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Collaborating Authors
SPE/PAPG Annual Technical Conference
Transformation of Failure to Success in Revival of Production by Overcoming Reservoir Damage in Carbonate Fractured Reservoir (Case Study)
Jadoon, M. Saeed (1 Oil and Gas Development Company Limited) | Majeed, Arsahd (1 Oil and Gas Development Company Limited) | Bhatti, Abid Husain (1 Oil and Gas Development Company Limited) | Akram, Mian M. (1 Oil and Gas Development Company Limited) | Saqi, Muhammad Ishaq (2 Pakistan Petroleum Limited)
Abstract Balanced drilling through naturally fractured reservoir and controlling loss for preventing reservoir damage and rehabilitation of normal production is a serious challenge in the Kohat-Potwar basin of Pakistan. The potential of hydrocarbons in these reservoir rocks has been masked by the overbalance drilling practices in this region. Due to overbalance drilling in fractured reservoirs and the use of heavy mud with barite blocks the fractures and that results in little or no flow during DST. The negative results of DSTs usually force the decision makers either to abandon the well or to re-test and establish the connectivity between the formation and the well bore. The well under study was drilled in fractured carbonate reservoir rock to a depth of more than 5000 meters in Kohat–Potwar basin to target Datta and Lockhart formations. During drilling, due to complexities, well could not reach the Datta formation. No wire line and image logs could be obtained in Lockhart formation due to slim hole. The last 5-7/8 inch hole of this well had to be drilled by using Oil Based Mud (OBM) to control well bore instability, the same mud was used in the reservoir sections. During drilling, losses were observed in the reservoir section. On the basis of drilling information, the well was directly completed in the Lockhart formation. After completion, well was allowed to flow but no hydrocarbon surfaced. As Lockhart formation is proven producer, and it became a challenge to evaluate the reservoir for its production potential and to find out the causes of no flow from the formation. After negative results of well test, all the data of G & G and mud logging was reviewed and detailed analysis of fractures network over the field were carried out to understand the well behavior. The data revealed that mud losses during drilling are indicative of fracture's presence in the tested zone(s) and fractures may have been plugged resulting in no flow during test. It was realized that reservoir has potential but connectivity between formation and the well bore need to be enhanced. Even after no flow during initial testing of the well for long period, bold decision of cleaning of the well was under taken andseries of Nitrogen kick off jobs were undertaken to facilitate the well to flow. The nitrogen kick off werecontinued for four months, longest cleaning job ever undertaken in Pakistan and close monitoring of well was put inplace. After four months, WHFP started improving and flow of the hydrocarbons was observed and finally 730 bbl/d of oil and 1.6MMscfdgas were recorded. After the flow of the well, stimulation, with special recipe after lab experiments for OBM, wascarriedout with very encouraging results. After producing about one year, the well is still cleaning under natural flow. In this paper, we would try to share our experiences about the use of OBM in fractured carbonate reservoirs, fracture characterization, reservoir damage and its remedial jobs. In addition to this, well performance, well cleaning and stimulation methodology, evaluation of non-flow behavior of well during initial testing and the lessons learned to transform failure to success will be explained.
- Geology > Rock Type > Sedimentary Rock (0.48)
- Geology > Petroleum Play Type > Unconventional Play > Fractured Carbonate Reservoir Play (0.45)
- Geology > Geological Subdiscipline > Geomechanics (0.34)
- Asia > Pakistan > Khyber Pakhtunkhwa > Kohat Basin > Kawagarh Formation (0.99)
- Asia > Pakistan > Khyber Pakhtunkhwa > Karak District > Lockhart Formation (0.99)
- Asia > Pakistan > Khyber Pakhtunkhwa > Peshawar District > Kohat Basin > Kohat Block (0.97)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
Abstract Nowadays the energy demand has become tripled resulting in advancingof the development activities in the petroleum industry to enhance hydrocarbon recoveries. It is reviewed from the literature that the current worldwide facts of research and technical observations have proved that the coal containing methane gas is not much efficient in terms of power, cost and environment friendly energy source. The objective of this research is to determine the technical and economic feasibility of carbon dioxide (CO2) and nitrogen gas (N2). Moreover, sequestration in coal seams and their environmental consequences for coal based methane recovery project. This research study is also covers the effective and efficient methodologyforextraction of methane gas from coal, which is coupled with the injection of CO2 and N2 into the coal seam complex structure. Moreover, this methodology is applied individually and simultaneously, along with the after effects of injection of CO2 and N2 on Coal bed methane (CBM) recovery. The results of this research study suggestsa method for generation of electric power in which CBM gas is used as an input source whilst the combustion gas, CO2 emissions are sequestrated into coal seams for environmental protection, extending the CBM recovery and reducing CO2 availability cost.
