Fracturing Height Growth Restriction Technique Successfully Extended into Horizontal Wells in Ostracod Formation

2022 ◽  
Author(s):  
Alexey Yudin ◽  
Mohamed ElSebaee ◽  
Vladimir Stashevskiy ◽  
Omar Almethen ◽  
Ahmed AlJanahi ◽  
...  

Abstract The Ostracod formation in the Awali brownfield is an extremely challenging layer to develop because the tight carbonate rock is interbedded with shaly streaks and because of the presence of a nearby water-bearing zone. Although the Ostracod formation has been in development since 1960, oil recovery has not yet reached 5% because past stimulation attempts experienced rapid production decline. The current project incorporated aggressive fracture design coupled with a unique height growth control (HGC) workflow, improving the development of Ostracod reserves. The HGC technology is a combination of an engineering workflow supported by geomechanical modeling and an advanced simulator of in-situ kinetics and materials transport to model the placement of a customized, impermeable mixture of particles that will restrict fracture growth. The optimized treatment design included injections of the HGC mixture prior to the main fracturing treatment. This injection was done with a nonviscous fluid to improve settling to create an artificial barrier. After the success of a trial campaign in vertical wells, the technique was adjusted for the horizontal wellbores. The high clay content within the Ostracod layers creates a significant challenge for successful stimulation. The high clay content prevents successful acid fracturing and leads to severe embedment with conventional proppant fracturing designs. We introduced a new approach to stimulate this formation with an aggressive tip-screenout design incorporating a large volume of 12/20-mesh proppant to obtain greater fracture width and conductivity, resulting in a significant and sustained oil production gain. The carefully designed HGC technique was efficient in avoiding fracture breakthrough into the nearby water zone, enabling treatments of up to 450,000 lbm to be successfully contained above a 20-ft-thick shaly barrier with small horizontal stress contrast. Independent measurements proved that the fracture height was successfully contained. This trial campaign in vertical wells proved that the combination of aggressive, large fracture designs with the HGC method could help unlock the Ostracod’s potential. Three horizontal wells were drilled and simulated, each with four stages of adjusted HGC technique to verify if this aggressive method was applicable to challenging sand admittance in case of transverse fractures. This rare implementation of HGC mixtures in horizontal wells showed operational success and proof of fracture containment based on pressure signatures and production monitoring. The applied HGC technique was modified with additional injections and improved by advanced modeling that only recently became available. These contributed to a significant increase of treatment volume, making the jobs placed in the Ostracod some of the world’s largest utilizing HGC techniques. The experience gained in this project can be of a paramount value to any project dealing with hydraulic fracturing near a water formation with insufficient or uncertain stress barriers.

2021 ◽  
Author(s):  
Abu M. Sani ◽  
Hatim S. AlQasim ◽  
Rayan A. Alidi

Abstract This paper presents the use of real-time microseismic (MS) monitoring to understand hydraulic fracturing of a horizontal well drilled in the minimum stress direction within a high-temperature high-pressure (HTHP) tight sandstone formation. The well achieved a reservoir contact of more than 3,500 ft. Careful planning of the monitoring well and treatment well setup enabled capture of high quality MS events resulting in useful information on the regional maximum horizontal stress and offers an understanding of the fracture geometry with respect to clusters and stage spacing in relation to fracture propagation and growth. The maximum horizontal stress based on MS events was found to be different from the expected value with fracture azimuth off by more than 25 degree among the stages. Transverse fracture propagation was observed with overlapping MS events across stages. Upward fracture height growth was dominant in tighter stages. MS fracture length and height in excess of 500 ft and 100 ft, respectively, were created for most of the stages resulting in stimulated volumes that are high. Bigger fracture jobs yielded longer fracture length and were more confined in height growth. MS events fracture lengths and heights were found to be on average 1.36 and 1.30 times, respectively, to those of pressure-match.


2021 ◽  
Author(s):  
Anna Vladimirovna Norkina ◽  
Iaroslav Olegovich Simakov ◽  
Yuriy Anatoljevich Petrakov ◽  
Alexey Evgenjevich Sobolev ◽  
Oleg Vladimirovich Petrashov ◽  
...  

Abstract This article is a continuation of the work on geomechanically calculations for optimizing the drilling of horizontal wells into the productive reservoir M at the Boca de Haruco field of the Republic of Cuba, presented in the article SPE-196897. As part of the work, an assessment of the stress state and direction was carried out using geological and geophysical information, an analysis of the pressure behavior during steam injections, cross-dipole acoustics, as well as oriented caliper data in vertical wells. After the completion of the first part of the work, the first horizontal wells were successfully drilled into the M formation. According to the recommendations, additional studies were carried out: core sampling and recording of micro-imager logging in the deviated sections. Presence of wellbore failures at the inclined sections allowed to use the method of inverse in-situ stress modeling based on image logs interpretation. The classification of wellbore failures by micro-imager logging: natural origin and violations of technogenic genesis is carried out. The type of breakout is defined. The result of the work was the determination of the stress state and horizontal stresses direction. In addition, the article is supplemented with the calculation of the maximum horizontal stress through the stress regime identifier factor.


