不同程度水洗油层聚合物驱适应性室内实验研究

Experiment Study on Adaptability of Polymers for Flooding Reservoirs of Different Water Flooded Degree

基于大庆油田杏12-3-检3222井葡Ⅰ3层取心解释资料，选取水驱油效率分别为70～80％、40～50％及10～20％的强、中、弱三种不同水洗程度天然岩心，测定黏度相同（40～45mPa·s）、浓度不同（1．5、1．3、1．1g／L）、名义相对分子质量M不同（1．7×10^7，2．5×10^7，3．5×10^7）的大庆HPAM聚合物溶液产生的残余阻力系数，均小于20，即均未引起岩心堵塞，考虑流量～压差曲线，排除了M最小的聚合物。在接长至30cm的洗油天然岩心上进行驱油实验，分别注入M、浓度（g／L）、45℃工作黏度（mPa·S）分别为2．5×10^7、2．0、194和3．5×10^7、15、173的聚合物溶液0．54PV，采收率分别比水驱增加4．513％和4．003％。强、中、弱水洗程度的3支30cm岩心并联驱油，分别注入聚合物溶液（M=2．5×10^7，浓度1．3g／L），聚合物凝胶调剖剂（至1／3、1／2岩心长度）＋聚合物，注入化学剂总量0．64Pv，采收率分别提高17．06％、21．12％、22．03％，调剖＋聚驱使中水洗特别是弱水洗岩心的采出程度明显增大。给出了半径1／3调剖＋聚驱的采收率、含水、岩心分流率曲线。M=2．5×10^7的聚合物较能适应大庆不同水洗油层，聚合物驱前深部调剖可提高中等和弱水洗油层的动用程度。图3表5参4。

Based on coring interpretation data of Xing12-3-3222 well at Pu 1 3 layer in Daqing, the strong, medium, and weak waterflozded reservoir cores with percentage oil displacement（OD） 70--80% ,40--50% and 10--20%, respectively, are injected with solutions of Daqing HPAM polymers of similar viscosity （40-45 mPa·s）, different concntration （1.5,1.3,1.1 g/L） and different nominal molar mass M（1.7 × 10^7, 2.5 × 10^7, and 3.5 × 10^7 ） and the residual resistance factor obtained is less than 20 in all these cores, indicating no polymer blockages created, the lowest M polymer is excluded with flow rate-pressure drop curves taken into consideration. In OD experiments on deoiled cores 30 cm long, injecting 0.54 PV of polymer solution （PS） of M = 2.5 × 10^7 or 3.5× 10^7, concentration 2.0 or 1.5 g/L, and working viscosity at 45℃ 149 or 173 mPa＇s leads to an enhancement in oil recovery （EiOR） 4. 513 % or 4. 003 %. In OD experiment on parallel three core sets of strong, medium, and weak waterflood degree, injection of （1）a PS （M=2.5× 10^7, 1.3 g/L） ,（2） a plymer gelling profiling agent to 1/3 core length followed by the PS, and （3） as （2） but to 1/2 core length in total volume of chemicals injected 0.64 PV leads to an EiOR of 17.06 %, 21.12 %, and 22.03 %, respectively, and the EiOR in medium and, particularly, in weak waterflooded cores is notably increased for the profiling＋ polymer rico：ling procedures. The oil recovery, water cut, and partial flow rate curves are presented for the 1/3 core length profiling ＋ polymer flooding procedure. It is concluded that Daqing＇s polymer of M= 2.5× 10^7 is adaptable to the Daqing reservoirs of various waterflood degree and an indepth profile modification followed by a polymer flood significantly promotes the oil mobilization in medium and weak walerflooded layers.