Data Of Horizontal Well Research Articles

Grid filtering method for shale reservoir 3-D property modeling using horizontal well data

Wells drilled in the core area of shale reservoir are predominantly horizontal compared to vertical wells in conventional reservoirs. Due to the different features of data in horizontal and vertical wells, the 3-D property modeling of shale reservoirs is distinct from the conventional reservoirs. Lateral drilling usually leads to the repeated sampling in the specific vertical intervals and the missing sampling in the bottom part of the shale reservoir. This biased sampling distorts the distribution characteristics in well data from the real reservoir properties. Moreover, because of the large inclination angle in the laterals, it is so common to penetrate only the upper or lower part of the grid. Given that the same method is utilized to assign well values to these partially penetrated girds and fully penetrated grids, the assigned value in these partially penetrated grids fail to represent the reservoir property in the associated grid layer. Therefore, we developed a grid filtering method to solve the issues arised from the biased sampling and the partially penetrated grids. It includes five parts: (1) divide wellbore into multiple well segments using formation top data; (2) recognize the type of well segments and well-penetrated grids to generate a grid filter; (3) process the log-format data of each complete sampling segment using the grid filter; (4) generate one dataset for analyzing distribution features and another dataset as the control points of geostatistic simulation algorithms; (5) build the 3-D property models using the analyzed distribution features and the control points as the input. By generating two independent datasets, we achieved the maximum utilization of log-format data in horizontal wells and eliminated the biased sampling effect. The total organic carbon content and shale lithofacies in the JY-1 district, Jiaoshiba Area, Eastern Sichuan Basin, were used to demonstrate our method.

Technical analysis of improving sand body penetration rate in horizontal well

Because the measurement data of horizontal well lags behind the actual position of bit, accurate geological guidance is the key to improve the rate of sand body drilling. Taking the thin and poor reservoir sand body at the edge of a development zone as an example, this paper introduces the horizontal well geosteering technology in detail, five techniques have been developed, including marker layer selection, seismic software aided guidance, target identification, lwd data analysis and rate of penetration control. The technique has achieved high sand body penetration rate in 7 horizontal wells. This technology provides a favorable guarantee for the effective development of thin and poor reservoirs in horizontal wells.

Quantifying hydraulically induced fracture height and density from rapid time-lapse distributed acoustic sensing vertical seismic profile data

Several recent studies have advanced the use of time-lapse distributed acoustic sensing vertical seismic profile data in horizontal wells for determining hydraulically stimulated fracture properties. Hydraulic fracturing in a horizontal well typically generates vertical fractures in the rock medium around each stage. We have modeled the hydraulically stimulated formation with vertical fracture sets about the lateral wellbore as a horizontally transverse isotropic medium. Rock-physics modeling is used to relate the anisotropy parameters to the fracture properties. This modeling is used to develop an inversion for compressional wave time delay to the fracture height and density of each stage. Field data from two horizontal wells are analyzed, and the fracture height evaluated using this technique is consistent with the microseismic analysis.

Permian Basin: Use of In-Situ Mechanical Rock Properties Improves Completions

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 191406, “Using In-Situ Mechanical Rock Properties To Target Landing Zones and Improve Completions in the Permian Basin,” by E.L. Scott, A.M. Hildick, and C. Glaser, Fracture ID, and E. Petre, Hunt Oil, prepared for the 2018 SPE International Hydraulic Fracturing Technology Conference and Exhibition, Muscat, Oman, 16–18 October. The paper has not been peer reviewed. Optimizing horizontal well placement is not limited to identifying the most-favorable reservoir, but also involves identifying the ideal target window within that reservoir. Gathering drill-bit geomechanics data provides a lower-cost and lower-risk method to acquire mechanical rock properties in long horizontal wellbores. By integrating data sets with mechanical rock properties recorded while drilling, operators can have significantly higher confidence in choosing a target landing zone and improving completions. The complete paper presents two detailed case studies from the Permian Basin. Introduction In this paper, the authors combine the characterization of petrophysical and geomechanical properties into what they call a petromechanical work flow. Typically, petrophysical and geomechanical properties are characterized using data acquired by wireline logs. In vertical wells, wireline logs represent, traditionally, the least-intrusive manner of acquiring high-resolution data. With additional cost and rig time, cores of the formation rock can be exhumed to analyze its properties on surface. In horizontal wells, both wireline logs and conventional cores are costly and operationally challenging. Because of the economic and operational burden, operators typically avoid collecting geomechanical data in horizontal wells. Besides these traditional measurements, the novel technique of using drill-bit geomechanics can enable measurement of geomechanical properties while drilling. Compared with wireline logs and core analysis, this technique is less costly and has a lower risk in long horizontal wells. Drill-Bit Geomechanics Drill-bit geomechanics provides mechanical properties through continuous, high-resolution measurements of drilling-induced vibrations. Triaxial accelerometers, which sample at 1 kHz, record the vibrations while positioned directly behind the drill bit. Earthquake seismology models allow a transformation of the high-frequency, triaxial, drilling-induced vibrations into mechanical rock•properties. The drill-bit geomechanics method determines mechanical properties by using stress-strain relationships and isotropic stiffness coefficients. Additionally, the method describes anisotropy by solving for transversely isotropic (TI) interpretations of the rock matrix. Typically, a vertically transverse isotropic (VTI) matrix contains high shale content or other laminar bedding, while a horizontally transverse isotropic (HTI) matrix contains vertical bedding or fractures. In this paper, the authors define VTI anisotropy as bedding and HTI anisotropy as fracture intensity.