2022 ◽  
Author(s):  
Martin Rylance ◽  
Yaroslav Korovaychuk

Abstract For as long as we have been performing hydraulic fracturing, we have been trying to ensure that we stay out of undesirable horizons, potentially containing water and/or gas. The holy grail of hydraulic fracturing, an absolute control of created fracture height, has eluded the industry for more than 70 years. Of course, there have been many that have claimed solutions, but all the marketed approaches have at best merely created a delay to the inevitable growth and at worst been a snake-oil approach with little actual merit. Fundamentally, the applied techniques have attempted to delay or influence the underlying equations of net-pressure and stress variation; but having to ultimately honour them and by doing so then condemned themselves to limited success or outright failure. Fast forward to 2020, and a reassessment of the relative importance of height-growth constraint and what may have changed to help us achieve this. The development of unconventionals are focused on creating as much surface area as possible in micro/nano-Darcy environments, across almost any phase, but with typically poor line of sight to profit. However, the more valuable business of conventional oil and gas is working in thinner and thinner reservoirs with an often-deteriorating permeability, but with a significantly higher potential economic return. What unconventional has successfully delivered however, is a rapid deployment and acceleration in a range of completion technologies that were unavailable just a few years ago. We will demonstrate that these technologies potentially offer the capability of finally being able to control fracture height-growth. Consideration of a range of previously applied height-growth approaches will demonstrate how they attempted to fool or fudge height growth creation mechanisms. With this clarity, we can consider what advances in completion technology may offer in terms of delivering height growth control. We suggest that with the technology and approaches that are currently available today, that height-growth control is finally within reach. We will go on to describe a multi-well Pilot program, in deployment and execution in 2020/021 in Western Siberia; where billions of barrels remain to be recovered in thin oil-rim, low permeability sandstone reservoirs below gas or above water. A comprehensive assessment of the myriad of height-growth approaches that have been utilized over the last 70 years was performed, but in each case demonstrated the fallibility and limitations of each of these. However, rather than the interpretation that such control is not achievable, instead we will show a mathematically sound approach, along with field data and evidence that this is possible. The presentation will demonstrate that completion advances over the last 10 - 15 years make this approach a reality in the present day; and that broader field implementation is finally within reach.


2021 ◽  
Vol 3 (2) ◽  
pp. 111-123
Author(s):  
A. S. Mardanov ◽  
R. A. Yussubaliev ◽  
A. A. Yergaliyev ◽  
A. M. Rakhmetullin

Due to the growing share of high-viscosity oils in Kazakhstan, task of their effective development is becoming more complicated. Development of terrigenous reservoirs that have a complex structure and contain high-viscosity oil lead to low rates of sampling and low values of oil recovery factor. Currently, technologies that ensure high efficiency in development of such deposits are very expensive. The paper considers a pilot section of the development horizon of cretaceous system of the Tengri field, drilled with vertical wells in accordance with current project document. Further the average characteristics of the parameters of horizontal wells are compared and measures are proposed to improve the efficiency of further operation of these wells.


1995 ◽  
Vol 35 (1) ◽  
pp. 494 ◽  
Author(s):  
A.J. Buffin ◽  
A.J. Sutherland ◽  
J.A. Gorski

Borehole breakouts and hydraulic fractures in­ferred from dipmeter and formation microscanner logs indicate that the minimum horizontal stress (σh) is oriented 035°N in the South Australian sector of the Otway Basin. Density and sonic check-shot log data indicate that vertical stress (σv) increases from approximately 20 MPa at a depth of one km to 44 MPa at two km and 68 MPa at three km. Assum­ing a normal fault condition (i.e. σy > σH > σh), the magnitude of σh is 75 per cent of the magnitude of the maximum horizontal stress (σH), and the magni­tude of σH is close to that of av. Sonic velocity compaction trends for shales suggest that pore pressure is generally near hydrostatic in the Otway Basin.Knowledge of the contemporary stress field has a number of implications for hydrocarbon produc­tion and exploration in the basin. Wellbore quality in vertical wells may be improved (breakouts sup­pressed) by increasing the mud weight to a level below that which induces hydraulic fracture, or other drilling problems related to excessive mud weight. Horizontal wells drilled in the σh direction (035°N/215°N) should be more stable than those drilled in the σH direction, and indeed than vertical wells. In any EOR operations where water flooding promotes hydraulic fracturing, injectors should be aligned in the aH (125°N/305°N) direction, and off­set from producers in the orthogonal σh direction. Any deviated/horizontal wells targeting the frac­tured basement play should be oriented in the σh (035°N/215°N) direction to maximise intersection with this open, natural fracture trend. Hydrocar­bon recovery in wells deviated towards 035°N/215°N may also be enhanced by inducing multiple hydrau­lic fractures along the wellbore.Considering exploration-related issues, faults following the dominant structural trend, sub-paral­lel to σH orientation, are the most prone to be non-sealing during any episodic build-up of pore pres­sure. Pre-existing vertical faults striking 080-095°N and 155-170°N are the most prone to at least a component of strike-slip reactivation within the contemporary stress field.


