MMH钻井液对裂缝性油气层损害规律的试验研究

An Experimental Study on Rules of Damage to the Fissured Reservoir from Positive Electric Colloidal Drilling Fluid

在 MMH钻井液中加入一种酸溶性纤维材料 LCD,利用高温高压动失水仪在人造裂缝岩心和非裂缝岩心上进行动态模拟损害评价 ;然后用渗透率梯度仪评价岩心受损害的程度和深度。经对比分析发现 ,这种钻井液在未加 LCD前 ,虽然具有良好的滤失特性和流变特性 ,但对油气层的损害较大 ;加入 LCD后 ,在岩心裂缝处形成有效封堵 ,固相侵入深度显著降低 ,而流变性和滤失特性均很好 ;在含有 LCD的钻井液所形成的滤饼上进行酸溶性实验 ,发现滤饼在 1 5%的盐酸中完全溶解。

By adding an acid dissolving matarial LCD to the positive electric colloidal drilling fluid, MMH, an instrument of high temperature and high pressure dynamic filtration is utilized to evaluate a dynamic simulation damage to the reservoir both on an artificially fractured core and a nonfractured core induced by MMH By means of a permeability gradient meter, the degree and depth of core damaged are determined It is found from comparison and analysis that, before adding LCD to the fluid, a bigger damage would be resulted from the fluid with a good filtration and rheology An effective plugging is formed at the core fracture after adding LCD and solid invading depth is reduced, with good rheology and filtration maintained An acid dissolving experiment conducted on a filter cake of the fluid containing LCD shows that the filter cake is completely dissolved in 15% hydrochloric acid