泥饼弹塑性影响因素研究

An Experim entalStudy on the FacAn Experim entalStudy on the Factors Influencing the Plastoelasticity of Drilling Fluid Filter Cake

泥饼弹塑性反映泥饼在渗透、压缩、多孔和摩阻等方面的综合特性．主要就惰性固相颗粒粒度分布和包被性聚合物对反映这些性能的各参数的影响进行了实验研究．证实了泥饼的弹塑性和泥饼的强度是一对矛盾．含有细的和粒度分布大的固相颗粒的泥饼结构致密，可压缩性和渗透性小．聚合物含量增大使泥饼结构疏松，含水率和压缩性大．对吐哈油田１７ 口井的现场泥浆的泥饼质量进行的检测表明，ＡＰＩ失水泥饼实厚一般不超过１ｍ ｍ ，其强度多在１００ ～１５０ｇ；ＨＴＨＰ泥饼实厚在１ ～１．５ｍ ｍ ，强度为１５０～４５０ｇ，最高可达到５００ｇ 以上．但由于ＨＴＨＰ泥饼密性好，致密层厚，一般韧性稍差．

The plastoelasticity ofdrilling fluid filter cake is the com prehensive behaviorofits perm eability, com pressibility, porosity and lubricity. The influence isstudied ofthe grain sizedistribution ofinertsolid parti- cles and inclusion polym ers in drilling fluid on the param eters. Experim entalstudy show s that the plastoelasti- city offilter cake is opposite to its strength. The fine solid particles distributing in a large grain size range in drilling fluid m ake the structure offiltercake denserand itscom pressibility and perm eability less. High contentofpolym er in drilling fluid m akesthe structure offiltercake looser, and itsporosity and com pressibility greater. Theevaluation ofthe quality ofthe filter cakesin 17 w ells show sthatthe realthicknessoffiltercake from API filtration testis generally m ore than 1m m , its strength is100～150g;the realthickness from high-tem perature and high-pressure(HTHP)filtration testisin therange of1～1.5m m , and thestrength is150～450g, even 500 g. HTHPfiltercake is denser, the thicknessofdense layer is greater, butitsductility isw orser.