大庆油田厚油层水淹变化及对注水开发的影响

前言大庆油田是一个陆相沉积的多油层油田,渗透率高、分布面积广、单层有效厚度大于4米的厚油层,是油田开发中的主力油层,对实现高产稳产起着决定性的作用。这种厚油层在注水开发中的水淹特点与薄油层截然不同。

CHANGES IN THE THICKNESS OF FLOOD COVERAGE OF A THICK PAY AND THEIR EFFECT ON DEVELOPMENT BY WATER FLOODING

Characteristics of water-flooding and oil production in four types of thick pay in the Daqing oil field are analysed. Composition of permeability, development of intercalations, thickness of pay, wettability and variations of pore structures are supposed to be the main factors effecting the increase of the thickness coverage of flood in a thick pay. It is proposed that the thickness change of flooding a pay is a process of gradually slowing down the rate of increase to 80% water cut as the maximum limit. With this limit as the dividing line, the development of a reservoir is divided into two stages; increasing the thickness of flood and raising the efficiency of sweep. This 80% water cut is also set as a theoretical limit for maintaining a stabilized output. The main characteristics of the two stages of development are examined and the tasks for realizing stabilized production discussed. The main objectives of study in production technology for each development stage and measures for stabilizing output are also proposed. The authors believe that finding out the laws of changes of the thickness coverage of flood in the pay to guide development by water flooding of sandstone oil pools is a new field of study that calls for immediate and wide attention.