Optimizing Tubing and Liner Completion Design to Improve Gas Production from Existing Wells: Case Study for ADNOC Onshore Field Abu Dhabi, UAE

2021 ◽  
Author(s):  
Magdy Farouk Fathalla ◽  
Mariam Ahmed Al Hosani ◽  
Ihab Nabil Mohamed ◽  
Ahmed Mohamed Al Bairaq ◽  
Djamal Kherroubi ◽  
...  

Abstract An onshore gas field contains several gas wells which have low–intermittent production rates. The poor production has been attributed to liquid loading issue in the wellbore. This study will investigate the impact of optimizing the tubing and liner completion design to improve the gas production rates from the wells. Numerous sensitivity runs are carried out with varying tubing and liner dimensions, to identity optimal downhole completions design. The study begins by identifying weak wells having severe gas production problems. Once the weak wells have been identified, wellbore schematics for those wells are studied. Simulation runs are performed with the current downhole completion design and this will be used as the base case. Several completion designs are considered to minimize the effect of liquid loading in the wells; these include reducing the tubing diameter but keeping the existing liner diameter the same, keeping the original tubing diameter the same but only reducing the liner diameter, extending the tubing to the Total Depth (TD) while keeping the original tubing diameter, and extending a reduced diameter tubing string to the TD. The primary cause of the liquid loading seems to be the reduced velocity of the incoming gas from the reservoir as it flows through the wellbore. A simulation study was performed using the various completion designs to optimize the well completion and achieve higher gas velocities in the weak wells. The results of the study showed significant improvement in gas production rates when the tubing diameter and liner diameter were reduced, providing further evidence that increased velocity of the incoming fluids due to restricted flow led to less liquid loading. The paper demonstrates the impact of downhole completion design on the productivity of the gas wells. The study shows that revisiting the existing completion designs and optimizing them using commercial simulators can lead to significant improvement in well production rates. It is also noted that restricting the flow near the sand face increases the velocity of the incoming fluid and reduces liquid loading in the wells.

2021 ◽  
Vol 73 (07) ◽  
pp. 57-57
Author(s):  
Leonard Kalfayan

As unconventional oil and gas fields mature, operators and service providers are looking toward, and collaborating on, creative and alternative methods for enhancing production from existing wells, especially in the absence of, or at least the reduction of, new well activity. While oil and gas price environments remain uncertain, recent price-improvement trends are supporting greater field testing and implementation of innovative applications, albeit with caution and with cost savings in mind. Not only is cost-effectiveness a requirement, but cost-reducing applications and solutions can be, too. Of particular interest are applications addressing challenging well-production needs such as reducing or eliminating liquid loading in gas wells; restimulating existing, underperforming wells, including as an alternative to new well drilling and completion; and remediating water blocking and condensate buildup, both of which can impair production from gas wells severely. The three papers featured this month represent a variety of applications relevant to these particular well-production needs. The first paper presents a technology and method for liquid removal to improve gas production and reserves recovery in unconventional, liquid-rich reservoirs using subsurface wet-gas compression. Liquid loading, a recurring issue downhole, can severely reduce gas production and be costly to remediate repeatedly, which can be required. This paper discusses the full technology application process and the supportive results of the first field trial conducted in an unconventional shale gas well. The second paper discusses the application of the fishbone stimulation system and technique in a tight carbonate oil-bearing formation. Fishbone stimulation has been around for several years now, but its best applications and potential have not necessarily been fully understood in the well-stimulation community. This paper summarizes a successful pilot application resulting in a multifold increase in oil-production rate and walks the reader through the details of the pilot candidate selection, completion design, operational challenges, and lessons learned. The third paper introduces and proposes a chemical treatment to alleviate phase trapping in tight carbonate gas reservoirs. Phase trapping can be in the form of water blocking or increasing condensate buildup from near the wellbore and extending deeper into the formation over time. Both can reduce relative permeability to gas severely. Water blocks can be a one-time occurrence from drilling, completion, workover, or stimulation operations and can often be treated effectively with solvent plus proper additive solutions. Similar treatments for condensate banking in gas wells, however, can provide only temporary alleviation, if they are even effective. This paper proposes a technique for longer-term remediation of phase trapping in tight carbonate gas reservoirs using a unique, slowly reactive fluid system. Recommended additional reading at OnePetro: www.onepetro.org. SPE 200345 - Insights Into Field Application of Enhanced-Oil-Recovery Techniques From Modeling of Tight Reservoirs With Complex High-Density Fracture Network by Geng Niu, CGG, et al. SPE 201413 - Diagnostic Fracture Injection Test Analysis and Simulation: A Utica Shale Field Study by Jeffery Hildebrand, The University of Texas at Austin, et al.


