Rheological property of low-damage,ideal packing,film-forming amphoteric/sulfonation polymer drilling fluids

Low-permeability dense reservoirs,including micro-fractured reservoirs,are commonly characterized by high content of clay substances,high original water saturation,high sensitivity to invasive fluids,high capillary pressure,complicated structure and anisotropic,high flow-resistance and micro pore throats etc,.Generally they also have lots of natural micro fractures,probably leading to stress sensibility.Main damaging factors in such reservoirs are water-sensibility and water-blocking caused by invasive fluids during drilling and production operations.Once damaged,formation permeability can rarely recovered.Numerous studies have shown that damaging extent of water-blocking ranges from 70% to 90%.Main damaging mechanisms and influencing factors of water-blocking were systematically analyzed.Also some feasible precaution or treating approaches of water-blocking were put forward.In a laboratory setting,a new multi-functional drilling fluid composed mainly of amphion polymer,sulfonation polymer,high effectively preventive water-blocking surfactants,ideal packing temporary bridging agents(TBA) and film-forming agents,etc.,were developed.New low-damage drilling fluids has many advantages,such as good rheological properties,excellent effectiveness of water-blocking prevention,good temporary plugging effect,low filtration and ultra-low permeability(API filtration≤5 mL,HTHP filtration≤10 mL,mud cake frictional coefficient≤0.14,permeability recovery>81%),can efficiently prevent or minimize damage,preserve natural formation and enhance comprehensive development-investment effect in TUHA Jurassic dense sandstone reservoir formation with low-permeability,the only one developing integrated condense gas field.Some references can be provided to similar reservoir formations.

Development of Film Forming Agent HN-1 and Its Application in Drilling Fluid

Borehole instability and reservoir damage had become the international technical problems of petroleum exploration and development of complicated area, and the water of drilling fluid invading borehole wall and petroleum reservoir was the main cause of borehole instability and reservoir damage. In order to prevent the water of drilling fluid invading borehole wall and petroleum reservoir, domestic and foreign scholars recently put forward the technology of ultra-low permeable drilling fluid. Film forming agent was the key treating agent of ultra-low permeable drilling fluid, the film forming agent (HN-1) was developed, which did not affect properties of the drilling fluid and could decrease the filter loss of drilling fluid applied in Enping 24-2 oil field. Based on this research, ultra-low permeable drilling fluid could be applied to Enping 24-2 oil field. By the methods of testing ultra-low permeable drilling fluid properties, the drilling fluid invasion sand-bed depth, drilling fluid high temperature/high pressure (HTHP) sand-bed filter loss, the pressure-bearing ability of rock core and the ability of reservoir protection were studied. By synergistic effect, HN-1 containing the organic silicate and natural fiber polymer modified by organic amine prevented the liquid and solids in drilling fluid invading reservoir, decreased drilling fluid invasion sand-bed depth and drilling fluid HTHP sand-bed filter loss, improved the pressure-bearing ability of rock core and the ability of reservoir protection. The drilling fluid could decrease reservoir damage to the maximal degree, and it offered efficiency guarantee for exploitation Enping 24-2 oil field.

Study on a Polyamine-Based Anti-Collapse Drilling Fluid System

In complex strata, oil-based drilling fluid is the preferred drilling fluid system, but its preparation cost is high, and there are hidden safety risks. Therefore, the new progress of high-performance anti-collapse water-based drilling fluid at home and abroad is analyzed. It is difficult to prevent and control the well collapse. Once the well wall instability problem occurs, it will often bring huge economic losses to the enterprises, and the underground safety accidents will occur. In order to ensure the stability of the well wall and improve the downhole safety, the key treatment agent of water-based collapse drilling fluid is selected, the anti-collapse drilling fluid system is formulated, the evaluation method of drilling fluid prevention performance is established, and a set of water-based drilling fluid system suitable for easy to collapse strata in China is selected to ensure the downhole safety. The development trend of high performance anti-collapse water-based drilling fluid is expected to provide a reference for the research of high performance anti-collapse water-based drilling fluid system and key treatment agent.

