IMPACTS AND LESSONS LEARNED FROM AN APPLIED CASE STUDY IN THE WILLISTON, UINTA AND DJ BASINS UTILIZING OPEN VERSUS CLOSED RETORT QUANTIFICATION

2021 ◽  
Author(s):  
Stephanie E. Perry ◽  
◽  
J. Alex Zumberge ◽  
Kai Cheng ◽  
◽  
...  
Keyword(s):  
Oil Recovery ◽  
Water Saturation ◽  
Measurement Techniques ◽  
Large Error ◽  
Lessons Learned ◽  
Crushed Rock ◽  
Improved Oil Recovery ◽  
Fluid Saturation ◽  
Rock Analysis ◽  
The Impact

Subsurface characterization of fluid volumes is typically constrained and validated by core analytical fluid saturation measurement techniques (example Dean-Stark or Open Retort methodology). As production in resource plays has progressed over time, it has been noted that many of these methods have a large error when compared to production data. A large source of the error seems to be that water saturations in tight rocks have been consistently underestimated in the traditional laboratory measurement techniques. Operators need improved fluid saturation measurements to better constrain their log-based oil-in-place estimates and forward-looking production trends. The overall goal of this study is to test a new laboratory workflow for fluid saturation quantification. Recent advancements have led to an innovative methodology where a closed retort laboratory technique is applied to samples from lithological rock types in the Williston, Uinta and Denever-Julesburg (DJ) basins. This new technique is specifically designed to better quantify and validate water measurements throughout the tight rock analysis process, as well as improved oil recovery and built-in prediction. A comparison of standard crushed rock analysis employing Dean-Stark saturation methods is compared to the closed retort results and observations discussed. Results will also be compared against additional laboratory methods that validate the results such as geochemistry and nuclear magnetic resonance. Finally, open-hole wireline logs will be utilized to quantify the impact on total water saturation and the oil-in place estimates based on the improved accuracy of the closed retort technique.

Field Evaluation of Improved Oil Recovery Methods in a Libyan Oilfield

2016 ◽  
Author(s):  
Augustine O. Ifelebuegu ◽  
Zydan H. Zydan
Keyword(s):  
Oil Recovery ◽  
Horizontal Well ◽  
Field Evaluation ◽  
Lessons Learned ◽  
Oil Field ◽  
Internal Rate Of Return ◽  
Daily Production ◽  
Improved Oil Recovery ◽  
Well Drilling ◽  
The Impact

ABSTRACT Intisar A oil field is a Libyan field located in Concession 103 and has been in production since 1968. In this paper, we report the field evaluation results of the various productions enhancement techniques and initiatives applied for incremental oil production. The impact of improved recovery by various waterflood optimisation processes including infill well drilling, installations of ESPs, current well re-completion, and conversion wells were evaluated taking into consideration surface facility constraints. An incremental total daily production of 9872 STB/D was achieved in the overall optimisation projects with infill horizontal well drilling producing the highest incremental recovery. The internal rate of return for the overall project was 72% and a payback period of 3.4 years. The lessons learned, and recommendations for future development of the field were established.

The Impact of Fault Rocks on Improved Oil Recovery

2007 ◽  
Author(s):  
S.M.S. Al-Hinai ◽  
Q.J. Fisher ◽  
C.A. Grattoni
Keyword(s):  
Oil Recovery ◽  
Fault Rocks ◽  
Improved Oil Recovery ◽  
The Impact

Feasibility of Waterflooding for a Carbonate Oil Field Through Whole-Field Simulation Studies

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Wenting Yue ◽  
John Yilin Wang
Keyword(s):  
Oil Recovery ◽  
Injection Rate ◽  
Carbonate Reservoir ◽  
Oil Field ◽  
Improved Oil Recovery ◽  
Smackover Formation ◽  
Artificial Lift ◽  
Production History ◽  
Current Production ◽  
The Impact

The carbonate oil field studied is a currently producing field in U.S., which is named “PSU” field to remain anonymity. Discovered in 1994 with wells on natural flow or through artificial lift, this field had produced 17.8 × 106 bbl of oil to date. It was noticed that gas oil ratio had increased in certain parts and oil production declined with time. This study was undertaken to better understand and optimize management and operation of this field. In this brief, we first reviewed the geology, petrophysical properties, and field production history of PSU field. We then evaluated current production histories with decline curve analysis, developed a numerical reservoir model through matching production and pressure data, then carried out parametric studies to investigate the impact of injection rate, injection locations, and timing of injection, and finally developed optimized improved oil recovery (OIR) methods based on ultimate oil recovery and economics. This brief provides an addition to the list of carbonate fields available in the petroleum literature and also improved understandings of Smackover formation and similar analogous fields. By documenting key features of carbonated oil field performances, we help petroleum engineers, researchers, and students understand carbonate reservoir performances.

