深水钻井抗高温水基钻井液体系研究及应用

深水钻井时存在易形成气体水合物、高温和低温并存对钻井液性能产生严重影响等问题。因此,为满足深水钻井作业的需要,通过对水合物抑制剂、抗高温增黏剂以及抗高温降滤失剂的优选与评价,研制了一套适合深水钻井施工的抗高温水基钻井液体系,并对钻井液体系的综合性能进行了评价。结果表明,该钻井液体系在低温到高温变化过程中黏度和切力变化幅度不大,仍能保持良好的流变性能;当钙膨润土的加量为15%时,钻井液体系仍能保持较好的流变性和较低的滤失量,具有良好的抗污染性能;钻井液体系的沉降因子在0. 5左右,具有良好的沉降稳定性;钻井液体系对储层钻屑的滚动回收率可以达到94. 5%,具有良好的抑制性。现场应用结果表明,S-1井钻井施工过程顺利,无井下复杂情况出现,说明该钻井液体系能够满足深水高温高压井的钻井施工需求。     

水基钻井液低温流变特性研究

深水钻井是中国石油近期和未来发展的必然趋势。温度对钻井液流变性能影响显著,深水低温给钻井液流变性调控带来了巨大挑战。分析了国外深水低温对钻井液流变性影响规律研究现状,利用自行研制的深水低温钻井液基本性能测试模拟实验装置和FANNIX77流变仪,研究了温度和压力对不同水基钻井液体系黏度和动切力的影响。结果表明,温度对不同钻井液体系的黏度影响规律基本相同,即随温度降低黏度增大,从高温到室温钻井液黏度增加比较缓慢,而从室温开始随温度降低黏度迅速升高;温度对含固相钻井液和无固相钻井液体系动切力的影响规律不同,无固相钻井液体系的动切力随温度降低而降低,而含固相钻井液动切力则随温度降低而增加;压力对水基钻井液体系黏度、动切力影响不大。研究结果为我国深水钻井实践提供了室内研究基础。     

深水恒流变无固相储层钻井液的制备与性能评价

在深水油气田钻井过程中,由于海底泥线附近的温度较低,易导致钻井液出现增稠、糊塞和跑浆等问题。针对该问题,以丙烯酰胺、N-乙烯基己内酰胺、二乙烯苯、烯丙基磺酸钠等为原料制备温敏增稠共聚物（ASSN）,再与香豆胶复配制得具有低温恒流变特性的流型调节剂。将流型调节剂与其他处理剂混合制得深水恒流变无固相储层钻井液。评价了ASSN、流型调节剂和钻井液的性能。结果表明,ASSN溶液的临界缔合温度为27℃。以0.5%ASSN和0.3%香豆胶作为流型调节剂,其水溶液的黏度在4～60℃较为稳定。流型调节剂对钻井液在低温下的流变性起到了良好的调控作用。加重剂对钻井液低温调控能力的影响较小。流型调节剂与钻井液其他处理剂的配伍性良好。钻井液具有良好的抗侵污性能、抑制性能、润滑性能和储层保护性能,满足现场钻井需求。     

一种新型抗高温降滤失剂的研究和应用

通过将4-乙烯基吡啶（VP）、N,N-二甲基丙烯酰胺（DMAA）、2-丙烯酰胺-2-甲基丙磺酸（AMPS）、N-乙烯基己内酰胺（NVCL）以过硫酸铵和亚硫酸氢钠作为氧化还原体系进行自由基共聚反应,合成了抗温达260℃的一种新型降滤失剂（PDANV）。通过设计正交实验确定了最优合成条件为:n_DMAA:n_AMPS:n_NVCL:n_VP=6:2:1:1,反应温度为60℃,反应时间为2 h,引发剂质量分数为单体总质量（20%）的0.5%,并利用傅里叶红外光谱（FT-IR）和核磁共振光谱（1H NMR）进一步确定了产物的分子结构。热重分析（TGA）显示PDANV热分解温度在301℃以后,表明其具有良好的热稳定性。同时,将PDANV应用于水基钻井液中,进一步评价其对水基钻井液流变和滤失性能的影响。结果显示,当PDANV加量为2.0%时,水基钻井液的滤失量仅为4.4 mL,260℃老化后滤失量为6.0 mL,高温高压滤失量为24 mL（150℃）,同时抗盐至饱和,抗钙20000 mg/L。此外,通过对黏土的粒径分析、SEM分析和Zeta电位分析以及不同浓度的PDANV对黏土颗粒的吸附量的测量,进一步揭示了PDANV在水基钻井液中的降滤失机理。      