2011 ◽  
Vol 134 (1) ◽  
Author(s):  
John Yilin Wang

Liquid loading has been a problem in natural gas wells for several decades. With gas fields becoming mature and gas production rates dropping below the critical rate, deliquification becomes more and more critical for continuous productivity and profitability of gas wells. Current methods for solving liquid loading in the wellbore include plunger lift, velocity string, surfactant, foam, well cycling, pumps, compression, swabbing, and gas lift. All these methods are to optimize the lifting of liquid up to surface, which increases the operating cost, onshore, and offshore. However, the near-wellbore liquid loading is critical but not well understood. Through numerical reservoir simulation studies, effect of liquid loading on gas productivity and recovery has been quantified in two aspects: backup pressure and near-wellbore liquid blocking by considering variable reservoir permeability, reservoir pressure, formation thickness, liquid production rate, and geology. Based on the new knowledge, we have developed well completion methods for effective deliquifications. These lead to better field operations and increased ultimate gas recovery.


2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Youwei He ◽  
Shiqing Cheng ◽  
Zhe Sun ◽  
Zhi Chai ◽  
Zhenhua Rui

Abstract Well production rates decline quickly in the tight reservoirs, and enhanced oil recovery (EOR) is needed to increase productivity. Conventional flooding from adjacent wells is inefficient in the tight formations, and Huff-n-Puff also fails to achieve the expected productivity. This paper investigates the feasibility of the inter-fracture injection and production (IFIP) method to increase oil production rates of horizontal wells. Three multi-fractured horizontal wells (MFHWs) are included in a cluster well. The fractures with even and odd indexes are assigned to be injection fractures (IFs) and recovery fractures (RFs). The injection/production schedule includes synchronous inter-fracture injection and production (s-IFIP) and asynchronous inter-fracture injection and production (a-IFIP). The production performances of three MFHWs are compared by using four different recovery approaches based on numerical simulation. Although the number of RFs is reduced by about 50% for s-IFIP and a-IFIP, they achieve much higher oil rates than depletion and CO2 Huff-n-Puff. The sensitivity analysis is performed to investigate the impact of parameters on IFIP. The spacing between IFs and RFs, CO2 injection rates, and connectivity of fracture networks affect oil production significantly, followed by the length of RFs, well spacing among MFHWs, and the length of IFs. The suggested well completion scheme for the IFIP methods is presented. This work discusses the ability of the IFIP method in enhancing the oil production of MFHWs.


2017 ◽  
Vol 10 (1) ◽  
pp. 37-47
Author(s):  
Qingsha Zhou ◽  
Kun Huang ◽  
Yongchun Zhou

Background: The western Sichuan gas field belongs to the low-permeability, tight gas reservoirs, which are characterized by rapid decline in initial production of single-well production, short periods of stable production, and long periods of late-stage, low-pressure, low-yield production. Objective: It is necessary to continue pursuing the optimization of transportation processes. Method: This paper describes research on mixed transportation based on simplified measurements with liquid-based technology and the simulation of multiphase processes using the PIPEPHASE multiphase flow simulation software to determine boundary values for the liquid carrying process. Conclusion: The simulation produced several different recommendations for the production and maximum multiphase distance along with difference in elevation. Field tests were then conducted to determine the suitability of mixed transportation in western Sichuan, so as to ensure smooth progress with fluid metering, optimize the gathering process in order to achieve stable and efficient gas production, and improve the economic benefits of gas field development.


