The objective of this work is to characterize the fault system and its impact on Mishrif reservoir capacity in the West Quran oil field. Determination and modelling of these faults are crucial to evaluate and understanding fluid flow of both oil and water injection in terms of distribution and the movement. In addition to define the structure away from the well control and understanding the evolution of West Qurna arch over geologic time.
In order to achieve the aim of the work and the structural analysis, a step wise approach was undertaken. Primarily, intensive seismic interpretation and building of structure maps were carried out across the high resolution of 3D-seismic survey with focusing on the main producing Mishrif reservoir of the field. Also, seismic attributes volumes provided a good information about the distribution and geometry of faults in Mishrif reservoir. The next step, it constructs 3-D fault model which will be later merged into the developed 3D geological model. West Qurna/1 oil field situated within the Zubair Subzone, and it is structurally a part of large anticline towards the north. The observation of seismically derived faults near Mishrif reservoir indicated en-echelon faults which refer to strike-slip tectonics along with extensional faults. The statistic of Mishrif interval faulting indicates a big number faults striking north-south along western wedge of anticline. The seismic interpretation, in combination with seismic attributes volumes, deliver a valuable structural framework which in turns used to build a better geological model.
In this paper, the work demonstrates a better understanding for the perspectives on the seismic characterization of the structural framework in the Mishrif reservoir, and also for similar heterogeneous carbonate reservoirs. Further, this work will ultimately lead to improve reservoir management practises in terms of production performance and water flooding plan.
This paper presents the traditional methods of hydrate mitigation used in the NKJ fields and the way in which a transient model was initially built and continuously improved. In thermal enhanced oil recovery there is one big ingredient: steam. A new startup from Germany believes it has found the oil industry’s cheapest way to make it. This study provides technical analysis of the viability of enhanced-oil-recovery (EOR) processes; the results indicate the potential for significant improvement in recovery efficiency over continued waterflooding. The first multilateral well in a North Kuwait field has been drilled recently.
The basic objective of this course is to introduce the overview and concept of production optimisation, using nodal analysis as a tool in production optimisation and enhancement. The participants are exposed to the analysis of various elements that help in production system starting from reservoir to surface processing facilities and their effect on the performance of the total production system. Depth conversion of time interpretations is a basic skill set for interpreters. There is no single methodology that is optimal for all cases. Next, appropriate depth methods will be presented. Depth imaging should be considered an integral component of interpretation. If the results derived from depth imaging are intended to mitigate risk, the interpreter must actively guide the process.
This paper describes a new approach to evaluating the effectiveness of the rotary-steerable-system (RSS) steering mechanism on wellbore tortuosity in horizontal wells. This paper demonstrates a work flow to determine optimal lateral lengths and trajectories in the Midland Basin by studying the effect of the lateral length and trajectory on well production. With the arrival and development of rotary steerable systems in the late 1990s, the industry thought that drilling a perfectly smooth and controlled trajectory would not be an issue. Range Resources' drilling head talks about how the company went from drilling the shortest laterals in the Marcellus to the longest and why. The Apollonia tight-gas chalk play is located in the Abu Gharadig Basin in the Western Desert of Egypt.
Burgan Marrat, a deep carbonate reservoir was transferred from exploration to development team for an accelerated production of the newly discovered oil. This multi-billion barrel reservoir is spread over 450 km2, has more than 40 faults, 8 compartments with large variation in oil-water contact and reservoir/fluid characteristics. The objective of this work is to understand the key uncertainties and quantify their impact on the reservoir offtake rate and oil recovery by conducting uncertainty assessment.
An interdisciplinary team identified the key uncertainty parameters expected to have significant impact on the reservoir development. The range and probability distribution law for each parameter was set considering the uncertainties due to limited measurements or variation in interpretations. A Response Surface Model (RSM) was created to evaluate the uncertainties by using a base dynamic model and applying an appropriate experimental design, which allowed to efficiently study the uncertainty space with a feasible number of simulations. Using the RSM, the primary effects and interaction between parameters were quantified to rank the uncertainties based on their impact on field production.
Key uncertainty parameters were identified including eight OWCs, six fault transmissibilities, horizontal and vertical permeability multipliers, and porosity multiplier. Latin Hypercube was found to be the appropriate Experimental Design for the study considering 17 parameters and the need of building a reliable RSM that includes interactions between them. The design recommended 155 simulation cases, which were prepared and submitted automatically by the software.
