scholarly journals Inflow Performance Analysis of a Horizontal Well Coupling Stress Sensitivity and Reservoir Pressure Change in a Fractured-Porous Reservoir

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Mingxian Wang ◽  
Zifei Fan ◽  
Wenqi Zhao ◽  
Ruiqing Ming ◽  
Lun Zhao ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Horizontal Wells ◽  
Pressure Change ◽  
Sensitivity Coefficient ◽  
Stress Sensitivity ◽  
Reservoir Pressure ◽  
Well Productivity ◽  
Damage Rate ◽  
Porous Reservoir ◽  
Inflow Performance

Abstract Stress sensitivity has always been a research hotspot in fractured-porous reservoirs and shows huge impacts on well productivity during the depletion development. Due to the continuous reservoir pressure change, accurate evaluation of stress sensitivity and its influence on well productivity is of great significance to optimize well working system. Taking horizontal well trajectory as the research object, the principal focus of this work is on the analysis of inflow performance for a horizontal well coupling stress sensitivity and reservoir pressure change in a fractured-porous reservoir. Firstly, a relationship between permeability damage rate and stress sensitivity coefficient was established to quantitatively evaluate the influence of reservoir pressure and stress sensitivity on reservoir permeability. Secondly, considering stress sensitivity and reservoir pressure drop, a set of practical productivity equations were derived for a horizontal well in a fractured-porous reservoir by adopting the equivalent seepage resistance method. Finally, the influence of relevant important factors on the inflow performance of horizontal wells was discussed in depth. Results show that a positive correlation exists between stress sensitivity coefficient and maximum permeability damage rate. At the same maximum permeability damage rate, high initial reservoir pressure corresponds to low stress sensitivity coefficient. In general, stress sensitivity coefficient mainly ranges from 0 to 0.2. Reservoir pressure change drastically affects the production dynamic characteristics of horizontal wells, and both the inflow performance curve and the production index curve decline and shrink as reservoir pressure decreases. Stress sensitivity is negatively correlated with horizontal well productivity, and the inflow performance/production index curve bends closer to bottom-hole pressure axis, and an inflection point can be observed with the aggravation of stress sensitivity. In addition, horizontal wellbore length and initial reservoir permeability also show significant effects on the inflow performance and are positively correlated with well productivity. For water cut, it has little effect on the well production when bottom-hole pressure drawdown is low, but its effect gets stronger as the drawdown becomes higher. Meaningfully, depending on these newly established productivity equations, a reasonable production system can be quantitatively optimized and achieved for the horizontal wells in fractured-porous reservoirs.

scholarly journals Productivity Evaluation of Vertical Wells Incorporating Fracture Closure and Reservoir Pressure Drop in Fractured Reservoirs

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Lun Zhao ◽  
Zifei Fan ◽  
Mingxian Wang ◽  
Guoqiang Xing ◽  
Wenqi Zhao ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Fractured Reservoirs ◽  
Stress Sensitivity ◽  
Reservoir Pressure ◽  
Vertical Wells ◽  
Well Productivity ◽  
Bottom Hole ◽  
Fracture Closure ◽  
Performance Curves ◽  
Inflow Performance

In most oilfields, many wells produce in pseudo-steady-state period for a long time. Because of large reservoir pressure drop in this period, fractured reservoirs always show strong stress sensitivity and fracture closure is likely to occur near wellbores. The primary goal of this study is to evaluate productivity of vertical wells incorporating fracture closure and reservoir pressure drop. Firstly, a new composite model was developed to deal with stress sensitivity and fracture closure existed in fractured reservoirs. Secondly, considering reservoir saturation condition, new pseudo-steady productivity equations for vertical wells were derived by using the proposed composite system. Thirdly, related inflow performance characteristics and influence of some factors on them were also discussed in detail. Results show that fracture closure has a great effect on vertical well inflow performance and fracture closure radius is negatively correlated with well productivity. In this composite model, the effects of stress sensitivity of the inner and outer zone on well productivity are rather different. The inner zone’s stress sensitivity affects well productivity significantly, but the outer zone’s stress sensitivity just has a weak effect on the productivity. Strong stress sensitivity in the inner zone leads to low well productivity, and both inflow performance and productivity index curves bend closer to the bottom-hole pressure axis with stress sensitivity intensifying. Meanwhile, both maximum productivity and optimal bottom-hole pressure can be achieved from inflow performance curves. In addition, reservoir pressure is positively correlated with vertical well productivity. These new productivity equations and inflow performance curves can directly provide quantitative reference for optimizing production system in fractured reservoirs.

