An optimization method of fidelity parameters of formation fluid sampling cylinder while drilling

A design idea of fidelity sampling cylinder while drilling based on surface nitrogen precharging and supplemented by downhole pressurization was proposed, and the working mode and optimization method of sampling parameters were discussed. The nitrogen chamber in the sampling cylinder functions as an energy storage air cushion, which can supplement the pressure loss caused by temperature change in the sampling process to some extent. The downhole pressurization is to press the sample into the sample chamber as soon as possible, and further increase the pressure of sample to make up for the pressure that the nitrogen chamber cannot provide. Through the analysis of working mode of the sampling fidelity cylinder, the non-ideal gas state equation was used to deduce and calculate the optimal values of fidelity parameters such as pre-charged nitrogen pressure, downhole pressurization amount and sampling volume according to whether the bubble point pressure of the sampling fluid was known and on-site emergency sampling situation. Besides, the influences of ground temperature on fidelity parameters were analyzed, and corresponding correction methods were put forward. The research shows that the fidelity sampling cylinder while drilling can effectively improve the fidelity of the sample. When the formation fluid sample reaches the surface, it can basically ensure that the sample does not change in physical phase state and keeps the same chemical components in the underground formation.

Analysis of Reservoir Sensitivity and Optimization of Drilling Fluid System in Block H9 of Tarim Oilfield

针对塔里木油田H9区块钻井过程中存在的储层损害问题,采用黏土矿物分析、扫描电镜及压汞法等方法,分析掌握了目标区块储层地质特征,并结合储层敏感性试验评价,明确了储层潜在敏感性损害因素,揭示了储层损害机理。结果表明,H9区块储层黏土矿物含量为10%~20%,具有中高孔渗特征,非均质性较好,且存在潜在的强速敏和强水敏性损害。针对现场用钻井液体系存在的抑制性、润滑性及储层保护效果存在的不足,室内优化了一套综合性能优良的KCl-聚合醇储层保护钻井液体系。通过模拟储层动态损害试验评价可知,储层岩心渗透率恢复值可达85%以上。现场试验结果表明,KCl-聚合醇钻井液体系可较好地抑制泥页岩水化膨胀分散,有效避免了井眼缩径、起下钻遇阻等井下复杂情况发生,保障了钻井施工高效、安全,且储层保护效果良好。

Numerical analysis of the effects of downhole dynamic conditions on formation testing while drilling

Formation testing while drilling is an innovative technique that is replacing conventional pressure testing in which the fluid sampling is conducted in a relatively short time following the drilling. At this time, mud invasion has just started, mudcake has not formed entirely and the formation pressure is not stable. Therefore, it is important to study the influence of the downhole dynamic environment on pressure testing and fluid sampling. This paper applies an oil-water two phase finite element model to study the influence of mudcake quality and mud filtrate invasion on supercharge pressure, pretest and sampling in the reservoirs of different permeability. However, the study is only for the cases with water based mud in the wellbore. The results illustrate that the mudcake quality has a significant influence on the supercharge pressure and fluid sampling, while the level of mud filtrate invasion has a strong impact on pressure testing and sampling. In addition, in-situ formation pressure testing is more difficult in low permeability reservoirs as the mud filtrate invasion is deeper and therefore degrades the quality of fluid sampling. Finally, a field example from an oil field on the Alaskan North Slope is presented to validate the numerical studies of the effects of downhole dynamic conditions on formation testing while drilling.

Determining the fluorescent components in drilling fluid by using NMR method

Fluorescent additives can reduce drilling operation risks, especially during high angle deviated well drilling and when managing stuck pipe problems. However, they can affect oil discovery and there is a need to reduce the level of fluorescents or change the drilling fluids to prevent loss of drilling velocity and efficiency. In this paper, based on the analysis of drilling fluids by NMR with high sensitivity, solid and liquid additives have been analyzed under conditions with different fluorescent levels and temperatures. The results show that all of the solid additives have no NMR signal, and therefore cannot affect oil discovery during drilling. For the liquid additives with different oil products, the characterizations can be quantified and evaluated through a T2 cumulated spectrum, oil peak(T2g), and oil content of the drilling fluids. NMR can improve the application of florescent additives and help us to enhance oil exploration benefits and improve drilling operations and efficiency.