深水聚胺高性能钻井液试验研究

聚胺高性能钻井液是性能最接近油基钻井液的水基钻井液,在深水钻井领域具有广阔的应用前景。为降低钻井液成本,在研制聚胺强抑制剂的基础上,考虑水合物抑制及低温流变性等因素,通过优选处理剂,构建了适用于深水钻井的聚胺高性能钻井液体系,并对其进行了综合性能评价。结果表明,该钻井液可抗150 ℃高温,且低温流变性优良,2 ℃和25 ℃的表观黏度比和动切力比分别为1.36和1.14;其抑制页岩水化分散效果与油基钻井液相当,体现了其强抑制特性;在模拟1 500 m水深的海底低温高压(1.7 ℃,17.41 MPa)条件下,具备120 h抑制水合物生成的能力;抗钙、抗劣土污染能力较强;无生物毒性,能满足深水钻井环保要求。其主要性能指标基本达到了用于深水钻井的同类钻井液水平,可满足深水钻井要求。      

深水窄密度窗口地层封堵承压钻井液技术

针对深水地层压实程度低、钻井液安全密度窗口窄、易导致井漏的技术难题,以烯类单体、大分子交联剂及层状结构硅酸盐矿物等为主要原料制备了柔性颗粒封堵剂,以此为基础构建了深水抗高温封堵承压水基钻井液。室内实验证明,柔性颗粒封堵剂韧性好,抗温达160 ℃,在10%盐水中性能稳定,对渗透性岩心、裂缝及砂床均具有良好的封堵效果,显著提高承压能力;构建的深水抗高温封堵承压钻井液160 ℃老化前后流变性能稳定,黏度和切力合适,4 ℃与25 ℃下的动切力比值小于1.35,具有显著的低温恒流变特性,封堵后岩心的渗透率接近于零,承压能力达11 MPa,抗膨润土粉及氯化钠污染的能力强,保护储层效果良好,岩心渗透率恢复率大于90%。该深水抗高温封堵承压水基钻井液在南海陵水区块进行了现场应用,提高了易漏地层的承压能力,承压能力提高6～11 MPa,确保了复杂井段的钻井安全。      

天然气管输过程中水合物抑制剂的制备及其性能研究

以乙烯基己内酰胺(VCL)为原料,偶氮二异丁腈为引发剂,在适当温度条件下,通过自由基聚合,合成了新型动力学抑制剂PVCL。     

深水钻井抗高温强抑制水基钻井液研制与应用

深水钻井时存在复杂地层井眼失稳、大温差下钻井液流变性调控困难等技术难题,需要研发适用于深水钻井的抗高温强抑制性水基钻井液。以丙烯酰胺、烷基季铵盐和2–丙烯酰胺基–2–甲基丙磺酸为单体,采用水溶液聚合法合成了深水钻井用低相对分子质量的聚合物包被抑制剂Cap;以Cap为主要处理剂,并优选其他处理剂,构建了深水抗高温强抑制水基钻井液。室内性能评价表明,低相对分子质量的聚合物包被抑制剂Cap对钻井液流变性的影响较小,包被抑制作用强;深水抗高温强抑制水基钻井液低温流变性良好,可抗160 ℃高温,高温高压滤失量小于9 mL,三次岩屑滚动回收率大于70%,抑制性强,可分别抗25.0%NaCl、0.5%CaCl₂和8.0%劣土污染。该钻井液在南海4口深水油气井钻井中进行了现场试验,取得了良好的应用效果,解决了低温增稠及井眼失稳等技术难题,具有现场推广应用价值。      

南海西部深水高温高压钻井液技术研究与应用

南海西部陵水区块高温高压引起深水钻井作业窗口进一步变窄,高温与低温并存使钻井液性能难以维护。在常规深水钻井液HEM体系的基础上,通过优选抗低温水合物抑制剂和抗高温降失水剂构建了南海西部深水高温高压钻井液体系。室内评价表明,所构建的钻井液体系具有良好的低温—高温流变性、抗污染能力、沉降稳定性、封堵承压性、储层保护性、泥页岩水化抑制性。该钻井液体系已在南海西部陵水区块3口深水高温高压井取得成功应用,可避免井漏、溢流等复杂情况,提高了作业效率,具有良好的推广应用价值。     

深水作业中钻井液在低温高压条件下的流变性

在深水钻井作业中,安全密度窗口非常窄,井下压力控制是面临的主要难题之一。随着水深的不断增加,环境温度随之降低,钻井液的黏度和切力随之升高;同时,由上千米隔水管内的钻井液所附加的静液柱压力使井底压力远大于浅水作业时相同井深的井底压力。这些因素的共同作用使得当量循环密度随之增加,进一步加大井底压力控制的难度。选择用于深水钻井的一种水基和一种合成基钻井液为研究对象,分别改变温度和压力等实验条件,利用FANN公司的ix77流变仪测量了钻井液在低温、高压下的流变参数,以此找出深水条件下钻井液流变性随温度和压力的变化规律。     