Evaluating the Performance of Horizontal Multi-Frac Wells in a Depleted Gas Condensate Reservoir in Sultanate of Oman

2022 ◽  
Author(s):  
Josef R. Shaoul ◽  
Jason Park ◽  
Andrew Boucher ◽  
Inna Tkachuk ◽  
Cornelis Veeken ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Horizontal Wells ◽  
Gas Condensate ◽  
Integrated Analysis ◽  
Single Fracture ◽  
Reservoir Pressure ◽  
Well Test ◽  
Vertical Wells ◽  
Fracture Conductivity ◽  
Half Length

Abstract The Saih Rawl gas condensate field has been producing for 20 years from multiple fractured vertical wells covering a very thick gross interval with varying reservoir permeability. After many years of production, the remaining reserves are mainly in the lowest permeability upper units. A pilot program using horizontal multi-frac wells was started in 2015, and five wells were drilled, stimulated and tested over a four-year period. The number of stages per horizontal well ranged from 6 to 14, but in all cases production was much less than expected based on the number of stages and the production from offset vertical wells producing from the same reservoir units with a single fracture. The scope of this paper is to describe the work that was performed to understand the reason for the lower than expected performance of the horizontal wells, how to improve the performance, and the implementation of those ideas in two additional horizontal wells completed in 2020. The study workflow was to perform an integrated analysis of fracturing, production and well test data, in order to history match all available data with a consistent reservoir description (permeability and fracture properties). Fracturing data included diagnostic injections (breakdown, step-rate test and minifrac) and main fracture treatments, where net pressure matching was performed. After closure analysis (ACA) was not possible in most cases due to low reservoir pressure and absence of downhole gauges. Post-fracture well test and production matching was performed using 3D reservoir simulation models including local grid refinement to capture fracture dimensions and conductivity. Based on simulation results, the effective propped fracture half-length seen in the post-frac production was extremely small, on the order of tens of meters, in some of the wells. In other wells, the effective fracture half-length was consistent with the created propped half-length, but the fracture conductivity was extremely small (finite conductivity fracture). The problems with the propped fractures appear to be related to a combination of poor proppant pack cleanup, low proppant concentration and small proppant diameter, compounded by low reservoir pressure which has a negative impact on proppant regained permeability after fracturing with crosslinked gel. Key conclusions from this study are that 1) using the same fracture design in a horizontal well with transverse fractures will not give the same result as in a vertical well in the same reservoir, 2) the effect of depletion on proppant pack cleanup in high temperature tight gas reservoirs appears to be very strong, requiring an adjustment in fracture design and proppant selection to achieve reasonable fracture conductivity, and 3) achieving sufficient effective propped length and height is key to economic production.

Single-Phase Inflow Performance Relationship for Horizontal, Pinnate-Branch Horizontal, and Radial-Branch Wells

SPE Journal ◽  
2012 ◽  
Vol 18 (02) ◽  
pp. 219-232 ◽  
Author(s):  
Huiqing Liu ◽  
Jing Wang ◽  
Jian Zheng ◽  
Ying Zhang
Keyword(s):  
Horizontal Well ◽  
Branch Length ◽  
Horizontal Wells ◽  
Finite Conductivity ◽  
Nonlinearity Coefficient ◽  
Oil Viscosity ◽  
Branch Number ◽  
Nonlinear Characteristics ◽  
Relative Roughness ◽  
Inflow Performance

