Case Study: An Approach for Hydraulic Fracturing Minifrac G-Function Analysis in Relation to Facies Distribution in Multilayered Clastic Reservoirs

2021 ◽  
pp. 1-8
Author(s):  
T. Jatykov ◽  
K. Bimuratkyzy
Keyword(s):  
Hydraulic Fracturing ◽  
Function Analysis ◽  
Flow Regimes ◽  
Fracture Geometry ◽  
Facies Distribution ◽  
Fracture Closure ◽  
Reservoir Conditions ◽  
Fracture Height ◽  
Function Interpretation

Summary An industry-accepted standard for minifrac analysis for evaluating and improving design of hydraulic fracturing treatments originated from the original Nolte analysis (Nolte 1979) of pressure decline, followed by the introduction of Castillo G-function in a Cartesian plot (Castillo 1987). The latter provides a graphical method for the identification of fracture closure pressures and stresses with subsequent derivation of other parameters such as fluid efficiency and fracture geometry. With the introduction of a more advanced consideration of the G-function interpretation for various reservoir conditions (Barree et al. 2007), subdividing the interpretation into calculations based on flow regimes and leakoff modes, this approach has become even more sophisticated. Particularly, interesting flow regimes and leakoff modes during fracture closure include the fracture height recession mode. This mode tends to result in rapid screenout and difficulty in placing high proppant concentrations. Regarding interpretation, the G-function derivative curve for this mode can have more than one plateau, an outcome that is possibly indicative of features that have not been widely considered to date or on which little to no data have been published. This paper presents a case study as an example of such height recession mode, along with a subsequent G-function interpretation and analysis and with consideration of the vertical facies distribution along the wellbore. Considerable attention is paid to the G-function derivative plateau analysis. Three distinctive wells, namely X-1,X-2, and X-3, are discussed. Using this technique can lead to an improved fracture calibration, optimized fracture design, and adoption of a successful completion strategy; additionally, the confirmation of 1D facies distribution can provide new insights into the fracture closure period.

scholarly journals OPTIMISATION OF HYDRAULIC FRACTURING DESIGN IN LOWER OLIGOCENE RESERVOIR, KINH NGU TRANG OILFIELD

2018 ◽  
Vol 18 (3) ◽  
pp. 323-337
Author(s):  
Nguyen Huu Truong
Keyword(s):  
Hydraulic Fracturing ◽  
Complex Structure ◽  
Power Requirement ◽  
Fracture Conductivity ◽  
Fracture Width ◽  
The North ◽  
Fracture Closure ◽  
Average Water ◽  
White Tiger ◽  
Fracture Height

Kinh Ngu Trang oilfield is of the block 09-2/09 offshore Vietnam, which is located in the Cuu Long basin, the distance from that field to Port of Vung Tau is around 140 km and it is about 14 km from the north of Rang Dong oilfield of the block 15.2, and around 50 km from the east of White Tiger in the block 09.1. That block accounts for total area of 992 km2 with the average water depth of around 50 m to 70 m. The characteristic of Oligocene E reservoir is tight oil in sandstone, very complicated with complex structure. Therefore, the big challenges in this reservoir are the low permeability and the low porosity of around 0.2 md to less than 1 md and 1% to less than 13%, respectively, leading to very low fracture conductivity among the fractures. Through the Minifrac test for reservoir with reservoir depth from 3,501 mMD to 3,525 mMD, the total leak-off coefficient and fracture closure pressure were determined as 0.005 ft/min0.5 and 9,100 psi, respectively. To create new fracture dimensions, hydraulic fracturing stimulation has been used to stimulate this reservoir, including proppant selection and fluid selection, pump power requirement. In this article, the authors present optimisation of hydraulic fracturing design using unified fracture design, the results show that optimum fracture dimensions include fracture half-length, fracture width and fracture height of 216 m, 0.34 inches and 31 m, respectively when using proppant mass of 150,000 lbs of 20/40 ISP Carbolite Ceramic proppant.