Experimental and computational analysis of the coolant distribution considering the viscosity of the cutting fluid during machining with helical deep hole drills

An experimental analysis regarding the distribution of the cutting fluid is very difficult due to the inaccessibility of the contact zone within the bore hole.Therefore,suitable simulation models are necessary to evaluate new tool designs and optimize drilling processes.In this paper the coolant distribution during helical deep hole drilling is analyzed with high-speed microscopy.Micro particles are added to the cutting fluid circuit bya developed high-pressure mixing vessel.After the evaluation of suitable particle size,particle concentration and coolant pressure,a computational fluid dynamics(CFD)simulation is validated with the experimental results.The comparison shows a very good model quality with a marginal difference for the flow velocity of 1.57%between simulation and experiment.The simulation considers the kinematic viscosity of the fluid.The results show that the fluid velocity in the chip flutes is low compared to the fluid velocity at the exit of the coolant channels of the tool and drops even further between theguidechamfers.Theflow velocity and the flow pressure directly at the cutting edge decrease to such an extent that the fluid cannot generate a sufficient cooling or lubrication.With the CFD simulation a deeper understanding of the behavior and interactions of the cutting fluid is achieved.Based on these results further research activities to improve the coolant supply can be carried out with great potential to evaluate new tool geometries and optimize the machining process.

阻尼模型的力学机制及对钻柱动力学特性的影响

钻柱动力学特性模拟中普遍采用Rayleigh阻尼模型来反映阻尼(包括钻井液阻尼)的作用,但很少关注选用该模型的合理依据,且其阻尼系数主要依赖经验确定.首先,在考虑非线性和钻井液阻尼作用的基础上建立了钻柱动力学有限元模型,实现钻柱动力学特性的模拟,然后,研究较为典型的Rayleigh阻尼模型、Caughey阻尼模型、Clough阻尼模型的力学机制及其内在联系,并基于实际算例研究3种阻尼模型对钻柱动力学特性的影响,比较不同阻尼模型下钻柱的横向位移、横向加速度、以及涡动轨迹和涡动速度.结果表明,l取−2∼1时的Caughey阻尼模型的阻尼值偏小,未能起到阻尼的黏滞作用,而l取其他数值时阻尼值又过大,可见取4项的Caughey阻尼模型并不适用于钻柱动力学模拟计算.Rayleigh阻尼模型和Clough阻尼模型可以有效反映钻井液的阻尼效应,所得钻柱动态特性比较贴合实际振动情况,但前者形式简洁,便于计算,更适用于目前钻井工程中的钻柱动力学模拟.

高温下水基钻井液核心组分微观行为分析

水基钻井液在高温下性能调控难度大,主要与核心胶体粒子的分散状态有关,而水基钻井液成分复杂,单一组分与多组分间受高温作用性能变化规律不同,对胶体粒子的分散状态均有影响。针对水基钻井液核心组分,通过高温高压流变性测试获得了膨润土胶体剪切应力-温度曲线,并测试了不同温度下胶体颗粒粒度分布,分析了黏土矿物胶体粒子在室温~220℃范围内的分散、絮凝与聚结状态及形成机制,同时利用SEM测试和黏土矿物晶层结构分析,从微观角度揭示了富含镁多孔纤维状黏土矿物胶体的高温稳定机理,此外,基于对高温热滚前后流变性和滤失量等性能变化的分析,从黏土矿物结构特征和聚合物断链、吸附特性等角度揭示膨润土/复配黏土矿物与聚合物类处理剂在高温下的互相作用机理,结合实验结果,明确了低浓度膨润土与海泡石复配胶体具有明显的高温稳定优势,为超高温水基钻井液的构建提供了理论支撑。

