A Novel Approach to Evaluate Deliverability of Gas Wells with Pressure Fluctuation

2021 ◽  
Author(s):  
Yongbin Zhang ◽  
Xiongwei Sun ◽  
Xiaojia Bai ◽  
Wei Jia ◽  
Bo Zhu ◽  
...  
Keyword(s):  
Pressure Fluctuation ◽  
Evaluation Method ◽  
Dynamic Change ◽  
Field Studies ◽  
Well Testing ◽  
Wax Deposition ◽  
Gas Well ◽  
New Approach ◽  
Wellhead Pressure ◽  
Geological Conditions

Abstract Majority of gas fields in Tarim Basin are HPHT (high-pressure/high temperature) reservoirs with buried depth more than 5000m. The special geological conditions made it a challenge for underground well testing due to safety issues. Additionally, wellhead pressure fluctuation is widely existed both from geological and engineering factors, including sand production, well casing integrity problems, contamination of downhole fracturing fluid and wax deposition in wellbore etc. Traditional deliverability evaluation method which relies on underground well testing is greatly limited as it is not capable of reflecting the dynamic change of gas well deliverability due to abnormal wellhead pressure fluctuation. In this study, a new approach is proposed to evaluate the deliverability of these kind of wells using dynamic data from wellheads. An apparent and a potential deliverability curves are based on binomial deliverability equation are established individually according to whether the additional skin caused by wellbore blockage is taken into consideration. The variation characteristic of gas well deliverability is obtained by comparison of potential and apparent absolute open flow. Finally, field studies of Dina abnormal wells are performed to verify the accuracy of the method. Deliverability analysis show that the new approach has a great advantage in evaluating the production potential of wells with pressure fluctuation, and furtherly provides the criteria for wellbore management.

Real-Time Estimation and Management of Hydrate Plugging Risk During Deepwater Gas Well Testing

SPE Journal ◽  
2020 ◽  
Vol 25 (06) ◽  
pp. 3250-3264 ◽  
Author(s):  
Jianbo Zhang ◽  
Zhiyuan Wang ◽  
Wenguang Duan ◽  
Weiqi Fu ◽  
Baojiang Sun ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Real Time ◽  
Hydrate Formation ◽  
Dynamic Effect ◽  
Time Estimation ◽  
Gas Production ◽  
Well Testing ◽  
Gas Well ◽  
Wellhead Pressure ◽  
Real Time Estimation

Summary Hydrate formation and deposition are usually encountered during deepwater gas well testing, and if hydrates are not detected and managed in time, a plugging accident can easily occur. In this study, we demonstrate a method for estimating and managing the risk of hydrate plugging in real time during the testing process. The method includes the following steps: predicting the hydrate stability region, calculating the hydrate formation and deposition behaviors, analyzing the effect of the hydrate behaviors on variations in wellhead pressure, monitoring the variations in wellhead pressure and estimating the hydrate plugging risk in real time, and managing the risk in real time. An improved pressure-drop calculation model is established to calculate the pressure drop in annular flows with hydrate behaviors, and it considers the dynamic effect of hydrate behavior on fluid flow and surface roughness. The pressure drops calculated at different times agree well with experimental and field data. A case study is conducted to investigate the applicability of the proposed method, and results show that with the continued formation and deposition of hydrates, both the effective inner diameter of the tubing and the wellhead pressure decrease accordingly. When the wellhead pressure decreases to a critical safety value under a given gas production rate, a hydrate inhibitor must be injected into the tubing to reduce the severity of hydrate plugging. It is also necessary to conduct real-time monitoring of variations in wellhead pressure to guarantee that the risk of hydrate plugging is within a safe range. This method enables the real-time estimation and management of hydrate plugging during the testing process, and it can provide a basis for the safe and efficient testing of deepwater gas wells.

Transient Simulation of Wellbore Pressure and Temperature During Gas-Well Testing

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Tong Liu ◽  
Hai-quan Zhong ◽  
Ying-chuan Li
Keyword(s):  
State Equation ◽  
Transfer Model ◽  
Pressure Curve ◽  
Well Testing ◽  
Gas Field ◽  
Gas Well ◽  
Wellhead Pressure ◽  
Wellbore Pressure ◽  
Abnormal Phenomenon ◽  
The Difference

An abnormal phenomenon may occur during gas-well testing: the wellhead pressure initially rises and then drops when shutting-in a well; the wellhead pressure initially drops and then rises when opening a well. To determine why and how this phenomenon occurs, a transient nonisothermal wellbore flow model for gas-well testing is developed. Governing equations are based on depth- and time-dependent mass, momentum equations, and the gas state equation. Temperature is predicted using the unsteady-state heat transfer model of Hasan. Boundary conditions include the restriction of formation inflow and wellhead throttling to the flow. The difference equations are established based on the implicit central finite difference method. The model can simulate the influences of temperature and flux (mass velocity). The model also considers the effects of formation inflow and surface throttling on the system. The results indicate wellhead pressure under flowing temperature is higher than that under static temperature, thus causing the abnormal phenomenon. A larger pressure difference makes the abnormal phenomenon more significant. Without considering temperature variation, simulated wellhead pressure would not exhibit the abnormity. Without considering flux variation, simulated pressure curve is not smooth. A new model has thus been validated using a gas field example.

