It is shown that severe casing deformation tends to occur where structural fractures are developed. Besides, casing deformation is mainly in the form of “S”-shape bending vertically. The severely deformed casing is also characterized by obviously transverse shear deformation caused by the high-angle sliding compression of rocks. Therefore, some suggestions
Rock Evaluation and Wellbore Stability
Wellbore Stability and Rock Evaluation Category contains papers and researches about how to determine they in a shale gas and shale (tight) oil industry.
Rock evaluation is the more important study to analyze the viability to develop a shale play. Maintaining wellbore stability is an important issue to save economic losses in drilling activities.
Data on shale-water based drilling fluid interaction for drilling operation
The dispersion test was conducted, and it involves exposing a weighted quantity of sized shale to the formulated mud in roller-oven. This test is used to design fluids and screen the effectiveness of inhibitor additives to maintain the integrity of the cuttings and minimize the interaction of fluids with the
Enhancing the rheological properties and shale inhibition behavior of water-based mud using nanosilica, multi-walled carbon nanotube, and graphene nanoplatelet
Abstract Five different drilling mud systems namely potassium chloride (KCl) as a basic mud, KCl/partial hydrolytic polyacrylamide (PHPA), KCl/graphene nanoplatelet (GNP), KCl/nanosilica and KCl/multi-walled carbon nano tube (MWCNT) were prepared and investigated for enhancement of rheological properties and shale inhibition. Nanoparticles were characterized in drilling mud using transmission electron microscope (TEM)
Anti-channeling cementing technology for long horizontal sections of shale gas wells
It is indicated that the near-bit three-centralizer drifting BHA used for casing stiffness simulation can decrease the casing running difficulty in the long horizontal section of a shale gas well and increase the time efficiency and safety of casing running; that the flushing efficiency of high-efficiency oil flushing spacer fluid
Adsorption damage and control measures of slick-water fracturing fluid in shale reservoirs
With the increase of pH value, the adsorption capacity decreased gradually, the adsorption capacity increased first and then decreased with the increase of temperature, and the adsorption capacity was the largest at 45°C. The adsorption patterns of polymers on shale were described by scanning electron microscopy and magnetic resonance imaging.
Shale hydration inhibition characteristics and mechanism of a new amine-based additive in water-based drilling fluids
Some amine functional groups exist in tallow amine ethoxylate structure which are capable of forming hydrogen bonding with surfaces of bentonite particles. This phenomenon decreased the water adsorption on bentonite particles' surfaces which results in reduction of swelling. Tallow amine ethoxylate is also compatible with other common drilling fluid additives. Introduction A
Elastic–Brittle–Plastic Behaviour of Shale Reservoirs and Its Implications on Fracture Permeability Variation: An Analytical Approach
Desorption of gas during production can cause shrinkage of the organic content of the rock. This becomes more important when considering the use of shales for CO2 sequestration purposes, where CO2 adsorption-induced swelling can play an important role. These phenomena lead to changes in the stress state within the rock
Development of a new correlation to determine the static Young’s modulus
The laboratory values are then used to correlate the dynamic values derived from the logs. Several correlations were introduced in the literature, but those correlations were very specific and when applied to different cases they gave very high errors and were limited to relating the dynamic Young’ modulus with the
Mudcake effects on wellbore stress and fracture initiation pressure and implications for wellbore strengthening
Numerical examples are provided to illustrate the effects of these mudcake parameters. The results show that a low-permeability mudcake enhances FIP, mainly through restricting fluid seepage and pore pressure increase in the near-wellbore region, rather than by mudcake strength. Fluid loss pressure (FLP) should be distinguished from FIP when a
Preparation and application of melamine cross-linked poly ammonium as shale inhibitor
The inhibition mechanism of DEM-8 was studied by thermogravimetric analysis and scanning electron microscope. The results demonstrate that DEM-8 can be adsorbed on clay surface through electrostatic interaction and hydrogen bonds by an anchoring effect and a hydrophobic effect. Introduction Shale oil/gas has been one of the technologies highlighted in the world
Thermogravimetry as a tool for measuring of fracturing fluid absorption in shales
In case of rocks which are drilled from the borehole, obtaining such large samples is very difficult; therefore, an attempt was made to determine the rock absorption on small samples, using the TG analysis. Thermogravimetric (TG/DTG) experiments were conducted in temperature range 40–300 °C in synthetic air environment. Shale rock
Cationic surfactant (CTAB) a multipurpose additive in polymer-based drilling fluids
Addition of cetyltrimethylammoniumbromide increased fluid retention capacity of the fluid even at very low concentration 0.1%(w/v) without affecting the mud properties. Also it is compatible with the commercially available fluid loss preventers like pre-gelatinized starch when used in combination. It also performed well in dissolved oxygen test, suggesting eliminating need
Experimental Study and Numerical Modeling of Fracture Propagation in Shale Rocks During Brazilian Disk Test
To incorporate the effects of shale formation heterogeneity in the simulation of crack paths, fracture properties of the specimens are defined as spatially random fields. A computational strategy on the basis of stochastic finite element theory is developed that allows to incorporate the effects of heterogeneity of shale rocks on
Fracking: How far from faults?
An alternative approach is to use microseismic data to infer the extent of fracture propagation and stress changes. Using published microseismic data from 109 fracking operations and analysis of variance, we find that the empirical risk of detecting microseismicity in shale beyond a horizontal distance of 433 m is 32%
An integrated approach to discretized 3D modeling of geomechanical properties for unconventional mature field appraisal in the western Canadian sedimentary basin
To overcome these challenges, this paper describes an integrated approach for deriving 3D geomechanical models of the reservoir by combining results of 3D geocellular models and basin models. The basin model reconstructs the geologic history (i.e., burial history) of the reservoir by back-stripping it to the original depositional thickness. Through