Summary Horizontal and multibranch wells are likely to become the major means of modern exploitation strategies; inflow performances for these wells are needed. Because this paper considers the finite conductivity of a horizontal well, it establishes the inflow performance relationships (IPRs) for different branch configurations of horizontal wells. We find that the IPR of a horizontal well presents nonlinear characteristics and is similar to Vogel's equation, which has been used extensively and successfully for analyzing the IPR of a vertical well in a solution-gas-drive reservoir. Instead of the effect of a two-phase (oil and gas) flow in a reservoir described by Vogel's equation, the nonlinear characteristics of horizontal wells are mainly the result of pressure drops caused by friction, acceleration, and gravity along the horizontal wellbore. The nonlinearity coefficient presents the pressure drop along the major branch, and it is a function of major-wellbore length, major-wellbore diameter, oil viscosity, and relative roughness. Then, the horizontal-well IPR is used to study the performance of the pinnate-branch horizontal well and the radial-branch (horizontal lateral) well. The branch number, branch length, major-wellbore length, major-wellbore diameter, oil viscosity, and relative roughness are combined into grouped parameters to present the effect on the deliverability incremental ratio JH and the nonlinearity coefficient ratio Rv of the pinnate-branch horizontal well to the conventional horizontal well, which show regression relationships with the grouped parameters for pinnate-branch horizontal wells. In addition, another binomial relationship between the deliverability incremental ratio JV and the grouped parameter combined by branch number, branch length, and equivalent oil drainage diameter is obtained for radial-branch (horizontal lateral) wells. The new IPR also covers conventional horizontal wells and vertical wells (with no branch) because the deliverability incremental ratios JH and JV in both cases are unity. The IPR is very valuable for calculating the productivity of horizontal wells, pinnate-branch horizontal wells, and radial-branch wells.

scholarly journals Productivity Evaluation for Long Horizontal Well Test in Deep-Water Faulted Sandstone Reservoir

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zhiwang Yuan ◽  
Li Yang ◽  
Yingchun Zhang ◽  
Rui Duan ◽  
Xu Zhang ◽  
...  
Keyword(s):  
Steady State ◽  
Deep Water ◽  
Horizontal Well ◽  
Evaluation Method ◽  
Horizontal Wells ◽  
Productivity Index ◽  
Test Time ◽  
Well Test ◽  
Well Productivity ◽  
Sandstone Reservoir

For deep-water faulted sandstone reservoirs, the general practice is to design long horizontal wells improving well productivity. During the project implementation stage, well tests are performed on all drilled wells to evaluate well productivity accurately. Furthermore, multisize chokes are often utilized in a shorten test time for loosen formation, high test cost, and high well productivity. Nevertheless, the conventional productivity evaluation approach cannot accurately evaluate the well test productivity and has difficulty in determining the underneath pattern. As a result, the objective of this paper is to determine a productivity evaluation method for multisize chokes long horizontal well test in deep-water faulted sandstone reservoir. This approach introduces a productivity model for long horizontal wells in faulted sandstone reservoir. It also includes the determination of steady-state test time and the productivity evaluation method for multisize chokes. In this paper, the EGINA Oilfield, a deep-water faulted sandstone reservoir, located in West Africa was chosen as the research target. Based on Renard and Dupuy’s steady-state equation, the relationship between the productivity index per meter and the length of horizontal section was derived. Consequently, this relationship is used to determine the productivity pattern for long horizontal wells with the same geological features, which can provide more accurate productivity evaluations for tested wells and forecast the well productivity for untested wells. After implementing this approach on the EGINA Oilfield, the determined relationship is capable to accurately evaluate the test productivity for long horizontal wells in reservoirs with similar characteristics and assist in examination and treatment for horizontal wells with abnormal productivity.

scholarly journals A Modeling Study of the Productivity of Horizontal Wells in Hydrocarbon-Bearing Reservoirs: Effects of Fracturing Interference

