Acquisition, Calibration, and Use of the In Situ Stress Data for Oil and Gas Well Construction and Production

2000 ◽  
Author(s):  
Jitendra M. Avasthi ◽  
Harvey E. Goodman ◽  
Ray P. Jansson
Keyword(s):  
Oil And Gas ◽  
In Situ Stress ◽  
Gas Well

scholarly journals Artificial Interference of Stress Field in a Near-Fracture show="" $6#?=""Zone by Water Injection in a Preexisting Crack

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Yongxiang Zheng ◽  
Jianjun Liu ◽  
Bohu Zhang
Keyword(s):  
Oil And Gas ◽  
Fractured Reservoirs ◽  
Water Injection ◽  
Fluid Pressure ◽  
In Situ Stress ◽  
Stress Intervention ◽  
Oil And Gas Resources ◽  
Favorable State ◽  
Artificial Stress

The in situ stress has an important influence on fracture propagation and fault stability in deep formation. However, the development of oil and gas resources can only be determined according to the existing state of in situ stress in most cases. It is passive acceptance of existing in situ stress. Unfortunately, in some cases, the in situ stress conditions are not conducive to resource development. If the in situ stress can be interfered in some ways, the stress can be adjusted to a more favorable state. In order to explore the method of artificial interference, this paper established the calculation method of the in situ stress around the cracks based on fracture mechanics at first and obtained the redistribution law of the in situ stress. Based on the obtained redistribution law, attempts were made to interfere with the surrounding in situ stress by water injection in the preexisting crack. On this basis, the artificial stress intervention was applied. The results show that artificial interference of stress can effectively be achieved by water injection in the fracture. And changing the fluid pressure in the crack is the most effective way. By stress artificial intervention, critical pressure for water channelling in fractured reservoirs, directional propagation of cracks in hydraulic fracturing, and stress adjustment on the structural plane were applied. This study provides guidance for artificial stress intervention in the exploitation of the underground resource.

The Experimental Study on the In Situ Stress of SongNan Block

2013 ◽  
Vol 395-396 ◽  
pp. 852-855 ◽  
Author(s):  
Li Gang Zhang ◽  
Hai Bo Wang ◽  
Xiao Dong Si ◽  
Shi Bin Li
Keyword(s):  
Principal Stress ◽  
Wave Velocity ◽  
Phase Angle ◽  
Oil And Gas ◽  
Maximum Principal Stress ◽  
In Situ Stress ◽  
Velocity Anisotropy ◽  
Oil And Gas Exploration ◽  
Tight Gas Reservoir

In view of the low pressure tight gas reservoir in Songnan block, the comprehensive experiment of in-situ stress is carried out. Firstly, the tuffaceous breccia of Longshen 301 and 307 has been cored and the flag line is depicted. Through the viscous remanence experiment, the secondary viscous remanence component at 0°C~200°C is gradually separated, and the average direction of the two groups core flag line are obtained, which are 92.0° and 114.7°. Then to mark the flag line as the baseline, using the wave velocity anisotropy experiment to measure the acoustic wave velocity under different phase angle, the minimum wave velocity phase angle of the two groups core are achieved, which are 23° and 44° . And combined with the direction of the flag line, the direction of maximum horizontal principal stress are determined for N69o E and N70.7o E. Finally, using DSA (differential strain) experiment, the strain recovery of 9 direction under hydrostatic pressure are measured, and the three principal strain, the magnitude and direction of the principal stress are obtained through the inversion, the maximum principal stress direction of which are N70.8o E and N71.7o E. Compared the wave velocity anisotropy experiments and DSA experimental results, both close, the direction of the regional maximum horizontal in-situ stress is determined for N70.5° E ± 1.5°. According to the above research results, the basis for the engineering design of Songnan block such as oil and gas exploration, development, drilling and production is provided.

Seismic field data displaying azimuthal anisotropy, 1986–2020

2020 ◽  
Vol 8 (4) ◽  
pp. SP135-SP156
Author(s):  
Heloise Lynn
Keyword(s):  
Field Data ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
In Situ Stress ◽  
Azimuthal Anisotropy ◽  
Amplitude Variation ◽  
Gas Industry ◽  
The Past ◽  
Vertically Aligned

