Study On Agent And Technique Of Water-shutoff For Horizontal Well

Horizontal well technique has been used in major oil fieldes over the world. It can increase productive area, produce at a lower pressure, improve oil recovery and raise recoverable reserves. Because of horizontal length, water is easy to break through in horizontal wells. It causes oil decrease and water increase sharply, and even leads to water passes, affects horizontal wells effect. Specific to the problem of water breakthrough easily for horizontal wells, it was studied about the reasons and types of water breakthrough and water detection methods in the paper; In accordance with performance requirements of agents for horizontal wells, five types of water shutoff agent systems were designed and researched about their performance, HPAM / Cr3+ delayed crosslinked gel system had a short gelation time and a high gel strength, 0.085MPa at 60℃; HPAM /phenolic delayed crosslinked gel system had a longer gelation time and a high gel strength, 0.08MPa at 80℃; two-groups secondary crosslinked gel system had a longer gelation time, a higher gel strength, good stability, 0.09MPa at 80℃; amphoteric polymer pre-crosslinked agent system had a larger expanded volume, a better viscoelasticity, 35 at 60×103mg/L; degradable plugging agent system had a short gelation time, a high gel strength and easily gelled out; It was measured about the performance of agent systems and assembles of agent slugs; According to different sites of water breakthrough in horizontal wells and different features of agent systems, three types of water shutoff technique were designed: bottom hole pressure balance method, general injection method and temporary water shutoff method. It guides to improve water shut-off performance of horizontal wells.