- North America > United States (1.00)
- Asia > Pakistan (0.69)
- North America > United States > Wyoming > Powder River Basin (0.99)
- North America > United States > Montana > Powder River Basin (0.99)
- Asia > Pakistan > Lower Indus Basin (0.99)
An Alternative Approach for Well Test Analysis and Production Performance in Tight Gas Reservoirs Considering Stress Dependent Permeability
Arif, Muhammad (1University of Engineering and Technology, Lahore) | Bhatti, Amanat Ali (1University of Engineering and Technology, Lahore) | Khan, Ahmed Saeed (1University of Engineering and Technology, Lahore) | AfrazHaider, Syed (2Kuwait Foreign Petroleum Exploration Company (KUFPEC), Pakistan)
ABSTRACT It has long been proved experimentally that the tight gas sands are more pronounced to stress changes as compared to moderate and high permeability reservoirs because of the narrow flow channels of the formation [1]. The consideration of the effect of stress in the evaluation and production performance of tight gas reservoirs is very important in order to make right decisions regarding their development. Due to hydrocarbon production, the effective stress increases causing a reduction in permeability and porosity of the porous medium. The conventional pressure transient analysis techniques in gas wells based on constant permeability would become unreliable [2]. Consequently, the incorrect evaluation of permeability leads towards wrong decision regarding well stimulation. Also the inflow performance modeling of tight gas reservoirs based on constant permeability will not be corrected as far as evaluation of well's production potential is concerned. Few studies on tight gas reservoirs considering the effect of stress sensitive permeability used the Raghavan's stress dependent pseudo-pressure approach [3] for which pressure vs. permeability data was determined experimentally. But, if laboratory data is not available then there is need to develop an analytical approach to generate the pressure vs. permeability data required for the use of stress dependent pseudo-pressure in reservoir evaluation and production performance studies in tight gas reservoirs. The objective of this paper is to develop an analytical approach, in the absence of lab data, to generate pressure vs. permeability data for the determination of stress dependent pseudo-pressure. This stress dependent pseudo-pressure is used for well test analysis to determine the stress sensitive formation permeability and also to generate production performance in tight gas reservoirs. The developed technique has also been implemented on the field data of a tight gas reservoir tovalidate the results by using actual well's production history.
- Asia > Middle East (0.46)
- Asia > Pakistan (0.31)
ABSTRACT Widening supply and demand gap in natural gas industry, the advent of tight gas policy and increasing interest of operators in tight gas sands and shale has opened new venues for development of unconventional plays in Pakistan. Middle Indus Basin hosts important gas fields of Pakistan. Most of the wells in this basin are completed in conventional lower Goru Sands. Lower Goru formation consists of inter-bedded sequences of sands and shale. Its unconventional sand and shale plays hold immense potential which has not yet been exploited due to lack of technology and promising economics. Moreover, Sembar shale is the well known source rock in this basin holding large shale gas potential. GIIP estimates for Lower Goru tight sands excluding the shale prospects are 8.4 TCF which are considered pessimistic due to lack of data in many fields. From the currently suspended or abandoned wellbores of the Middle Indus Basin, a pilot project needs to be defined in each of the fields, to prove the technical and economical feasibility of tight Gas Potential of the Basin. Commencement of production from unconventional sands will enhance the production in a cost effective manner due to availability of infrastructure and facilities. This paper focuses on the utilization of existing wellbores as well as data set and highlighting additional data acquisition requirements coupled with completion and multi-stage fracturing techniques for designing a pilot project. Case study of a pilot project in one of the fields of this basin is discussed. It encompasses the basic workflow, candidate selection criterion, Geo-mechanics, sector modeling, hydraulic fracture design and risk evaluation coupled with its use in full field development projects.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Asia > Pakistan > Sindh > Lower Indus Basin > Goru Formation (0.99)
- Asia > Pakistan > Sindh > Khairpur District > Indus Basin > Kadanwari Field (0.99)
- Asia > Pakistan > Sindh > Sanghar District > Sembar Formation (0.98)
Determining Average Reservoir Pressures in Multilayered Completed Wells Using Selective Inflow Performance (SIP) Technique
