Evaluation of sweet spots and horizontal-well-design technology for shale gas in the basin-margin transition zone of southeastern Chongqing,SW China

The shale gas accumulation conditions in the basin-margin transition zone of southeastern Chongqing in SW China are complex.In order to improve single-well productivity in this area,the geologic characteristics,major factors controlling the occurrence of sweet spots,and drilling/fracturing optimization were investigated in this study.The sweet spot evaluation system and criteria were established,and the horizontal-well-design technology was developed.The following three conclusions were drawn.First,the accumulation and high-productivity-oriented approaches for sweet spot evaluation are proposed and the criteria are established based on screened key indicators.Second,the horizontal well was designed based on:(1)the“six-map”method,to identify both the geology and engineering sweet spots for well locations;and(2)seismic attributes,to predict the development of fractures and cavities,and thus,avoid mud loss and improve the drilling efficiency.The target window,well-azimuth optimization,and the curvature were forecasted to improve the fracturing performances.Third,the Pingqiao anticline,Dongsheng anticline,Jinfo slope,and Wulong syncline were selected as Type I sweet spots.Currently,shale gas has been successfully discovered in the basin-margin transition zone and is being commercially developed.

Performance analysis and optimal design for well patterns in anisotropic formations

The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation, fluid flow analysis, and reservoir development concepts. Anisotropy of permeability has reconstructive effects on well patterns. The originally designed flooding units are broken up, and new pattern units are made up of the wells that belong to different original units. The behavior possesses strong randomness, and leads to a complicated relationship among the injection and production wells, and unpredictable productivity of the formations. To prevent the break-up of well patterns, well lines should be either parallel or perpendicular to the maximum principal direction of the anisotropic permeability （i.e. the fracture direction）. To optimize the development effects ofanisotropic formations, the latitudinal and longitudinal well spacing of the well network are calculated from the principal values of the anisotropic permeability.

Study on Deep Well Dewatering Optimization Design in Deep Foundation Pit and Engineering Application

Based on analyses of the theories of groundwater unsteady flow in deep well dewatering in the deep foundation pit, Theis equations are chosen to calculate and analyze the relationship between water level drawdown of confined aquifer and dewatering duration. In order to reduce engineering cost and diminish detrimental effect on ambient surrounding, optimization design target function based on the control of confined water drawdown and four restriction requisitions based on the control of safe water level, resistance to throwing up from the bottom of foundation pit, avoiding excessively great subsidence and unequal surface subsidence are proposed. A deep well dewatering project in the deep foundation pit is optimally designed. The calculated results including confined water level drawdown and surface subsidence are in close agreement with the measured results, and the optimization design can effectively control both surface subsidence outside foundation pit and unequal subsidence as a result of dewatering.

Designing of an Automatic Paraffin Controlling Device for a Beam Well

Aiming at the paraffin-deposition problem of a beam well, the automatic paraffin-controlling device is designed by making use of ratchet-pallet mechanism, cam mechanism and modern designing method. The device has four main functions： paraffin-controlling, paraffin removal, centralizing the pumping rod, and improving the safety of well tubing. This device integrates the advantages of the paraffin control, such as strong magnetic paraffin controlling and mechanical paraffin-cutting. Theoretical analysis shows that this device has fine working reliability. It turns out to be a new device which can solve the paraffin-deposition problem of a beam well economically and efficiently.

Differences of Gas Lift Design between Deviated and Vertical Wells and the Analysis of Sensitivity Parameters

尽管气举越来越多地被应用到大斜度井、水平井的举升采油中,但倾斜井气举设计与直井气举设计存在什么差异,这些差异随倾斜角度的增大将怎样变化,以及哪些气举设计所需参数对这种差异比较敏感,即如何对倾斜井气举设计所需参数进行合理选择,以便对倾斜井气举设计进行优化的研究较少,这也一直是倾斜井合理气举设计的难点问题。鉴于此,笔者以某油田一口倾斜井为例,通过实测数据进行了倾斜井产能预测方法优选和多相管流压力计算方法优选,然后在该基础上采用等套压降气举设计方法对比分析了倾斜井气举设计与同等条件下直井气举设计的差异,并逐一分析了各种气举设计所需重要参数分别取不同值时气举设计注气深度和产量随井斜角度的变化规律,从而得到了倾斜井气举设计的敏感性参数,可为倾斜井气举设计的参数优化和调整提供参考依据,是倾斜井气举高效生产的有力保障。

Integrated risk management: a Petrobras application in offshore well construction safety to minimize critical emergency disconnections

In order to avoid mistakes and to save a great deal of time in analysis, an innovative methodology was developed that can analyze the well operations and rig characteristics involved to define the best emergency disconnect sequence （EDS） available. A solution was developed based on the characteristics of the rigs and blowout preventers （BOPs）, and six variables were considered that directly affect the choice of EDS. All possible combinations of 64 scenarios were analyzed, and the priority of choice of the EDS was defined empirically. This paper presents an approach to EDS risk management and examples of exposure time （time without riser safety margin and shear capability） for the same well, which can be lowered from 13% to 0.1%. The impact of this reduction is related to the ability of the BOP to cut some of the heavy casings, in addition to improved availability of EDS modes. This implementation opened up many possibilities for the performance of risk exposure analysis, enabling comparison of several BOP configurations of contracted rigs and selection of the best options. This innovative approach allowed a better management of the rig schedules, prioritizing safety aspects and making it possible to allocate the fleet in a systematic way.