高密度水基钻井液高温高压流变性研究

高密度水基钻井液属于较稠的胶体-悬浮体分散体系,固相含量大,固相颗粒分散程度高,自由水量少,在深井高温高压条件下流变性容易失控。以室内研制的抗高温高密度淡水基和盐水基钻井液为基础,采用Fann50SL高温高压流变仪对钻井液在不同温度下的流变性进行了测试。结果表明,温度是影响高密度水基钻井液流变性的主要因素。随着温度升高,淡水基钻井液的表观黏度和塑性黏度都出现降低趋势;而盐水基钻井液的塑性黏度在150℃达到最低值,然后升高,表观黏度呈降低趋势。利用测试数据,运用宾汉、幂律、卡森和赫 巴4种流变模式进行线性拟合发现,无论是淡水基还是盐水基钻井液,赫-巴模式最佳,幂律模式最差。建立了预测淡水基钻井液表观黏度与温度、压力关系的数学模型,实测数据验证表明,该模型可以应用于生产实际。     

抗高温抗盐聚合物增黏剂的研制与性能评价

针对聚合物类增黏剂在高温和高盐环境下降解失效,不易现场维护等问题,以丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸、N-乙烯基吡咯烷酮、白油及配套乳化剂为主要原料,采用反相乳液聚合法合成了高相对分子质量的抗温抗盐聚合物增黏剂DQVIS,考察了该剂的抗老化性、增黏性、降滤失性,并以DQVIS替代原深层水基体系中的增黏剂考察了DQVIS对钻井液体系性能的影响。研究表明:DQVIS的抗温能力突出,质量分数1%的DQVIS溶液在180℃老化16 h后仍能达到72%的黏度保留率,能够满足深井钻井中钻井液提黏要求。DQVIS具有优良的降滤失能力,分别向淡水基浆、盐水基浆和饱和盐水基浆中加入0.6%DQVIS后,180℃老化前/后的滤失量分别为6.8 mL/8.2 mL、8.0 mL/14.8 mL和10.0 mL/15.8 mL,DQVIS与深层体系中其他处理剂配伍良好,加量少,溶解速度快,尤其可以满足冬季施工的需求。     

High temperature and high pressure rheological properties of high-density water-based drilling fluids for deep wells

To maintain tight control over rheological properties of high-density water-based drilling fluids, it is essential to understand the factors influencing the rheology of water-based drilling fluids. This paper examines temperature effects on the rheological properties of two types of high-density water-based drilling fluids (fresh water-based and brine-based) under high temperature and high pressure (HTHP) with a Fann 50SL rheometer. On the basis of the water-based drilling fluid systems formulated in laboratory, this paper mainly describes the influences of different types and concentration of clay, the content of a colloid stabilizer named GHJ-1 and fluid density on the rheological parameters such as viscosity and shear stress. In addition, the effects of aging temperature and aging time of the drilling fluid on these parameters were also examined. Clay content and proportions for different densities of brine-based fluids were recommended to effectively regulate the rheological properties. Four rheological models, the Bingham, power law, Casson and H-B models, were employed to fit the rheological parameters. It turns out that the H-B model was the best one to describe the rheological properties of the high-density drilling fluid under HTHP conditions and power law model produced the worst fit. In addition, a new mathematical model that describes the apparent viscosity as a function of temperature and pressure was established and has been applied on site.     

用于冻土区天然气水合物钻探的聚合物钻井液低温流变响应

陆域天然气水合物（以下简称水合物）主要赋存于高原冻土区,为保证顺利钻探,要求钻井液既能够有效抑制水合物分解、 维持其相态平衡,又能在低温环境下具有良好的流变性能。为此,以新研制的低失水抗低温聚合物钻井液配方为研究对象,对其在 低温条件下的流变性能进行了测试,并利用回归分析法和最小二乘法对试验数据进行计算与分析。结果表明：①赫谢尔-巴尔克莱 模式是描述该钻井液体系低温流变性能的最佳模式;②应用该模式计算得到了低温条件下钻井液流变性能参数,其变化规律表现出 随着温度降低,钻井液动切力呈近似波动变化,钻井液的稠度系数和流性指数均大致呈线性增长的趋势,但增长幅度较小。结论认为： 所建立的钻井液表观黏度低温响应数学模型拟合精度高,可准确预测井内钻井液在低温下的流变性能。     