Applying Slim Dipole Sonic Tool to Evaluate Hydraulic Fracture Geometry and Orientation Using the Differential Sonic Method

2022 ◽  
Author(s):  
Azzan Al-Yaarubi ◽  
Sumaiya Al Bimani ◽  
Sataa Al Rahbi ◽  
Richard Leech ◽  
Dmitrii Smirnov ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Oil Recovery ◽  
Critical Role ◽  
Differential Method ◽  
Optimum Number ◽  
Well Test ◽  
Fracture Geometry ◽  
The Subject ◽  
Fracture Height ◽  
Depth Of Investigation

Abstract Successful hydraulic fracturing is critical for hydrocarbon recovery from tight reservoirs. Fracture geometry is one essential quality indicator of the created fracture. The geometry provides information about the size of the created fracture and containment and verifies the pre-job modeling. Different techniques are applied to determine fracture geometry, and each has its own advantages and limitations. Due to its simplicity, the radioactive tracer log is commonly used to determine fracture placement and fracture height. Its main drawbacks include shallow depth of investigation, time dependency, and the requirement for multiple interventions for multistage fracturing operations. The crosswell microseismic technique probes a larger volume and it is potentially capable of providing fracture height, length, and orientation. Operational complexity and long processing turnaround time are the main challenges of this technique. Time-lapse shear slowness anisotropy analysis is an effective method to determine hydraulic facture height and orientation. In this technique, the shear slowness anisotropy is recorded before and after the fracture is created. The observed shear anisotropy difference indicates the intervals where the fractures were created, allowing these intervals lengths to be measured. Combining this analysis with gyroscopic data allows determining the fracture orientations. Compared to a tracer log, the differential casedhole sonic anisotropy (DCHSA) has a deeper depth of investigation, and it is time independent. Thus, the repeated log can be acquired at the end of the multistage fracturing operations. Compared to the microseismic technique, this new technique provides more precise fracture height and orientation. The new generation slim dipole sonic technology of 2.125-in. diameter extends the applicability of the DCHSA technique to smaller casing sizes. The shear differential method was applied to a vertical well that targeted the Athel formation in the south of the Sultanate of Oman. This formation is made of silicilyte and is characterized by very low permeability of about 0.01 md on average. Thus, hydraulic fracturing plays a critical role for the economic oil recovery in this reservoir. Aiming to achieve a better zonal contribution, the stimulation design was changed from a limited number of large fractures to an extensive multistage fracturing design in the subject well. Sixteen hydraulic fracturing stages were planned. The DCHSA was applied to provide accurate and efficient fracture geometry evaluation. The DCHSA accurately identified fracture intervals and their corresponding heights and orientations. This enabled effectively determining the created fracture quality and helped explain the responses of the production logs that were recorded during the well test. This study provided a foundation for the placement and completion design of the future wells in the subject reservoir. It particularly revealed adequate fracturing intervals and the optimum number of stages required to achieve optimum reservoir coverage and avoid vertical overlapping.

Fracturing With Height Control Extends the Life of Mature Reservoirs in the Pannonian Basin

2021 ◽  
Vol 73 (01) ◽  
pp. 53-54
Author(s):  
Chris Carpenter
Keyword(s):  
Hydraulic Fracturing ◽  
Pannonian Basin ◽  
Oil Production ◽  
High Water ◽  
Economic Feasibility ◽  
Fracture Geometry ◽  
Height Control ◽  
Control Techniques ◽  
Fracture Height ◽  
Water Cut

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 200588, “Fracturing With Height Control Extends the Life of Mature Reservoirs: Case Studies From the Pannonian Basin,” by Ruslan Malon, SPE, Independent, and Jonathan Abbott, SPE, and Ludmila Belyakova, SPE, Schlumberger, et al., prepared for the 2020 SPE Europec featured at the 82nd EAGE Conference and Exhibition, originally scheduled to be held in Amsterdam, 1-3 December. The paper has not been peer reviewed. Hydraulic proppant fracturing is an effective tool in mature, low-permeability reservoirs found in the Pannonian Basin. However, for wells already producing with high water cut, even a small fracture extension into a water-bearing zone offsets the gains in hydrocarbon production. Fracture-geometry-control (FGC) techniques limit increases in water cut. The complete paper describes the first implementation of a solution to control fracture height for conventional wells in the Pannonian Basin. An integrated engineering approach was applied, including a new proppant-transport model to predict fracture geometry improvement using the FGC solution. Decreased Recovery in A and B Fields Oilfield A began producing in 1984. In addition to an interruption by the war in Yugoslavia in the 1990s, production has been in decline, and most wells are at risk of being shut in because of low production rates. During the last 10 years, propped fracturing was integrated into the production strategy for this mature field. Field A comprises Lower Pontian (Miocene) sandstones. Another sandstone formation exists between 5 and 15 m below the production target reservoir, with high water saturation as confirmed by log analysis and well testing. The proximity of the oil target to the water-bearing interval still presents a risk to production considering that hydraulic fracturing is required to extend field life. An impermeable shale streak that may act as a geomechanical barrier exists below the target formation. With a lower risk of fracture propagation into the water zone, Field A was one of the first candidate fields for propped fracturing and was later considered for advanced fracture-height-control techniques to prevent the increase of water cut after stimulation. Hydraulic fracturing would not be trialed in Field B—the characteristics of which are provided in the complete paper—until the advanced height-control techniques had been proved on the basis of experience with Field A. Oilfield A: Early Fracturing Results Early campaigns proved the economic feasibility of propped fracturing, resulting in a 2.1-fold average increase in oil production during the first 6 months of production. Unfortunately, production after this early period declined rapidly. Increases in water cut, seen in several fracturing campaigns, clearly were related to hydraulic fracture growth. Although the resulting uplift in oil production warranted continued fracturing, avoiding water was a key issue to address before expansion of propped fracturing further in this field and to other fields with an even higher risk of water.

