DRILLING IN OVERPRESSURED FORMATIONS IN AUSTRALIA AND PAPUA NEW GUINEA

1973 ◽  
Vol 13 (1) ◽  
pp. 157
Author(s):  
F. H. Lepine ◽  
J. A. W. White
Keyword(s):  
Hydrostatic Pressure ◽  
Papua New Guinea ◽  
Shale Gas ◽  
Back Pressure ◽  
Formation Water ◽  
Formation Pressure ◽  
Large Reservoir ◽  
Natural Formation ◽  
Low Volume ◽  
Definition Of

The accepted definition of an overpressured formation is one in which the pressure of the formation fluid is in excess of the theoretical hydrostatic pressure of the natural formation water if the formation water extended to surface. For the purposes of this paper, formations which have a pressure in excess of that corresponding to a gradient of 0.47 psi/ft from the surface to the depth of the formation are considered overpressured; this corresponds to the gradient of saturated saltwater. It is not necessary for a large reservoir to exist before drilling problems can be occasioned by abnormally pressured formations.Various means of determining the presence of overpressured formations exist and these formations have been encountered in many Australian basins including the Papuan Basin, the Bowen Basin, the offshore portion of the Carnarvon Basin, the Bonaparte Gulf Basin and in the Perth Basin. The usual means of combating abnormal pressures are by addition of barytes to the mud, by back pressure drilling or by allowing the formation pressure to partially deplete. This last alternative is only practical in low volume "shale-gas" occurrences. In the offshore Papuan Basin, a modified form of back pressure drilling known as the floating mud-cap technique was used for a productive reservoir containing a lengthy gas column.

Using Seismic Data to Predict Shale Pore Pressure and Overpressure Sweet Spots: A Case Study from the Lower Silurian Longmaxi Formation in Sichuan Basin, China

2021 ◽  
Author(s):  
Sheng Chen ◽  
Qingcai Zeng ◽  
Xiujiao Wang ◽  
Qing Yang ◽  
Chunmeng Dai ◽  
...  
Keyword(s):  
Prediction Model ◽  
Wave Velocity ◽  
Shale Gas ◽  
Seismic Data ◽  
P Wave ◽  
Formation Pressure ◽  
S Wave ◽  
P Wave Velocity ◽  
New Formation ◽  
Sweet Spots

Abstract Practices of marine shale gas exploration and development in south China have proved that formation overpressure is the main controlling factor of shale gas enrichment and an indicator of good preservation condition. Accurate prediction of formation pressure before drilling is necessary for drilling safety and important for sweet spots predicting and horizontal wells deploying. However, the existing prediction methods of formation pore pressures all have defects, the prediction accuracy unsatisfactory for shale gas development. By means of rock mechanics analysis and related formulas, we derived a formula for calculating formation pore pressures. Through regional rock physical analysis, we determined and optimized the relevant parameters in the formula, and established a new formation pressure prediction model considering P-wave velocity, S-wave velocity and density. Based on regional exploration wells and 3D seismic data, we carried out pre-stack seismic inversion to obtain high-precision P-wave velocity, S-wave velocity and density data volumes. We utilized the new formation pressure prediction model to predict the pressure and the spatial distribution of overpressure sweet spots. Then, we applied the measured pressure data of three new wells to verify the predicted formation pressure by seismic data. The result shows that the new method has a higher accuracy. This method is qualified for safe drilling and prediction of overpressure sweet spots for shale gas development, so it is worthy of promotion.

scholarly journals Abnormal Pressure Distribution of Tertiary age formations in Middle & South Iraqi Oil Fields

2021 ◽  
Vol 7 (4) ◽  
pp. 46-63
Author(s):  
Dr. Faleh H. M. Almahdawi ◽  
Dr. Kareem A. Alwan ◽  
Ahmed K. H. Alhusseini
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Distribution ◽  
Oil Fields ◽  
Formation Pressure ◽  
Abnormal Pressure ◽  
Drilling Operations ◽  
South Of Iraq ◽  
Abnormal Formation Pressure ◽  
Formation Pore Pressure ◽  
Pore Pressure Gradient