Research on evaluation method of wellbore hydrate blocking degree during deepwater gas well testing

2018 ◽  
Vol 59 ◽  
pp. 168-182 ◽  
Author(s):  
Wenyuan Liu ◽  
Jinqiu Hu ◽  
Xiangfang Li ◽  
Fengrui Sun ◽  
Zheng Sun ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Well Testing ◽  
Gas Well ◽  
Research On Evaluation ◽  
Blocking Degree

scholarly journals The hydrochemical characteristics and quality assessment of groundwater in Shuangliao City, China

2019 ◽  
Vol 98 ◽  
pp. 01034 ◽  
Author(s):  
Mingjun Liu ◽  
Changlai Xiao ◽  
Xiujuan Liang
Keyword(s):  
Groundwater Quality ◽  
Human Activities ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Hydrochemical Characteristics ◽  
Analytic Hierarchy ◽  
Liaohe River ◽  
Geological Conditions ◽  
Type Water

In this study, a hydrochemical investigation was conducted in Shuangliao city to identify the hydrochemical characteristics and the quality of groundwater using descriptive statistics and correlation matrices. And on that basis, combined with Analytic hierarchy process (AHP), an improved two-level fuzzy comprehensive evaluation method is used to evaluate the groundwater quality. The results indicate that the major cations and anions in groundwater are Ca2+ and HCO3-, respectively. The chemical types are mainly HCO3—Ca type water, some areas are complicated due to the influence of human activities. The evaluation results show that the water quality in the area is mostly III type water, and the groundwater quality in some areas is IV or V water due to the influence of primary geological conditions or human activities. The groundwater quality in the East Liaohe River Valley and Shuangliao urban area is relatively poor, and in the northwest part which is the saline alkali soil area is also relatively poor.

scholarly journals A Comprehensive Coal Reservoir Classification Method Base on Permeability Dynamic Change and Its Application

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 644 ◽  
Author(s):  
Xinlu Yan ◽  
Songhang Zhang ◽  
Shuheng Tang ◽  
Zhongcheng Li ◽  
Yongxiang Yi ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Dynamic Change ◽  
Initial Permeability ◽  
Gas Production ◽  
Gas Desorption ◽  
Reservoir Permeability ◽  
Geological Conditions ◽  
Production Stages ◽  
Productivity Potential ◽  
Coal Reservoir

Due to the unique adsorption and desorption characteristics of coal, coal reservoir permeability changes dynamically during coalbed methane (CBM) development. Coal reservoirs can be classified using a permeability dynamic characterization in different production stages. In the single-phase water flow stage, four demarcating pressures are defined based on the damage from the effective stress on reservoir permeability. Coal reservoirs are classified into vulnerable, alleviative, and invulnerable reservoirs. In the gas desorption stage, two demarcating pressures are used to quantitatively characterize the recovery properties of permeability based on the recovery effect of the matrix shrinkage on permeability, namely the rebound pressure (the pressure corresponding to the lowest permeability) and recovery pressure (the pressure when permeability returns to initial permeability). Coal reservoirs are further classified into recoverable and unrecoverable reservoirs. The physical properties and influencing factors of these demarcating pressures are analyzed. Twenty-six wells from the Shizhuangnan Block in the southern Qinshui Basin of China were examined as a case study, showing that there is a significant correspondence between coal reservoir types and CBM well gas production. This study is helpful for identifying geological conditions of coal reservoirs as well as the productivity potential of CBM wells.

Pushing 30 Years Multiple Brown Fields Limits Through Artificial Lift and Facilities Improvement

2021 ◽  
Author(s):  
Mohd Hafizi Ariffin ◽  
Muhammad Idraki M Khalil ◽  
Abdullah M Razali ◽  
M Iman Mostaffa
Keyword(s):  
New Technology ◽  
Lessons Learned ◽  
Oil Fields ◽  
Submersible Pump ◽  
Large Space ◽  
Gas Well ◽  
Wellhead Pressure ◽  
Artificial Lift ◽  
Electrical Submersible Pump ◽  
Gas Lift

