Novel Water-Based Drilling and Completion Fluid Technology to Improve Wellbore Quality During Drilling and Protect Unconventional Reservoirs

The efficient exploration and development of unconventional oil and gas are critical for increasing the self-sufficiency of oil and gas supplies in China.However,such operations continue to face serious problems(e.g.,borehole collapse,loss,and high friction),and associated formation damage can severely impact well completion rates,increase costs,and reduce efficiencies.Water-based drilling fluids possess certain advantages over oil-based drilling fluids(OBDFs)and may offer lasting solutions to resolve the aforementioned issues.However,a significant breakthrough with this material has not yet been made,and major technical problems continue to hinder the economic and large-scale development of unconventional oil and gas.Here,the international frontier external method,which only improves drilling fluid inhibition and lubricity,is expanded into an internal-external technique that improves the overall wellbore quality during drilling.Bionic technologies are introduced into the chemical material synthesis process to imitate the activity of life.A novel drilling and completion fluid technique was developed to improve wellbore quality during drilling and safeguard formation integrity.Macroscopic and microscopic analyses indicated that in terms of wellbore stability,lubricity,and formation protection,this approach could outperform methods that use typical OBDFs.The proposed method also achieves a classification upgrade from environmentally protective drilling fluid to an ecologically friendly drilling fluid.The developed technology was verified in more than 1000 unconventional oil and gas wells in China,and the results indicate significant alleviation of the formation damage attributed to borehole collapse,loss,and high friction.It has been recognized as an effective core technology for exploiting unconventional oil and gas resources.This study introduces a novel research direction for formation protection technology and demonstrates that observations and learning from the natural world can provide an inexhaustible source of ideas and inspire the creation of original materials,technologies,and theories for petroleum engineering.

The study of formulation and performance of formate drilling and completion fluid system

Formate drilling and completion fluid system is a new type of clean organic salt brine system which has been developed from inorganic salt brine drilling fluid system. It is beneficial to protecte and find hydrocarbon reservoir. Due to the solid free system, the damage of solid phase particles on reservoir, especially low permeability oil and gas layer, can be greatly eliminated, at the same time, drilling fluid and completion fluid have greater compatibility. It will avoid that precipitation which is not compatible with drilling and completion fluid and generates damages on reservoir. And because mud cake of the solid free system is thin and resilient, it is conductive to improve cementing quality greatly. Experiments show that the formate drilling and completion system has good rheological property, strong inhibition ability, good lubricating performance, good compatibility with reservoir rocks and formation water at high temperature.

Research and application of non-clay low damage temporary bridging drilling/completion fluids system

Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate (CaCO3) particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drilling,NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours,respectively,and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability. The results showed that the permeability recovery rate of the core reached 90% or so,and the damaged depth was less than 1 cm,which demonstrates that NLTDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system. NLTDFS has been used to drill many horizontal wells,and four of them have obtained high yield of natural gas. The yield of natural gas of LP1 well reached 85×104 m3/day after completion with the rump pipe. The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.

Drilling Fluid System & Technology in Sichuan Gas Field

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Laboratory Evaluation Procedures of Formation Damage Induced by Completion Fluids in Horizontal Wells

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Petroleum Patent Used Such Monitoring Technological Like Innovation Process of Drilling Fluids with Xanthan Gum ——World Panorama

This paper aims to discuss the importance of patenting and publishing as an instrument of incentive to technological innovation in the petroleum chemistry area. The present study has examined the publications and the patent applications published from 1974 to 2014. A technological monitoring methodology for patents in drilling fluid with xanthan gum has been compared using profiles of patent application in the world, with emphasis on Industrial Property Databases available on the internet (INPI-Br, Derwent, Espacenet, Patent Scope and USPTO) with intention to assess the main inventors, applications, applications’ countries, the IPC classification, years of application and category of claims as well as discuss the importance of patents as a means of encouraging technological innovation of xanthan gum. The United States and China stand out both in relation to the publication of papers as well as in the amount of patent filing in scientific publications with the theme drilling fluid with additive xanthan gum classified by the authors’ country of origin. It is observed that Brazil and the US lead the ranking with 15 publications (about 23.1% of the total). Among the 72 institutions obtained as a result, both Petrobras SA and Universidade Federal do Rio de Janeiro, in Brazil, lead the world ranking, with 6 publications each;in relation to the areas of knowledge, it is observed that engineering stands out in the publication of papers and the areas of chemistry, engineering, energy fuels and polymer science are noticeable in numbers of patent applications. The analysis of patent filings in the periods proposed features a significant percentage associated with the classification C09K.