Multiple fault diagnosis of down-hole conditions of sucker-rod pumping wells based on Freeman chain code and DCA

It is important to achieve continuous, stable and efficient pumping well operation in actual oilfield operation. Down-hole pumping well working conditions can be monitored in real-time and a reasonable production scheme can be designed when computer diagnosis is used. However, it is difficult to make a comprehensive analysis to supply efficient technical guidance for operation of the pumping well with multiple faults of down-hole conditions, which cannot be effectively dealt with by the common methods. To solve this problem, a method based on designated component analysis （DCA） is used in this paper. Freeman chain code is used to represent the down-hole dynamometer card whose important characteristics are extracted to construct a designated mode set. A control chart is used as a basis for fault detection. The upper and lower control lines on the control chart are determined from standard samples in normal working conditions. In an incompletely orthogonal mode, the designated mode set could be divided into some subsets in which the modes are completely orthogonal. The observed data is projected into each designated mode to realize fault detection according to the upper and lower control lines. The examples show that the proposed method can effectively diagnose multiple faults of down-hole conditions.

The productivity evaluation model and its application for finite conductivity horizontal wells in fault block reservoirs

It is very difficult to evaluate the productivity of horizontal wells in fault block reservoirs due to the influence of fault sealing.On the basis of the method of images and source-sink theory,a semianalytical model coupling reservoir and finite conductivity horizontal wellbore flow dynamics was built,in which the influence of fault sealing was taken into account.The distribution of wellbore flow and radial inflow profiles along the horizontal interval were also obtained.The impact of the distance between the horizontal well and the fault on the well productivity was quantitatively analyzed.Based on this analysis,the optimal distance between the horizontal well and the fault in banded fault block reservoirs could be determined.According to the field application,the relative error calculated by the model proposed in this paper is within ±15%.It is an effective evaluation method for the productivity of horizontal wells in fault block reservoirs.The productivity of the horizontal well increases logarithmically as the distance between the horizontal well and the fault increases.The optimal distance between the horizontal well and the fault is 0.25-0.3 times the horizontal well length.

Thermal stresses analysis of casing string used in enhanced geothermal systems wells

In the enhanced geothermal systems wells, casing temperature variation produces casing thermal stresses, resulting in casing uplift or bucking. When the induced thermal stresses exceed casing material's yield strength, the casing deforms and collapses. The traditional casing design standard only considers the influence of temperature variation on casing material's yield strength. Actually, for commonly used grades of steel pipe, casing's material properties-such as yield strength, coefficient of thermal expansion, and modulus of elasticity change with temperature variation. In this paper, the modified thermal stress equation is given. Examples show that the allowable temperature of the material grade N80's casing is only 164 ℃, which is much lower than that of the traditional design standard. The effective method to improve the casing pipe's allowable temperature is pre-stressed cementing technology. Pre-stressed cementing includes pre-tension stress cementing and pre-pressure stress cementing. This paper focuses on the design method of full casing pre-tension stress cementing and the ground anchor full casing string pre-tension cementing construction process.

四川盆地超深井钻井关键技术及发展方向

四川盆地海相碳酸盐岩油气资源丰富,但构造地层条件复杂,井筒环境苛刻。近年来,盆地深井超深井钻井关键技术的形成,支撑了油气的增储上产,为特深层油气资源勘探开发奠定了技术基础。特深层油气资源的开发需持续开展地质工程一体化设计技术攻关,通过精细刻画复杂地质体建立三维地质力学模型,指导井身结构和井眼轨道设计,同时开展基于膨胀管、随钻扩眼技术的井身结构拓展研究,并通过岩石可钻性剖面指导钻头及提速工具设计。针对深井超深井井口溢流异常监测识别滞后及钻柱振动剧烈的问题,持续研发基于大数据分析的复杂防控技术。深入开展适用于超高温超高压环境的工具、钻井液研发,研发攻关110钢级及以上膨胀管管材、抗220℃的高密度水基钻井液、抗260℃的油基钻井液体系、抗温240℃以上的水泥浆体系、高性能固井材料以及抗高温堵漏材料。同时,应紧密结合物联网、新型通信、大数据等智能技术,实现钻井全过程运算分析及管理。

