Method for increasing initial production speed of SAGD (Steam Assisted Gravity Drainage)

• Main Authors: CHEN SEN, ZHANG SHENGFEI, LI XIULUAN, WANG HONGZHUANG, SANG LINXIANG, WANG LIANG, FAN YUXIN
• Format: Patent
• Language: English
• Published: 23.12.2015
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS

The invention provides a method for increasing initial production speed of SAGD (Steam Assisted Gravity Drainage). The method comprises the steps as follows: minimum principal stress of reservoirs of an oil deposit is ensured to be in the horizontal direction; 2), a steam injection well and a production well are arranged in the vertical direction of the oil deposit respectively; 3), a liquid-phase mixed solvent is injected into the production well and the steam injection well by stages, so that inter-well pressure is formed and the wells are communicated; besides, a vertical dilatation zone is formed above the horizontal wells; 4), after the liquid-phase mixed solvent is enabled to enter the dilatation zone and is immersed, a vertical low-viscosity region is formed above the steam injection well; 5), steam is injected into the two horizontal wells, or steam is injected into the production well separately, and circulating preheating is carried out; and 6), a semi-SAGD stage is shifted to, and when injection withdrawal balance between the two wells is realized and the production well and the steam injection well are in the same pressure system, a normal SAGD stage is shifted to. According to the method, the initial low-yielding time of traditional SAGD is reduced; the initial production speed and the initial oil-producing rate of the SAGD are increased; the arrival of the peak oil production is accelerated; and the economic benefit of the project is increased.