钻屑回注泵液力端有限元分析

岩屑回注技术是有效处理钻井废弃物以及消除其对环境影响的重要手段。但由于岩屑回注浆体中含有大量微小颗粒,在回注过程中对于回注泵液力端的磨损较大,导致岩屑回注泵寿命较短。为此,通过ANSYS数值模拟软件的FLOTRAN CFD模块分析液力端内的流场分布,分析发现:吸入工况下,流体流经吸入凡尔时流道过流面积最小,所形成的流速最高;排出工况下,流体在排出凡尔左侧壁面形成最大流速,且在出口附近产生漩涡。液力端基体材料采用沉淀硬化性不锈钢合金,延长了液力端凡尔周围材料的耐磨性,延长回注泵使用寿命。

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。

油基钻井液提切剂标准用基浆探讨

为了满足高温深井、大斜度定向井、页岩长水平井等复杂井的钻探需求,提高油基钻井液的切力相当重要。目前提切剂产品标准制定不统一,均为各企业标准,且没有统一的基准物,无法对提切剂进行对比分析。收集了6种现场用提切剂,讨论了提切剂评价所需的基浆,为提切剂的检验统一标准基础,同时为提切剂标准的制定提供参考,有利于提切剂质量分析。

新型钻井液加重化学剂在石油钻井中的应用

在石油钻井中,通过在钻井液中适当增添加重材料可以更好地控制井筒压力。传统的加重材料例如碳酸钙、重晶石等虽然可以有效地提升钻井液的密度,但是也同样会存在地层损坏、颗粒沉降、井筒腐蚀等一系列问题,亟需一种新型的钻井液加重材料保证石油钻井作业的正常进行。因为目标作业区使用油基钻井液,所以使用硫酸钙作为加重化学剂是一个较为良好的选择。硫酸钙作为一种成本低廉、较易制备的化学材料,在研究中通过密度、流变性、滤失量等多项实验将其作为油基钻井液的加重材料进行可行性研究,并与传统的加重材料(碳酸钙、重晶石等)进行比较,硫酸钙在实验中以3种不同质量浓度(0.06、0.120、0.165 mg·L^(-1))混合在基础钻井液中。结果表明:硫酸钙与在0.12 mg·L^(-1)的相同质量浓度下测试的其他加重材料相比,更好地控制了钻井液损失,证明硫酸钙是一种良好的钻井液加重材料。

钻井液旋转粘度测试中双圆筒力矩分析

流体的粘度能够直接反映不同流体的特性,其测量对于鉴定流体质量及确定其使用方向具有十分重要的意义。在钻探工作中钻井液粘度的变化会影响润滑油功能的实现,以粘度作为钻井液选用的依据,对钻井液粘度的测量就显得尤为重要。然而对于传统的旋转式粘度仪,由于内筒下表面所产生的附加力矩也同时作用在弹簧上,因此计算出液体作用在整个内筒上的摩擦力矩偏大,且底部平底面上各点的速度梯度及剪切应力均不相同,问题较为复杂。本文在传统的旋转式圆筒粘度计结构的基础上,对计算原理进行了改进补充,并通过采用有限元软件分析双圆柱绕流的流动特性,仿真结果与理论分析相一致,验证了推导公式的合理性。应用于钻井液在完整地层中的流动特性,可为进一步研究钻井液在破碎地层中的剪切应力提供基础,为预防孔内事故提供支撑。

Effective Components of Dried Ginger in Warming Lung to Reduce Watery Phlegm and In vivo Tissue Distribution Based on the“Syndrome-Efficacy-Biological Sample Analysis”Method

