方位伽马在煤层气水平井中的应用

Application of azimuth gamma in coal bed methane horizontal wells

水平井作为煤层气开发的一种井型,施工难度相对较大,主要体现在安全着陆、钻遇率、储层保护、防塌防卡等,其中煤层钻遇率是提高产气量的重要指标。随着钻井技术和随钻仪器的不断发展,保障储层钻遇率的相关地质参数探管、短节和地质导向技术也相继应用在煤层气水平井施工中。现阶段在煤层气水平井中,伽马探管,特别是方位伽马探管的运用较广,利用伽马测井划分岩性、地层对比、计算地层视倾角的功能,为现场决策者提供井内地质参数,能够有效地为钻井服务。本文通过一口煤层气水平井的施工,介绍了方位伽马在煤层气水平井中的应用。

As one of the well types for coal seam methane development,horizontal wells present difficulties for drilling,including safe landing,coalbed intersection rate,reservoir protection,anti‑collapse and anti‑sticking;and among them the coal seam intersection rate is an important index to improve gas productivity.With the continuous development of drilling technology and MWD tools,geological logging probes,short subs and geo‑steering technology have also been applied in the drilling of coal bed methane horizontal wells.At present,gamma probes,particularly azimuth gamma probes,have found wide use in coal bed methane horizontal well drilling.Gamma probes can provide downhole geological parameters for the field decision‑makers with their functions of lithological identification,formation correlation,and apparent formation dip calculation;thus,effectively serving the drilling.This paper describes the application of azimuth gamma probes in coal bed methane horizontal well drilling in the context of drilling of a coal bed methane horizontal well.