新型堵漏材料的研制及性能评价

传统堵漏材料存在一定的“缺陷”,比如矿物颗粒密度过大且脆性太强,配浆易沉降且在架桥成功后会因裂缝闭合而崩解破碎,植物颗粒密度过小配浆易漂浮,经高温高压“水煮”后会变软,贝壳片、云母片脆性太强、不易变形而容易造成“封门”。它们复配堵漏成功后,在后期作业中,易失效并发生复漏。为解决传统堵漏材料存在的缺陷,通过特殊制备工艺,研制了LCC系列堵漏材料。该材料中LCC100密度在1.30～2.30 g/cm3之间可调,在25 MPa承压破碎率小于10%,在pH值为12的NaOH溶液中,150℃下热滚48 h,强度无明显变化,具有良好的耐压、耐温、耐碱性能;LCC200刚柔相济;LCC300可在压差作用下以变形的方式深入裂缝封堵,提高封堵强度。实验结果表明,LCC对孔隙型和裂缝型漏失都有较好的封堵效果;LCC在API堵漏仪钢珠床中形成的封堵层可承受7 MPa的压力而不被压穿。以水基或油基钻井液为基液配制的LCC堵漏浆,在高温高压堵漏仪中150℃下封堵楔形裂缝时可承受20 MPa的压力而不崩漏,并最终可稳压在19.8 MPa以上。 

The Development and Evaluation of A Set of New Lost Circulation Material

Conventional lost circulation materials (LCM) have some "deficiencies", for example, the particles of mineral LCM have too big density and are too brittle, thus it is easy for the particles to settle down in drilling fluids, and to crush when the formation fractures are closing. The particles of plant LCM have densities that are too low for them to mix evenly with drilling fluid, and are always float at the top of the LCM slurries. These plant LCM become soft at HTHP conditions, no longer suitable for stopping mud losses. Flake LCM, such as seashells and mica, are also too brittle and the mouth of the opening of fractures are easy to be covered by these flake LCM. In subsequent operations, the flakes are eroded away, inducing mud losses to occur again. To solve these problems, a series of new LCM, the LCC series, have been developed using special techniques. In the LCC series, the LCC100 has densities adjustable between 1.30-2.30 g/cm3, and the ratio of particles broken at 25 MPa is less than 10%. After hot rolling in NaOH solution with pH 12, no obvious changes in the strength of the particles have been found, meaning that LCC100 has good pressure resistance, temperature resistance and high pH tolerance. LC200 is an LCM that is both ductile and rigid. LCC300 can make its way into fractures under pressure, strengthening the plugging and sealing of mud loss channels. It has been demonstrated that LCC series are effective in controlling mud losses into fractures and pores; they remain their integrity at a pressure of 7 MPa on API LCM tester. Oil base or water base LCM slurries made with LCC series can stand 20 MPa on HTHP LCM tester (with wedge-shaped fractures) at 150℃, without being pierced, and the pressure can be stabilized at 19.8 MPa.