束鹿凹陷致密油复合体积压裂技术

Hybrid stimulated reservoir volume technology for tight oil in Shulu sag

针对制约束鹿凹陷致密油储层改造瓶颈问题,以储层改造为核心,逆向设计,利用物模与数模方法论证体积压裂可行性,优选针对性压裂液体系,形成了提高砾岩-泥灰岩裂缝复杂化程度的清洁酸压与加砂压裂结合的特色体积改造压裂技术:1开展储层脆性、裂缝弱面、两向应力差等体积改造地质条件分析,结合数模结果得出体积压裂的可行性;2开展3种完井方式与5种改造工具的配套优选,形成利于提高排量促进复杂缝网形成的"筛套结合"完井方式;3针对储层超低渗易伤害的特点,进行低伤害酸液和新型液体评价实验,形成与储层配伍和低伤害特点的清洁酸与新型压裂液体系;4针对砾岩、泥灰岩不同岩性,开展清洁转向酸裂缝刻蚀实验,利用岩板进行酸与支撑剂的裂缝导流能力优化,提出砾岩、泥灰岩酸压与加砂压裂相结合的复合改造新工艺;5形成束鹿凹陷致密油改造现场高效施工及压后分层求产的配套技术。通过该种技术在束探1H等3口井15段改造中的综合应用,稳定日产油量由以往的1.2t/d提高到11.3t/d。

Aiming at tight oil reservoir in Shulu sag, this study was focused on reservoir reconstruction, and carried out reverse de- sign. The feasibility of stimulated reservoir volume was demonstrated using physical model and numerical simulation, and an optimal targeted liquid system was selected to form a special stimulated reservoir volume technology featured by integration of the clean acid fracturing with improved complexity degree of rudstone-calcilutite fissures and sand fracturing： （1） an analysis was conducted on res- ervoir brittleness, fissure weak plane, two-direction stress difference and other geological conditions of stimulated reservoir volume, in combination with aumerieal simulation results to obtain feasibility of stimulated reservoir volume; （2） the matching optimization of three kinds of completion methods and five kinds of reconstruction tools was conducted, forming the screen-casing combined comple- tion method favorable to improve discharge capacity and promote formation of complex fissure network; （3） the reservoir is more prone to damage by ultra-low permeability, assessment experiments were carried out on low-damage acid and new liquid, and devel- oped an clean acid which was compatible with reservoir and low damage to reservoir, as well as new-type fracturing fluid system; （4） according to different lithologies of rudstone and calcilutite, experiments were made on fissure erosion using visco-elastic surfactant acid, and rock plate was applied to optimize fissure conductivity of acid and proppant, thus proposing a new hybrid reconstruction technology combining rudstone-calcilutite acid fracturing with sand fracturing; （5） the matching technology of tight oil effective field reconstruction and post-fracturing stratified production was developed. Through comprehensive application of above technologies in the reconstruction of 15 sections of 3 wells such as Well ST l H, steady daily oil production was increased from 1.2 t/d to 11.3 t/d.