Productivity analysis of horizontal wells intercepted by multiple finite-conductivity fractures

Horizontal wells in the anisotropic reservoirs can be stimulated by hydraulic fracturing in order to create multiple finite-conductivity vertical fractures. Several methods for evaluating the productivity of the horizontal wells have been presented in the literature. With such methods, however, it is still difficult to obtain an accurate result. This paper firstly presents the dimensionless conductivity theory of vertical fractures. Then models for calculating the equivalent wellbore radius and the skin factor due to flow convergence to the well bore are proposed after analyzing the steady-state flow in porous reservoirs. By applying the superposition principle to the pressure drop, a new method for evaluating the productivity of horizontal wells intercepted by multiple finite-conductivity fractures is developed. The influence of fracture conductivity and fracture half length on the horizontal well productivity is quantitatively analyzed with a synthetic case. Optimum fracture number and fracture space are further discussed in this study. The results prove that the method outlined here should be useful to design optimum fracturing of horizontal wells.

Steam Flooding after Steam Soak in Heavy Oil Reservoirs through Extended-reach Horizontal Wells

This paper presents a new development scheme of simultaneous injection and production in a single horizontal well drilled for developing small block reservoirs or offshore reservoirs. It is possible to set special packers within the long completion horizontal interval to establish an injection zone and a production zone. This method can also be used in steam flooding after steam soak through a horizontal well. Simulation results showed that it was desirable to start steam flooding after six steam soaking cycles and at this time the oil/steam ratio was 0.25 and oil recovery efficiency was 23.48%. Steam flooding performance was affected by separation interval and steam injection rate. Reservoir numerical simulation indicated that maximum oil recovery would be achieved at a separation section of 40-50 m at steam injection rate of 100-180 t/d; and the larger the steam injection rate, the greater the water cut and pressure difference between injection zone and production zone. A steam injection rate of 120 t/d was suitable for steam flooding under practical injection-production conditions. All the results could be useful for the guidance of steam flooding projects.

WELL建筑标准在住宅中的设计理念

随着社会的发展,科技的进步,我国对于健康绿色建筑越来越重视。人们的身体健康与住宅建筑有着紧密的联系,绿色建筑成为近年来较为热议的话题。美国提出了WELL建筑标准,作为健康建筑设计的基础。本文以住宅为例,详细阐述了WELL建筑标准在项目设计理念上的实际实施情况,进而分析了这些理念设计对于人们身体健康的积极影响。希望在住宅设计中通过运用WELL建筑标准,为人们提供更优质的住宅环境,促进人们的身体健康,营造良好的住宅氛围。以下讨论仅供参考。

WELL健康建筑标准升级及其对中国健康建筑的启示

“健康建筑”是中国建筑发展的重要趋势之一,源于美国的WELL建筑标准,其是目前国际上最领先与完善的健康建筑标准。2018年,WELL推出了v2版本的先行版,这是WELL建筑标准一次具有重要意义的版本升级。本文将WELL建筑标准的v2、v1版本与中国健康建筑标准进行对比,通过对比分析,探讨国际健康建筑领域的发展趋势,从而为我国健康建筑发展提供参考。

Modeling, analysis, and screening of cyclic pressure pulsing with nitrogen in hydraulically fractured wells

Cyclic pressure pulsing with nitrogen is studied for hydraulically fractured wells in depleted reservoirs.A compositional simulation model is constructed to represent the hydraulic fractures through local-grid refinement.The process is analyzed from both operational and reservoir/hydraulic-fracture perspectives.Key sensitivity parameters for the operational component are chosen as the injection rate,lengths of injection and soaking periods and the economic rate limit to shut-in the well.For the reservoir/hydraulic fracturing components,reservoir permeability,hydraulic fracture permeability,effective thickness and half-length are used.These parameters are varied at five levels.A full-factorial experimental design is utilized to run 1250 cases.The study shows that within the ranges studied,the gas-injection process is applied successfully for a 20-year project period with net present values based on the incremental recoveries greater than zero.It is observed that the cycle rate limit,injection and soaking periods must be optimized to maximize the efficiency.The simulation results are used to develop a neural network based proxy model that can be used as a screening tool for the process.The proxy model is validated with blind-cases with a correlation coefficient of 0.96.