Experimental study of low-damage drilling fluid to minimize waterblocking of low-permeability gas reservoirs

This paper discusses the systematic design and development of low-damage drilling fluid to protect the low-permeability gas reservoir of the Sulige block in the Ordos Basin, Inner Mongolia Autonomous Region, China. Based on investigation of the geological characteristics and the potential formation damage of the Permian formation of the reservoir, waterblocking due to invasion of drilling or completion fluids was identified one of the most severe causes of damage to gas well deliverability. By adopting the phase trap prevention method, ideal packing theory, and film-forming technology, a lowdamage drilling fluid, sodium formate brine containing efficient waterblocking preventing surfactants, optimized temporary bridging agents （TBAs）, and film-forming agents has been developed. The performance of the new drilling fluid was evaluated by using a variety of techniques. The results show that the fluid has good rheological properties, good strong shale-swelling inhibition, good temporary plugging effect, ultra-low filtration, and good lubricity. It can efficiently minimize waterblocking and can be used to drill horizontal wells with minimal intervention of the reservoir in the Sulige Gas Field.

连山关地区铀矿地质钻探技术优化

由于连山关地区存在着地层复杂、岩石胶结松散、水敏性强等诸多不利因素,钻探施工中存在钻孔漏失、掉块卡钻以及坍塌埋钻等问题,导致钻孔报废,降低了铀矿地质钻探施工的经济效益。为了解决以上问题,以ZK93-1孔钻为对象,针对铀矿地质地层特性以及常用设备、泥浆等存在的不利因素,对钻孔设备进行优化,选用CSD-1800A型全液压动力头钻机、HQ绳索取心钻具,并配备镦粗钻杆的NQ绳索取心钻具,提高了钻进效率及安全性,也降低了劳动强度;选用成膜防塌无固相冲洗液,有效降低钻孔偏斜,保证了岩矿心采取率,降低了施工成本,为类似地质条件地区的钻探工作提供参考依据。

铝土岩水平井快封堵防塌钻井液技术

陇东铝土岩属于长庆油田重要的资源接替储层,近期完试的陇**井、宁**井在太原组铝土岩勘探获得重大突破。针对该类储层溶孔和裂缝发育,井壁垮塌、漏失风险高及井眼清洁能力差的技术难题,通过铝土岩物性参数、理化性能、力学性能和敏感性测试分析等,明确了陇东铝土岩主要坍塌因素,研发出适用于铝土岩安全钻进的快封堵防塌钻井液技术。该体系在170℃高温高压滤失量小于10 mL,钻井液二次回收率大于91%,铝土岩样品在钻井液体系中浸泡15 d后和清水浸泡15 d后的抗压强度相比提升81.8%。快封堵防塌钻井液技术在长庆首口铝土岩水平井陇4**井进行了试验应用,助力该井700 m水平段的安全钻进,该井投产获日产无阻流量3.53×10^(6)m^(3)高产气流,创鄂尔多斯盆地上古生届勘探开发50多年新纪录,为该类储层的勘探开发提供了技术支撑。

深层煤层气防塌钻井液优化研究

辽河油田宜川-黄龙地区井壁失稳、阻卡等问题严重制约了开发进程。针对该地区深层煤层气A井井壁失稳问题,对煤岩矿物组成、微观结构进行了分析并揭示了井壁失稳机理。发现:钻井过程中滤液侵入,易发生水化膨胀和裂缝扩展等情况,导致井壁失稳。构建了适用于该地区的防塌钻井液体系,特征为强封堵、强抑制性,以及较好的流变性和耐高温性,且在现场应用中表现出良好的性能。为深层煤层气井的高效开发提供了有效的技术支持。

水基钻井液复合纳米成膜封堵剂的制备及性能

以改性纳米SiO_(2)为刚性粒子,丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸、苯乙烯和醋酸乙烯酯为聚合单体,壬基酚聚氧乙烯醚(10)和十二烷基磺酸钠为乳化剂,过硫酸铵和亚硫酸氢钠为引发剂,合成了一种有机/无机复合纳米成膜封堵剂。采用FTIR、SEM、动态光散射(DLS)和TGA对产物进行了表征和测试。考察了不同质量分数复合纳米成膜封堵剂对水基钻井液的流变性、滤失性及封堵性能的影响。结果表明,复合纳米成膜封堵剂呈球形,并保持纳米级分布,中值粒径为325 nm;340℃时的质量损失率为14%;120℃、16 h老化后较老化前表观黏度和塑性黏度均明显增加。当复合纳米成膜封堵剂质量分数为3%时,水基钻井液的静滤失量为10 mL;当质量分数≥2%后,砂床滤失量为0;当质量分数从0增至4%时,高温高压滤失量从104 mL减至29 mL,渗透性为1.56×10^(–2)mD,封堵率为90.7%。

