顶气边水窄油环油藏高效开发技术与实践

Efficient development technology of narrow oil rim with gas cap and edge water & its practice

对于顶气边水窄油环油藏开发,成熟的开发经验较少,高效开发难度很大。针对渤海海域JZ油田顶气边水窄油环油藏开发初期井网优选、开发中后期剩余油挖潜和气窜水锥后管理难度大的问题,以大气顶弱边水和小气顶强边水油藏为代表,开展了顶气边水油藏井网优选、油气水三相运移规律、剩余油挖潜策略、气窜水淹特征及稳油控水(控气)技术等方面研究。根据研究结果提出了水平井井网新模式,对于大气顶弱边水油藏,水平段垂向位置设计位于油柱高度的1/3处,对于小气顶强边水油藏,水平段垂向位置设计位于油柱高度的2/3处;大尺度三维物理模型及数值模拟表明,采油速度越大,油气界面及油水界面往生产井移动速度越大;结合水平井井间剩余油为"土豆状"分布的认识,提出了井间加密方案;结合工区内试采生产资料,利用油藏工程方法和数值模拟方法分别建立了见气诊断图版和见水诊断图版,有效指导了油田稳油控气(控水)措施实施。根据以上研究,JZ油田采用该系列技术开发10年,含水率控制在25.0%以内,气油比维持在700m^3/m^3以下,预计生产25年可提高采收率2.3个百分点。该研究对同类顶气边水窄油环油藏的开发具有一定的指导意义。

There is less mature experience on the development of oil rim with gas cap and edge water and its efficient development is very difficult.The narrow oil rim with gas cap and edge water in JZ Oilfield in the Bohai Sea area is faced with a series of problems during its development,e.g.well pattern optimization in the early stage of development,remaining oil potential tapping in the middle and late stages and high-difficulty management after gas channeling and water coning.To solve these problems,the well pattern optimization,oil-gas-water three-phase migration laws,remaining oil potential tapping strategies,gas channeling and water flooding characteristics and oil production stabilizing & water production controlling(gas production controlling)technologies of oil reservoir with gas cap and edge water were studied by taking the oil reservoir with large gas cap and weak edge water and that with small gas cap and strong edge water as the representatives.And according to the research results,a new model of horizontal well pattern was established.The horizontal well in the oil reservoir with large gas cap and weak edge water is vertically located at 2/3 of the vertical distance of the gas-oil contact;and that in the oil reservoir with small gas cap and strong edge water is vertically located at 1/3 of the vertical distance of the gas-oil contact.Large-scale 3D physical model and numerical simulation show that the higher the oil production rate is,the faster the oil-gas contact and the oil-water contact move towards the production well.Then,based on the cognition that the remaining oil between horizontal wells is distributed in the shape of “ potato”,the interwell filling scheme was prepared.Based on the production test data of the working area,3 gas breakthrough diagnosing charts and 2 water breakthrough diagnosing charts were set up by means of reservoir engineering method and numerical simulation method,and they play an effective role in guiding the implementation of oil production stabilizing & water production controlling(gas production controlling)measures.It is predicted from above mentioned studies that the recovery factor can be increased by 2.3% if JZ Oilfield is developed by using these technologies for 10 years with the water cut below 25.0% and gas/oil ratio below 700 m^3/m^3.The research results can be used as the reference for the development of similar narrow oil rims with gas cap and edge water.