Abstract Most of the oil fields in Sarawak has already producing more than 30 years. When the fields are this old, the team is most certainly facing a lot of problems with aging equipment and facilities. Furthermore, the initial stage of platform installation was not designed to accommodate a large space for an artificial lift system. Most of these fields were designed with gas lift compressors, but because of the space limitation, the platforms can only accommodate a limited gas lift compressor capacity due to space constraints. Furthermore, in recent years, some of the fields just started with their secondary recovery i.e. water, gas injection where the fluid gradient became heavier due to GOR drop or water cut increases. With these limitations and issues, the team needs to be creative in order to prolong the fields’ life with various artificial lift. In order to push the limits, the team begins to improve gas lift distribution among gas lifted wells in the field. This is the cheapest option. Network model recommends the best distribution for each gas lifted wells. Gas lifted wells performance highly dependent on fluid weight, compressor pressure, and reservoir pressure. The change of these parameters will impact the production of these wells. Rigorous and prudent data acquisitions are important to predict performance. Some fields are equipped with pressure downhole gauges, wellhead pressure transmitters, and compressor pressure transmitters. The data collected is continuous and good enough to be used for analysis. Instead of depending on compressor capacity, a high-pressure gas well is a good option for gas lift supply. The issues are to find gas well with enough pressure and sustainability. Usually, this was done by sacrificing several barrels of oil to extract the gas. Electrical Submersible Pump (ESP) is a more expensive option compared to a gas lift method. The reason is most of these fields are not designed to accommodate ESP electricity and space requirements. Some equipment needs to be improved before ESP installation. Because of this, the team were considering new technology such as Thru Tubing Electrical Submersible Pump (TTESP) for a cheaper option. With the study and implementation as per above, the fields able to prolong its production until the end of Production Sharing Contract (PSC). This proactive approach has maintained the fields’ production with The paper seeks to present on the challenges, root cause analysis and the lessons learned from the subsequent improvement activities. The lessons learned will be applicable to oil fields with similar situations to further improve the fields’ production.

Case History: Lessons learned From Retrieval of Coiled Tubing Stuck by Massive Hydrate Plug When Well Testing in an Ultra Deep Water Gas Well in Mexico

2011 ◽  
Author(s):  
Victor Gerardo Vallejo ◽  
Aciel Olivares ◽  
Pablo Crespo Hdez ◽  
Eduardo R. Roman ◽  
Claudio Rogerio Tigre Maia ◽  
...  
Keyword(s):  
Deep Water ◽  
Case History ◽  
Lessons Learned ◽  
Well Testing ◽  
Gas Well ◽  
Coiled Tubing ◽  
Hydrate Plug ◽  
Water Gas

Changing Wellbore Storage Effects In Gas Well Testing

1997 ◽  
Author(s):  
S. Al-Haddad ◽  
M. LeFlore ◽  
T. Lacy
Keyword(s):  
Well Testing ◽  
Gas Well ◽  
Wellbore Storage ◽  
Storage Effects

Optimal Robust Fixture Configuration Design Using Computer Experiment

Manufacturing ◽  
2003 ◽  
Author(s):  
L. Shelley Xie ◽  
Agus Sudjianto
Keyword(s):  
Evaluation Method ◽  
Robustness Analysis ◽  
Optimal Solution ◽  
Computer Experiment ◽  
System Response ◽  
New Approach ◽  
New Information ◽  
Reliability Method ◽  
Fixture Configuration

A new FEA based design approach of optimal robust fixture configuration is proposed in this paper, which employs a surrogate model through computer experiment to significantly reduce the intensive computing effort involving numerous FEA system response evaluations. The effects of the fixture variability to the workpiece performance variability are assessed through an efficient robustness evaluation method, First Order Reliability Method (FORM), based on the surrogate computer model. Not restricted to primary datum surface, this new approach enables simultaneous determination of robust locator/clamp locations and clamping forces for a deformable workpiece and thus captures interaction between locating and clamping. The effectiveness of this approach is illustrated though an application example. The results of robustness analysis reveal new information and suggest that the optimal solution resulted from deterministic optimization may not be the best solution when the design is subjected to variability.

scholarly journals An Approach for Estimating Geothermal Reservoir Productivity under Access Limitations Associated with Snowy and Mountainous Prospects

2021 ◽  
Author(s):  
Mitsuo Matsumoto
Keyword(s):  
Early Time ◽  
Geothermal Field ◽  
Geothermal Reservoir ◽  
Well Testing ◽  
Reservoir Pressure ◽  
New Approach ◽  
Frequency Distributions ◽  
Arbitrary Time ◽  
Active Exploration ◽  
Time Limitations

This chapter describes an approach to estimate reservoir productivity during the active exploration and development of a geothermal prospect. This approach allows a reservoir model to be updated by overcoming the severe time limitations associated with accessing sites for drilling and well testing under snowy and mountainous conditions. Performed in parallel with the conventional standard approach, the new approach enables us to obtain a first estimate of the reservoir productivity at an early time and to make successful project management decisions. Assuming a practical geothermal field, the procedures of the new approach are demonstrated here in detail. Finally, frequency distributions for the expected production rates and changes in the reservoir pressure at an arbitrary time are obtained during an assumed operational period.

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