Multi-time Responses were analyzed qualitatively to identify the top 5 uncertainties having material impact on field production over 20 years considering 6 existing wells and 30 new well locations. The RSM quantitative evaluation showed three parameters (OWC2, OWC4 and OWC1) having a total effect on the response higher than 10%; followed by PERMX and OWC3 with less than 5%. The other 12 parameters have total effects less than 2%, and the interactions effect is less than 0.5% for any interaction between two parameters. Contrary to the intuition, none of the faults proved impact on the reservoir production.
The results prove very useful to make a right development and appraisal strategy in early life of the reservoir. The new well locations can be ranked and prioritized to optimize the development and effectively appraise the areas with high risks.
Uncertainty assessment has value throughout the life of the reservoir. However, this study indicates that its application in early life of the reservoir can bring immense value. An uncertainty analysis on the reservoir production helps in decision-making regarding the number of wells and their locations to reach a target production by managing the risks.
Ayyad, Hazim (Schlumberger) | Dashti, Bashaiyer (Kuwait Oil Company) | AL-Nabhan, Abdulrazzaq (Kuwait Oil Company) | Al-Ajmi, Afrah (Kuwait Oil Company) | Khan, Badruzaman (Kuwait Oil Company) | Sassi, Khaled (Schlumberger) | Liang, Lin (Schlumberger) | Nagaraj, Guru (Schlumberger)
In Umm Niqa field, Lower Fars (LF) is a shallow, unconsolidated, sour heavy oil and low-pressure sand reservoir. During the current appraisal and exploratory phases, oil production forecasts based on reservoir simulation models were observed to be significantly higher than actual production. Furthermore, unexpected early water breakthrough and the rapid increase in the water cut added more complexity to the reservoir production. This paper will focus on how these challenges were addressed with a unique workflow.
If the reservoir is producing more than one phase, then relative permeability determination becomes essential for the production forecast as well as production optimization to delay the water breakthrough. Due to the unconsolidated nature of LF reservoir, it was challenging to perform coring operation in this environment. In the few cases where cores were obtained, it was almost impossible to perform the relative permeability analysis on the core plugs. Therefore, there was a need to obtain this information by exploring other technique or methodology. Hence in-situ relative permeability technique was implemented in three different wells.
To address the relative permeability determination challenge, an innovative approach was implemented in three different wells. This approach determines the relative permeability at downhole conditions by utilizing the fluids clean-up and sampling data during the wireline downhole formation testing as well as some advanced petrophysical measurements such as the array resistivity, the nuclear magnetic resonance (NMR), and the dielectric dispersion. The data obtained were used as inputs for a multi-physics integrated workflow, which inverts for the relative permeability curves based on the modified Brooks-Corey model.
In this paper, it will be demonstrated how the relative permeability results obtained from this technique in these three wells were applied to update the reservoir simulation models. The production forecasts were found to be significantly improved and close to the actual production figures. The early water breakthrough is better anticipated; therefore, the production rate can be adjusted to delay it and maximize the oil recovery. This method provides an alternative and efficient way to derive the relative permeability curves when it is challenging to obtain from the conventional core analysis techniques. This helped to better understand the number of wells required to be drilled to achieve the planned production target.
This paper adds to the literature unique case studies where relative permeability determination is required, however, not possible to be obtained through conventional industry techniques such as core analysis due to a highly unconsolidated formation. Hence, an innovative workflow was adopted to measure the relative permeability at downhole conditions.
Al-shammari, Baraa Sayyar (Kuwait Oil Company) | Rane, Nitin (Kuwait Oil Company) | Ali, Shareefa Mulla (Kuwait Oil Company) | Sultan, Aala Ahmad (Kuwait Oil Company) | Al Sabea, Salem Hamad (Kuwait Oil Company) | Al-naqi, Meqdad (Kuwait Oil Company) | Pandey, Mukul (Weatherford) | Solaeche, Fernando Ledesma (Weatherford)
The Kuwait Integrated Digital Field project for Gathering-Center 01 (KwIDF GC-01) at Burgan Field acquires real-time data from wells and processing facilities as input for its production-surveillance program. Live data from the field is fed into an integrated production model for analyzing and optimizing pump performance. An automated workflow process generates alarms for critical well and facility parameters to identify wells with potential scaling issues. KwIDF workflows are integrated with updated well models to visualize the effect of scale build up on the wellhead performance and thereby assist in quantifying the associated production losses caused by scale deposition. A sensitivity analysis is also performed to identify current and optimal pump operating conditions and prioritize scale cleaning jobs.
