页岩膨胀性及分散性特征实验分析  

An experimental analysis of expansibility and diffusion of shale rocks

作　　者：付永强[1] 曾立新[1] 马发明[1] 黄玲[1] 黄成惠[1] 何亚锐[1] 

机构地区：[1]中国石油西南油气田公司采气工程研究院

出　　处：《天然气工业》2012年第9期48-51,130-131,共4页Natural Gas Industry

基　　金：中国石油西南油气田公司科研项目(编号:2011ZD0405-02-03)

摘　　要：页岩通常含有一定比例的黏土矿物,大液量、大排量压裂施工可能导致黏土矿物膨胀、水化分散,而目前开展的研究工作还没有建立起相关的评价体系。为此,在借鉴前人研究成果的基础上,采用自吸实验法、吸水膨胀实验法、X射线衍射(XRD)矿物成分分析等方法对其膨胀、分散特征进行了大量的实验研究。结论认为:①对于烃源页岩而言,自吸实验、吸水膨胀实验等可作为页岩气藏膨胀和分散特征评价的有效方法;②具备生、储烃能力的页岩虽然具有较高的黏土含量,但膨胀和分散特征明显不同于常规的泥页岩及黏土含量较高的砂岩;③岩心CST(毛细管吸入时间)实验结果及膨胀实验结果表明,对于页岩气藏而言,如何有效抑制初期的自吸及膨胀应该引起高度的重视;④对四川盆地的页岩气藏而言,完井及压裂过程中由于化学原因导致的页岩膨胀、分散特征等不属于井壁稳定性及压裂方案设计考虑的主要因素。Shale is a fine-grained,clastic sedimentary rock composed of mud that is a mix of clay minerals and tiny fragments of other minerals.Such a huge volume of liquids load and discharge which is inevitable in the fracturing treatment of shale gas reservoir development will most probably lead to swelling and hydrous disintegration of clay minerals in the shale.However,there is no such a related evaluation system discovered in current research.In view of this,based on the previous study results,a great number of experimental studies are conducted on the expansibility and diffusion of shale rocks by use of capillary suction time(CST),water-swelling test,and X-ray Diffraction(XRD).The following conclusions are drawn.(1) As for the shale as source rocks,the above mentioned testing methods are effective for the evaluation of expansibility and diffusion of shale gas reservoirs.(2) Although shale with great capacity of hydrocarbon generation and preservation has a high content of clay minerals,its expansibility and diffusion are totally different from those of conventional mudstones or sandstones with a high content of clay minerals.(3) From the CST and water-swelling test results,attention should be first paid to how to effectively inhibit the preliminary self-suction and swelling in shale gas reservoirs.(4) As for shale gas reservoirs in the Sichuan Basin,such features as swelling and diffusion due to chemical reasons in the process of well completion and fracturing treatment should not be considered to be the major factors in maintaining wellbore stability and designing fracturing schemes.

关 键 词：四川盆地 页岩气藏 压裂 黏土矿物 膨胀性 分散特征 自吸实验 吸水膨胀实验 

分 类 号：P618.13[天文地球—矿床学]