低产低渗裂缝油田吞吐采油试验研究

头台油田是构造—岩性油藏。裂缝型、特低渗透是其显著特点，常规注水开发后经常出现严重的油井水淹，造成油田开发低效。本文以头台油田研究为例，认为对于裂缝型特低渗透油田，采用注水吞吐采油技术，通过套管直接向地层注水，利用储层毛管力作用，进行油水置换，实现单井自注自采吞吐采油，可以改善油田开发效果，减缓产量递减。适合注水吞吐采油基本条件是岩石润湿性为弱亲水和岩石饱和非润湿相。影响注水吞吐采油效果的主要因素是储层吸水状况、微缝发育状况、储层非均质性、注入体积和关井压力等。吞吐采油技术可作为改善裂缝型特低渗透油藏开发效果的一种新的模式来研究和推广。

Study on Huff and Puff Test of Oil Extraction in Ultra-Low Permeable and Fractural Reservoirs

Toutai Oilfield is a reservoir controlled by tectonic and lithologic traps with obvious characteris tics of fracture, ultra-low permeability. Water swept formation is serious when the traditional method of water injection is used. And it causes low development efficiency. Basing on the study of huff and puff technique of oil extraction through casing directly, this paper takes Toutai Oilfield as an example and gives results: for an ultra low permeable and fractural reservoir, after huff and puff oil extraction of single well through capillary force, the development efficiency of the oilfield can be improved and the decreasing production of well can be prevented by oil and water conversion. The basic condictions of huff and puff oil extraction are the weak water-loving of rock wettability and the saturanted non-wettability phase fluids in rock. Main influence factors of huff and puff of oil extraction are as follows: water absorbtion, the developing condition of mic-fractures, the inhomoge neousness of the reservoir beds, the injection water volume and the pressure of well shut-in. The huff and puff techonique of oil extraction could be applied widely as a new pattern for improving development efficitency of fractural, ultra-low permeable reservoirs.