To exert the imbibition between cracks and matrix effectively enhance development effect of tight oil reservoirs, a physical simulation method for in different scales cores is developed by combining high-pressure large-model system nuclear magnetic resonance technology (NMR) to investigate influencing factors process construct quantitative evaluation water flooding. The results show that counter-current imbibition, lower permeability, later droplet precipitation, longer equilibrium time,...

The Triassic Yanchang Formation Chang7 Member tight oil reservoir in Ordos Basin, featuring complex pore-throat structures, low porosity, permeability, rich micro-fractures and pressure coefficient, is difficult to produce by advanced water-flooding from cluster vertical wells with individual-well producing rate. With Block A as an example, the material balance calculation, numerical simulation field practical analysis showed that horizontal well production would increase significantly using...

Based on core, imaging logging, and thin section data, the distribution features of natural fractures in tight oil reservoirs Ordos Basin are examined. The rich fractures, mainly high-angle structural shear continuous step arrangement. Affected by rock mechanical anisotropy present stress field, NE trending dominating seepage flow direction. These feature high angle, small cutting depth, aperture short extension, controlled lithology single layer thickness development degree, most developed...

Some tight sandstone gas reservoirs contain mobile water, and the water generally has a significant impact on flowing in pores. The flow behavior of pores is different than conventional formations, yet there lack adequate models to predict production describe gas-water behaviors water-bearing reservoirs. Based experimental results, this paper presents mathematical formations; threshold pressure gradient, stress sensitivity, relative permeability are all considered our models. A numerical...

Abstract Shale oil development in Ordos Basin, China, primarily relies on the displacement of crude during post-fracturing shut-in stage (PFSIS) horizontal wells. Reservoir wettability significantly influences duration and even approach. However, due to strong heterogeneity super tight characteristics, reservoir usually shows an mixed wettability, it was hard differentiate different pore sizes. With this mind, study focuses core samples from shale Longdong region basin quantitatively analyze...

Summary A significant amount of associated gas has been produced from shale oil reservoirs in the Ordos Basin, northern China, recent years, which provided an opportunity for using low-cost, enhanced recovery (EOR) projects. However, there are few other reports EOR projects gas, and a quantitative evaluation technique is needed. Therefore, we conducted waterflooding experiments samples at constant gradually increasing injection pressure while monitoring spatial distribution movable residual...

Abstract One of the main challenges during drilling is wellbore instability. Traditionally, geomechanical model construction and stability (WBS) analysis are manually executed by geomechanics experts for well planning drilling. The procedures usually complicated time-consuming due to subsurface complexity, results highly depend on executor's expertise. This makes WBS far from ideal automatic. In this study, we present a physics-incorporated machine learning method that performs in simple...

Abstract Geoengineering is an important integrated approach for oilfield development. Conventional geoengineering focuses on geology and reservoir studies using analytical or numerical methods. A new uses data mining machine learning as input to completion optimization. Compared conventional practice, this innovative allows field development optimization be based statistics instead of models. The application means converting understanding into a form that supports the well engineering. work...

Carbonated water injection (CWI) refers to a method that using carbonated (CO2 dissolved in under high pressure) as injected fluid displace oil the reservoir. At present there is no report about CWI study tight reservoirs. Based on reservoir condition and material of formation Changqing Oilfield, we investigate core displacement performances CWI, alternating Gas (CO2), surfactant injection, active (adding water) injection. Experimental results demonstrate recovery 7.2% more than 2.7% WAG...

Authigenic chlorite, which is frequently found in sandstone, has a controlling effect on the reservoirs tight oil adsorbed during hydrocarbon filling. In this study, content, occurrence state, timing, mechanism and influence of authigenic chlorite micro-occurrence states were studied using Thin Section (TS), Fluorescent (FTS), X-Ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM), Environmental Scanning (ESEM), Energy Dispersive Spectroscopy (EDS). The results...

Abstract Shale oil in Ordos basin, China, is being developed using horizontal well and volume fracturing. Elastic energy, dissolved gas expansion etc. are the main driving forces for fluid flowing from matrix to wellbore. However, flow mechanism varies greatly when hydrocarbon flows artificial fractures then wellbore, due huge differences sizes of channel, nano-scale pore-throat meter-scale channel Thus, a reasonable mathematical description structural characteristics complex fracture...

It has become a consensus that viscosity an important impact on boundary layer of tight reservoirs. However, there are few quantitative studies the effect by core experiments. NMR analysis based high-speed centrifugal gas-water and gas-oil displacement low-temperature adsorption experiment were implemented in this study typical reservoir parallel cores Ordos Bohai Bay basins. Total bound water/oil saturation, specific surface area ratio micro pore quantitatively finally obtained, which used...

Abstract Inspired by the success of North American unconventional resources, many shale oil operators in China adopted intensive completion and fracturing practice for field development. The intention aggressive scheme was to improve individual well productivity as ultimate recovery. Similar counterpart America, however, frequent frac hits have been reported recent years, increase engineering parameters has not always increased productivity. Based on geo-engineering work Ordos basin, we...

It is reported that the flooding rate in low permeability sandstones and oil recovery hard to increase after water breakthrough. Understanding characteristics of waterflood hence important for improvement. In this work, tests on were conducted. The corresponding investigated by means CT scanning Nuclear Magnetic Resonance. Effects irreducible different rates also discussed detail. Experimental results reveal a piston-like displacement at samples. saturation profile steep almost vertical...

Abstract The reasonable well pattern arrangement is a key factor that ultra-low permeability oilfield are developed successfully because it usually relative to fracture. By using numerical modeling, driving replacement etc reservoir engineering methods after reviewing the evolution of for Changqing reservoir, paper presents rhombus inverted nine-spot and rectangle matching best fracture injection-production pressure system. In development practice, we adopt square nine-spot, according...

Based on high-speed centrifugal gas-water and gas-oil displacement experiment using NMR low-temperature adsorption for typical tight reservoir parallel cores of Ordos Bohai Bay basins, This study obtained total bound water/oil saturation, specific surface area ratio micro pore the quantitatively, which were used calculating irreducible film thickness reservoir, analyzing influence viscosity movable oil boundary layer. Research show that, saturation core saturated with high is 23% 26% lower...

Abstract The challenges of lacustrine shale oil reservoirs include not only subsurface heterogeneity reservoir quality and but also the effect natural fractures on propagation hydraulic associated fracture hits. intercalated sandstone in a gravity deposit setting result significant variation quality. Meanwhile, conditions become even more complicated when are naturally fractured. objective this study is to characterize quality, fractures, completion with well, seismic, fracturing data,...

Abstract Engineered completion designs consider reservoir quality (RQ) and (CQ) for horizontal well optimization. This is more effective than the geometric strategy that sometimes used. However, both RQ CQ are derived from wellbore logs, which means true geology properties inside model (e.g., thickness of pay zone or rocks) not fully utilized. That information often hidden 3D geological grid properties, current fracturing practice cannot use data optimizations. To address this challenge, we...