Ilyas, Asad (1 MOL Pakistan Oil & Gas Co. B.V Islamabad-Pakistan) | Arshad, Safwan (1 MOL Pakistan Oil & Gas Co. B.V Islamabad-Pakistan) | Ahmed, Jawad (1 MOL Pakistan Oil & Gas Co. B.V Islamabad-Pakistan) | Khalid, Arsalan (2 Schlumberger, Islamabad-Pakistan) | Mughal, Muhammad Haroon (2 Schlumberger, Islamabad-Pakistan)
ABSTRACT This paper describes the challenges in determining average reservoir pressures in multi-layer completed wells during the span of their production period. The wells with single production tubing and get comingled flow from different reservoir layers exhibit complex down holeflow profiles. Therefore, it becomes difficult to acquire average pressures of each producing layer separately. Production log data can be utilized in these kinds of wells to calculate average individual layer pressures with the help of Selective Inflow Performance (SIP) technique for better production allocation and also to monitor pressure depletion effects with time. The SIP provides a mean of establishing the IPR for each rate-producing layer. The well is flowed at several different stabilized surface rates and for each rate, a production log is run across the entire producing interval(s) to record simultaneous profiles of downhole flow rates and flowing pressure. Measured in-situ rates can be converted to surface conditions using PVT data. Although SIP theory only applies to single phase flow, the interpreter can restrict the IPR's computations to a particular phase; only contribution of the selected phase will be taken into account. To each reservoir zone corresponds for each survey/interpretation a couple [rate, pressure], used in the SIP calculation. The different types of IPR equations can be used for SIP interpretation: Straight line, Fetkovitch or C&n, and LIT relations. In the case of a gas wells, the pseudo pressure m(p) can be used instead of the pressure "p" to estimate the gas potential. Although SIP is a useful technique to estimate average reservoir pressure in multi-layered system, but it has some limitations under certain circumstances. The Selective Inflow Performance (SIP) technique has been implemented on some of the producing wells in north of Pakistan. These wells have been completed in multiple producing reservoirs. Initially all these reservoirs were tested separately (with DST) to estimatetheir reservoir pressures and other parameters. However, due to adapted completion strategy, the producing layers were comingled with the option to monitor each layer's pressure depletion with the help of SIP technique in future. As per reservoir surveillance activity, Production logs are run on routine basis by utilizing SIP method and the same has been utilized for reservoir management and for simulation model updates.
- Reservoir Description and Dynamics > Formation Evaluation & Management > Well performance, inflow performance (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
Effects of Economic Analysis on Re-Developent of a Gas Field – Lessons Learned from a Reservoir Simulation Study
Akram, Agha Hassan (1 Schlumberger, Pakistan) | Majeed, Arshad (2 OGDCL, Pakistan) | Ashraf, Zaid (2 OGDCL, Pakistan) | Khan, Waqar A. (1 Schlumberger, Pakistan) | Rahman, Shah Abdur (1 Schlumberger, Pakistan)
Abstract The subject Gas Field is located in the Sulaiman Fold Belt (SFB) in Pakistan. A realistic 3D static model was constructed for the challenging multiple reservoirs in the Field which included both clastics and carbonates. Four main reservoir horizons were modeled. The steps involved in the Reservoir engineering analyses were: analyze PVT, well test, Static Pressure Data, and Core. The static pressure analysis helped define hydraulic compartmentalization in the field. WHFP measurements were not available in the desired accuracy and density. A surface network model was used with plant inlet pressure as the primary constraint in order to obtain the required information. Satellite based elevation information was used to establish an accurate model with respect to pressure drop due to liquid hold up in pipelines. The History Match in the field was performed on a Zone by Zone basis. In the absence of a 3D seismic cube, many of the faults in the field could not be interpreted, yet their presence was predicted by a closely matching Sand Box Model. This was an important clue which led to a useful approach regarding the location of simulation faults distributed in the entire field. An innovative approach was used in order to calibrate the size of sand lenses in one of the zones. The final step was the forecasting and development of Optimal Scenario using Economic analysis. Many scenarios were tested, and the optimal scenario was identified. Maximum use was made of existing wellbores through re-completion, and new drilling was minimized. Furthermore, the impact of increasing the currently low Gas Price was tested. It was concluded that doubling of the gas price of the field would increase the NPV 3 times delay abandonment by 6 years.
