摘要
四川盆地南部地区(以下简称川南地区)的长宁国家级页岩气示范区是四川盆地页岩气开发的主战场,为厘清页岩气井水平段及压裂长度增加带来的气井产能动态影响,以川南地区的长宁区块奥陶系五峰组—志留系龙马溪组的336口气井为研究对象,采用大数据分析方法,深入剖析影响气井效益开发的靶体、压裂、排采生产一体化动态因素。研究结果表明:①高产气井具有靶体钻遇率大于70%、钻遇长度大于1200 m的特征,改进钻井工艺技术可保障高靶体钻遇率进而保障产量;②流体压力降和孔眼摩阻会削弱施工作业强度,严重影响压裂效果,采用低黏压裂液和差异化射孔工艺可有效克服该难题;③前序段“相对低排量+相对密簇距”、后序段“相对高排量+相对大簇距”可实现有效改造,并能解决邻井长期生产带来的影响;④跟端和趾端垂深差异较大易造成井底积液,严重影响前序压裂段簇效率和产量,跟趾端垂深差异在±300 m、斜率在±0.15内有利于气井高产。结论认为,长水平段压裂是气井一体化动态影响因素的综合反映,长宁区块最优水平段压裂长度为2200 m左右,研究成果为后续川南地区页岩气规模效益开发提供了理论支撑。
s:The Changning National Shale Gas Demonstration Area in the southern Sichuan Basin is a principal battlefield of shale gas development in the Sichuan Basin.In order to clarify the dynamic influences of shale gas well horizontal sections and the increase of fracturing length on well productivity,this paper takes 336 wells of Ordovician Wufeng Formation to Silurian Longmaxi Formation in Changning Block of southern Sichuan Basin as the research objects to deeply analyze the integrated dynamic factors(i.e.,target,fracturing and production)influencing the benefit development of gas wells by means of big data analysis.And the following research results are obtained.First,the target drilling rate of high-yield gas wells is more than 70%and the drilling length is more than 1200 m.The improvement of drilling technology can guarantee the high target drilling rate and even production rate.Second,fluid pressure drop and pore friction can weaken the operation intensity and seriously impact the fracturing effect.And this difficulty can be effectively overcome by using low-viscosity fracturing fluid and differentiated perforating technology.Third,the mode of"lower displacement+smaller cluster spacing"in the foresequence section and"higher displacement+larger cluster spacing"in the backsequence section can provide effective stimulation and eliminate the influence of long-term production of neighboring wells.Fourth,the vertical depth difference between heel and toe is larger,which can easily result in liquid loading at the bottom hole,so as to seriously impact the cluster efficiency and production rate of pre-fracturing stage.It is conducive to the high yield of gas wells when the vertical depth difference between heel end and toe is±300 m and the slope is±0.15.In conclusion,fracturing in long horizontal sections is a comprehensive reflection of integrated dynamic factors of gas wells,and the optimal fracturing length of horizontal section in Changning Block is about 2200 m.The research results provide a theoretical support for the subsequent scale benefit development of shale gas in the southern Sichuan Basin.
作者
沈骋
吴建发
付永强
曾波
SHEN Cheng;WU Jianfa;FU Yongqiang;ZENG Bo(Shale Gas Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2022年第2期123-132,共10页
Natural Gas Industry
基金
中国石油天然气股份有限公司科学研究与技术开发项目“水平井体积改造技术提升重大攻关专项”(编号:2021CGCGZ005)。
关键词
长宁国家级页岩气示范区
长水平井段
压裂
一体化动态评估
簇间距
垂深差异
最优压裂段长
规模效益开发
Changning National Shale Gas Demonstration Area
Long horizontal section
Fracturing
Integrated dynamic evaluation
Cluster spacing
Vertical depth difference
Optimal fracturing section length
Large-scale benefit development
作者简介
沈骋,1990年生,高级工程师,本刊青年编委,博士,主要从事非常规油气储层沉积、非常规储层增产改造理论与技术科研工作。地址:(610051)四川省成都市成华区建设北路一段83号。ORCID:0000-0002-6552-4513。E-mail:shencheng2018@petrochina.com.cn。
