An Integrated and Automated Workflow to Enhance Production Efficiency and Compliance in a Giant Offshore Field

Daily production compliance is fundamental to sustain reservoir management excellence and ultimately achieve an optimum oil recovery. The production activities execution is critical to adhere to the reservoir management guidelines and best practices. It is a more challenging task in brownfields due to the limitation of controlling system and limited access especially in offshore fields. A timely and efficient approach is undoubtedly necessary to enhance production efficiency and compliance. An integrated and automated tool has been innovated to analyze and report well production status against the guidelines and requirements in a mature offshore field with more than 50 years history. This systematic approach has been developed through integrating the planned rate, daily actual production rate, latest flow tests, and current well performance. Noncompliance is reported automatically on a user defined time scale, including daily, weekly, monthly or any customized time range within the month time. Daily violation report is generated automatically and sent to production operation for prompt adjustments and other requested actions. The automated workflow enables both daily production reporting and production compliance reporting. Daily production reporting is a routine work, which usually takes a lot of time every day. The workflow is capable of reducing 90% of the time comparing to the manual way. Production compliance reporting is currently mainly focusing on the comparison of actual production to planned rate and guideline rate. Any exception will be reported as violation. The violation dashboard summarizes the details based on the user selected time range. On daily basis, an email containing the violation details could be generated and sent to the corresponding teams for corrective actions. In this giant brown field, production GOR is a primary controlling parameter. The latest flow tests have been taken into account to evaluate the gas production compliance. Any violation to the GOR guidelines will be reported in the same communication email for timely correction. With the innovated tool, the violation ratio of the giant offshore field has been successfully reduced and controlled. The usual responding time for corrections has been dramatically reduced from months to days.

Rapid and Efficient Waterflood Optimization Using Augmented AI Approach in a Complex Offshore Field

Waterfloods are amongst the most widely implemented methods for oil field development. Despite their vast implementation, operational bottlenecks such as lack of surveillance and optimization tools to guide fast paced decisions render most of these sub-optimal. This paper presents a novel machine-learning, reduced-physics approach to optimize an exceptionally complex off-shore waterflood in the Gulf of Suez. Leveraging a hybrid data-driven and physics approach, the water flooding scheme in Nezzezat reservoir was optimized to improve reservoir voidage replacement, increase oil production, and reduce water production by identifying potential in wells. As a by-product of the study, a better understanding of the complex fault system was also achieved. Including the geological understanding and its uncertainty is one of the key elements that must be preserved. All geological attributes, along with production rates are used to solve for pressure and inter-well communication. This is later supplemented by machine-learning algorithm to solve for the fractional flow of inter-well connections. Combining the inter-well connectivity and fractional flow, an optimization was performed to reach the best possible conditions for oil gains and water-cut reduction. A global optimization is possible thanks to the low computational demand of this approach, as thousands to millions of realizations must be run to reach the best solution while satisfying all constraints. This is all done in a fraction of the time it takes to run a traditional reservoir simulation. For the present case, the paper will present the underlying physics and data-driven algorithms, along with the blind tests performed to validate the results. In addition to the method's inner workings, the paper will focus more on the results to guide operational decisions. This is inclusive of all the complex constraints of an offshore field, as well as the best reservoir management practices, when reaching optimal production and injection rates for each well. An increase in production was achieved with some reduction in water-cut, while honoring well and platform level limitations. While these represent the gains for a particular month, optimization scenarios can be run weekly or monthly to capture the dynamic nature of the problem and any operational limitations that might arise. The ability to update the models and run optimization scenarios effortlessly allows pro-active operational decisions to maximize the value of the asset. The approach followed in this paper solves for the critical physics of the problem and supplements the remaining with machine learning algorithms. This novel and extremely practical approach facilitate the decision making to operate the field optimally.