Combined Approach Improves Fault Description for Horizontal-Well Geosteering

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 191695-18RPTC, “Complex Approach to Fault Description While Geosteering for Maximization of Reservoir Contact in Horizontal Wells in West Siberia Oil Fields,” by Vladislav V. Krutko, Tatyana A. Yurkina, SPE, and Dmitriy Y. Kushnir, Baker Hughes, a GE Company, and Valery B. Karpov, RITEK, prepared for the 2018 SPE Russian Petroleum Technology Conference, Moscow, 15–17 October. The paper has not been peer reviewed. This paper presents an interdisciplinary approach to the description of tectonic dislocations made on the basis of interpretation of seismic data, petrophysical analysis of well-logging data in horizontal wells, and inversion of a multifrequency propagation tool. A consistent approach to fault identification and description is presented on the basis of seismic surveys and logging-while-drilling (LWD) data in horizontal wells in a western Siberian oil field. Seismic Methods of Tectonic-Fault Interpretation Estimation of seismic methods of fault detection was performed on materials acquired from one of the fields in the Frolov oil-and-gas district. The observed territory of the oil field is characterized by complex geological structure—namely low effective reservoir thickness, thin layering of sandstones and silts, low porosity, low-permeability reservoir zones, and tectonic block structure. When drilling in reservoirs of low thickness, knowing the precise position of the horizontal wellbore relative to the structure is critical. The basis of drilling planning is a structural map of the reservoir top. After field jobs were complete and the results of the wide-aperture 3D seismic survey of the considerable refinement of the top structure of the reservoir were obtained, the morphology of all earlier identified structural forms was completed. A faulted and blocked principal model of the reservoir was created that formed the basis for a well-pad positioning scheme, as well as for usage in horizontal-well drilling. Horizontal Well 2301G was planned in the northwest region of the field. For reservoir-model construction, a structural map prepared from seismic-survey interpretation was used. An outcrop of the structural map with Well 2301G in place is presented in Fig. 1. A rare well network in the drilling area led to high uncertainty regarding structure parameters and risk of penetrating a fault. As an offset, Well 75B3 was used (Fig. 1). In this offset well, the horizon AC3 represented a thin layering of silt, shaly sandstone, and tight rocks. The thickness of the AC3 horizon was 13.2 m. During the drilling of the transport section, the wellbore of Well 2301G penetrated the top of the AC3 horizon at 1912.12-m true vertical depth, which coincided with the structural surface prognosis made on the basis of seismic data. The blocked model of the AC33 horizon is complex; the vision of the structure of the target reservoir can change significantly while drilling and penetrating the reservoir. According to seismic data, the possibility exists of crossing three faults along the planned horizontal section of Well 2301G.

A comprehensive evaluation index for shale reservoirs and its application: A case study of the Ordovician Wufeng Formation to Silurian Longmaxi Formation in southeastern margin of Sichuan Basin, SW China

Aiming at the disadvantages of existing shale reservoir evaluation methods, a new comprehensive index was proposed to accurately predict the distribution of high quality shale reservoirs and favorable fracturing intervals. The comprehensive index can be calculated using the physical properties index and fracturing index by the equivalent method. Computed by logging rock-electric parameters and mineral bulk physical model, the physical properties index characterizes reservoir property and gas-bearing property; the fracturing index characterizes reservoir fracability and is acquired by equivalent porous medium model considering mineral components. According to the comprehensive index, combined with the macro-micro characteristics of cores and logging data, the shale reservoirs in the Ordovician Wufeng Formation to Silurian Longmaxi Formation of Jiaoshiba area in the southeastern margin of Sichuan Basin are subdivided into four types, the high terrigenous siliceous and high authigenic siliceous types are the best in reservoir property and fracability, followed by the middle siliceous and then low siliceous. The comprehensive index can be used to interpret the logging data of horizontal well to figure out the proportion of reservoirs of different types, identify the spatial distribution of reservoirs with good physical properties and good fracability. The predicted results match well with actual production after fracturing.

Технологии интерпретации данных геофизических исследований горизонтальных скважин: настоящее и будущее

Технологии интерпретации данных геофизических исследований горизонтальных скважин: настоящее и будущее