With the increasing demand for oil exploration and subsurface resource development,density imaging plays an increasingly important role in identifying thin layers.However,conventional density imaging tools are limited...With the increasing demand for oil exploration and subsurface resource development,density imaging plays an increasingly important role in identifying thin layers.However,conventional density imaging tools are limited by poor vertical resolution and therefore suffer from errors in accurately estimating the thickness and relative dip angle of thin layers.This affects the accurate evaluation of thin layer oil and gas reserves.To address this issue,this study evaluates the feasibility of employing novel methods based on advanced tool design.First,an electronically controllable X-ray source is selected to replace the traditional Cs-137 source,aiming to improve the tool's vertical resolution while reducing the radioactive risks commonly associated with chemical sources.Simulation results show that the X-ray tool provides sufficient depth of investigation with better vertical resolution while maintaining the same level of measurement sensitivity.Once the tool design is established,Fisher's optimal segmentation method is improved to enhance the estimation of thin layer thickness and relative dip angle.This is completed by transforming identifying thin layer interface into a mathematical clustering problem.The thin layer interface is fitted using the nonlinear least squares method,which enables the calculation of its parameters.The results demonstrate a 38.5%reduction in RMSE(root mean square error)for thin layer thickness and a 33.7%reduction in RMSE for relative dip angle,demonstrating the superior performance of enhanced X-ray tool in thin layer identification.This study provides a new perspective on the design of density imaging tools and assessment of thin layer,which can help in future thin layer hydrocarbon reserves evaluation and development decisions.展开更多
无线随钻测井(Logging While Driling,LWD)仪器是当前钻井行业中普遍采用的一种先进测量工具,LWD可实时探测钻头井斜、方位和地层伽马值等数据,并实时上传到地面,指导钻头所走轨迹符合设计轨迹。瘦身井技术是一种通过减少钻柱直径,降低...无线随钻测井(Logging While Driling,LWD)仪器是当前钻井行业中普遍采用的一种先进测量工具,LWD可实时探测钻头井斜、方位和地层伽马值等数据,并实时上传到地面,指导钻头所走轨迹符合设计轨迹。瘦身井技术是一种通过减少钻柱直径,降低井眼直径的技术,减少了钻杆和套管等材料用量,减少固废产生量,降低钻井成本。但是,由于瘦身井的井眼为非常规井眼,常规的LWD仪器不能满足其井眼尺寸和泥浆排量的要求,施工时会造成立管压力升高、钻具强度降低等问题,严重影响施工进度。为解决这一难题,国产LWD仪器通过对产品技术升级,优化脉冲器流筒、限流环、提升杆、定子导流器和悬挂短节等零件结构和材质,可有效满足瘦身井的测井服务。展开更多
There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal we...There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method （3D-FEM） simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis.展开更多
Most of the carbonate formation are highly heterogeneous with cavities of different sizes, which makes the prediction of cavity-filled reservoir in carbonate rocks difficult. Large cavities in carbonate formations pos...Most of the carbonate formation are highly heterogeneous with cavities of different sizes, which makes the prediction of cavity-filled reservoir in carbonate rocks difficult. Large cavities in carbonate formations pose serious threat to drilling operations. Logging-whiledrilling （LWD） is currently used to accurately identify and evaluate cavities in reservoirs during drilling. In this study, we use the self-adaptive hp-FEM algorithm simulate and calculate the LWD resistivity responses of fracture-cavity reservoir cavities. Compared with the traditional h-FEM method, the self-adaptive hp-FEM algorithm has the characteristics of the self-adaptive mesh refinement and the calculations exponentially converge to highly accurate solutions. Using numerical simulations, we investigated the effect of the cavity size, distance between cavity and borehole, and transmitted frequency on the LWD resistivity response. Based on the results, a method for recognizing cavities is proposed. This research can provide the theoretical basis for the accurate identification and quantitative evaluation of various carbonate reservoirs with cavities encountered in practice.展开更多
In this paper, responses of a new dual-induction resistivity logging-while-drilling （LWD） tool in 3D inhomogeneous formation models are simulated by the vectorfinite element method （VFEM）, the influences of the bo...In this paper, responses of a new dual-induction resistivity logging-while-drilling （LWD） tool in 3D inhomogeneous formation models are simulated by the vectorfinite element method （VFEM）, the influences of the borehole, invaded zone, surroundingstrata, and tool eccentricity are analyzed, and calibration loop parameters and calibrationcoefficients of the LWD tool are discussed. The results show that the tool has a greater depthof investigation than that of the existing electromagnetic propagation LWD tools and is moresensitive to azimuthal conductivity. Both deep and medium induction responses have linearrelationships with the formation conductivity, considering optimal calibration loop parametersand calibration coefficients. Due to the different depths of investigation and resolution, deepinduction and medium induction are affected differently by the formation model parameters,thereby having different correction factors. The simulation results can provide theoreticalreferences for the research and interpretation of the dual-induction resistivity LWD tools.展开更多
