新疆准噶尔盆地白家海凸起深部煤层气勘探开发进展及启示  

Exploration and exploitation of deep coalbed methane in the Baijiahai uplift,Junggar Basin:progress and its implications

作　　者：兰浩[1] 杨兆彪[2] 仇鹏[1] 王彬[1] 刘常青 梁宇辉 王钰强 LAN Hao;YANG Zhaobiao;CHOU Peng;WANG Bin;LIU Changqing;LIANG Yuhui;WANG Yuqiang(Exploration and Development Research Institute of PetroChina Xinjiang Oilfield Company,Karamay 834000,China;Key Laboratory of CBM Resources and Dynamic Accumulation Process,Ministry of Education of China,China University of Mining and Technology,Xuzhou 221008,China)

机构地区：[1]中国石油新疆油田分公司勘探开发研究院,新疆克拉玛依834000 [2]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221008

出　　处：《煤田地质与勘探》2024年第2期13-22,共10页Coal Geology & Exploration

基　　金：国家自然科学基金项目(42272195,42130802);中国石油天然气股份有限公司攻关性应用性科技项目(2023ZZ18,2023ZZ1804)。

摘　　要：白家海凸起侏罗系煤是国内深部煤层气直井产量很早取得突破的地方,为准噶尔盆地的重要靶区。煤储层为特低灰、低水分、中高挥发性煤,孔渗系统较好。具有“古生新储”和“自生自储”两种成藏模式,煤层含气量高、游离气占比高、含气饱和度高,为优质煤层气储层。历经多年的勘探开发证明:多数直井试采无需排水降压即可快速见气(2~5 d),排采初期日产气量较高(2100~9890 m^(3)),日产水量少甚至不产水(<5 m^(3)),可自喷生产,返排率低,长期试采压力均衡下降,且具有一定的稳产期(25~60 d);煤层射孔层厚度、压裂液体系、压裂加砂比均可影响煤层气试气效果,其中冻胶、胍胶体系优于活性水-清洁压裂液体系。最新施工的彩探1H水平井试采表现出压裂开井后即高产,试采最高日产气量5.7万m^(3),日产水量少(0.5~3.0 m^(3)),表现出常规天然气特征,随后衰减稳定,表现为吸附气与游离气共同产出;与直井对比,水平井产量高、稳产时间长、压降速率小。基于研究区储层特征和含气性特征,及勘探开发历程,得到3方面启示。一是深部多类型气藏富集规律再认识:需重视油气运聚圈闭的成藏演化研究,重视深部位气水空间分配和富集规律的研究。二是深部中低阶煤储层可压性评价:针对凸起高部位孔渗系统好的中低煤阶储层,需形成适合的压裂工艺体系。三是深部多类型气藏开发方式优化:针对游离气占比高的气藏,实现游离气-吸附气的接续产出,保持降压面积稳定扩展,排采控制尤为关键。The Jurassic coals in the Baijiahai uplift,with breakthroughs made in the deep coalbed methane(CBM)production of vertical wells in the early stage in China,serve as an important exploration target of the Junggar Basin.Their coal reservoirs feature an ultra-low ash content,a low moisture content,medium-to-high volatility,and favorable porosity and permeability systems.With gas accumulation modes,namely,the paleo-source and young-reservoir made and the self-source and self-reservoir mode,the coal seams enjoy favorable gas-bearing properties,such as a high gas content,a high proportion of free gas,and high gas saturation,which establish them as high-quality CBM reservoirs.As corroborated by many years of exploration and exploitation practice of Jurassic coals in the Baijiahai uplift,the trial production of most vertical wells can quickly yield gas(2‒5 days),without requiring drainage and pressure reduction.The early-stage trial production tends to exhibit relatively high daily gas production(2100‒9890 m^(3)),low or even zero daily water production(<5 m^(3)),a capacity of natural flowing,and a low backflow rate.In contrast,the prolonged pilot production experiences a uniform pressure drop and a certain period of steady production(25‒60 days).The outcomes of the verticalwell-based pilot production can be influenced by the perforation layer thickness of coal seams,the fracturing fluid system,and the proppant ratio for fracturing.For the fracturing fluid system,gelled and guanidine gel systems outperform the active water-clean systems.The newly constructed horizontal well Caitan 1H yielded high production after fracturing,with a maximum daily gas production of 57000 m^(3)and a small daily water production(0.5‒3.0 m^(3)),characteristic of conventional natural gas.Subsequently,the production of this well exhibited decayed and stabilized,with adsorbed and free gas produced jointly.Compared to vertical wells,this horizontal well featured higher production,a longer period of steady production,and a lower pressure dro

关 键 词：准噶尔盆地 白家海凸起 深部煤层气 孔渗系统 成藏特征 勘探开发进展 

分 类 号：TE132[石油与天然气工程—油气勘探] P618.11[天文地球—矿床学]