2021 ◽  
Author(s):  
Yaowen Liu ◽  
Wei Pang ◽  
Jincai Shen ◽  
Ying Mi

Abstract Fuling shale gas field is one of the most successful shale gas play in China. Production logging is one of the vital technologies to evaluate the shale gas contribution in different stages and different clusters. Production logging has been conducted in over 40 wells and most of the operations are successful and good results have been observed. Some previous studies have unveiled one or several wells production logging results in Fuling shale gas play. But production logging results show huge difference between different wells. In order to get better understanding of the results, a comprehensive overview is carried out. The effect of lithology layers, TOC (total organic content), porosity, brittle mineral content, well trajectory is analyzed. Results show that the production logging result is consistent with the geology understanding, and fractures in the favorable layers make more gas contribution. Rate contribution shows positive correlation with TOC, the higher the TOC, the greater the rate contribution per stage. For wells with higher TOC, the rate contribution difference per stage is relatively smaller, but for wells with lower TOC, it shows huge rate contribution variation, fracture stages with TOC lower than 2% contribute very little, and there exist one or several dominant fractures which contributes most gas rate. Porosity and brittle minerals also show positive effect on rate contribution. The gas rate contribution per fracture stage increases with the increase of porosity and brittle minerals. The gas contribution of the front half lateral and that of latter half lateral are relatively close for the "upward" or horizontal wells. However, for the "downward" wells, the latter half lateral contribute much more gas than the front half lateral. It is believed that the liquid loading in the toe parts reduced the gas contribution in the front half lateral. The overview research is important to get a compressive understanding of production logging and different fractures’ contribution in shale gas production. It is also useful to guide the design of horizontal laterals and fractures scenarios design.


2021 ◽  
Author(s):  
Hajar Ali Abdulla Al Shehhi ◽  
Bondan Bernadi ◽  
Alia Belal Zuwaid Belal Al Shamsi ◽  
Shamma Jasem Al Hammadi ◽  
Fatima Omar Alawadhi ◽  
...  

Abstract Reservoir X is a marginal tight gas condensate reservoir located in Abu Dhabi with permeability of less than 0.05 mD. The field was conventionally developed with a few single horizontal wells, though sharp production decline was observed due to rapid pressure depletion. This study investigates the impact of converting the existing single horizontal wells into single long horizontal, dual laterals, triple laterals, fishbone design and hydraulic fracturing in improving well productivity. The existing wells design modifications were planned using a near reservoir simulator. The study evaluated the impact of length, trajectory, number of laterals and perforation intervals. For Single, dual, and triple lateral wells, additional simulation study with hydraulic fracturing was carried out. To evaluate and obtain effective comparisons, sector models with LGR was built to improve the simulation accuracy in areas near the wellbore. The study conducted a detailed investigation into the impact of various well designs on the well productivity. It was observed that maximizing the reservoir contact and targeting areas with high gas saturation led to significant increase in the well productivity. The simulation results revealed that longer laterals led to higher gas production rates. Dual lateral wells showed improved productivity when compared to single lateral wells. This incremental gain in the production was attributed to increased contact with the reservoir. The triple lateral well design yielded higher productivity compared to single and dual lateral wells. Hydraulic fracturing for single, dual, and triple lateral wells showed significant improvement in the gas production rates and reduced condensate banking near the wellbore. A detailed investigation into the fishbone design was carried out, this involved running sensitivity runs by varying the number of branches. Fishbone design showed considerable increment in production when compared to other well designs This paper demonstrates that increasing the reservoir contact and targeting specific areas of the reservoir with high gas saturation can lead to significant increase in the well productivity. The study also reveals that having longer and multiple laterals in the well leads to higher production rates. Hydraulic fracturing led to higher production gains. Fishbone well design with its multiple branches showed the most production again when compared to other well designs.