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lei Huang ◽  
Peijia Jiang ◽  
Xuyang Zhao ◽  
Liang Yang ◽  
Jiaying Lin ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Horizontal Well ◽  
Finite Difference Methods ◽  
Horizontal Wells ◽  
Fracture Initiation ◽  
Design Parameters ◽  
Porous Media Flow ◽  
Propagation Mechanism ◽  
Well Productivity ◽  
Fracturing Process

Commercial production from hydrocarbon-bearing reservoirs with low permeability usually requires the use of horizontal well and hydraulic fracturing for the improvement of the fluid diffusivity in the matrix. The hydraulic fracturing process involves the injection of viscous fluid for fracture initiation and propagation, which alters the poroelastic behaviors in the formation and causes fracturing interference. Previous modeling studies usually focused on the effect of fracturing interference on the multicluster fracture geometry, while the related productivity of horizontal wells is not well studied. This study presents a modeling workflow that utilizes abundant field data including petrophysical, geomechanical, and hydraulic fracturing data. It is used for the quantification of fracturing interference and its correlation with horizontal well productivity. It involves finite element and finite difference methods in the numeralization of the fracture propagation mechanism and porous media flow problems. Planar multistage fractures and their resultant horizontal productivity are quantified through the modeling workflow. Results show that the smaller numbers of clusters per stage, closer stage spacings, and lower fracturing fluid injection rates facilitate even growth of fractures in clusters and stages and reduce fracturing interference. Fracturing modeling results are generally correlated with productivity modeling results, while scenarios with stronger fracturing interference and greater stimulation volume/area can still yield better productivity. This study establishes the quantitative correlation between fracturing interference and horizontal well productivity. It provides insights into the prediction of horizontal well productivity based on fracturing design parameters.

Study on Multilateral well Productivity Prediction Technology

2013 ◽  
Vol 827 ◽  
pp. 232-238
Author(s):  
Xiao Dong Wu ◽  
Rui He Wang ◽  
Yi Ning Wang ◽  
Zhuang Zhang
Keyword(s):  
Horizontal Well ◽  
Physical Simulation ◽  
Horizontal Wells ◽  
Coupling Model ◽  
Laboratory Method ◽  
Well Productivity ◽  
Vertical Well ◽  
Reservoir Flow ◽  
Wellbore Flow ◽  
Productivity Prediction

The production of a multilateral horizontal well is higher than the production of a vertical well, even than that of a unilateral horizontal well. Nonetheless, the stimulation effect is significantly influenced by the branch parameters, and the impacts of branch parameters on the productivity of a multilateral horizontal well are rather complex. In this paper, the factors which affect the productivity of multilateral horizontal wells are preliminarily analyzed with the laboratory method of physical simulation. Then, a semi-analytical coupling model of wellbore flow and reservoir flow is built, and the multilateral horizontal wells are simulated to investigate the impacts of branch parameters on the stimulation effect of multilateral horizontal wells.

A Holistic Study on Performance Evaluation of Horizontal Wells and its Implications on Tight Spacing Drilling Strategy in Mauddud Reservoir

2021 ◽  
Author(s):  
Lakshi Konwar ◽  
Bader Alhammadi ◽  
Ebrahim Alawainati ◽  
Ajithkumar Panicker
Keyword(s):  
Performance Evaluation ◽  
Future Development ◽  
Horizontal Well ◽  
Horizontal Wells ◽  
Productivity Index ◽  
Water Production ◽  
Vertical Wells ◽  
Productivity Improvement ◽  
Well Productivity ◽  
Improvement Factor