New Recommendations for Offshore Wellhead Platform Structural Design Due to Well Conductor Casings Failures: Outcome of a Study Based on Actual Findings

Detailed study on structurally failed well conductors on offshore wellhead platforms lead us to believe that existing assumptions of conductors transfer only lateral loadings to wellhead platforms while entire well vertical loading will be carried by conductor itself; could be wrong. The well conductors could become ‘forced’ to carry a very large vertical loads incase the conductors are structurally failed; especially once exceeded its original design life. As such, some new considerations during the wellhead platform design, which need to be followed, are recommended here. These are to cater any catastrophic eventuality of conductor failures which will restrain further collapse of the conductors or to avoid any progressive collapse of the platform. The recommendations are from a study based on actual findings observed recently in the offshore field. The connection between conductors and platforms are conventionally designed as guided based on the load transfer assumptions. That is the huge vertical loadings from internal conductor casings and associated items were not a concern for platform design structural engineers, traditionally, and as such the conductors were designed to be structurally connected to the wellhead platforms using vertical guides. Due to extended design service life of platforms, in many cases the design life went up to two times of their original design life, severe degradation of structural integrity of the conductors were observed in the field. Structural analysis and assessment were carried out on many old intact and failed conductors, in the offshore field, in order to assess its structural and loading behavior with respect to supporting wellhead platforms. The study provided that the failed conductors were leaning / collapsing to the wellhead platform resulting in transferring a huge vertical loads which originally were designed to be carried by conductors alone. This huge transfer of vertical loads from conductor to the platform was unexpected and was not considered in platforms original design. Therefore, the platform should have sufficient structural strength to cater such extreme eventuality to avoid the risk of complete collapse. A risk assessment of a tilted / failed conductors indicated that the consequence of total failure of a conductor could be catastrophic in case the platform failed to resist the collapsing conductors. This paper presents the details of the study carried out on aged wellhead platforms, having failed long serving conductors, in Giant offshore field, Abu Dhabi, along with details of new recommendations to be followed while designing new wellhead platforms. The paper also recommends the structural design consideration to be followed while designing wellhead platforms in-case a conductor repair is necessitated in future.

Integrated Geomechanical Operations for Successful Field Development: A Case Study from Western Offshore, India

This paper deals with the field development study for an offshore field in the western part of India. The main points of focus are holistic execution of integrated workflows for the delivery of subsea oil and gas wells from a jack up platform in this region. Given that the encountered formations encountered in wells posed significant challenges during the drilling phase, a field level geomechanics study was commissioned to understand and mitigate any challenges and effect smooth drilling and logging operations. Understanding the geomechanical effects by analysing the offset wells drilled in the region provided significant insights into the potential challenges faced while exploring target formations. The proposed well locations were drilled in a structurally complex geological setting. From the analysis of previously drilled wells in the region, it was evident that the variation in insitu properties of the lithologies and the extreme heterogeneity and vugular nature of the encountered carbonates caused significant drillability issues with subsequent losses, excessive cuttings, and several back reaming cycles impacting rig time and leading to generally poor borehole conditions. On the other hand, the shales encountered at shallower depths presented a different challenge, especially with a high swelling tendency, adding to progressively worsening hole conditions and significant fluid invasion. Finally, the basal clastics and the depleted zones with variable rock strengths added to the borehole instability issues, with particular zones projecting losses while others showed influxes. In light of such a plethora of issues, an integrated approach including dynamic real time monitoring of operations, structured LWD and wireline logging programmes, a high level petrophysics, formation evaluation and borehole acoustics for shear radial profiling was carried out. A fit for purpose geomechanical model was built encompassing the results of these analyses and was continually updated in real time during the operations phase. Given the variability in the pressures, temperatures and operational mud weights in each section, execution for successful delivery of the wells was further aided by identification of the optimal mud systems, critical casing setting depths and real time drilling optimization, ensuring good borehole quality throughout for further logging and testing programmes.

Adsorption Inhibitor Role in a Constant Salinity Surfactant-Polymer CSSP Flooding Design for an Offshore Field Application

A base chemical flooding formulation using alkaline-surfactant-polymer (ASP) has been developed for application in offshore environments. The formulation uses combination of conventional alkali (sodium carbonate) with amphoteric surfactant. The field is currently under waterflooding using sea water as injection water. However, since alkali is incompatible with divalent ions in sea water, an alternative formulation using seawater with no additional water treatment is also being developed and considered for application. The alternative formulation uses combination of alkyl propoxy sulfate (APS) and alkyl ethoxy sulfate (AES). Coreflood recovery performance of both formulations is similar. Without alkali, high surfactant adsorption becomes major concern for the alternative formulation. Thus, an adsorption inhibitor (AI) agent – polyacrylic acid type, is being considered as an additive to address this concern. While AI showed potential in reducing surfactant adsorption and improving oil recovery efficiency, it can also increase overall cost for the surfactant in sea water chemical formulation. Hence, the merit to apply AI was not clearly observed.

