摘要
针对深部煤储层埋藏深、渗透率低、应力环境复杂等开发难题,总结大宁—吉县区块近5a勘探开发取得成果,明确了资源富集条件、有效改造体积、水平段长、良好储盖组合条件是气井高产关键因素.在"人造气藏"开发理论指导下,建立了地质-工程一体化背景下的深部煤层气高效开发技术体系:①基于储层资源条件、构造保存条件和工程改造条件三大类11项指标,建立深部煤层气地质工程开发甜点评价标准;②基于微幅构造刻画、多尺度裂缝预测、三维地质模型构建等技术,形成"地质+工程"全要素定量化、可视化表征的煤储层精细评价技术;③按照"地质小尺度、三维地震微尺度、轨迹走靶体、少调快钻"导向思路,形成以钻前轨迹精优设计、精准入靶及靶后微调为核心的三阶段地质工程一体化导向技术;④按照实现资源动用和采收率最大化为目标,形成"地应力场、天然裂缝场、人工裂缝场、井型与方位、井网井距"五位一体井网优化设计技术;⑤依据深部煤层气赋存特征、渗流机理和气井生产特征,形成以产量不稳定分析法为主,经验产量递减法、数值模拟法和经验类比等多方法结合的气井产能评价及EUR预测技术;⑥遵循"四位一体"精准选段和"井间交错+段内差异化"设计原则,形成以构建人造气藏为目标的大规模体积压裂技术;⑦根据气井气水变化特征,形成全生命周期不同生产阶段排采优化控制技术;⑧结合当前AI技术进展与深部煤层气开发规律、集输等特征,探索了地质、工程、地面等多专业一体化协同环境下集输和数智化技术.在这一成果指导下,已投产 29口水平井生产初期日产量5×104～16×104 m3,平均 10.2×104 m3,区块日产气量突破 300万m3,对加快鄂尔多斯盆地东缘深部煤层气规模上产具有重要指导意义,也为同类资源高效开发建立了参考标准.
Abstract
Aiming at the development problems of deep coal reservoirs,such as deep burial,low permeability and com-plex stress field,this paper clarifies that the resource enrichment conditions,effective fracturing volume,effective hori-zontal section length,and good reservoir conditions are the key factors for high productivity on the basis of summarizing the exploration and development practice of the Daning-Jixian Block in the past five years.Under the guidance of the the-ory of"artificial gas reservoir"development,a technical system for the efficient development of deep coalbed methane was preliminarily established as follows.①According to the reservoir resource conditions,structural preservation condi-tions and engineering fracturing conditions,a total of 11 indicators in three categories established the geological-engineer-ing"dessert"evaluation standards of deep coalbed methane.②Based on the techniques such as microstructural character-ization,multi-scale fracture prediction,and 3D geological model construction,the quantitative and visual characterization of all elements of"geology + engineering"of deep coal seam was achieved.③Based on the guiding idea of"geological small scale,three-dimensional seismic microscale,drill along the target,less adjustment and fast drilling",a three-stage geological-engineering geo-steering technology with an excellent design of pre-drilling trajectory,precise target entry and post-target fine-tuning as the core was developed.④The optimization design of the five-in-one well network based on"in-situ stress field,natural fracture field,artificial fracture field,well type and orientation,well network and well spacing"realized the maximization of resource utilization and the maximization of gas field recovery.⑤According to the occur-rence characteristics,seepage mechanism and production characteristics of deep coalbed methane,a reasonable produc-tion capacity evaluation and EUR prediction technology based on the rate-transient analysis method,the empirical produc-tion decline method,the numerical simulation method,and the empirical analogy method was formed.⑥Following to the design principle of"four-in-one"precision fracturing section and"fracture staggering + differentiation between fracturing segments",a large-scale volumetric fracturing technology aimed at constructing artificial gas reservoirs was proposed.⑦According to the characteristics of gas-water variation in gas wells,the optimal control technology of drainage and pro-duction in different production stages through the whole life cycle of wells was put forwarded.⑧Combined with the cur-rent progress of AI technology,and the characteristics of deep coalbed methane development law,gathering and transport-ation,the technology of gathering,transportation and digital intelligence integrating geological,engineering,and ground aspects was explored.Under the guidance of this achievement,29 horizontal wells that have been put into production,with an initial production of 5×104-16×104 m3/d,an average of 10.2×104 m3/d,and the daily gas production of the block has ex-ceeded 3 million cubic meters,which has important guiding significance for accelerating the large-scale production of deep coalbed methane in the eastern margin of the Ordos basin.Also the study establishes a reference and standard for the efficient development of similar resources.
基金项目
中国石油前瞻性基础性科技攻关计划(2021DJ2301)
中国石油科技专项(2023ZZ1804)
维普
万方数据