Exploring the Promises and Challenges of Urban Air Mobility (UAM)

This paper is focused on a higher-level report of a new generation of Unmanned Aerial Vehicle (UAV) technologies. Starting from the structural scalability of civil tiltrotors, design strategy and requirements for UAVs, and advanced composite materials, the increased speed and productivity requirements for tiltrotors have spawned several investigations associated with proprotor aero elastic stability augmentation and aerodynamic performance enhancements. The research emphasized the Large Civil Tilt Rotor as the configuration with the best potential to meet the technology goals, and the design, including the challenges of the Large Civil Tilt Rotor (LCTR). The design presented was economically competitive, with the potential for substantial impact on the air transportation system. The research includes some manufacturers of helicopters, drones and tiltrotors carrying out design studies and production of prototypes, as well as research projects aimed at designing, manufacturing, qualifying, and flight-testing the new wing of the Next-Generation Civil Tiltrotor Technology Demonstrator. Promises of Vertical Take-off and Landing (VTOL) aircraft, UAVs, Digitalization of Urban Air Mobility (UAM), and the “U-space” concept are discussed in the paper. The eight SUMP principles and possibilities of future advancements are emphasized.

Research progress and prospect of plugging technologies for fractured formation with severe lost circulation

By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured formations have been summarized. Meanwhile, based on the types of lost circulation materials, the advantages, disadvantages, and application effects of corresponding plugging technologies have been analyzed to sort out the key problems existing in the current lost circulation control technologies. On this basis, the development direction of plugging technology for severe loss have been pointed out. It is suggested that that the lost circulation control technology should combine different disciplines such as geology, engineering and materials to realize integration, intelligence and systematization in the future. Five research aspects should be focused on:(1) the study on mechanisms of drilling fluid lost circulation and its control to provide basis for scientific selection of lost circulation material formulas, control methods and processes;(2) the research and development of self-adaptive lost circulation materials to improve the matching relationship between lost control materials and fracture scales;(3) the research and development of lost circulation materials with strong retention and strong filling in three-dimensional fracture space, to enhance the retention and filling capacities of materials in fractures and improve the lost circulation control effect;(4) the research and development of lost circulation materials with high temperature tolerance, to ensure the long-term plugging effect of deep high-temperature formations;(5) the study on digital and intelligent lost circulation control technology, to promote the development of lost circulation control technology to digital and intelligent direction.

钻井利器的故事之“护壁堵漏材料”

近年来,作为入地最为关键手段的钻探所面临的地层越来越复杂,钻孔垮塌、掉块、缩径和超径等事故发生概率增加,严重制约了钻探工程质量与效率的提升。护壁堵漏材料是钻探工程不可或缺的关键性工程材料,护壁堵漏技术则是保证钻进工作安全、快速以及持续进行的重要技术环节,是复杂地层钻孔处理的主要内容。本文从科普的角度介绍了护壁堵漏材料的基本概念与组成、冲洗液护壁堵漏作用、水泥基材料护壁堵漏作用、护壁堵漏材料的进一步发展空间等,以期加深对护壁堵漏材料的认识,促进新型护壁堵漏材料的研发和应用。

渤海C油田馆陶组储层堵塞实验评价研究

为了分析明确渤海C油田导管架期间预钻井的12口生产井,在组块安装后投产产量达不到配产目标的原因,针对有机质沉积、原油乳化堵塞、流体配伍性、钻完井液漏失与返排等潜在储层伤害因素,开展了储层堵塞实验评价研究。实验结果表明:1)免破胶无固相钻开液(EZFLOW)漏失量越高渗透率伤害程度越大,同时考虑钻完井液漏失时,天然岩心的渗透率伤害程度为37%,伤害程度中等;2)有机质沉积对储层伤害较为明显,注入0.4 PV原油后渗透率伤害程度达到98%,且随有机质沉积量的增加,储层伤害越大;3)油包水型乳状液(W/O型)驱替对岩心渗透率伤害程度高达75.01%,水包油型乳状液(O/W型)驱替对岩心渗透率伤害程度为25.21%,低含水层受原油乳化堵塞影响较明显。综合分析认为,渤海C油田12口预钻井低产原因为导管架预钻井后待组块安装期间关井静置过程中有机质沉积和原油乳化伤害。同时,渤海C油田12口预钻井目的层馆陶组储层物性因子较小,产液指数较低是导致低产的原因之一。研究结论为后续增产措施以及方案提供了依据。

干热岩定向钻井关键技术研究与应用

为推动干热岩产业化步伐,中国地质调查局在青海共和盆地部署了我国首例干热岩试验性开发工程,采用一口直井注入和两口定向井采出的开发模式,文章就定向井钻井关键技术进行研究与应用。青海共和盆地干热岩主要为花岗岩,地层硬度大、研磨性强、温度高,加上大规模储存改造的影响,定向井钻井作业存在机械钻速低、碎岩工具寿命短、测量仪器耐温差、信号不稳定、井眼轨迹控制难度大等技术难题。为保证钻井作业顺利推进,从井眼轨迹控制、提高井下工具耐温耐磨能力、提高钻井液高温流变性能、钻井液主动降温等技术手段入手,创新研发了耐高温MWD、抗高温聚合物钻井液体系、螺旋板式钻井液冷却装置等关键技术与装备,优选了“牙轮钻头+单弯螺杆+MWD”钻具组合,安全高效地完成了双靶点定向井施工,AB靶心的中靶精度分别为4.85 m和8.97 m,钻井周期缩短20%以上,并取得了最高进尺175.00 m、最快机械钻速3.74 m/h的提速增效成果。