Abstract The objective of this paper is to present the comparative results of comprehensive analysis of horizontal well productivity and completion performance with vertical wells drilled and completed within same time window in the Mauddud reservoir in the Bahrain Oil Field. The study also focuses on performance evaluation of horizontal wells drilled in different areas of the field. Key reservoir risks and uncertainties associated with horizontal wells are identified, and contingency and mitigation plans are devised to address them. Besides controlling gas production, the benefits of using cemented horizontal wells over vertical wells are highlighted based on performance of recently completed workovers and economic evaluation. Reservoir and well performance are analyzed using a variety of analytical techniques such as well productivity index (PI), productivity improvement factor (PIF), normalized productivity improvement factor (PIFn), well productivity coefficient (Cwp), in conjunction with a statistical distribution function to reflect the average and most likely values. In addition, average oil/gas/water production, cumulative production, reserves, and estimated ultimate recovery (EUR) are compared for both vertical and horizontal wells using decline curve analysis. Furthermore, economics are evaluated for tight spacing drilling with vertical wells, as well as horizontal cemented wells, to optimize future development of Mauddud reservoir. Based on the evaluation, it is inferred that the average horizontal well outperforms a vertical well in terms of production rate, PI, PIF, reserves, and EUR in the field except in waterflood areas. Based on average cumulative oil, reserves and EUR, and well productivity coefficient, overall performance of horizontal wells are better in the GI area in comparison their counterparts in the North/South areas of the Mauddud reservoir, where the dominant mechanism is strong water drive. High gas and water production in horizontal wells are attributed to open-hole completions of the wells and the possibility of poor cementing. A trial has been completed recently in a few horizontal wells using cased-hole cemented completion with selected perforations, resulting in improved oil rates and the drastic reduction of gas to oil ratio. Furthermore, two new cased-hole cemented horizontal wells are planned in 2021 as a trial. A detailed cost-benefit analysis using a net present value concept is performed, leading to a rethink of future development strategies with a mix of both vertical as well as horizontal wells in the GI area. Using the dimensionless correlations and distribution functions, the productivity and PIF of new horizontal wells to be drilled in any area can be predicted during early prognosis given the values of average reservoir permeability, well length, and fluid properties. This study can be used as a benchmark for the development of a thin oil column with a large and expanding gas cap under crestal gas injection using both vertical and horizontal wells.

Comparative Study on Inflow Performance Model of Short Horizontal Wells

2011 ◽  
Vol 361-363 ◽  
pp. 425-432
Author(s):  
Min Ruan ◽  
Jing Wang ◽  
Xiang Fang Li
Keyword(s):  
Horizontal Well ◽  
Horizontal Wells ◽  
Performance Model ◽  
Oil Field ◽  
Oil Fields ◽  
Steady State Model ◽  
The World ◽  
High Yields ◽  
Gas Fields ◽  
Inflow Performance

High yields and higher efficiency can be acquired by using horizontal well as it has a lager contact area reservoir. So the horizontal well has become a better choice to gas fields all over the world, especially to low permeability oil fields in the world. There are several inflow performance models for horizontal wells. This paper studies several horizontal well models currently widely used in the word through an example of Chinese oil field. These include steady state model of Giger model, Joshi model and Renard and Dupuy model. And pseudo steady model of Babu and Odeh model. The results show that Giger model give greater production rate from our procedure and calculation.

Evaluation of Inflow Performance of Multiple Horizontal Wells in Closed Systems

1999 ◽  
Vol 122 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Suwan Umnuayponwiwat ◽  
Erdal Ozkan
Keyword(s):  
Horizontal Well ◽  
Transient Flow ◽  
Horizontal Wells ◽  
Vertical Wells ◽  
Well Pattern ◽  
Horizontal And Vertical Wells ◽  
Closed Systems ◽  
Inflow Performance

This work presents a model to investigate the inflow performance relationships (IPR) of horizontal and vertical wells in a multi-well pattern. The model can be used to compute the overall and individual well performances. It is shown that stabilized IPRs may not be sufficient for the evaluation of horizontal well performances due to prolonged transient flow periods. The results presented in this paper clearly indicate that inflow performance of wells in a multi-well pattern is a dynamic concept; and, especially in the prediction of future performances, dynamic rather than static IPR models should be used. [S0195-0738(00)00801-3]

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