超低渗透油藏合理开发技术政策的认识与实践

UNDERSTANDINGS AND PRACTICE OF TECHNICAL POLICY FOR RATIONAL DEVELOPMENT OF EXTRA-LOW PERMEABILITY OIL RESERVOIRS

近年来，随着储量品位的逐年降低，超低渗透油藏的开发成为油田开发的重点。以鄂尔多斯盆地靖安油田大路沟二区油藏为例，通过开展“小井距矩形井网、小水量超前注水、前置酸加砂压裂、合理生产参数”等开发技术政策的探讨，研究提高超低渗透储层开发效果的配套技术，并取得了一些阶段性成果与认识。现场实践表明研究区的合理开发技术政策为：采用小井距矩形部署井网，井排走向与最大主应力方向一致，井排距500m×120m；坚持“小水量、长周期”超前注水政策，超前注水量2600—3000m^3，超前注水天数为140d，压力保持水平达到110％～120％时投产；油井改造推广应用前置酸加砂压裂工艺，针对个别厚油层采用多级加砂压裂工艺技术；采油井流压控制在3．5～4．5MPa，生产压差控制在7．5MPa左右。为鄂尔多斯盆地超低渗透储层的高效开发提供借鉴。

In recent years, with the gradual decrease of reserves quality, the development of extra-low permeability oil reservoirs is becoming the key point of oilfield development. Taking the oil reservoirs of Dalugou No. 2 Block in Qianhn Oilfield of Erdos Basin as example, through exploring the development technology policies including small- spacing rectangle well pattern, small amount of advance water injection, prepad acid sandfra, reasonable produc- tion parameters and so on, the set techniques of enhancing the development effects of extra-low permeability reservoirs are studied and a few stage achievements and understandings are obtained. The field practice shows that the technical policies of rational development are as follows： adopting small-spacing rectangle well patiern and making sure of consistent direction between well array （500m × 120m） strike and maximum main stress; Persisting in advance water injection of ＂ small amount of water rate （ 2600 - 3000m3 ） and long period （ 140d ） ＂, putting into production when the pressure kept 110% - 120% ; the technique of prepad acid sandfra popularized and applied in oil producer fracturing, and furthermore for individual thick oil layers, the technique of multi-graded sandfra is used; controlling the flow pressure of oil producers within 3.5 -4.5MPa and maintaining production pressure dif- ferential at 7.5MPa or so. All the achievements above have afforded lessons＇ for the high-efficiency development of the extra-low permeability reservoirs in Erdos Basin.