摘要
造成钻井泥浆漏失的原因有天然渗透层的漏失和重泥浆压裂诱导缝的漏失两种,其后者由于裂缝穿层长度大,漏失泥浆量大,且堵漏工程难于奏效,因此严重地影响了正常钻进。重泥浆压裂漏失的机理是由于井下存在着各种应力,当泥浆密度足够大时,这些应力将在井壁的最大主应力方向上产生足以使井壁发生张性破裂的张应力。根据该机理,便可得出这种人工压裂缝的基本特征是发生于最大主应力方向上的纵向长度很大的高角度裂缝,因此它具有特殊的测井响应。最典型的响应是深、浅双侧向测井所表现出的"双轨"现象。利用双侧向测井,再配合成像、井温、流体等测井资料就可判断泥浆漏失的层位和性质,为堵漏措施提供依据。最后,列举了井下实例并作了分析,均得到了RFT测量和试井结果的证实。
There are 2 reasons that cause the loss of drilling mud ,one is through the natural permeable formation and the other is through the fractures caused by heavy mud. As the induced fractures penetrate a long distance in the formation,the mud loss is serious and hard to prevent,so the drilling process are greatly affected. The mechanism of fracturing and leakage caused by heavy mud is the existance of various kinds of stress in the downhole. As the density of mud is great enough,these stresses will form the tensile stress that will cause the tension fracture along the maximum major stress on the well wall. Based on this mechanism,we know that these artificial fractures are high-angle fractures with a long longitudinal distance along the maximum major stress. This kind of fractures has special log response, that is'double trace'phenomenon in deep-shallow dual laterolog. Based on dual laterlog and some log data about imaging, well temperature and fluid ,the zone and properties of mud loss can be determined.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
1996年第2期19-22,共4页
Natural Gas Industry
关键词
钻井液
压力
压裂裂缝
机理
测井解释
Drilling fluid pressure,Fracturing fracture,Mechanism,Log interpretation
