物在不同条件下的膨胀程度、利用试管法以及显微镜观察法测定了原油乳状液的析水率和乳状液形态,最后利用室内驱替实验测定了防膨剂和破乳剂在提高采收率方面的效果。研究表明,利用3%的AYL防膨效果最好且岩心伤害率最低,黏土膨胀率只有16.87%,远低于在地层水中的膨胀率29.6%;洗井液与原油形成的乳状液最稳定,浓度为1.5%的PRJ1破乳效果好于PRJ2;浓度为3%的AYL和1.5%的PRJ1岩心驱替后采收率从29.25%增至45%,说明该配方在一定程度上可以缓解洗井液渗入近井地带对储层造成的伤害。该研究对强水敏性储层的洗井清蜡操作具有重要的指导意义。In G reservoir,after the oil wells are thermally washed to remove the wax,some wells have the flushing fluid for a long time,resulting in reservoir pollution caused by generation of crude oil emulsions.Furthermore,the clay minerals in G reservoir contain 35%of the smectite/smudge layer,which is prone to clay swelling and strong water sensitivity.The hydration swelling experiment was used to quantitatively analyze the swelling degree of clay minerals in this block in different conditions.Bottle test and microscope were used to test water dissolution rate and observe emulsion morphology,separately.Core flooding experiments were performed to check the effect of clay stabilizer and demulsifier in enhanced oil recovery.The study showed that the use of 3%AYL had the best anti-swelling effect,and the clay swelling rate was only 16.87%,which was much lower than the swelling rate in formation water 29.6%,and the core damage rate was the lowest.The emulsion formed by the well flushing fluid and the crude oil is the most stable,and it is easy to block the pores,and PRJ1 with a concentration of 1.5%has better demulsification effect than PRJ2.Based on core flooding experiments,after adding AYL anti-swelling agent with a concentration of 3%and PRJ1 with a concentration of 1.5%to the well flushing fluid,the recovery factor increases from 29.25%without additives to 45%,which can alleviate the damage to the reservoir caused by the penetration of the well flushing fluid into the near-wellbore zone to a certain extent.This study has important guiding significance for the well flushing and wax removal operation in highly water-sensitive reservoirs.

关 键 词：洗井清蜡 水化膨胀 黏土稳定剂 原油乳状液 采收率 

分 类 号：TE258[石油与天然气工程—油气井工程]