Prediction of formation pore pressure gradient is a very important factor in designingdrilling well program and it help to avoid many problems during drilling operations such as lostcirculation, kick, blowout and other problems.In this study, abnormal formation pressure is classified into two types; abnormal highpressure (HP) and abnormal low pressure (LP), therefore any pressure that is either above orbelow the hydrostatic pressure is referred to as an abnormal formation pressure.This study concerns with abnormal formation pressure distribution and their effect ondrilling operations in middle & south Iraqi oil fields. Abnormal formation pressure maps aredrawn depending upon drilling evidence and problems.Three formations are considered as abnormal formations in the region of study, theseformations geologically existed in Tertiary age and they from shallower to deeper are: LowerFars, Dammam and Umm Er Radhuma, Formations. The maps of this study referred to eitherhigh formations pressure such as (Lower Fars and Umm Er Radhuma) or the low formationspressure such as (Dammam) in middle and south of Iraq. Finally these maps also suggested andshowed the area, where no field is drill until now, which may behave as high, low and normalformation pressure for every formation understudy.

scholarly journals Updated definitions on piezophily as suggested by hydrostatic pressure dependence on temperature

2020 ◽  
Author(s):  
Alberto Scoma
Keyword(s):  
Hydrostatic Pressure ◽  
Deep Sea ◽  
Ambient Pressure ◽  
Environmental Parameters ◽  
Microbial Life ◽  
Deep Waters ◽  
Microbial Response ◽  
Definition Of ◽  
Substrate Ph ◽  
Cell Functionality

AbstractMicrobial preference for elevated hydrostatic pressure (HP) is a recognized key feature of environmental and industrial processes. HP effects on macromolecules and, consequently, cell functionality has been accurately described in the last decades. While there is little debate about the importance of HP in shaping microbial life, a systematic definition of microbial preference for increased HP is missing. The lack of a consensus about ‘true’ piezophiles, and ‘low’ or ‘high’ HP levels, has deleterious repercussions on microbiology and biotechnology. As certain levels are considered ‘low’ they are not applied to assess microbial activity. Most microorganisms collected in deep waters or sediments have not been tested (nor isolated) using the corresponding HP at which they were captured. Microbial response to HP is notoriously dependent on other environmental parameters, most notably temperature, but also on availability of nutrients, growth substrate, pH and salinity. This implies that countless isolates retrieved from ambient pressure conditions may very well require increased HP to grow optimally, as already demonstrated in both Archaea and Bacteria.In the present study, I collected the data from described piezophilic isolates and used the fundamental correlation existing between HP and temperature, as first suggested in seminal works by Yayanos, to update the definition of piezophiles. Thanks to the numerous new piezophilic isolates available since such seminal studies, the present analysis brings forward updated definitions which concern 1) the actual beginning of the piezosphere, the area in the deep sea where piezophiles thrive; 2) the HP thresholds which should be considered low, medium and high HP, and their implications for experimental design in Microbiology; and 3) the nature of obligate piezophiles and their location in the deep sea.

Measurement of small values of hydrostatic pressure difference / Pomiar małych wartości różnicy ciśnień hydrostatycznych

2012 ◽  
Vol 57 (1) ◽  
pp. 157-167
Author(s):  
Krzysztof Broda ◽  
Wiktor Filipek
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Distribution ◽  
Atmospheric Pressure ◽  
Free Water ◽  
Reynolds Numbers ◽  
Measurement Results ◽  
Order Of Magnitude ◽  
Hydraulic Gradients ◽  
Accuracy Of Measurement ◽  
Definition Of

In order to describe the fluid flow through the porous centre, made of identical spheres, it is necessary to know the pressure, but in fact - the pressure distribution. For the flows in the range that was traditionally called laminar flow (i. e. for Reynolds numbers (Bear, 1988; Duckworth, 1983; Troskolański, 1957) from the range 0,01 to 3) it is virtually impossible with the use of the tools directly available on the market. Therefore, many scientists who explore this problem have concentrated only on the research of the velocity distribution of the medium that penetrates the intended centre (Bear, 1988) or pressure distribution at high hydraulic gradients (Trzaska & Broda, 1991, 2000; Trzaska et al., 2005). It may result from the inaccessibility to the measurement methods that provide measurement of very low hydrostatic pressures, such as pressure resulting from the weight of liquid located in the gravitational field (Duckworth, 1983; Troskolański, 1957). The pressure value c. 10 Pa (Troskolański, 1957) can be generated even by 1 mm height difference between the two levels of the free water surface, which in fact constitutes the definition of gauging tools of today measuring the level of the hydrostatic pressure. Authors proposed a method of hydrostatic pressure measurement and devised a gauging tool. Then a series of tests was conducted aiming at establishing what is the influence of various factors, such as temperature, atmospheric pressure, velocity of measurement completion, etc. on the accuracy and method of measurements. A method for considerable reduction of hysteresis that occurs during measurement was also devised. The method of measurement of small hydrostatic difference measurements allows for the accuracy of measurement of up to 0.5 Pa. Measurement results can be improved successfully by one order of magnitude, which for sure would entail necessary temperature stabilization of the tool. It will be more difficult though to compensate the influence of atmospheric pressure on the measurement process.