适于西非深水油田的水基钻井液室内评价

通过分析西非深水油田钻井液技术难点,针对钻井液低温流变性调控与井眼清洗问题、气体水合物的生成与控制以及活性泥页岩井壁失稳问题,提出了相应的技术对策,构建了新型深水高性能水基钻井液体系。实验评价表明,该钻井液具有较低的黏度和较高的动切力,φ6读数保持在7~10,有利于井眼清洗;钻井液流变性受低温影响较小,2℃和25℃的表观黏度比和动切力比分别为1.28和1.10。该钻井液在不同层位的泥页岩岩样回收率均在90%以上,抑制性明显优于以往使用的KClPHPA钻井液体系,且在动态和静态条件下均具有优良的水合物抑制效果,抗污染能力强,满足西非深水油田钻井液技术需求。     

Application of silica (SiO2) nanofluid and Gemini surfactants to improve the viscous behavior and surface tension of water-based drilling fluids

Further studies into drilling fluids especially to reduce the use of oil and synthetic-based drilling fluids are ever-growing due to their contributions to environmental pollution. This study, therefore, attempts to evaluate the thermal, viscosity, surface tension, and filtration loss properties of water-based drilling fluids (WBDFs) upon the addition of Gemini surfactant-silica nanofluid. This surfactant-nanofluid was formed by dissolving silica nanofluid in the surfactant solution, and ultra-sonication was used to attain homogeneity. Characterization of the Gemini surfactant-silica (SiO₂) nanofluid was done by Fourier Transform Infrared Spectroscopy (FTIR). The viscosity, surface tension, and filtration loss properties were studied using the rheometer, tensiometer, and low-pressure, low-temperature (LPLT) filter press respectively. The experimental results showed that Gemini surfactants contributed to the highest increase in drilling fluid viscosity compared to a conventional surfactant. Also, when combined with silica-nanoparticles showed better thermal stability with an 11% average change in viscosity with increasing temperature and a decrease in surface tension and filtration loss both showing a 17% and 12% decrease respectively.     

The use of grass as an environmentally friendly additive in water-based drilling fluids

Excellent drilling fluid techniques are one of the significant guaranteed measures to insure safety,quality,efficiency,and speediness of drilling operations.Drilling Quids are generally discarded after the completion of drilling operations and become waste,which can have a large negative impact on the environment.Drilling materials and additives together with drill cuttings,oil.and water constitute waste drilling fluids,which ultimately are dumped onto soil,surface water,groundwater,and air.Environmental pollution is found to be a serious threat while drilling complex wells or high-temperature deep wells as these types of wells involve the use of oil-based drilling fluid systems and high-performance water-based drilling(luid systems.The preservation of the environment on a global level is now important as various organizations have set up initiatives to drive the usage of toxic chemicals as drilling fluid additives.This paper presents an approach where grass is introduced as a sustainable drilling fluid additive with no environmental problems.Simple waterbased drilling fluids were formulated using bentonite,powdered grass,and water to analyze the rheological and filtration characteristics of the new drilling fluid.A particle size distribution test was conducted to determine the particle size of the grass sample by the sieve analysis method.Experiments were conducted on grass samples of 300.90.and 35 μm to study the characteristics and behavior of the newly developed drilling fluid at room temperature.The results show that grass samples with varying particle sizes and concentrations may improve the viscosity,gel strength,and tiltration of the bentonite drilling fluid.These observations recommend the use of grass as a theological modifier,filtration control agent,and pH control agent to substitute toxic materials from drilling fluids.     

Solution and drilling fluid properties of water soluble AM–AA–SSS copolymers by inverse microemulsion

The present work had the purpose of developing a new class of polymeric additives for water based drilling fluid. The additives were obtained through the copolymerization of acrylamide, acrylic acid and sodium 4-styrenesulfonate (SSS) by inverse microemulsion polymerization. Solution and drilling fluid properties of water-based polymeric drilling fluids were investigated. Results indicate that SSS content in the polymeric drilling fluids has an important impact on the rheological properties, filtrate loss and filter cake morphologies of the polymeric drilling fluid, and the water-based polymeric drilling fluid has a high value of yield point to plastic viscosity, high viscosity, excellent shear thinning and thixotropic behavior, good thermal stability and salt resistance. Hence, it can be used as polymeric drilling fluid under the salty and high temperature environment.     

涪陵页岩气田低黏低切聚合物防塌水基钻井液研制及现场试验

为了解决涪陵地区焦石坝区块二开钻井过程中钻井液黏度高、摩阻高、扭矩大及定向托压严重等问题,研究了一种低黏低切聚合物防塌水基钻井液。室内试验表明,该水基钻井液抑制性、润滑性、封堵性良好,抗温能达100℃,且具有很好的抗污染能力。该钻井液在涪陵地区焦石坝区块二开井段进行了现场试验,有效解决了因地层钻屑水化造浆而造成的钻井液黏度升高、密度升高及井下托压严重等问题,保证了井下作业的正常进行,缩短了钻井周期,提高了钻井效率。