2003 ◽  
Author(s):  
M. Bai ◽  
R.H. Morales ◽  
R. Suarez-Rivera ◽  
W.D. Norman ◽  
S. Green

2021 ◽  
Author(s):  
Marat Rafailevich Dulkarnaev ◽  
Yuri Alexeyevich Kotenev ◽  
Shamil Khanifovich Sultanov ◽  
Alexander Viacheslavovich Chibisov ◽  
Daria Yurievna Chudinova ◽  
...  

In pursuit of efficient oil and gas field development, including hard-to-recover reserves, the key objective is to develop and provide the rationale for oil recovery improvement recommendations. This paper presents the results of the use of the workflow process for optimized field development at two field clusters of the Yuzhno-Vyintoiskoye field using geological and reservoir modelling and dynamic marker-based flow production surveillance in producing horizontal wells. The target reservoir of the Yuzhno-Vyntoiskoye deposit is represented by a series of wedge-shaped Neocomian sandstones. Sand bodies typically have a complex geological structure, lateral continuity and a complex distribution of reservoir rocks. Reservoir beds are characterised by low thickness and permeability. The pay zone of the section is a highly heterogeneous formation, which is manifested through vertical variability of the lithological type of reservoir rocks, lithological substitutions, and the high clay content of reservoirs. The target reservoir of the Yuzhno-Vyintoiskoye field is marked by an extensive water-oil zone with highly variable water saturation. According to paleogeographic data, the reservoir was formed in shallow marine settings. Sand deposits are represented by regressive cyclites that are typical for the progressing coastal shallow water (Dulkarnaev et al., 2020). Currently, the reservoir is in production increase cycle. That is why an integrated approach is used in this work to provide a further rationale and creation of the starting points of the reservoir pressure maintenance system impact at new drilling fields to improve oil recovery and secure sustainable oil production and the reserve development rate under high uncertainty.


SPE Journal ◽  
2020 ◽  
Vol 25 (05) ◽  
pp. 2251-2264
Author(s):  
Yongzan Liu ◽  
Kan Wu ◽  
Ge Jin ◽  
George Moridis

Summary Low-frequency distributed acoustic-sensing (LF-DAS) data are promising attributes for detecting fracture hits and fracture characterization. However, measured signals from different wells exhibiting various characteristics and mechanisms attributing to the difference are not well understood, which makes the interpretation of field LF-DAS data most challenging. In this study, our in-house hydraulic fracturing simulator is used to simulate fracture propagation. The induced rock deformation and corresponding strain-rate variations along offset monitor wells are analyzed and related to specific fracture features. The mechanisms for LF-DAS signals are investigated through five synthetic case studies with single fracture propagation. A typical strain-rate waterfall plot of LF-DAS measurements during the fluid injection phase of a fracturing treatment can be divided into two distinct regions. A heart-shaped extending region forms as the fracture approaches to the monitor well, indicating that the magnitude of extension keeps increasing as the fracture tip gets closer to the monitor well. After the fracture hits the monitor well, the extending region shrinks to a line (the field-measured data may be a wide band, depending on the spatial resolution of the measurement), and a two-wing compressing zone is observed, illustrating large compressional strain variations on both sides of the fracture. As the fracture continues propagating, the strain rate tends to be stable, the characteristics of which depend on specific fracture geometry and propagation conditions. The size and shape of observable signatures on LF-DAS data are directly influenced by fracture width, height, and height growth. Larger fracture width results in larger sizes of heart-shaped extending region and two-wing compressing region in the strain-rate waterfall plot. Larger fracture height also induces a larger heart-shaped extending region before the fracture hits. However, a fracture with larger height could lead to larger extension along the fiber near the fracture, which results in less overall compression and a zone of decreasing compression in the vicinity of the fracture as the fracture propagates away from the fiber after the fracture hit. This signature is more pronounced when the fracture height growth is considered. The interpretation of a field example with four clusters based on our forward physical modeling results indicates that, although the distinct signatures of field data are not as obvious as the simulation results because of low measurement resolution and unavoidable noise, they do convey valuable information on fracture characteristics. There is a shrinkage of the extending zone from a heart shape to a band at the fracture-hit time. During simultaneous multifracture propagation, fracture-hit time of each fracture, which determines the fracture propagation speed and perforation efficiency, can be identified. The discontinuous extending band after fracture hit could be attributed to the intermittent stop and restart of fracture propagation and relative fracture opening/closing. The results of this study help to better interpret the real-time LF-DAS data and provide critical insights into hydraulic fracture characterization using LF-DAS data.


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