- Geology > Structural Geology > Fault (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.68)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.48)
- Information Technology > Modeling & Simulation (1.00)
- Information Technology > Communications > Networks (0.69)
Abstract Pakistan's production to date is characterized by large oil and gas reservoirs undergoing natural depletion with the help of strong natural aquifer drives. In a few fields, natural aquifer support is supplemented by pattern or peripheral water flood. However, there has been no systematic attempt to define the Enhanced Oil Recovery (EOR) potential within the country. This study is an attempt to extrapolate the potential lies in Pakistani reservoir using Enhanced Oil Recovery methods. This study revisits the screening criteria for the selection of Enhanced Oil Recovery method published by several authors. This study also defines the methodology to screen the Enhanced Oil Recovery method for particular reservoir. Screening criteria is then applied to Pakistani reservoirs. The approach has been integrated into the software in order to make repetitive analysis in an easy way. Finally, after the best selection of Enhanced Oil Recovery Method, the future directions are set and cost analysis is shown in order to proceed the project. The methods considered in this analysis were: water injection, Water alternating Gas injection (miscible and immiscible), polymer, and surfactant – polymer, steam (cyclic and continuous). This study helps to select the optimum Enhanced Oil Recovery method to improve the recovery factor in a quick and efficient way. This is beneficial for the companies that are planning to initiate Enhanced Oil Recovery Project.
- Asia > Pakistan (1.00)
- North America > United States > California (0.46)
- Asia > Middle East > Qatar (0.28)
- Asia > Middle East > Qatar > Arabian Gulf > Rub' al Khali Basin > Al Shaheen Field > Shuaiba Formation (0.99)
- Asia > Middle East > Qatar > Arabian Gulf > Rub' al Khali Basin > Al Shaheen Field > Nahr Umr Formation (0.99)
- Asia > Middle East > Qatar > Arabian Gulf > Rub' al Khali Basin > Al Shaheen Field > Mauddud Formation (0.99)
- (8 more...)
First Application of Extended Range Electromagnetic MWD Technology in Pakistan for a Horizontal Well Drilled Underbalanced-Case Study and Lesson Learned
Saleem, Saad (1Pakistan Petroleum Limited) | Sattar, Muhammad Suhail (1Pakistan Petroleum Limited) | Shahzad, Atif (2Weatherford Oil Tools M.E. Limited, Pakistan) | Ziadat, Wael (2Weatherford Oil Tools M.E. Limited, Pakistan) | Sabir, Shahid Majeed (2Weatherford Oil Tools M.E. Limited, Pakistan)
Abstract The name "Sui" has become synonymous with natural gas in Pakistan. Sui is Pakistan Petroleum Limited's (PPL) flagship gas field. Commercial exploitation of this field began in 1955. Two major reservoirs of this field are Sui Main Limestone (SML) and Sui Upper Limestone (SUL). Both the reservoirs have become highly depleted by time. Conventional drilling technologies in these formations result in complete loss of drilling fluid, stuck pipe and severe formation damage issues. Pakistan Petroleum Limited (PPL) planned to drill a horizontal well Sui-93(M), where target reservoir was Sui Main Limestone (SML). Drilling a horizontal well with conventional drilling techniques can cause a complete loss of drilling fluid. Underbalanced Drilling integrated with electromagnetic telemetry transmission was successfully used to drill this well to a target depth of 2200m MD with complete directional controls. Electromagnetic transmission modeling was performed on the resistivity data of offset wells to determine signal attenuation for Sui-93(M) Well. Based on modeling results it was decided to run an extended range set-up with a downhole antenna. The main reason for using EM-MWD was to provide real time data for annular pressure (APWD sensor) and directional controls in UBD environment. The APWD (annular pressure while drilling-real time ECD) sensor was considered mandatory to monitor and ensure underbalanced condition while drilling, thereby avoiding significant problems such as lost circulation and stuck pipe. This paper discusses the planning, results, problems and lessons learned during the first application of the Extended Range EM-MWD (Electromagnetic-Measurement while drilling) technology in Sui-93(M) well. The application of EM-MWD along with UB technology represents a stepwise progression for improving PPL's ability to exploit mature reservoirs, especially those that are severely depleted like in Sui Gas Field, Pakistan.