绒囊暂堵液堵漏机理研究

绒囊流体因其具有较好堵漏性能,广泛应用于钻完井、修井等石油工程勘探开发各个阶段。明确绒囊流体堵漏的微观机理可以更好的指导现场堵漏。室内测定了绒囊内绒囊的粒径分布、封堵岩心的孔喉分布及封堵压力,利用微观实验装置观测其基质孔隙内的充填暂堵过程,最后结合理论分析明确绒囊流体微观堵漏机理。结果表明,体系内绒囊的粒径分布0~350 μm,岩心孔喉的粒径分布0.7~15 μm,同一绒囊流体封堵4种岩心封堵压5.42~17.65 MPa且随着渗透率的减小而增大,绒囊通过聚集、变形可对基质孔喉、微裂缝进行全面封堵。根据拉普拉斯定理结合室内实验结果可知,绒囊流体堵漏的微观机理为:岩心内的绒囊流体在流动过程中压缩变形产生了附加阻力,大量的附加阻力相互叠加产生了封堵压力,阻止了井漏的发生。

浅谈金坛储气库钻井提速提质技术

金坛储气库已经钻井近20年,在钻进中存在漏失、盐层段井径扩大率高、砂砾石钻头磨损大等施工问题,导致钻井周期长、钻进时效低。针对金坛盐矿钻进中出现玄武岩漏失、阜宁组盐层易溶解、砂砾岩发育、直井轨迹控难、固井质量要求高等问题,总结现有已钻井施工的问题,形成了防斜打直钻井技术、新型饱和盐水钻井液技术、防漏堵漏技术、防气窜固井技术等金坛矿区盐井钻井关键技术,为后续钻井的设计和施工提供新的思路。

琼东南盆地所在区块系列井钻井液侵入损害综合分析及优化

琼东南盆地属于中孔低渗储层,储层易发生水化、水锁等伤害。当前区块系列井所用深水钻井液侵入损害类型、机理不明,且传统的钻井液伤害评价方法误差大,不能直观地量化损害程度。因此设计了以钻井液污染实验、扫描电子显微镜(scanning electron microscope,SEM)分析、计算机断层扫描(computed tomography,CT)结合的方式分析钻井液固相以及液相侵入损害储层的方法。结果表明,深水钻井液与地层水配伍性良好,储层水锁损害率处于19.8%~31.4%,液相侵入损害主要为水锁损害;岩心SEM扫描结果显示其孔隙连通性差,EDS测试结果中Ba^(2+)、Ca^(2+)含量较高,分析固相侵入损害主要由加重剂引起,且蒸馏水返排后岩心CT扫描结果显示孔隙度微幅上升表明固相堵塞很难通过自然返排的方式清除。于是通过研发降滤失剂和优选加重剂粒径配比的手段优化深水钻井液储层保护性能。根据理想充填理论,确定最佳配比为1000目CaCO_(3)、600目CaCO_(3)和200目CaCO_(3)的比例为5∶11∶9。优化后体系滤失量显著降低,固相颗粒中径在90μm左右,滤饼致密程度明显提高;渗透率恢复值提高12.1%~19.68%,对该区块钻井液储层保护性能优化具有指导意义。

基于专利情报的全球钻井液技术进展与我国发展对策研究

本文基于Incopat和Innography两个专利数据库平台,应用专利信息分析方法,对全球钻井液技术领域专利申请趋势、技术生命周期、技术来源及分布国家/地区、主要申请人等进行全景展示,并着重对水基钻井液、油基钻井液及合成基钻井液技术功效和关键技术进展路线进行了深度研究。研究结果表明,全球钻井液技术处于成熟期,当前及未来一段时间内专利申请量保持高位,发展前景较好但准入门槛较高;中美两国是全球钻井液技术领域的领导者,但美国相关企业表现更为突出;提升井壁稳定性、加强储层保护、满足环保要求等是当前钻井液技术研究的重点,实现钻井液的智能化和定制化则将成为钻井液技术未来的研究目标,我国相关研究人员及企业应及时跟进,在技术创新和专利布局上同步占据有利位置。