绳索取芯技术应用中的井壁稳定性研究

随着深孔钻探环境愈加复杂,绳索取芯钻进技术实施过程中井壁失稳现象愈加突出。为破解该技术难题,从地质因素和工程因素两方面详细论述了绳索取芯过程中导致井壁不稳定的因素。以某重大供水工程中的重点勘察钻孔DZK4为例,结合深孔复杂岩层实际情况,提出“阳离子-高黏结-润湿反转-化学抑制-密度合理支撑”的协同防塌机理,结合该机理形成钻井液配方。应用情况表明,钻井液密度、失水量等相关指标都达到控制标准,钻井液性能较为稳定。

一种环保型水基钻井液体系设计与性能评价

随着能源需求的不断增长,页岩气作为一种重要的非常规能源,其开发利用受到了广泛关注。针对页岩气水平井钻井中的技术难题,设计并评价了一种高效环保型水基钻井液体系。通过室内实验,优选出了一套适合区块的钻井液体系(质量分数):3%膨润土浆+3%ASAA+2%ASAB+2%暂堵剂+2%ASAC1+5%KCl。所设计的钻井液体系在1.2 g∙cm^(-3)密度下的表观黏度平均值为42 mPa∙s,动塑比为0.39,高温高压失水量为5.6 mL;在1.6 g∙cm^(-3)密度下,体系的表观黏度为73.1 mPa∙s,动塑比为0.41,高温高压失水量为5.5 mL。此外,该体系具有良好的封堵性能和环境友好性,重金属含量和生物降解性均符合环保要求。研究结果表明,所设计的环保型水基钻井液体系能有效满足页岩气水平井钻井的技术要求,具有重要的实际应用价值和环境保护意义。

复合盐成膜钻井液技术研究

为解决松辽盆地长岭断陷长裸眼硬脆性泥页岩井段的塌漏失共存的技术难题,在优选活度调节剂和成膜封堵防塌剂的基础上,研制了复合盐成膜防塌钻井液体系。该体系流变性能可控,滤失造壁性能佳,抑制和防塌性能优异。在腰登15HF井的现场应用中,成功解决了长裸眼硬脆性泥页岩井段的塌漏失共存的问题,起下钻、电测和下套管作业无遇阻,推广前景广阔。

龙凤山气田防塌防漏钻井液研究与应用

东北工区龙凤山气田地层裂隙发育,各地层之间不整合交界,极易发生井壁失稳和漏失。针对该区块的地质特性和钻井要求,通过滤失评价实验和压力传递实验,优选SMSHIELD-2和FF-Ⅲ作为封堵防塌剂;通过砂床滤失实验,优选了SMGF-1为主剂作为随钻堵漏材料,最终形成了一套适用于龙凤山气田的防塌防漏钻井液体系,并对其性能进行了综合评价。实验结果表明,该钻井液体系流变性能稳定,抗温性能优良,且具有较佳的防塌防漏效果。在北213-16HF井的现场应用中,钻井液性能稳定,起下钻、电测和下套管作业顺利,全井无漏失,满足了现场钻井施工的需要。

柳州地区页岩气地质调查井钻探技术研究与应用

页岩气地层裂隙发育,胶结性差,表现为岩石破碎、水敏性强、孔壁强度低。在钻进过程中容易出现坍塌、掉块、缩径等复杂情况,从而引发孔壁失稳、卡钻、埋钻等孔内事故。对广西柳州地区页岩气地质调查井工程进行钻探技术研究,应用PVA1788成膜体系无固相冲洗液和成膜防塌体系无固相冲洗液、绳索取心液动锤钻进技术、膨胀波纹管护壁新技术、螺杆钻具定向钻进纠斜技术,在现场勘探施工中取得了良好的效果,保证了项目的顺利施工。

义284区块定向防塌钻井液技术

义284区块位于济阳坳陷沾化凹陷渤南洼陷北部陡坡带,由于该区块地质构造复杂,定向过程中钻井液井壁稳定、井眼净化及润滑防卡技术难度大。通过优选处理剂,构建聚胺强抑制润滑防塌钻井液体系,该体系在义284区块8口井进行了现场应用,配合现场钻井液维护处理工艺,结果发现:钻进过程中井壁稳定,井眼净化效果好,定向顺畅,目的层井段平均井径扩大率为6.52%;与区块前期施工井相比,平均钻井周期降低8.41%,平均完井周期降低9.13%,平均机械钻速提高9.17%,达到了优快钻井的良好效果。