Objective: This study aimed to investigate effective components of dried ginger(DG) in warming lung to reduce watery phlegm and in vivo tissue distribution on the syndrome of cold fluid retained in lung of rats with chronic obstructive pulmonary disease(COPD) by means of the "syndrome?efficacy?biological sample analysis" method and then to explore its meridian tropism. Methods: Wistar rats were given nasal drops of 200-μL lipopolysaccharide and smoke 30 min two times a day, then put the appropriate dose of ice water, and freeze for an hour to build model rats. On the 16 th day, the drug group was orally administered of DG(500 mg/mL) until the 30 th day. Blood samples and biological tissues were collected from the orbital venous plexus into heparinized hemostasis tubes at 5, 10, 15, 30, 45, 60, 90, 120, 180, 240, and 360 min after the last administration. Using ultraviolet-high-performance liquid chromatography(Waters, USA) method, the effective components were tested, and DAS 3.0 software(Mathematical Pharmacology Professional Committee of China, Shanghai, China) was used to analyze the results. Results: The compounds of DG entering into blood were 6-gingerol, 6-shogaol, and 8-gingerol. Tissue distribution analysis indicates that three active ingredients are widely present in the lung, spleen, kidney, liver, heart, large intestine, stomach, small intestine, and other organs of rats with COPD. Conclusions: 6?gingerol, 6?shogaol, and 8?gingerol belong to effective components of DG in curing the syndrome of cold fluid retained in lung of rats with COPD and mainly distributed in organs including the spleen, stomach, lung, kidney, liver, and heart.

Experimental study on the degree and damage-control mechanisms of fuzzy-ball-induced damage in single and multi-layer commingled tight reservoirs

Fuzzy-ball working fluids(FBWFs)have been successfully applied in different development phases of tight reservoirs.Field reports revealed that FBWFs satisfactorily met all the operational and reservoir damage control requirements during their application.However,the damage-control mechanisms and degree of formation damage caused by fuzzy-ball fluids have not been investigated in lab-scale studies so far.In this study,the degree of fuzzy-ball-induced damage in single-and double-layer reservoirs was evaluated through core flooding experiments that were based on permeability and flow rate indexes.Additionally,its damage mechanisms were observed via scanning electron microscope and energy-dispersive spectroscopy tests.The results show that:(1)For single-layer reservoirs,the FBWF induced weak damage on coals and medium-to-weak damage on sandstones,and the difference of the damage in permeability or flow rate index on coals and sandstones is below 1%.Moreover,the minimum permeability recovery rate was above 66%.(2)For double-layer commingled reservoirs,the flow rate index revealed weak damage and the overall damage in double-layer was lower than the single-layer reservoirs.(3)There is no significant alteration in the microscopic structure of fuzzy-ball saturated cores with no evidence of fines migration.The dissolution of lead and sulfur occurred in coal samples,while tellurium in sandstone,aluminum,and magnesium in carbonate.However,the precipitation of aluminum,magnesium,and sodium occurred in sandstone but no precipitates found in coal and carbonate.The temporal plugging and dispersion characteristics of the FBWFs enable the generation of reservoir protection layers that will minimize formation damage due to solid and fluid invasion.

基于轻烃分析的复杂储层流体随钻评价新技术

针对渤中西南环古近系储层流体性质随钻评价难度大、多解性强、录井与测井资料响应特征矛盾等问题,在深度研究轻烃录井数据的基础上,建立了基于轻烃敏感参数的含水性分析、井场轻烃碳环优势分析、基于烷烃系列对比的生物降解分析以及基于主成分分析和支持向量机的数学算法等的井场轻烃流体评价方法,并进行了实例应用。评价结果表明:基于轻烃敏感参数的储层含水性图版及烷烃系列对比的生物降解程度解释图版,识别研究区流体性质效果好;井场轻烃碳环优势分析法可用于对比分析油气藏成因及来源,与常规录井方法相比,对多期次充注复杂油气藏流体评价优势明显;基于主成分分析和支持向量机的数学算法的轻烃分析方法评价复杂储层流体性质符合率较高,可达85%左右。该技术方法在研究区应用效果良好,为复杂储层流体随钻评价提供了新的思路,具有较好的应用前景。

纳米二氧化硅对水基钻井液滤失影响预测模型及机理分析

采用2级-2因子复合分析法,证明了纳米二氧化硅和膨润土加量对滤失量和泥饼厚度具有较大影响。同时考虑膨润土悬浮液的结构动力学和纳米颗粒的胶体行为,建立了新的添加纳米材料的钻井液滤失模型。通过Minitab数据软件对新滤失模型与API滤失模型进行对比分析,新模型标准误差为0.41~0.81cm^(3)、决定系数为99.3%~99.89%,具有较高可信度。将新模型预测数据与实验数据进行了对比,实验结果吻合良好。通过对泥饼进行X衍射分析和能谱分析发现,纳米二氧化硅影响滤失机理为纳米二氧化硅中的Si4+取代了泥饼中Fe2+、Mg2+等游离的阳离子,使得纳米二氧化硅颗粒进入泥饼微裂缝中,从而降低泥饼渗透率和滤失量。

