低渗透油层新型降阻剂降压增注技术

PRESSURE-DECREASING AND INJECTION INCREASING TECHNIQUE OF NEW ANTIFRICTION AGENT FOR LOWPERMEABILITY OIL RESERVOIRS

受储层物性及开发方式影响,低渗透油藏在注水开发过程中存在压力传递慢、注入压力高、油井产量下降快等问题.目前主要通过酸化等方式降压增注,存在有效期短和对套管损害等缺点.通过开展室内实验,对新型降阻剂进行了筛选,并从润湿性、吸附、黏土膨胀、自发渗吸、阻垢率、抑制细菌、相对渗透性等方面进行了评价.室内实验结果表明,新型降阻剂具有较好的界面张力,很强的抗吸附能力及抑制阳离子交换能力,防膨和黏土稳定性好.矿场试验证明,新型降阻剂注入效果明显,有效地改善了吸水状况,试验井组注入压力下降,注入量增加,对应油井的产量提高,井区地层能量得到恢复.

Due to influences of the physical properties and development modes of the reservoirs, there are the fol- lowing problems such as lower pressure transmission, higher injection pressure, faster production decline, etc. for the low-permeability oil reservoirs in the process of water flooding development. At present, the main pressure-de- creasing and injection-increasing measures are acidizing and so on, while some disadvantages of shorter period of validity, casing damage and so forth are followed. Through the conducted indoor experiments, a new type of anti- friction agent is screened and evaluated from the aspects of wettability, adsorption, clay swelling, spontaneous im- bibition, scale inhibition rate, bacteria restraint and relative permeability. The experimental results show that the new agent is characterized by much better interfacial tension （ IFT）, stronger anti-absorption capacity and power to restrain anion exchange and moreover the much better swelling-proof and clay-stabilizing abilities. The field test proves that the injection effects of the new agent are obvious, thus the water intaken performances are effectively improved： for the testing well group, the injection pressures are all decreased and the injection rates are increased as well; for the corresponding oil producers, the oil productions are increased and furthermore the formation energy in the test block is restored.