The exception-based surveillance of key real-time parameters for wells utilizing electrical submersible pumps (ESPs) in Burgan field has significantly improved diagnostics of scale deposition at wellhead chokes and flowlines. Automated workflows calibrate an integrated production model in real-time, which enables engineers to run a quick analysis of current pump operating conditions and make a proactive plan of action. The application of real-time data and automated models has aided the operator's production team in making informed and timely decisions that enable them to run pumps at optimal operating conditions, with the result that they are able to sustain well production at target levels.
This paper describes an innovative approach to applying real-time data and integrated models in an automated workflow process for enhancing capabilities to diagnose scale deposition in the surface flow network. Examples are presented to demonstrate the application of integrated technology for identifying scaling at wellhead chokes and flowlines and prioritizing a scale removal program for optimizing pump performance.
For mature oil fields with complicated reservoir architecture, reservoir surveillance is key to track reservoir performance. Reservoir surveillance may include various monitoring tools from complicated horizontal production logging tools down to regular well tests. One of the main surveillance methods is running formation pressure measurement tools such as Formation Pressure Testers (FPT) or as historically known to the industry, Repeated Formation Tester (RFT). This paper describes the use of this important tool integrated with production data to understand reservoir production and depletion behavior and hence support the Bahrain Field development plan.
A study was conducted on the Ostracod and Magwa reservoirs; complicated carbonate reservoirs in the Bahrain Field. The Ostracod Zone is a sequence of inter-bedded limestone and shale in the upper Rumaila formation of the middle Cretaceous Wasia group. It is over 200 feet thick and consists of three main units: B0, B1, and B2. The Magwa reservoir is the lower member of the Rumaila Formation. It is 120 feet thick and conformably underlies the Ostracod reservoir. It consists of three main units: M1, M2, and M3.
The main objectives of this study are:
Evaluating pressure depletion from the initial reservoir pressure for each unit in both reservoirs, which defined the existence of flow barriers in this inter-bedded complicated carbonate. Evaluating the relationship between pressure depletion in each unit and the spacing between offset wells to the FPT location. Evaluating the Ostracod/Magwa pressure depletion per unit with time. Linking the pressure depletion to the cumulative production from the area offset by the FPT data.
Evaluating pressure depletion from the initial reservoir pressure for each unit in both reservoirs, which defined the existence of flow barriers in this inter-bedded complicated carbonate.
Evaluating the relationship between pressure depletion in each unit and the spacing between offset wells to the FPT location.
Evaluating the Ostracod/Magwa pressure depletion per unit with time.
Linking the pressure depletion to the cumulative production from the area offset by the FPT data.
The results of this study helped define the depletion risk on the future infill opportunities in such complicated reservoirs. It also helped in locating highly depleted units and determining the optimal locations for the new infill wells.
Ahmadi Reservoir is one of the Reservoirs producing in the Bahrain Field. It has been producing for more than eighty years. Ahmadi is a tight carbonate Reservoir that belongs to the Wasia Cretaceous group. It consists of two main limestone units which are AA and AB. Like most Carbonates in the Middle East, Ahmadi production is dominated by secondary permeability which means that the reservoir has a dual exponential type Curve. Dual exponential in Ahmadi means a high flush initial production period and then a longer period of stabilized production.
Because of this behaviour, using conventional methods to monitor reservoir performance could be misleading. Hence, a new parameter was created to make sure that reservoir performance monitoring accounts for production in a more representive way. This parameter was called Normalized Production Index.
Normalized Production Index has been used to analyse reservoir performance in Ahmadi Reservoir as it accounts for both the flush rate and the stabilized production rate of wells. This parameter helps monitor and observe reservoir performance as it effectively identifies low and high productive areas, and hence leads to better decisions during reservoir development planning.
In this study, a Normalized Production Index of more than 246 wells was considered. These wells vary in area, dip direction, trajectory, and Horizontal length. The objective was to determine the most effective way of these to maximise production in Ahmadi.
Based on the analysis done using Normalized Production Index, it was found that the average oil production for horizontal wells is more than double that of a vertical/directional well. It was also found that wells oriented in an up-dip direction of the structure are performing better than wells oriented in a down-dip direction of the structure in some areas. These conclusions were considered in managing the reservoir. Some actions were taken based on these conclusions and resulted in positive performance, which verified the effectiveness of the Normalized Production Index.