钻井液用抑制剂络合铝中铝离子含量的测定方法

采用双氧水热解酸化法处理可将偏铝酸根转变为铝离子,再用氟盐置换EDTA容量法滴定分析测定铝离子含量,从而可以计算出样品中偏铝酸根的含量。结果表明∶此种测定方法的加标回收率超过98%、重复性试验得到相对标准偏差小于0.3%,该方法可操作性强、适用范围广、结果可靠准确,是测定钻井液用抑制剂络合铝中铝离子含量的有效方法。该方法不仅有利于抑制剂络合铝产品的质量控制,还可对络合铝的现场应用提供技术指导。

高频钻井液压力波衰减模型及规律研究

高频钻井液压力波信息传输技术传输速率高,是实现自动化、智能化钻井的关键技术之一,由于高频钻井液压力波在传输过程中存在较大的衰减,阻碍了该技术的现场应用,探明其衰减规律对于高速传输技术开发具有重要意义。在假设同一钻柱截面钻井液压力相等且钻井液流速存在径向分布的基础上,基于二维轴对称瞬态流动理论,采用小信号分析方法,综合考虑了压力波信号参数、钻柱尺寸及钻井液参数的影响,建立了高频钻井液压力波衰减模型并给出了适用条件。最后采用地面实验验证了该模型的正确性。随后分析钻井液压力波频率、压力波传输距离、钻井液密度及黏度、钻柱内径对高频压力波衰减的影响。结果表明:高频钻井液压力波幅值衰减量随钻井液压力波频率、压力波传输距离及钻井液黏度的增加而增大,且变化规律为指数型;幅值衰减量受频率影响最大,并随钻井液密度及钻柱内径增加逐渐减小。本研究可为高频钻井液压力波信息传输技术研发提供理论指导。

基于XGBoost的钻井液体系分类预测模型研究

根据钻井液体系设计的原则,结合实际钻井液设计资料,应用一种新的机器学习方法建立了钻井液体系分类预测模型。钻井液体系分类数据经过独热编码(one-hot)之后,通过灰色关联度分析方法,选择出钻井液体系分类预测的20个特征参数,其中压力的关联度最大,为0.8233。将选择的地质设计参数和工程设计参数,基于一种极端梯度增强算法(XGBoost)针对4种钻井液体系进行分类预测。结果显示,基于XGBoost的钻井液体系分类预测模型4类钻井液体系训练集的准确率都为100%,测试集的平均准确率为99.89%,精确率为99.97%,召回率为98.89%,F1值为0.98。将该模型应用于胜利油田M区块,分类结果符合实际钻井要求,能够辅助选择钻井液体系,为实现钻井液智能化设计提供了帮助。

各向异性对页岩地层钻井液安全密度窗口的影响

为揭示页岩储层井壁失稳机理,开展了不同层理倾角页岩的抗压强度实验,采用Jaeger弱面准则拟合页岩强度实验数据,为井壁稳定分析模型提供输入参数;评估了各向异性对井周应力集中的影响,并基于横观各向同性介质井周应力模型,建立了钻井液安全密度窗口分析模型,研究安全密度窗口对各向异性的敏感性。结果表明:随着原地应力异性的增加,破裂压力与坍塌压力的差值减小,即钻井液安全密度窗口变窄,与地应力各向同性时的情况相比,地应力异性导致井筒失稳风险增大;随着页岩弹性模量异性度的增加,井壁破裂压力和坍塌均逐渐减小,因此维持井壁稳定的钻井液安全密度窗口迅速变窄。泊松比异性度对井壁破裂压力和坍塌压力的敏感性分析表明,泊松比各向异性对维持井壁稳定的安全密度窗口的影响十分有限;而弹性模量是引起钻井液安全密度窗口变化的关键因素。