Integrated Hydraulic Fracture Geometry Evaluation Based on Pre-Cambrian Tight Silicylate Reservoir in South Oman Salt Basin

2022 ◽  
Author(s):  
Dmitrii Smirnov ◽  
Omar AL Isaee ◽  
Alexey Moiseenkov ◽  
Abdullah Al Hadhrami ◽  
Hilal Shabibi ◽  
...  
Keyword(s):  
Best Practices ◽  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Hydraulic Fractures ◽  
Bond Quality ◽  
Fracture Geometry ◽  
Acoustic Anisotropy ◽  
Sonic Log ◽  
Before And After ◽  
Fracture Height

Abstract Pre-Cambrian South Oman tight silicilyte reservoirs are very challenging for the development due to poor permeability less than 0.1 mD and laminated texture. Successful hydraulic fracturing is a key for the long commercial production. One of the main parameter for frac planning and optimization is fracture geometry. The objective of this study was summarizing results comparison from different logging methods and recommended best practices for logging program targeting fracture geometry evaluation. The novel method in the region for hydraulic fracture height and orientation evaluation is cross-dipole cased hole acoustic logging. The method allows to evaluate fracture geometry based on the acoustic anisotropy changes after frac operations in the near wellbore area. The memory sonic log combined with the Gyro was acquired before and after frac operations in the cased hole. The acoustic data was compared with Spectral Noise log, Chemical and Radioactive tracers, Production Logging and pre-frac model. Extensive logging program allow to complete integrated evaluation, define methods limitations and advantages, summarize best practices and optimum logging program for the future wells. The challenges in combining memory cross-dipole sonic log and gyro in cased hole were effectively resolved. The acoustic anisotropy analysis successfully confirms stresses and predominant hydraulic fractures orientation. Fracture height was confirmed based on results from different logging methods. Tracers are well known method for the fracture height evaluation after hydraulic frac operations. The Spectral Noise log is perfect tool to evaluate hydraulically active fracture height in the near wellbore area. The combination of cased hole acoustic and noise logging methods is a powerful complex for hydraulic fracture geometry evaluation. The main limitations and challenges for sonic log are cement bond quality and hole conditions after frac operations. Noise log has limited depth of investigation. However, in combination with production and temperature logging provides reliable fit for purpose capabilities. The abilities of sonic anisotropy analysis for fracture height and hydraulic fracture orientation were confirmed. The optimum logging program for fracture geometry evaluation was defined and recommended for replication in projects were fracture geometry evaluation is required for hydraulic fracturing optimization.

Hydraulic Fracturing of Ultrahigh Stress Tight Oil Reservoir - A Case Study of Yumen Oilfield in China

2016 ◽  
Author(s):  
Peng Yi ◽  
Weng Dingwei ◽  
Xu Yun ◽  
Wang Liwei ◽  
Lu Yongjun ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Tight Oil ◽  
Oil Reservoir ◽  
Tight Oil Reservoir

Data Analytics to Help Improve Hydraulic Fracture Geometry Prediction Using Support Vector Regression: Case Study

2020 ◽  
Author(s):  
Avinash Wesley ◽  
Bharat Mantha ◽  
Ajay Rajeev ◽  
Aimee Taylor ◽  
Mohit Dholi ◽  
...  
Keyword(s):  
Support Vector Regression ◽  
Hydraulic Fracture ◽  
Data Analytics ◽  
Support Vector ◽  
Fracture Geometry
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