Anomalous Foam-Fractional-Flow Solutions at High-Injection Foam Quality

2013 ◽  
Vol 16 (01) ◽  
pp. 40-50 ◽  
Author(s):  
A.. Roostapour ◽  
S.I.. I. Kam
Keyword(s):  
Oil Recovery ◽  
Water Saturation ◽  
Mobility Control ◽  
Injection Velocity ◽  
Fractional Flow ◽  
Improved Oil Recovery ◽  
High Injection ◽  
Constant State ◽  
Dry Conditions ◽  
First Time

Summary A thorough understanding of foam fundamentals is crucial to the optimal design of foams for improved oil recovery (IOR) or enhanced oil recovery (EOR). This study, for the first time, presents anomalous foam-fractional-flow solutions that deviate significantly from the conventional solutions at high-injection foam qualities by comparing method-of-characteristics and mechanistic bubble-population-balance simulations. The results from modeling and simulations derived from coreflood experiments revealed the following: The fraction of grinding energy contributed by the flowing gas (fg)There are three regions—Region A with relatively wet (or high fw) injection conditions in which the solutions are consistent with the conventional fractional-flow theory; Region C with very dry (or low fw) injection conditions in which the solutions deviate significantly; and Region B in between, which has a negative dfw/dSw slope showing physically unstable solutions.For dry-injection conditions in Region C, the solutions require a constant state (IJ) between initial (I) and injection (J) conditions, forcing a shock from I to IJ by intersecting fractional-flow curves, followed by spreading waves or another shock to reach from IJ to J.The location of IJ in fw vs. Sw domain moves to the left (or toward lower Sw) as the total injection velocity increases for both weak and strong foams until it reaches limiting water saturation. Even though foams at high-injection quality are popular for mobility control associating a minimum amount of surfactant solutions, foam behaviors at dry conditions have not been thoroughly investigated and understood. The outcome of this study is believed to be helpful to the successful planning of foam IOR/EOR field applications.

Water Mixing During Waterflood Oil Recovery: The Effect of Initial Water Saturation

SPE Journal ◽  
2011 ◽  
Vol 17 (01) ◽  
pp. 43-52 ◽  
Author(s):  
Arne Graue ◽  
Martin A. Fernø ◽  
Robert W. Moe ◽  
Bernard A. Baldwin ◽  
Riley Needham
Keyword(s):  
Oil Recovery ◽  
Water Saturation ◽  
Core Sample ◽  
Initial Water ◽  
Connate Water ◽  
Fluid Saturation ◽  
Secondary Recovery ◽  
Tracer Imaging ◽  
Displacement Processes

Summary This work studies the mixing of injected water and in-situ water during waterfloods and demonstrates that the mixing process is sensitive to the initial water saturation. The results illustrate differences between a waterflooded zone and a preflooded zone during, for example, water-based EOR displacement processes. The mixing of in-situ, or connate, water and injected water during laboratory waterfloods in a strongly water-wet chalk core sample was determined at different initial water saturations. Dynamic 1D fluid-saturation profiles were determined with nuclear-tracer imaging (NTI) during waterfloods, distinguishing between the oil phase, connate water, and injected water. The mixing of connate and injected water during waterfloods, with the presence of an oil phase, resulted in a displacement of all connate water from the core plug. During displacement, connate water banked in front of the injecting water, separating (or partially separating) the injected water from the mobile oil phase. This may impact the ability of chemicals dissolved in the injected water to contact the oil during secondary recovery and EOR processes. The effect of the connate-water-bank separation was sensitive to the initial water saturation (Swi). The time difference between breakthrough of connate water and breakthrough of injected water at the outlet showed a linear correlation to the initial water saturation Swi. The results obtained in chalk confirmed earlier findings in sandpacks (Brown 1957) and thus demonstrated the generality in the results.