抗高温水基钻完井液作用机理及性能评价

随着深水油气资源开发逐渐转向高温高压油气田,钻完井液体系面临着极端温压条件下维持性能稳定性的挑战。采用高温高压失水仪和岩心流动实验装置,对新配制的抗高温水基钻完井液体系进行了一系列封堵性能和动态损害评价实验。结果表明:在160℃/16 h老化条件下,该钻井液体系展现了优异的流变性和滤失性能,API滤失量从4.3mL减少至2.8 mL,HTHP滤失量控制在11.5 mL以内。此外,通过加入1%~2%柔性颗粒RXK显著提高了岩心渗透率的恢复,截至岩心2 cm部分后的渗透率恢复值大多达到70%以上。该研究证明了所研制钻完井液在HTHP条件下具有出色的封堵效果和渗透率保护能力,对于实际高温高压油气井的钻探作业具有重要的应用价值和实际意义。

基于定向钻探技术的深部矿井突水点封堵方案优化

随着矿井开拓深度增加,深部突水点封堵难度高、工程量大等问题日益突出。地面多分支水平定向钻探技术是解决问题的有效手段,施工技术难点主要是井眼轨迹控制、井壁稳定控制和注浆效果提升。基于以上问题,以焦作矿区吴村矿为例,提出突水点的优化封堵方案;采用增加偏心垫块的方法改进螺杆钻具结构,以提高对井眼轨迹的控制;采用钾铵基聚合物钻井液体系优化处理剂配比方案,以改进井壁稳定控制;采用变频调速注浆泵及二次搅拌工艺,以提升注浆效果。结果表明:工程结束后吴村矿井筒水位最大降幅达6.53 m,堵水效果显著。

南缘超高压致密气藏应力敏感及钻井液污染研究

储层低渗特征和钻井液污染是影响低渗气藏有效建产的主要因素。基于耐超高温高压实验系统和CT扫描技术研究了新疆油田南缘区块1个高温超高压致密气藏(158.6℃,146 MPa)渗透率应力敏感性以及钻井液污染特征。研究结果表明,1)储层岩芯孔隙中90%以上为粒间孔,且少量粒间孔被方解石胶结物和沥青全充填半充填;2)在净应力110 MPa下,所考察的两块柱塞岩芯(0.0019 mD,0.0325 mD)的应力敏感渗透率降低率(相对于储层实际净应力下)分别为39.28%和16.04%,属于中等偏弱和弱敏感;3)定性和定量表征了另外两柱塞块岩芯(0.0042 mD,0.0290 mD)在实际操作工况下钻井液侵入特征,发现钻井液均没有突破两块岩芯长度,侵入渗透率为0.0290 mD岩芯的深度为3.86 cm,但引起的表皮系数达到6.54,表现为严重污染。研究成果对于掌握高温超高压气藏储层特征、钻井液污染认识以及后续储层保护措施建立提供了重要技术支持。

硅基材料在钻井液中的应用及研究进展

在钻井工程领域,硅基材料因其出色的物理化学特性展现巨大的应用潜力,尤其在深井、特深井的高温、高压、高盐等恶劣环境下的井下作业中。本文综述了含硅类处理剂的分类及其在钻井液中的研究现状,阐述了由无机硅酸盐、纳米二氧化硅、有机硅、复合硅作为主要成分的硅基处理剂在加强井壁稳定性、控制钻孔恶性漏失以及改善钻井液综合性能等方面的具体应用。同时,本文还探讨了硅基材料在未来油气矿产勘探开发应用中面临的技术挑战和研究方向。这对于进一步优化硅基材料技术,使其应用于复杂地层钻井工程具有重要意义。

页岩油上下地层漏失井控漏提速钻井技术

国内页岩油钻探技术趋于成熟,但钻探过程中依然存在钻井液漏失严重、机械钻速低和钻井周期长等问题,严重制约着页岩油开发的提速提效。通过分析青海页岩油前期6口井钻井数据,在明确了地层复杂情况和漏失特点基础上,将常规四开井身结构精简为二开,减少套管层序的同时实现固封漏失地层;根据漏失类型选择钻井液体系,通过改进BH-WEI钻井液关键处理剂配比,提高钻井液的稳定性、抑制性和封堵性,降低漏失量,实现有效预防漏失;同时,将螺杆钻具上下扶正器距离调整为12 m,降低滑动钻进比例;通过优化PDC钻头结构,水平段采用“高造斜率旋导ATC+低速直螺杆”定向工具等钻井技术,提高机械钻速,形成了青海页岩油控漏提速关键钻井技术。在青海页岩油区块的8口井应用了该技术,与前期钻探的6口井相比,平均单井漏失量由335.02 m^(3)降至21.08 m^(3),机械钻速由4.45 m/h提高至7.36 m/h,钻井周期由94.77 d缩短至68.26 d。现场应用结果表明,该技术可解决青海页岩油钻井技术难点,为青海页岩油资源的有效开发提供了技术支撑。