- Asia > Pakistan > Sindh > Central Gas Basin > Sui Main Limestone Formation (0.99)
- Asia > Pakistan > Balochistan > Dera Bugti District > Lower Indus Basin > Guddu Block > Sui Field (0.99)
ABSTRACT Gas hydrates are clathrate non-stoichiometric compounds, in which the gas molecules are encaged in crystalline cells, consisting of water molecules retained by the energy of hydrogen bonds. They are also called clathrate hydrates or "flammable ice". Considering the planet as a whole, the quantity of natural gas in sedimentary gas hydrates greatly exceeds conventional natural gas resources. As a result, numerous studies have been dedicated to the energy resource potential of gas hydrates. Hydrates of hydrocarbon gases occur naturally and attention has been drawn to develop these naturally occurring methane-hydrate reservoirs as an energy resource. The amount of carbon stored in these deposits is estimated to be 2-7 times higher than the amount present in the known fossil fuel deposits. Analysis indicates that hydrates can occupy as much as 500 m of sediments. Gas Hydrates research in the last two decades has taken various directions ranging from ways to understand the safe and economical production of this enormous resource to drilling problems and challenges. Gas Hydrates are stable at low temperature and high pressures. Studies are also underway for exploring the gas hydrates in the offshore area of Pakistan; initial exploration activities indicates very positive results for the presence of gas hydrates in the offshore Makran region (Western Costal Areas). This paper does a review on occurrence of gas hydrates. This paper discusses drilling related challenges for exploiting of gas hydrates and proposes some solutions. Finally, future considerations and recommendations are presented in paper to that may help our industry to unwrap this Fuel for Future.
- Asia > Pakistan (1.00)
- Europe (0.95)
- North America > United States > South Carolina (0.28)
Abstract Because stochastic seismic inversion generates a large number of elastic impedance realizations, only a few of these realizations must be selected for more rigorous geological interpretation and reservoir modelling. Static sand body volume (SBV) and SBV geometrically connected to the wells are generally used as the ranking measures. However, this approach does not take into account the dynamic flow field and the impact of reservoir heterogeneity and petrophysical properties on the fluid flow. Hence, this approach under or overestimates the P10, P50 & P90 ranking most of the time and invalidates the field development studies in turn. The main goal of this study is to prove the concept of using dynamic measures to rank the seismic inversion realizations and develop a ranking work flow. Streamline simulations, because of its generic option of reduced flow physics provides a faster way to run hundred of millions cell realizations, enabling a quick ranking based on dynamic measures. Typical seismic inversion models consists of several million cells (6 million in this case), and flow simulation over models of this size is computationally extensive. To reach reasonable runtimes, the size of the model is reduced; either by extracting a sector model (2 million cells sector in this case), or by decimating/up-scaling the full field model (1.7 million cells in this case). Tracer simulations over both of the reduced size models are compared with the full field tracer simulation model. The upscaled model is shown to be a closer approximation to the full field model. Finally, the tracer upscaled model is compared with a physically more realistic waterflood upscaled simulation model and is shown as a valid approximation. The sensitivity of various dynamic parameters to connectivity variations is analyzed to determine which parameter is the best suited ranking measure. Due to significant variability in spatial sand bodies distribution and connectivity between the sand bodies across the realizations, cumulative oil recovery (COR) has proved to be a much better ranking measure in comparison to the recovery factor (RF). The static and dynamic ranking measures are compared. The difference between SBV or connected sand body volume (CSBV) and COR rankings highlights the importance of ranking based on dynamic measures. Additionally, the factors which can generally influence the ranking based on dynamic measure (COR) are determined and it is concluded that the changes in ranking will be dependent on the CSBV and petrophysical properties of the connected sand bodies across the realizations. Finally, ranking based on the best ranking measure as well on a combination of COR, STOIIP and RF is done and individual realizations (P10, P50 and P90) are selected in order to cover the range of uncertainty in spatial distribution and volumes of sand bodies. This uncertainty range can be translated into economic uncertainty for the determined optimum number of wells and distances. The approach defined in this paper to rank and select the P10, P50 & P90 realizations based on dynamic measures is generic and can be applied to any form of geo-statistical realizations. The streamline simulations proved to be an effective screening tool.
- Europe (1.00)
- North America > United States > Texas (0.28)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Inversion (1.00)