scholarly journals PROBLEMS OF COMPATIBILITY OF FORMATION WATER AND INJECTED WATER IN THE OIL FIELDS OF WESTERN SIBERIA

2017 ◽  
pp. 34-37 ◽  
Author(s):  
T. V. Semenova
Keyword(s):  
Industrial Wastewater ◽  
Western Siberia ◽  
Oil Fields ◽  
Oil Reservoirs ◽  
Oil Reservoir ◽  
Formation Water ◽  
Formation Pressure ◽  
Wide Spread ◽  
Calculation Methods ◽  
Almost All

A method of maintaining reservoir pressure using a system for formation pressure maintenance of oil reservoirs in the oil fields of Western Siberia is extremely wide-spread. In oil fields as a system for formation pressure maintenance are widely used almost all types of water resources including surface water, groundwater and industrial wastewater. Different calculation methods for predicting the formation and precipitation of salts based on quantitative criteria are used to forecast possible precipitation of calcium carbonate in the flooded oil reservoir areas.

Pressure Index (PI): A Novel Practical Method for Evaluating Pressure in Offshore Malaysia

2020 ◽  
Author(s):  
Y., E. Sugiharto
Keyword(s):  
Hydrostatic Pressure ◽  
Practical Method ◽  
Hydrostatic Equilibrium ◽  
Reservoir Pressure ◽  
Formation Pressure ◽  
Pressure Data ◽  
Pressure Index ◽  
Plot Analysis ◽  
Conventional Unit ◽  
Pressure Analysis

Pressure analysis is concerned with the study of systematic variations of reservoir pore pressure with depth. The most common interpretation for pressure analysis is pressure-depth plot analysis, but other techniques that magnify understated pressure differences are also available. Formation pressure measurement is of immense value in quantitative evaluation and risking of prospects. Once the pressure data has been acquired, we need to understand how to interpret the data received because reservoir pressure data has numerous applications and interpreting it wrongly could make the results misleading. At equilibrium state (i.e. there are no net forces, and no acceleration), a fluid in the system is called hydrostatic equilibrium. Hydrostatic pressure increases with depth measured from the surface due to the increasing weight of fluid exerting downward force from above. The traditional pressure evaluation is usually done in conventional unit such as psi, kPa, psi/feet, psi/m, kPa/m, ppg. The current work will introduce the concepts and definitions of formation pressure evaluation using Pressure Index (PI) with the unit g/cc. For better understanding of the application of PI, some reservoir studies are also discussed in this paper.

Compaction of Ti-6Al-4V Powder by ECAE with Back-Pressure

2007 ◽  
Vol 29-30 ◽  
pp. 33-36 ◽  
Author(s):  
Rimma Lapovok ◽  
Dacian Tomus ◽  
Barry C. Muddle
Keyword(s):  
Powder Metallurgy ◽  
Hydrostatic Pressure ◽  
Relative Density ◽  
Shear Deformation ◽  
Vickers Hardness ◽  
Room Temperature ◽  
Low Cost ◽  
Hot Isostatic Pressing ◽  
Back Pressure ◽  
Angular Pressing

Powder metallurgy is widely used to produce alloys with low cost of production. The main drawback using powders is the level of residual porosity of final product which often implies the application of a complicated and costly hot isostatic pressing process. However, this issue can be overcome by using equal channel angular pressing (ECAE) with back pressure (BP). The use of severe shear deformation, with imposed hydrostatic pressure, allows a reduction in the range of compaction temperatures compare to those used in conventional practice. The compaction of Ti-6Al-4V powder by the ECAE method has been investigated. The compaction has been performed at temperatures starting from room temperature (RT) and increasing up to 400°C with various back pressures ranging from 0 to 350MPa. A billet processed by ECAE with 43MPa back-pressure at 400°C was found to have improved relative density of 97.5% and increased Vickers hardness of 369HV, compared to values of 96.7% and 325HV respectively obtained at RT. A relative density of 98.2% and 426HV hardness were measured for billets processed with BP = 262MPa at 400°C. A fully compact billet was obtained by applying 350 MPa of BP at 400°C.

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