摘要
射孔完井技术的发展与完善对油气田的高效测试和开采具有重要的现实意义和实用价值。但低渗透储层(如低渗煤层)采用常规聚能射孔完井时,存在压实损坏带,导致渗流阻力大、产能降低等问题。为改善低渗透储层的开发效果,提出了自清洁、后效体等新型射孔技术,但其射孔效果、适用性等问题尚不明确。基于LS-DYNA的显示时间积分算法及流固耦合机理,形成地层-水泥环-套管-射孔弹动态射孔有限元模型建立方法,制定了不同射孔技术条件下动态射孔数值模拟方案,建立了不同射孔技术的有限元模型,并开展了不同射孔技术动态射孔仿真模拟研究,基于数值模拟研究结果,对2种射孔技术的适用性进行了分析研究。结果表明:自清洁和后效体射孔较常规射孔孔深有所下降,但孔径较常规射孔扩大15%左右。孔深和孔径与抗压强度、弹性模量、围压成反比,与孔隙率成正比,负压对单一射孔效果的影响较小。针对中孔低渗、低孔低渗油气藏,自清洁、后效体射孔技术孔道容积较常规分别增大9.55%、12.23%左右,射孔效果突出。上述研究结果可为自清洁与后效体射孔技术的设计与应用提供理论支撑,对两种射孔技术的发展及其对低渗储层(如低渗煤层)油气井的增产有着重要的意义。
The development and improvement of perforated completion techniques hold great practical significance and value for efficient testing and exploitation of oil and gas fields.However,conventional shaped-charge perforation for well completion of low-permeability reservoirs(e.g.,low-permeability coal seams)suffered high seepage resistance and reduced productivity due to the presence of compaction damage zones.To achieve enhanced exploitation efficiency of low-permeability reservoirs,novel perforation techniques,including self-cleaning and after-effect perforation,have been proposed.However,their perforation performance and applicability remain ambiguous.Based on the explicit time integ-ration algorithm and fluid-structure interaction mechanism of LS-DYNA,this study proposed a method for finite ele-ment modeling of dynamic perforation simulations involving strata,cement sheaths,casings,and perforation charges.For self-cleaning and after-effect perforation techniques,this study developed a dynamic numerical simulation scheme,constructed finite element simulation models,and conducted dynamic simulations.Finally,based on numerical simula-tion results,this study analyzed the applicability of the two perforation techniques.Key findings of this study are as fol-lows:(1)Compared to the conventional perforation technique,self-cleaning and after-effect perforation techniques ex-hibit decreased perforation depths but enlarged perforation diameters,which increased by approximately 15%.(2)The perforation depth and diameter were inversely proportional to compressive strength,elastic modulus,confining pressure,and directly proportional to porosity.Meanwhile,negative pressures posed minor effects on individual perforation per-formance.(3)For medium-porosity,low-permeability hydrocarbon reservoirs and those with low porosity and low per-meability,self-cleaning and after effect perforation techniques increased the perforation channel volume by about 9.55%and 12.23%,respectively compared to conventional perforation,suggesting outstanding perforation performance.The findings of this study will provide theoretical support for the design and application of self-cleaning and after effect per-foration techniques,thus holding great significance for the development of both techniques and their application to low-permeability reservoirs(e.g.,low-permeability coal seams)for production growth of oil and gas wells.
作者
毕刚
元沛杰
韩斐
付帅帅
吴捷敏
马颖
BI Gang;YUAN Peijie;HAN Fei;FU Shuaishuai;WU Jiemin;MA Ying(College of Petroleum Engineering,Xi’an Shiyou University,Xi’an 710065,China;Shaanxi Provincial Key Laboratory of Oil and Gas Well and Reservoir Seepage and Rock Mechanics,Xi’an 710065,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2024年第5期67-76,共10页
Coal Geology & Exploration
基金
陕西省自然科学基金研究计划项目(2023-JC-YB-361)
国家自然科学基金项目(52104033)。
关键词
自清洁射孔
后效体射孔
动态仿真
LS-DYNA
适用性分析
self-cleaning perforation
after-effect perforation
dynamic simulation
LS-DYNA
applicability analysis