ADAPTATION OF CRUSHED ROCK ANALYSIS TO INTACT ROCK ANALYSIS FOR IMPROVING WATER SATURATION ASSESSMENT AND FAST PRESSURE DECAY PERMEABILITY QUANTIFICATION

2021 ◽  
Author(s):  
Kai Cheng ◽  
◽  
J. Alex Zumberge ◽  
Stephanie E. Perry ◽  
Patrick M. Lasswell ◽  
...  
Keyword(s):  
Water Saturation ◽  
Total Porosity ◽  
Volume Measurement ◽  
Intact Rock ◽  
Crushed Rock ◽  
Fluid Loss ◽  
Pressure Decay ◽  
Matrix Permeability ◽  
Analysis Workflow ◽  
Rock Analysis

Legacy crushed rock analysis, as applied to unconventional formations, has shown great success in evaluating total porosity and water saturation over the previous three decades. The procedure of crushing rock into small particles improves the efficiency of fluid recovery and grain volume measurements in a laboratory environment. However, a caveat to crushed rock analysis is that water and volatile hydrocarbon evaporate from the rock during the preparatory crushing process, causing significant uncertainty in water saturation assessment. A modified crushed rock analysis incorporates nuclear magnetic resonance (NMR) measurements before and after the crushing process to quantify the volume of fluid loss. The advancements improve the overall total saturation quantification. However, challenges remain in the quantification of partitioned water and hydrocarbon loss currently derived from NMR spectrum along with its uncertainty. Furthermore, pressure decay permeability from crushed rock analysis has been reported to have two to three orders of magnitude difference between different labs. The calculated pressure decay permeability of the same rock could even vary several orders of magnitude difference with different crushed size, which questions the quality of the crushed pressure decay permeability. In this paper, we introduce an intact rock analysis workflow on unconventional cores for improved assessment of water saturation and enhanced quantification of fast pressure decay matrix permeability from intact rock. The workflow starts with acquisition of NMR T2 and bulk density measurements on the as-received state intact rock. Instead of crushing the rock, the intact rock is directly transferred to a retort chamber and heated to 300 °C for thermal extraction. The volumes of thermally-recovered fluids are quantified through an image-based process. The grain volume measurement and a second NMR T2 measurement are performed on post retort intact rock. The pressure decay curve during grain volume measurement is then used for calculating pressure decay matrix permeability. Total porosity is calculated using bulk volume and grain volume of the rock. Water saturation is quantified using total volume of recovered water. In addition, the twin as-received state rocks are processed through the crushed rock analysis workflow for an apple-to-apple comparison. Meanwhile, pressure decay permeability is cross-validated against the steady state permeability of the same sample. The introduced workflow has been successfully tested on different formations, including Bakken, Bone Spring, Eagle Ford, Cotton Valley, and Niobrara. The results show that total porosities calculated from intact rock analysis are consistent with total porosities from crushed rock analysis, while water saturations from the new workflow are average 8%SU (0.2–0.7%PU of bulk volume water) higher than those from the prior crushed rock workflow. The study also indicated that for some formations (e.g., Bone Spring) the fluid loss during crushing process is dominated by water, however, for some other formations (e.g., Bakken), hydrocarbon loss is significant. Pressure decay permeability quantified using intact rock analysis is also confirmed within an order of magnitude of steady state matrix permeability.

Adaptation of Crushed Rock Analysis to Intact Rock Analysis To Improve Assessment of Water Saturation and Fast Pressure Decay Permeability

SPE Journal ◽  
1900 ◽  
pp. 1-13
Author(s):  
Kai Cheng ◽  
J. Alex Zumberge ◽  
Stephanie E. Perry ◽  
Patrick M. Lasswell ◽  
Themi Vodo
Keyword(s):  
Water Saturation ◽  
Total Porosity ◽  
Volume Measurement ◽  
Intact Rock ◽  
Crushed Rock ◽  
Fluid Loss ◽  
Pressure Decay ◽  
Matrix Permeability ◽  
Analysis Workflow ◽  
Rock Analysis