油气井人工举升生产分析优化决策系统软件Well Lift

针对油气人工举升井生产参数设计的要求和特点,本文通过对油层流入动态、井筒多相流动、举升工艺的运动学及动力学特征以及相互之间的耦合作用关系研究,研发了Well Lift油气井人工举升生产分析优化决策系统。该软件具备采油方式评价、产能预测、高压物性计算、流动保障计算、单举升及组合举升生产参数设计、智能调参、经济评价等功能。软件采用模块化设计,用户可以根据实际需要进行配置,灵活多变,可扩展性强。既可用来进行单井生产工程分析设计,也可满足开采工程方案编制的需要。

超深断控碳酸盐岩缝洞储集体地震预测与井轨迹设计——以顺北油田4号断裂带中北部为例

顺北断控缝洞型油气藏主要受走滑断裂控制,断裂带的活动强度控制了储层发育程度,储集空间主要为断裂破碎形成洞穴、孔洞、裂缝,储层的空间展布非均质性强,缝洞体的空间定位和量化表征是制约井位井型的选择和高效动用的关键。综合测井、地震、地质等资料对顺北4号带断裂北段碳酸盐岩储集体进行立体半定量化表征研究。结果表明,顺北碳酸盐岩储集体沿断裂带呈不规则分布,储集体纵向延伸大(高度50~800 m),沿断裂面非均质性强,走滑断裂带拉分段、平移段及挤压段不同分段的储集体规模、组成差异较明显。拉张段储集体体积空间最大,孔洞占比最高(35%)、裂缝(65%);平移段体积空间较小,洞穴占比较低(44%)、裂缝(56%)。并根据储层预测及储集体空间展布进行井轨迹分类设计,拉分段平面宽度较大、断裂面与储集体夹角在0~30°,采用垂向大斜度角顺穿断裂带,最大限度地钻遇储集体;平移段断面窄,储集规模小,断面与储集体夹角在30~50°,采用垂向中斜坡角斜穿断裂带,钻井揭示储集体长度相比横穿可提高1.8倍,实现高产稳产。上述技术方法取得了良好的钻探效果。

贵州省地热流体资源可开采资源量研究

综合贵州省地热研究相关成果资料,分析贵州省地热流体资源赋存条件及地热水资源分布特征,以此为基础将贵州省划分为110个地热资源量估算区,参照省内地热流体资源主要集中在断裂带周边的实际特点,采用设计布井法、泉(井)流量统计法和比拟法对贵州地热流体可开采资源量进行估算。结果表明:贵州地热流体资源的形成和分布,受省内地质构造特点及其在全国构造所处部位的控制,地热资源成因类型可划分为沉积盆地传导型地热储和隆起山地断裂对流型地热储,总体热储温度一般小于90℃,为低温地热资源;估算出贵州省地热流体可开采资源总量为23190.37 m^(3)/a,其中设计布井法估算的资源量为15926.22 m^(3)/a,天然温泉可开采资源量1183.34 m^(3)/a,地热井可开采资源量6080.80 m^(3)/a,总热能906933.97 Kw,年开采累计可利用热能量476.68×10^(8)MJ。所估算的地热流体可采资源量可为贵州省地热资源的勘查开发规划提供参考依据。

由美而乐:人的发展视角下乡村旅游从业者审美幸福感研究

共产主义的终极目标是人的自由而全面发展,中国传统文化视域下的最高人生理想是超越功利的自然审美之境。审美,作为充实主体情感、激发生命活力和促进全面发展的感性存在,已然活跃于乡村旅游的现实情境。乡村旅游从业者若想自身抑或是使游客“观照神与美”,先需自身“似神而美”,其在审美意境中的幸福感知既表现为对日常生活审美化的肯定性感受,亦表现为理欲交融的审美愉悦。文章基于人的发展视角,依托认知神经美学与空间设计美学原理,以安徽西递、宏村为案例地,采用实地调研、扎根理论与回归分析等研究方法,探究旅游驱动下乡村旅游从业者审美诞生并向审美幸福感转变的过程和机制。研究发现:乡村旅游从业者审美表现为审美观念判断、审美体验感知与审美设计能力3个方面,且其审美诞生的关键因素是旅游情境中其内在认知方式的变化,即从一般认知模式转变为审美认知方式。乡村旅游从业者的审美幸福感主要源于空间美学设计的徽派协调性感知、元素多样性感知、徽派典型性感知和设计新颖性感知,且其审美幸福感的诞生有助于推动知、情、意相协调的人的自由而全面发展,从而检验旅游的人本价值与人的发展目标实现。

基于五感疗法的养老机构户外健康景观设计研究——以武汉楠山康养基地为例

人口老龄化的加剧导致国内老龄化环境建设越发紧迫,营造养老机构户外健康景观已成为创造宜居养老环境的重要组成部分。文章以五感疗法理念为切入点,结合武汉楠山康养基地的设计实践,在对老年人群的生理、心理、行为特征及其空间使用需求分析的基础上,以构建适合老年人的户外认知景观环境、户外感知景观环境及户外安全性景观环境为目标,在空间营造、感官要素等方面提出养老机构户外健康景观的设计优化策略,以期为养老社区户外景观环境建设与发展提供一些启示与参考。