大庆油田深层气开发钻完井关键技术应用与实践

Application and practice of key drilling and completion technologies for deep gas development in Daqing Oilfield

大庆油田外围天然气资源丰富,气藏埋深通常在4000m左右,地质条件复杂,储层可钻性差,开采难度较大,使用常规技术难以有效开发。针对深部地层硬度大、钻速慢、地温高、裸眼封固段长等技术瓶颈问题,开展了深层气开发完钻井关键技术的研究,持续优化井身结构、钻头优选、提速工具的应用及钻井液、深层气固井技术。在钻井提速和钻完井质量提升等方面不断实践,形成了3种井身结构设计模板。钻头优选应用方面,在技套中上部,多采用国产高效PDC钻头;在技术套管下部夹层、含砾地层,多采用复合钻头;登娄库组至营城组含砾火山岩地层采用非平面齿PDC钻头,充分发挥各类型钻头的特点。钻井参数强化方面,实施大钻压、大排量、大扭矩、高转速、高泵压实施“三大两高”式钻井。钻井液技术方面,深层气钻井液可达到抗温220℃,堵漏工艺可以实现对1~5mm裂缝的有效封堵。固井技术方面,形成了大温差低密度水泥浆体系和胶乳膨胀水泥浆体系等7项配套技术。形成了大庆油田深层气钻完井技术系列,为油田天然气稳定上产提供了有力技术支撑。

There are abundant natural gas resources in the periphery of Daqing Oilfield,and the buried depth of the gas reservoir is about 4,000m with complex geological conditions,poor drillability of the reservoir.It is difficult to develop the gas reservoir effectively by using the conventional technology.In order to solve the technical bottlenecks such as high hardness of deep formation,slow drilling penetration rate,high formation temperature and long open hole cementing section,the research on key drilling and completion technologies for deep gas development was carried out.Through the continuous optimization of wellbore structure,bit optimization,application of speed-up tools and research on drilling fluid and deep gas cementing technology,the continuous practice of speed-up drilling and completion quality improvement has formed three kinds of wellbore structure design templates.For the optimum application of bits,the domestic high-efficiency PDC bits were mostly used in the middle and upper part of the technical casing;the composite bits were mostly used in the interbed and gravel-bearing strata at the lower part of the technical casing;and PDC bit with non-plane teeth was adopted for the gravel-bearing volcanic rock strata from Denglouku Formation to Yingcheng Formation to give full play of the characteristics of all kinds of bits.In order to strengthen the drilling parameter,the drilling mode of large WOB,large volume displacement,large torque,high rotation speed and high pump pressure was implemented.As for drilling fluid technology,deep gas drilling fluid could reach the temperature resistance of 220℃,and the plugging process could effectively seal 1-5mm fractures.As for cementing technology,seven supporting technologies,such as low density cement slurry system with large temperature difference and latex expansion cement slurry system have been formed.A series of deep gas drilling and completion technologies in Daqing oilfield has been formed,which has provided the strong technical support for the stable production of natural gas in the oilfield.