油基钻井液堵漏用共混聚合物研究

Study on Polymer Blend Used for Controlling Loss of Oil Based Drilling Fluids

为提高油基钻井液堵漏材料的驻留能力及封堵层的稳定性,制备一种亲油共混聚合物TP-C作为堵漏材料。该材料由非晶态亲油聚合物AP、结晶聚合物聚丙烯PP及添加剂等混炼而成。在高温油相介质中,TP-C中AP部分吸油膨胀,具有表面黏结性;PP部分具有晶格结构,可有效控制TP-C中AP部分的溶解性。在80℃油相介质中,TP-C吸油2~3倍,同时具有弹性变形性和黏结性。在130℃油相介质下,TP-C整体为高弹态,具有较好的弹性强度。通过黏结及挤压架桥的协同作用,TP-C可在光滑的裂缝缝板上有效驻留;基于TP-C复配其它材料形成的堵漏剂配方,可在2 mm的裂缝缝板中形成整体密实黏结的段塞封堵层,提高封堵层的稳定性及承压能力,承压达7.5 MPa以上,能有效封堵漏层。

A lost circulation material(LCM)TP-C was developed for use in oil base muds to improve the residence of LCMs and the stability of the resident LCMs in fluid loss channels.TP-C is made by blending an amorphous lipophilic polymer AP,a crystalline polymer polypropylene(PP)and some other additives.In high temperature oils,the AP component of TP-C absorbs oils and swells,acquiring surface adhesion property;the PP component of TP-C has a lattice structure which is able to effectively control the solubility of the AP component.In an oil of 80℃,TP-C can absorb oil that is 2-3 times of the volume of TP-C itself,and also retains elastic deformability and adhesive capacity.In an oil of 130℃,TP-C as a whole shows high elasticity and has good elastic strength.Through the synergy of adhesion and squeezing bridging,TP-C is able to effectively reside on the slick walls of a fracture.A lost circulation control slurry formulated with TP-C and other materials was developed to control mud losses;it can form a whole densely bonded plug inside a 2 mm fracture,thereby improving the stability and pressure bearing capacity(which is at least 7.5 MPa)of the formations which are effectively plugged by the LCM slurry.