LWD(Logging While Drilling)曲线在实时地层评价和随钻跟踪地质目标中有着重要的应用。在随钻测井曲线单一的情况，可根据邻近的直眼井或水平井的测井和录井资料，借助于回归分析法和神经网络法可模拟生成多条测井曲线。本文介绍了在...LWD(Logging While Drilling)曲线在实时地层评价和随钻跟踪地质目标中有着重要的应用。在随钻测井曲线单一的情况，可根据邻近的直眼井或水平井的测井和录井资料，借助于回归分析法和神经网络法可模拟生成多条测井曲线。本文介绍了在水平井地质导向钻井中，如何利用实测的随钻伽马曲线和实时构造的随钻伽马、电阻率和中子孔隙度等曲线来实时跟踪地质目标层的方法和技术。将其结果用于MB油田3口水平井的实时钻井中，取得了明显的随钻跟踪地质目标效果。展开更多
基金the support of theNational Natural Science Foundation of China(U23B20151 and52171253)。
文摘With the increasing demand for oil exploration and subsurface resource development,density imaging plays an increasingly important role in identifying thin layers.However,conventional density imaging tools are limited by poor vertical resolution and therefore suffer from errors in accurately estimating the thickness and relative dip angle of thin layers.This affects the accurate evaluation of thin layer oil and gas reserves.To address this issue,this study evaluates the feasibility of employing novel methods based on advanced tool design.First,an electronically controllable X-ray source is selected to replace the traditional Cs-137 source,aiming to improve the tool's vertical resolution while reducing the radioactive risks commonly associated with chemical sources.Simulation results show that the X-ray tool provides sufficient depth of investigation with better vertical resolution while maintaining the same level of measurement sensitivity.Once the tool design is established,Fisher's optimal segmentation method is improved to enhance the estimation of thin layer thickness and relative dip angle.This is completed by transforming identifying thin layer interface into a mathematical clustering problem.The thin layer interface is fitted using the nonlinear least squares method,which enables the calculation of its parameters.The results demonstrate a 38.5%reduction in RMSE(root mean square error)for thin layer thickness and a 33.7%reduction in RMSE for relative dip angle,demonstrating the superior performance of enhanced X-ray tool in thin layer identification.This study provides a new perspective on the design of density imaging tools and assessment of thin layer,which can help in future thin layer hydrocarbon reserves evaluation and development decisions.
文摘无线随钻测井(Logging While Driling,LWD)仪器是当前钻井行业中普遍采用的一种先进测量工具,LWD可实时探测钻头井斜、方位和地层伽马值等数据,并实时上传到地面,指导钻头所走轨迹符合设计轨迹。瘦身井技术是一种通过减少钻柱直径,降低井眼直径的技术,减少了钻杆和套管等材料用量,减少固废产生量,降低钻井成本。但是,由于瘦身井的井眼为非常规井眼,常规的LWD仪器不能满足其井眼尺寸和泥浆排量的要求,施工时会造成立管压力升高、钻具强度降低等问题,严重影响施工进度。为解决这一难题,国产LWD仪器通过对产品技术升级,优化脉冲器流筒、限流环、提升杆、定子导流器和悬挂短节等零件结构和材质,可有效满足瘦身井的测井服务。
基金supported by the National Science and Technology Major Project of China(Nos.2016ZX05014-002-001,2016ZX05002-005-001,and 2017ZX05005-005-005)
文摘There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method （3D-FEM） simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis.
基金supported by the National Natural Science Foundation of China(No. 41074099)
文摘Most of the carbonate formation are highly heterogeneous with cavities of different sizes, which makes the prediction of cavity-filled reservoir in carbonate rocks difficult. Large cavities in carbonate formations pose serious threat to drilling operations. Logging-whiledrilling （LWD） is currently used to accurately identify and evaluate cavities in reservoirs during drilling. In this study, we use the self-adaptive hp-FEM algorithm simulate and calculate the LWD resistivity responses of fracture-cavity reservoir cavities. Compared with the traditional h-FEM method, the self-adaptive hp-FEM algorithm has the characteristics of the self-adaptive mesh refinement and the calculations exponentially converge to highly accurate solutions. Using numerical simulations, we investigated the effect of the cavity size, distance between cavity and borehole, and transmitted frequency on the LWD resistivity response. Based on the results, a method for recognizing cavities is proposed. This research can provide the theoretical basis for the accurate identification and quantitative evaluation of various carbonate reservoirs with cavities encountered in practice.
基金supported by the National Oil and Gas Major Projects(No.2011ZX05020-002)
文摘In this paper, responses of a new dual-induction resistivity logging-while-drilling （LWD） tool in 3D inhomogeneous formation models are simulated by the vectorfinite element method （VFEM）, the influences of the borehole, invaded zone, surroundingstrata, and tool eccentricity are analyzed, and calibration loop parameters and calibrationcoefficients of the LWD tool are discussed. The results show that the tool has a greater depthof investigation than that of the existing electromagnetic propagation LWD tools and is moresensitive to azimuthal conductivity. Both deep and medium induction responses have linearrelationships with the formation conductivity, considering optimal calibration loop parametersand calibration coefficients. Due to the different depths of investigation and resolution, deepinduction and medium induction are affected differently by the formation model parameters,thereby having different correction factors. The simulation results can provide theoreticalreferences for the research and interpretation of the dual-induction resistivity LWD tools.
文摘LWD(Logging While Drilling)曲线在实时地层评价和随钻跟踪地质目标中有着重要的应用。在随钻测井曲线单一的情况，可根据邻近的直眼井或水平井的测井和录井资料，借助于回归分析法和神经网络法可模拟生成多条测井曲线。本文介绍了在水平井地质导向钻井中，如何利用实测的随钻伽马曲线和实时构造的随钻伽马、电阻率和中子孔隙度等曲线来实时跟踪地质目标层的方法和技术。将其结果用于MB油田3口水平井的实时钻井中，取得了明显的随钻跟踪地质目标效果。
