双相复合凝胶堵水体系研究与应用

Research and application of dual phase colloid water plugging system

针对目前海上油田化学堵水体系难注入、封堵强度低、有效期短的问题,研制出适应海上油田的双相复合凝胶堵水体系(Dual Phase Colloid,简称DPC),并开展了相关室内实验研究,结果表明,该体系溶解时间小于5 min,初始黏度低(3 mPa·s^8 mPa·s),适应地层温度60℃~170℃,凝固后强度高(针入深度2 mm^18 mm);该体系具有良好的注入性,对油水具有选择性封堵功能,处理量为0.3 PV时,对高含水层封堵率为78.4%,中含水层封堵率为35.1%,低含水层的封堵率为15%;不同渗透率条件下,体系优先进入并封堵高渗层,渗透率级差越大,体系越不容易进入低渗层。基于研究成果,采用复合堵水体系对南海油田1口水平井开展了该技术的矿场应用,施工后措施井平均含水率下降约4%,目前含水率90%,平均日增油10.8 m3,井组累计增油量5536 m3,有效期已达8个月,控水增油效果明显。

Aiming at the problems of difficult injection,low plugging strength and short validity period in chemical water shutoff of offshore oilfield,dual phase colloid chemical water shutoff system suitable for offshore oilfield was developed.Laboratory studies show that composite DPC has the characteristics of short dissolution time(less than 5 min),low initial viscosity(3 mPa·s^8 mPa·s),suitable for formation temperature of 60℃~170℃,and high strength after solidification(insert depth 2 mm^18 mm).At the same time,DPC has selective plugging function for oil and water.When the treatment capacity is 0.3 PV,the plugging rate of high aquifer is 78.4%,that of medium aquifer is 35.1%,and that of low aquifer is 15%.Under different permeability conditions,composite system preferentially enters and blocks the high permeability layer.The greater the permeability difference is,the more difficult it is for the system to enter the low permeability layer.Based on the research results,a horizontal well in Nanhai oilfield was plugged by DPC.After construction,the average water cut of the well decreased by about 4 percentage points.At present,the water cut is 90%,and the average daily oil production is 10.8 m3.The cumulative oil increment of well group is 5536 m3.The effective period has reached 8 months,and the effect of water control and oil increase is obvious.