2021 ◽  
Author(s):  
Michael Hardcastle ◽  
Ryan Holmes ◽  
Frank Abbott ◽  
Jesse Stevenson ◽  
Aubrey Tuttle

Abstract Connacher Oil and Gas has deployed Flow Control Devices (FCDs)on an infill well liner as part of a Steam Assisted Gravity Drainage (SAGD) exploitation strategy. Infill wells are horizontal wells drilled in between offsetting SAGD well pairs in order to access bypassed pay and accelerate recovery. These wells can have huge variability in productivity, based on several factors: variable initial temperature due to variable steam chamber development and initial mobility variable injectivity from day one limiting steam circulation and stimulation significant hot spots during production that limit drawdown of the well and oil productivity FCDs have shown great value in several SAGD schemes and are becoming common throughout SAGD applications to manage similar challenges in SAGD pairs, but their application in infill wells is less prevalent and presents a novel challenge to design and evaluate performance. This case study will examine the theory, operation, and early field results of this field trial. Density-based FCDs designed for thermal operations were selected to minimize the impact of viscous fluids commonly encountered early in cold infill well production. The design also limited steam outflow during the stimulation phase, where steam is injected in order to initiate production of the well. Distributed Temperature Sensing (DTS) data, pressures and rates are utilized to analyze the impact of the FCDs towards conformance of the well in the early life. The value of FCDs has led to further piloting of this technology in a second group of nine infill wells, where further value is to be extracted using slimmer wellbores.


1976 ◽  
Vol 16 (1) ◽  
pp. 107
Author(s):  
M. A. Delbaere

Oilfield operators have always looked for ways of reducing the costs of oil and gas development projects and especially when investment costs were critical to project economics. Tubingless completions have evolved over the last 30 years in North America to fill the need for reduced investment costs particularly in the case of fields with either limited reserves or limited profitability.Tubingless completions basically utilise small diameter tubulars to function as both production casing and flowstring. The tubulars are cemented in the borehole, not to be removed or recovered until the field is depleted and/or the well abandoned. The technique is limited in application to those fields with no corrosion or wax or hydrate problems and with a limited requirement for reservoir stimulation and workovers. The greater the number of operations performed within the tubingless well bore the greater the risk of losing the well.The main benefits of tubingless completions are as follows:Reduction in development well completion costs.Marginally productive hydrocarbon zones can be completed and tested.Completion of individual gas zones of multi-pay wells within their own permanently segregated flowstrings at much lower capital and operating costs.The experience this far with Kincora gas field development wells indicates the tubingless completion method to be completely feasible for gas wells drilled in the Surat Basin and possibly in other areas of Australia.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
André L. R. Alves ◽  
T. A. Netto

Abstract This work presents a methodology for evaluating the uncontrolled external leakage probability of a subsea well during the production phase. Based on a barrier diagram, an algorithm for possible leak path identification is proposed, considering different operation modes: gas lift operation, free-flowing, or well closed at the subsea Christmas tree. Considering the equivalency between these paths and the minimum cut sets from a fault tree modeling, the uncontrolled external leakage probability is calculated using the upper bound approximation. The effect of common cause failures is considered for the failure mode fail-to-close-valve. The instantaneous availability function of each component is considered. Non-repairable, repairable, and periodically tested items are used. Probability distribution parameters are estimated in order to make a case study. The failure rate functions determined are used as input for the proposed model, regarding the following failure modes: fail-to-close, external-leakage, and internal-leakage at the closed position. Finally, failure probability results and sensitivity analysis are demonstrated for a base case study. Parameters like time between tests, inspections, and component reliability are varied in order to identify the impact on the uncontrolled external leakage probability. The main objective of the proposed methodology is to support decision-making on the well integrity management system during the production phase of a subsea well. To this end, actual and reliable input data should be considered.


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