... Abstract A combination of small sample testing and numerical modelling offers a powerful tool for identification of mud chemistry effects on wellbore stability in shales. The tool allows for modelling of how the stability limits for the mud-weight varies with time, based on measured time scales...

.... In sandstones, the decrease was 50% or more. A bulk modulus decreased of 50% causes the compressibility near the wellbore to increase by 50%. Depending on the lithology, Poisson's ratio decreased or increased slightly. For limestones and shales, the differences between the moduli of lased and unlased samples...

... Abstract It is generally accepted that shale deterioration and borehole instability are significantly influenced by excessive pore pressure, ion exchange between drilling fluids and shale, and the anisotropy of the in-situ stress state as well as the formation. This paper describes a model...

... Abstract This paper describes an integrated methodology to characterize shales from an engineering point of view. Shale samples from offshore Brazil were used throughout the study. The proposed methodology includes laboratory tests designed to characterize the rock individual constituents, i.e...

... Abstract Shales encountered in the overburden above hydrocarbon reservoirs often pose challenges to the stability of boreholes. Consequently, there is a keen interest in borehole stability prediction, which is complicated by the laminated structure of shale that arises as a consequence...

... isrm 78214 upstream oil & gas surface area displacement porosity-permeability relationship permeability reservoir simulation fluid dynamics reduction specific surface area porosity coefficient rutter spe isrm 78214 shale friction Introduction Faults can serve as both seals...

... Abstract Cutting experiments were carried out to quantify the dependence of the specific energy e (the energy required to cut a unit volume of rock) on the bottom-hole pressure p m and on the pore pressure p o in shales. The experiments were conducted with an instrumented cutting...

... Abstract Preserved shale samples, from four different shale cores, were exposed to various fluids while under simulated downhole stress conditions. Prior to fluid exposure, the samples were not contacted by any aqueous fluid, including simulated pore fluid. Time-dependent measurements of pore...

... and performance verification of the drilling fluids. Specialised test equipment, including a membrane efficiency screening equipment, an autonomous triaxial cell and a high pressure triaxial test equipment and associated test procedures, were either developed or modified for simulation of key drilling fluid-shale...

... (NLBSU) is used to develop the process. The NLBSU wells require hydraulic fracturing to generate economic production rates. The NLBSU produces from Cretaceous-age Mesaverde sandstone that is composed of thinly bedded sand and shale layers. The reservoir heterogeneity caused by these layers complicates...

... Abstract The results from laboratory and theoretical work pertaining to the permeability of fractures in shale are presented. The main objective of the work is to improve existing models for hydraulic fractures in basin simulators. A simple theoretical model is proposed to quantify the effect...

... Abstract The presence of smectitic shales can cause problems for drillers in the form of wellbore stability problems resulting from the presence of swelling clays and overpressures due to low permeability. Prediction of overpressures in such sediments is hampered by interlayer water...

... Abstract Drilling experience in K-shale in the Malay Basin of Peninsular Malaysia highlighted the issue of wellbore stability in the formation. A wide range of drilling problems has been experienced, ranging from sloughing shale to tight hole and stuck pipe. Subsequently, a major collaborative...