Success Story of First Malaysia Flare Tips Decommissioning in Sarawak Offshore Field Platform

The project was for part production enhancement project which to cater for brownfield & greenfield project. To cater to the production (oil) increment for the brownfield project, the existing flare tips and separation system need to be upgraded with higher capacity. The inclusive project was upgrading existing. Part of the scope was decommissioning the existing flare tip and associated system, e.g., ignition panel and ignition pipe. The project will decommission the current flare tips and replaced it with new higher capacity flare tips with Low Pressure (LP) & High Pressure (HP) connection. The existing flare panel was a single-type ignition system. The existing flare tip had LP & HP tip with 8″ inch size; the weight for both tip was estimated at 300 kg. The concept selection was discussed on the suitable method to lifting down the decommissioning flare tip at the offshore platform. There were 2 suitable techniques selected at the initial of the concept selection. One was lifting down the decommissioning flare tip directly from flare boom to vessel. Another method was manual rigging of the flare tips from the flare boom to the lower deck. After several discussions and workshops, it was decided to proceed with manual rigging of the decommissioning flare tip to the safe deck area. The removal of the decommissioning flare tip was performed during turnaround. The total days for the overall activity of the decommissioning & installation of the new flare tip was 3 days, 2 days ahead from planned duration 5 days.

Analysis of Oscillating Fishing Tool Efficiency for Stuck Assembly Recovery in Field X

As conventional fishing assembly offers a degree of recovery chance, such chance can be increased by utilizing an Oscillating Fishing Tool (OFT). The OFT is a fishing Bottom Hole Assembly (BHA) component that delivers low-magnitude; high-frequency oscillation. The continuous motion that the tool provides complements the impact generated by the fishing jar. This paper reviews the successful case history in Field X, which was in fact the first utilization of OFT for a fishing application in the field. Method of analysis involve comparing fishing sequence without and with the OFT. The OFT was used in Offshore Field X to recover a mechanically stuck 550-meter long Tubing Conveyed Perforating Gun assembly inside 9 5/8" casing that could potentially lead to loss of access into the 6 oil reserves candidate perforation zones. Initially the assembly had been stuck for two days, during which conventional fishing BHA was used to retrieve it to no avail, even after jarring for most of that time. OFT was then incorporated in the final fishing BHA and operated in combination with jarring operation. After around twelve hours of oscillating and jarring, the fish was able to be released from the initial stuck point. When tripping the string out, however, the assembly was stuck at high dog-leg severity area near the surface. At that point, in combination with applying substantial overpull, OFT was utilized further to recover the entire string. Upon fish retrieval, it was evident that post detonation, the TCP gun had swelled into 8.6 inches in diameter. In summary, oscillating and jarring for thirty-six cumulative hours successfully released the swelled TCP gun assembly from the stuck occurrences. In conclusion, the operation showed that the OFT serves as a higher level of fishing tool option that offers a particular excitation mode to the stuck assembly. Stuck assembly in a cased hole presents potential loss of oil reserves. Particularly in offshore application, the situation can also be costly. With reduced chance of recovery as time passes by, operation is hindered from being able to proceed to the next completion phase. The case proved OFT to have played an important role in improving fishing probability of success and should be considered as standard fishing BHA in the future.

Optimization approach for Arctic field development design using subsea production systems

Russian experience in the design of trunk pipelines and Arctic studies have been used to develop an efficient model and method for Arctic field development design using the subsea production system (SPS). Compared to 2D models used in the past, the new design technique offers an opportunity to make 3D models and can be used for optimization of offshore field development projects. The proposed optimization model is based on the Bellman - Ford algorithm developed for 3D networks. This approach has been used for the first time to capture key features and specific subsea production system design processes. The algorithm and block diagrams developed for the proposed SPS design method is universal. This method can be used to address tasks of a more general nature. Optimization of the particular case between a single start point (well location) and single end point (SPS facility) is implemented as a separate software package, but the scope of applications is not limited by such cases and may be extended even further. It can also be very efficient for Arctic subsea field development.