摘要
外围三低油田经过多年开发,单井及油田产量逐年递减,初次压裂失效后单井及油田产能的恢复必须通过重复压裂才能得以保证。随着同井同层重复压裂次数增多,常规复压技术增油效果和有效期大幅度下降,油井储量动用程度差。这是由于常规同井同层重复压裂只能张开老裂缝,可以部分恢复老缝导流能力,但受老缝壁面的压实作用和井网条件限制,即使规模增大,增产效果也不理想。为此,针对外围油田压裂形成垂直裂缝的特点,研究应用了裂缝转向重复压裂新工艺,形成了以重复压裂裂缝转向机理、储层地应力场变化规律、转向裂缝参数设计优化、转向裂缝监测识别及裂缝转向重复压裂施工工艺为核心的配套工艺技术。通过实施可实现压开一条与原缝方向不同的水力裂缝,增加了新的泄油面积,提高了外围重复压裂井效果。
Peripheral oilfields with low permeability, low abundance and low productivity in Daqing have been de- veloped for many years. Single well and total production declines year by year. After first fracturing, single well and total oilfield productivity must be guaranteed only by repeated fracturing. With increasing times of fracturing for same well and same layer, increasing oil effect and effective period dramatically decline by using conventional re- peated fracturing technique, with low producing degree. The reason is, conventional repeated fracturing for same well and same layer only opens old fractures and can partly restore their flow conductivity. Limited by compaction of old fracture walls and well patterns, extending fracturing scale cannot get high stimulation effect. Thus, based on the characteristics of vertical fractures formed by fracturing in peripheral oilfields, new technique of fracture re-ori- ented repeated fracturing is developed, form supporting techniques including fracture re-orientation mechanism of repeated fracturing, variation rules of reservoir stress field, parameters design optimization of re-orientated fracture, monitoring identification of re-orientated fracture and operation of re-oriented repeated fracturing. Using these tech- niques can get a hydraulic fracture with opposite direction to original fracture, so as to increasing drainable area and improving repeatable fracturing effect.
出处
《大庆石油地质与开发》
CAS
CSCD
北大核心
2009年第6期200-204,共5页
Petroleum Geology & Oilfield Development in Daqing
关键词
特低渗透
重复压裂
转向机理
改造效果
ultra-low permeability
repeated fracturing
re-orientation mechanism
stimulation effect