沁水盆地寿阳区块煤层气排采动态成因机理及排采对策  

Formation mechanism of well performance and CBM development strategy in Shouyang Block,Qinshui Basin

作　　者：康永尚[1,2] 张兵[3,4] 鱼雪 王金[1] 姜杉钰 叶建平 张守仁[3,4] 

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]油气资源与探测国家重点实验室,北京102249 [3]中海石油(中国)有限公司非常规油气分公司,北京100011 [4]中联煤层气有限责任公司,北京100011 [5]中海石油(中国)有限公司非常规油气管理处,北京100010

出　　处：《天然气地球科学》2017年第1期116-126,共11页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2011ZX05042)资助

摘　　要：以寿阳区块的静态地质资料和动态排采资料为基础,分析了寿阳区块的排采动态特征并从系统分析观和地质因素2个方面解释了排采动态的成因机理,提出了寿阳区块的排采对策。研究表明:寿阳区块排采动态呈现出单井产水量高,产气量低或不见气的特点,合层排采井的典型日产水量大于单采井产水量之和,表现出"1+1>2"的现象;典型日产气量与典型日产水量呈现负向包络关系,高产水对产气有抑制作用;造成寿阳区块煤层气井高产水的原因有2个,一是寿阳井筒—排采煤层系统为开放系统,断裂或压裂缝沟通煤层上下的含水层,造成煤层气井低效降压;二是寿阳区块煤系地层中分支河道砂体发育,且因该区发育的断裂多为高倾角断裂,当多层合层排采时,断裂沟通含水层的概率大大上升。因此,在培育高产气井时,首先要避开断层开放型系统,远离断层,其次是避开垂直压裂缝压穿型系统,因寿阳区块煤层更易压裂,故压裂时要适当降低前期采用的压裂规模,针对具体井层,需根据顶底板隔水层的厚度,保证在不压穿顶底板隔水层的前提下,优化压裂规模,以实现在规避围岩含水层不利影响的条件下最大程度地改善煤储层的渗透率。Based on the geological data and drainage dynamic data, the characteristics of drainage dynamic was analyzed,formation mechanism of well performance was explained from system theory and geological factors and CBM development strategy was proposed in Shouyang block. The study shows that the single well in Shouyang block is characteristized by ＂high water yield but low gas production＂ in the process of drainage.Multi-layer drainage produces more water than that of one layer,which leads to a phenomenon of ＂1 ＋l〉2＂.The typical daily gas production shows a negative enveloping relationship with typical daily wa- ter production meaning that high water production is detrimental to gas production.There are two factors for high water production.First,the wellbore-drainage system is an open system since faults or vertical hy- draulic fractures connect sandstone aquifers, which leads to low efficient depressurization. Second, with branch channel sand body extensively developed and high dip angle existed, faults easily connect sand aqui- fers for multi-layer drainage.Building a high productive well is essential to create a closed system borehole- drainage system by staying away faults firstly, and then avoiding vertical hydraulic fractures connecting sand aquifers.Since the coal seam is easier to fracturing,it is proposed to reduce the fracturing volume a- dopted before for future CBM exploration and development practice in Shouyang block.For a coal interval to be hydraulically fractured in a well, the fracturing volume should be optimized on considering the thick- ness of proof and floor aquifluids to avoid hydraulic link between the fracturing interval and nearby sand- stone aquifers.

关 键 词：煤层气 寿阳区块 排采动态 包络关系 含水层 开放系统 压裂规模优化 

分 类 号：TE332[石油与天然气工程—油气田开发工程]