车斜577井深部地层防塌钻井液技术难点分析与研究

车斜577井下部地层地质构造复杂,沙河街组层理、孔隙及微细裂缝发育,施工中井壁坍塌严重;三开井眼小,地层压力系数低,施工中易发生井漏等复杂情况;井底温度高达180℃,高温下钻井液体系流变性控制较难。为此,分析钻井液技术难点,通过使用复合盐防塌钻井液体系和抗高温无固相钻井液体系,配合相应的钻井液体系维护处理工艺,解决了下部地层的井壁失稳难题,为区块的后续勘探开发提供了技术支持。

广西苗儿山大厚度水敏性地层冲洗液技术研究及应用

广西苗儿山地区铀矿找矿潜力巨大,但局部地区地层复杂,存在大厚度水敏性地层及破碎地层,钻探施工中频繁遇到孔壁坍塌及钻孔超径等难题,导致孔内事故频发,严重影响施工进度。因此,对该地区水敏性岩心进行了矿物成分和微观特征分析,分析结果表明水敏性地层含有大量蒙脱石、高岭石、水云母等粘土矿物,且微裂隙发育,水化膨胀严重。针对以上问题,通过室内实验评价,优选了新型成膜护壁材料,进一步研制了护壁性良好的成膜护壁冲洗液体系,其最优配方为:5%成膜A剂+3%成膜B剂+1.5%改性沥青+1%随钻堵漏剂+1%封堵剂+0.6%增粘剂+0.2%包被剂。该冲洗液API滤失量为5~8 mL,相对膨胀降低率达到87%以上,可有效抑制水敏性岩心水化膨胀,护壁效果明显。该技术在苗儿山地区3个试验钻孔成功应用,顺利钻穿水敏性地层,未发生岩心分散、孔壁坍塌等问题,取得了良好的应用效果,初步形成了针对该地区水敏性地层的成膜护壁冲洗液技术。

张集煤矿多分支井强封堵防塌钻井液体系研究及应用

张集煤矿多分支井是一口为查明3号异常区地质(陷落柱、薄煤带和地堑等)与水文地质特征开展的1直5支支井钻探工程。T3孔主要目的层为3_(上)和3_(下)煤层,煤层机械强度低,裂缝和割理发育,均质性差,存在较高剪切应力作用,煤层段井壁极不稳定,在钻井过程中极易发生井壁坍塌、井漏、卡钻甚至埋掉井眼等井下复杂情况。本文通过对施工中钻井液的主要技术难点进行分析,研制了多分支井强封堵防塌聚合物钻井液体系,主要配方:基浆+0.5%KPAM+1%铵盐+1%腐殖酸钾+1%降滤失剂+1%防塌剂+3%NS封堵剂。主要性能:粘度35~50 s,密度1.05~1.2 g/cm^(3),失水量4~6 mL。完成钻井工程量2506.23 m,岩心取心率92%,满足了施工的要求。

曲9区块水平井钻井液优快钻井技术

曲9区块明化镇组和馆陶组地层沉积较厚,地层发育大段易水化软泥岩。水平井钻进过程中钻井液井壁稳定、井眼净化、润滑防卡和储层保护技术难度大。通过优选聚合醇润滑防塌钻井液体系,辅助现场钻井液维护处理工艺,保证了该区块3口水平井的顺利施工,钻完井时效较前期施工井有明显提高,达到了优快钻井的良好效果。

小秦岭金矿田3500 m特深孔冲洗液技术

小秦岭金矿田3500 m特深孔(ZK001孔)位于河南省灵宝市,是小秦岭构造带上深部探测的第一口全孔连续取心特深钻孔,该钻孔地层岩性十分复杂,软、硬、碎地层交互出现,护壁极其困难,钻进中伴随孔壁坍塌、掉块、水化分解造浆、高地应力断层泥缩径和微裂隙失水等多种复杂工况。本文针对地层变化调整冲洗液体系,上部采用低固相冲洗液,下部采用低固相聚合物防塌冲洗液体系,不断优化冲洗液配方,及时维护调整性能参数,有效解决了孔内各种难题。为小秦岭地区提供了一种可靠的深孔岩心钻探冲洗液技术。

中江区块沙溪庙组井壁失稳机理及烷基糖苷防塌钻井液

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