烷基糖苷衍生物钻井液研究及其在页岩气井的应用

昭通黄金坝YS108页岩气区块目的层为下志留统龙马溪组，岩性以灰色、黑色页岩为主，存在页岩地层易掉块垮塌，长水平段摩阻大、易卡钻，井眼清洁困难等技术难题。针对黄金坝页岩气水平井的地质和工程情况，研发并应用了以NAPG、CAPG和APG为核心主剂的烷基糖苷衍生物水基钻井液技术。NAPG聚醚胺基烷基糖苷是在APG分子上引入聚醚和胺基基团而制得，提升了抑制性、抗温性和润滑性等，CAPG阳离子烷基糖苷通过在APG分子上引入季铵盐阳离子基团而制得，提升了抑制性和抗温性等，他们通过吸附成膜、嵌入及拉紧晶层等可有效降低龙马溪岩屑的Zeta电位绝对值，降低岩屑活性。体系以APG为主润滑剂，以不同粒度级配（0.03~100 μm）纳米-微米封堵材料和烷基糖苷类小分子增稠剂满足昭通区块龙马溪页岩微孔微裂缝的封堵需求。该钻井液7.5 min中压滤失量为0 mL，高温高压滤失量不大于5mL，在密度2.30 g/cm3之内，极压润滑系数小于0.10，为强抑制、强封堵和高效润滑的钻井液体系，该体系解决了以上难题，实钻过程中井壁稳定，钻井液携砂及润滑性能良好，起下钻通畅，机械钻速较使用高性能水基钻井液的6口邻井和相邻区块井位提高14.6%~18.8%。该体系较好地满足了页岩气水平井钻井、完井施工技术要求。 

Study on Alkyl Polyglucoside Derivative Drilling Fluid and Its Use In Shale Gas Drilling

The YS108 shale gas block is located in Huangjinba, Zhaotong, Yunnan Province, and the pay zone of this block is the Longmaxi formation of the lower Silurian series. The lithology of the pay zone is mainly gray, black shales which are easy to slough and collapse. In horizontal drilling, high friction and drag, pipe sticking and diffculties in hole cleaning are problems that have been frequently encountered. To mitigate these diffculties, an alkyl polyglucoside (APG) derivative drilling fluid was formulated with NAPG, CAPG and APG as the main additives. NAPG is a polyether amino APG made from APG by introducing polyether and amino groups into the APG molecular structure. NAPG has better inhibitive capacity, high temperature stability and lubricity. CAPG is made from APG by introducing quaternary ammonium group into the APG molecular structure. CAPG has better inhibitive capacity and high temperature stability. NAPG and CAPG effectively reduce the Zeta potential and hence the activity of shales. APG was used in the drilling fluid as the main lubricant, plugging agents of different sizes (0.03-100 μm) and low molecular weight alkyl glucoside viscosifer were used to satisfy the needs of plugging micro fractures found in the Longmaxi shales. This drilling fluid had 7.5 min API flter loss of 0 mL, HTHP flter loss≤5 mL. The extreme pressure friction coeffcient was less than 0.10 if mud density was less than 2.30 g/cm3. As a drilling fluid with strong inhibitive capacity, good plugging capacity and good lubricity, the APG derivative drilling fluid successfully helped solve the diffculties previously encountered. In feld application, gauge hole, good hole cleaning and good lubricity were obtained. Compared with 6 wells drilled nearby with high performance water base drilling fluids and wells drilled in an adjacent block, the well drilled with this drilling fluid had ROP increased by 14.6%-18.8%. The use APG derivative drilling fluid has satisfed the needs for horizontal shale gas drilling and well completion.