The azimuthal (az’l) processing of 3D full-azimuth full-offset P-P reflection seismic data can enable better imaging, thus yielding improved estimates of structure, lithology, porosity, pore fluids, in situ stress, and aligned porosity that flows fluids (macrofracture porosity). In the past 34 years, the oil and gas industry has significantly advanced in the use of seismic azimuthal anisotropy, in particular, to gain information concerning unequal horizontal stresses and/or vertically aligned fractures, and possibly more importantly, to improve the prestack imaging especially in complex structure. The important development stages during the past 40 years were enabled by industry advancements in acquisition, processing, theory, and interpretation. The typical important techniques became evident in PP amplitude variation with angle and azimuth (AVAaz) and orthorhombic imaging. These techniques addressed the complications due to wave propagation in birefringent media. PP AVAaz, now industry standard for vertically aligned fracture characterization, is accompanied by a near-angle azimuthal amplitude variation when aligned connected porosity that flows fluids is present. Birefringence is present with unequal horizontal stresses and/or vertically aligned fractures that flow fluids. I have focused on the field-data documentation of the relationships among azimuthal P-P reflection data, S-wave birefringence, and hydrocarbon production. With increases and improvements in acquisition and processing, plus today’s powerful versatile interpretation platforms, continual advances beyond orthorhombic (ORT) into monoclinic and triclinic symmetries are to be expected. The use of 3D azimuthal seismic for time-lapse changes of the in situ stress field, fracture populations, and pore fluids, as rocks undergo production processes (oil and gas reservoir production processes, wastewater disposal, etc.) and at plate boundaries where stresses change, offers great potential to benefit not just the oil and gas industry but all of humanity.

scholarly journals Self-Sensing Well Cement

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1235
Author(s):  
Kamila Gawel ◽  
Dawid Szewczyk ◽  
Pierre Rolf Cerasi
Keyword(s):  
Acoustic Emission ◽  
Stress State ◽  
Oil And Gas ◽  
Conductive Filler ◽  
In Situ Stress ◽  
Resistance Response ◽  
Gas Well ◽  
Stress Changes ◽  
Emission Changes ◽  
Well Cement

Chemical reactions with reservoir fluids and geology related in-situ stress changes may cause damages to cement sealing material in plugged and abandoned oil, gas and CO2 wells. To avoid leakages, a legitimate monitoring technique is needed that could allow for early warning in case such damages occur. In this paper, we test the utility of oil and gas well cement with a conductive filler in sensing stress changes. To this end, we have measured the resistance response of Portland G—oil and gas well cement with carbon nanofibers (CNF) to axial load during uniaxial compressive strength test. Simultaneously, the microseismicity data were collected. The resistance of the nanocomposite was measured using two-point method in the direction of loading. The resistance changes were correlated with acoustic emission events. A total of four different material response regions were distinguished and the resistivity and acoustic emission changes in these regions were described. Our results suggest that the two complementary methods, i.e., acoustic emission and resistance measurements, can be used for sensing stress state in materials including well cement/CNF composites. The results suggest that the well cement/CNF composites can be a good candidate material to be used as a transducer sensing changes in stress state in, e.g., well plugs up to material failure.

Containment of Massive Hydraulic Fractures

1978 ◽  
Vol 18 (01) ◽  
pp. 27-32 ◽  
Author(s):  
E.R. Simonson ◽  
A.S. Abou-Sayed ◽  
R.J. Clifton
Keyword(s):  
Hydraulic Fracture ◽  
Oil And Gas ◽  
Fracture Propagation ◽  
Rocky Mountain ◽  
In Situ Stress ◽  
Hydraulic Fractures ◽  
Pressure Gradients ◽  
In Situ Stresses ◽  
Gas Bearing