Summary Legacy crushed rock analysis, as applied to unconventional formations, has shown great success in evaluating total porosity and water saturation over the previous three decades. The procedure of crushing rock into small particles improves the efficiency of fluid recovery and grain volume measurements in a laboratory environment. However, a caveat to crushed rock analysis is that water and volatile hydrocarbons evaporate from the rock during the preparatory crushing process, causing significant uncertainty in water saturation assessment. A modified crushed rock analysis incorporates nuclear magnetic resonance (NMR) measurements before and after the crushing process to quantify the volume of fluid loss. The advancements improve the overall total saturation quantification. However, challenges remain in the quantification of partitioned water and hydrocarbon loss currently derived from the NMR spectrum along with its uncertainty. Furthermore, pressure decay permeability from crushed rock analysis has been reported to have two to three orders of magnitude difference between different laboratories. The calculated pressure decay permeability of the same rock could even vary by several orders of magnitude with different crushed sizes, which questions the quality of the crushed pressure decay permeability. In this paper, we introduce an intact rock analysis workflow on unconventional cores for improved assessment of water saturation and enhanced quantification of fast pressure decay matrix permeability from intact rock. The workflow starts with acquisition of NMR T2 and bulk density measurements on the as-received state intact rock. Instead of crushing the rock, the intact rock is directly transferred to a retort chamber and heated to 300°C for thermal extraction. The volumes of thermally recovered fluids are quantified through an image-based process. The grain volume measurement and a second NMR T2 measurement are performed on post-retort intact rock. The pressure decay curve during the grain volume measurement is then used for calculating the pressure decay matrix permeability. Total porosity is calculated using the bulk volume and grain volume of the rock. Water saturation is quantified using the total volume of recovered water. In addition, the twin as-received-state rocks are processed through the crushed rock analysis workflow for an apple-to-apple comparison. Meanwhile, the pressure decay permeability of the post-retort intact sample is cross-validated against the steady-state gas permeability of the same post-retortsample. The introduced workflow has been tested successfully on different formations, including Bakken, Bone Spring, Eagle Ford, Cotton Valley, and Niobrara. The results show that total porosities calculated from intact rock analysis are consistent with total porosities from crushed rock analysis, while water saturations from the new workflow are an average 8% saturation unit (SU) [0.2 to 0.7% porosity unit (PU) of bulk volume water (BVW)] higher than those from the prior crushed rock workflows. The study also indicates that for some formations (e.g., Bone Spring), the fluid loss during the crushing process is dominated by water; however, for some other formations (e.g., Bakken), the hydrocarbon loss is significant. Pressure decay permeability quantified using intact rock analysis is also confirmed within an order of magnitude of steady-state matrix permeability.

Technology Focus: Oilfield Chemistry (September 2021)

2021 ◽  
Vol 73 (09) ◽  
pp. 57-57
Author(s):  
Jonathan Wylde
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Oil And Gas ◽  
New Technology ◽  
Oil And Gas Industry ◽  
Lessons Learned ◽  
Improved Oil Recovery ◽  
Gas Industry ◽  
Nanocomposite Hydrogels ◽  
Water Shutoff

As production chemists, we are all aware of the overall concepts of improved oil recovery (IOR) and enhanced oil recovery (EOR). Perhaps, though, fewer of us are aware of the different idiosyncrasies that exist within (and even between) these two broad categories of recovery and then how chemistry and chemicals can have an effect upon these processes. I would like to propose that the lines once were quite distinct between IOR and EOR: IOR was a standard waterflood operation, and EOR (from a chemist’s perspective) was the addition of chemistry to that waterflood (typically polymer or surfactant). Nowadays, the science has evolved massively to create many sub-genres of IOR and EOR. A waterflood is rarely just a waterflood anymore. We can alternate water and gas injection. We can add chemical conformance aids to direct better the flow of water. We can change the salinity of the water to promote better wettability for higher recovery factors. The list goes on. One just has to search out the number of EOR papers vs. (pretty much) every other discipline of production chemistry to see the commitment this industry still has to the research of this discipline. In recent years, the focus has tended to move away from deep-reservoir EOR to focus on near-wellbore stimulation. Interestingly, the mechanistic considerations that we make as production chemists are nearly identical in all cases, and significant synergies exist between these subdisciplines. Therefore, from the recent research published by SPE, two focused topics of IOR/EOR have arisen: the use of nanoparticles and the use of water-shutoff technologies. Nanoparticle use is gaining significant traction in the oil and gas industry, and field applications are now being reported. The area of IOR/EOR is no exception. Water shutoff is not a new technology area. However, are these established, production-sustaining IOR techniques seeing a resurgence caused by the headwinds our industry has faced during the COVID-19 pandemic? Recommended additional reading at OnePetro: www.onepetro.org. OTC 30123 - Thermal and Rheological Investigations on N,N’-Methylenebis Acrylamide Cross-Linked Polyacrylamide Nanocomposite Hydrogels for Water-Shutoff Applications by Mohan Raj Keishnan, Alfiasal University, et al. IPTC 20210 - Chemical and Mechanical Water Shutoff in Horizontal Passive ICD Wells: Experience and Lessons Learned in Giant Darcy Reservoir by Mohamed Abdel-Basset, Schlumberger, et al. SPE 203831 - Efficient Preparation of Nanostarch Particles and Mechanism of Enhanced Oil Recovery in Low-Permeability Oil Reservoirs by Lei Zhang, China University of Geosciences, et al.

Sign in / Sign up

Export Citation Format

Share Document