Abstract Hydraulic fracture containment is discussed in relationship to linear elastic fracture mechanics. Three cases are analyzed,the effect of different material properties for the pay zone and the barrier formation,the characteristics of fracture propagation into regions of varying in-situ stress, propagation into regions of varying in-situ stress, andthe effect of hydrostatic pressure gradients on fracture propagation into overlying or underlying barrier formations. Analysis shows the importance of the elastic properties, the in-situ stresses, and the pressure gradients on fracture containment. Introduction Application of massive hydraulic fracture (MHF) techniques to the Rocky Mountain gas fields has been uneven, with some successes and some failures. The primary thrust of rock mechanics research in this area is to understand those factors that contribute to the success of MHF techniques and those conditions that lead to failures. There are many possible reasons why MHF techniques fail, including migration of the fracture into overlying or underlying barrier formations, degradation of permeability caused by application of hydraulic permeability caused by application of hydraulic fracturing fluid, loss of fracturing fluid into preexisting cracks or fissures, or extreme errors in preexisting cracks or fissures, or extreme errors in estimating the quantity of in-place gas. Also, a poor estimate of the in-situ permeability can result in failures that may "appear" to be caused by the hydraulic fracture process. Previous research showed that in-situ permeabilities can be one order of magnitude or more lower than permeabilities measured at near atmospheric conditions. Moreover, studies have investigated the degradation in both fracture permeability and formation permeability caused by the application of hydraulic fracture fluids. Further discussion of this subject is beyond the scope of this paper. This study will deal mainly with the containment of hydraulic fractures to the pay zone. In general, the lithology of the Rocky Mountain region is composed of oil- and gas-bearing sandstone layers interspaced with shales (Fig. 1). However, some sandstone layers may be water aquifers and penetration of the hydraulic fracture into these penetration of the hydraulic fracture into these aquifer layers is undesirable. Also, the shale layers can separate producible oil- and gas-bearing zones from nonproducible ones. Shale layers between the pay zone and other zones can be vital in increasing successful stimulation. If the shale layers act as barrier layers, the hydraulic fracture can be contained within the pay zone. The in-situ stresses and the stiffness, as characterized by the shear modulus of the zones, play significant roles in the containment of a play significant roles in the containment of a hydraulic fracture. The in-situ stresses result from forces in the earth's crust and constitute the compressive far-field stresses that act to close the hydraulic fracture. Fig. 2 shows a schematic representation of in-situ stresses acting on a vertical hydraulic fracture. Horizontal components of in-situ stresses may vary from layer to layer (Fig. 2). For example, direct measurements of in-situ stresses in shales has shown the minimum horizontal principal stress is nearly equal to the overburden principal stress is nearly equal to the overburden stress. SPEJ P. 27

scholarly journals Finite Element Simulation of Oil and Gas Reservoir In Situ Stress Based on a 3D Corner-point Grid Model

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Liu Yuyang ◽  
Liu Shiqi ◽  
Pan Mao
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Simulation ◽  
Oil And Gas ◽  
Corner Point ◽  
In Situ Stress ◽  
Grid Model ◽  
Conversion Algorithm ◽  
Element Simulation

A three-dimensional (3D) corner-point grid model gives a relatively accurate description of the structural properties and spatial distribution of oil and gas reservoirs than Cartesian grids. The finite element simulation of the stress field provides a relatively probable presentation of the in situ stress distribution. Both methods are of great importance to the exploration and development of oil and gas fields. Implementing the finite element simulation of in situ stress on a 3D corner-point grid model not only retains the structural attributes of a reservoir but also allows the accurate simulation of the 3D stress distribution. In this paper, we present a method for implementing the finite element simulation of in situ stress based on a 3D corner-point grid model. We first established a fine 3D reservoir model with corner-point grids and then converted the grids into corresponding 3D finite element grid models using a grid conversion algorithm. Next, we simulated the in situ stress distribution with the finite element method. The stress model is then resampled to corresponding corner-point grid geological models using the reverse algorithm. The grid conversion algorithm is to provide data support for the subsequent numerical simulation and other research efforts, thereby guaranteeing procedure continuity and data consistency. Finally, we simulated the stress distribution of a real oil field, the X region. Comparing the simulated result with the measured result, the high agreement validated the effectiveness and accuracy of the proposed method.

Affect of Casing Eccentricity on Stress at the Cement Ring Interface

2015 ◽  
Vol 1088 ◽  
pp. 829-833
Author(s):  
Jing Fu Zhang ◽  
Bo Wang ◽  
De Bing Zhang ◽  
Xun Wang
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
In Situ Stress ◽  
The Body ◽  
Cement Stone ◽  
Mechanics Model ◽  
Stress And Deformation ◽  
Casing Pressure ◽  
Narrow Gaps

In the process of the oil and gas well construction work such as casing pressure test、fracturing, etc. Casing and cement ring induration will be resulted in stress and deformation response. Under the condition of high load, may be give rise to the body damage of cement ring, and cementing interface tear and other forms of structural failure, also the function of cement ring sealing was endangered. The casing-cement ring-strata finite element mechanics model was established by using the mechanics theory and finite element theory in this paper. The affect of casing eccentricity on stress at the cement ring interface was analyzed. The results showed that, the greater eccentricity, narrow gaps of cement stone was easier to be crushed after load when the load value was near to the in-situ stress.The greater the degree of the eccentricity, narrow gaps of cementation interface was easier to be tore after unload when the load value differ greatly with the in-situ stress.

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