A cost-effective water management strategy for the thermal development should ensure the availability of right quality and quantity of water during the lifetime of the field. This paper presents an actual case for field water management, which includes availability, use, re-use and safe disposal of both source and effluent water. Thermal projects are notorious for their large volume of produced water through the life of the field. While treatment of produced water is a major issue; in a country like Kuwait where water is scarce, part of the produced water need to be recycled and re-used for steam generation. The methods and procedure followed are based on the practices used in the current Large Scale Thermal Pilots (LSTPs). The process involves field observations and performance, facility set-up and limitations, technical analysis and mitigation plan; so as to reach to an efficient water management plan and deliver better quality water. Heavy oil field development in Northern Kuwait is currently one of the few thermal "mega-projects" in the world. The development started initially with Cyclic Steam Stimulation (CSS), followed by Steam Flood (SF). These projects need dedicated used water disposal wells. Water disposal wells, initially completed, showed poor injectivity even after CTU acid stimulation with 15% HCl. Based on lab test results and analysis, injectivity was restored with suitable anti-scalant injection and precipitate removal. Another aspect of these wells was the injection casing shoe-setting depth. A multi-disciplinary team reviewed and established the optimum placement interval for shoe that meets the regulatory and design criteria. The new shoe setting-depth eliminated repeated well interventions during the life of these wells. The learnings were disseminated to various other projects within the company. Quality of source water was also a focus area for the team. Water quality of the source water at various depths were analyzed and tested. Based on the results, optimum well depth and location was ascertained which resulted in improved water quality and quantity. A novel approach, with key focus on competitive scoping and sustainable development and the combined effort from various stakeholders through an integrated approach have enabled significant savings to reduce the cost of this project. The learnings gathered, and the uniqueness of the project will add significant value to similar projects elsewhere in the world.
This paper presents the preliminary results of a Cyclic Steam Stimulation (CSS) trial in a horizontal well for the first time in the State of Kuwait. The horizontal well was completed in a viscous crude oil bearing shallow unconsolidated sandstone reservoir of Middle Miocene age located in north of the State of Kuwait, in an area where currently several pilot projects are undergoing execution using mobile production facilities and permanent production facilities. The drilling of the horizontal well was a challenge in terms of reservoir shallowness utilizing conventional drilling rig for vertical wells. The well was completed with 5" slotted liner sizes in an open hole section to prevent sand production and maintain hole stability. The artificial lift method deployed was high temperature tolerance All Metal Progressive Cavity Pumps (AMPCP). The well was equipped with unified Rod BOP which allow CSS operation without any intervention. The unified rod BOP reduces the nonproductive time (NPT) and oil deferment during the CSS process. Therefore, no need to change the X-Mass tree as the setup is applicable for injection and production phases. The horizontal well started production for a short period of cold production phase followed by a Cyclic Steam Stimulation Cycle (CSS) for well productivity evaluation. The well's cold production, injection performance, production performance post CSS, and the AMPCP artificial lift performance shall be presented in this paper. Monitoring and surveillance detailed plans including nearby drilled observation wells were utilized in CSS performance assessment. The overall wells performance is showing encouraging and promising results for further optimization and field development.
Workover operations in shallow low pressure heavy oil unconsolidated sandstone reservoir in Kuwait presents a major challenge due to significant killing fluid loss which causes wellbore plugging, incremental operational costs due to more rig days, excess brine volumes, and more importantly the impact of deferred production due to formation damage. This paper presents an innovative fluid-loss control pill added to killing fluids, which has resulted in significant cost savings and well productivity improvements. The subject heavy oil reservoir have formation pressure equivalent to 6.3 PPG versus 9.3 PPG Potassium Chloride brine used as killing fluid. This overbalance condition is a requirement as safety barrier but conversely it leads to hundreds of barrels of killing fluid losses with the consequently invasion and formation damage. Kuwait Oil Company recently added a new customized fluid loss control pill of high purity vacuumed dried evaporated salt to the well killing procedure. Using this fluid loss control pill both drilling and reservoir engineers achieved their aim in terms of safety operation and no formation damage. To test this new pill, two shallow wells with 220 psi reservoir pressure and perforation set at 630 ft were selected to record the losses. The first well had undergone workover including recordings from caliper, cement, and ultrasonic logs, which measured the positive impact of the new control pill on logs quality by excluding fluid pumping while logging and having constant fluid level at surface, which saved cable head from unnecessary tensions. In a second well, there was hanged standalone screen on a packer against the perforation and there is no direct access to the perforation. The control pill was customized to be pumped into the screen, which sealed the screen itself perfectly. The control pill flowed back easily in both wells and same loss rate was observed after removing the pill, which confirmed no negative impact on reservoir permeability. KOC confirmed that the two jobs were successful and the pill to be approved for full field implement in other operations. The achieved success criteria summarized as follows: Hydrostatic column is a safety barrier that assuring fluid level at surface during workover is safety requirement especially in high Gas oil ratio wells.Full circulation enhances sand cleanup operation.Fluid level at surface results in accurate logging by eliminating invasion into reservoir and support improved operations.
Cold horizontal and vertical producers in a Kuwait heavy oil green field are generally completed with conventional Progressive Cavity Pumps (PCP) which in case of failure a rig work over intervention is required to replace the pump. As part of an initiative to optimize operational expenditures (OPEX) an Insert Progressive Cavity Pump (I-PCP) was installed for the first time in one well as new artificial lift technology trial. In wells with I-PCP intervention costs and oil deferment associated with pump replacement are reduced significantly, which impacts OPEX and profitability. The trial showed pump run life for eight months without any intervention and several positive economic impacts like eliminating the need for a service rig to pull the production tubing to change a downhole pump as it can be performed by utilizing flush-by units equipped for rod handling, reducing the oil deferment as the oil is accelerated earlier in the flow line compared to rig intervention which can go up to two weeks. The paper describes the first successful implementation and operation of Insert PCP systems in Kuwait Oil Company. The paper also compares the pump run life, service rig work-over times and reduction of production achieved with the insert PCPs when compare to conventional tubing deployed PCP. In general, the field trial results have demonstrated the benefits of using this technology. The way forward will be to install the I-PCP in other cold producers.
Finding a reliable artificial lift pumping system for heavy oil thermal recovery has been a challenge mainly due to the high operating temperatures (>150°C). Available options such as Rod Pumps, Electrical Submersible Pumps (ESP) and Elastomer Progressive Cavity Pumps (PCP) have their peculiar limitations for thermal production.Through research work conducted by PCM, a patented high temperature elastomer free PCP system, the All Metal PCP (AMPCP) known as the PCM Vulcain™, has been developed to meet such challenges capable of pumping extremely hot (350°C/660°F) fluid. The first ever AMPCP was installed in late 2005 in CSS wells in Northern Canada. Since then, over three hundred pumps of this kind have been operated around the world.Following its successful application worldwide, Kuwait Oil Company decided to utilize the AMPCP in its Heavy Oil fields. A small scale CSS pilot is on-going to establish the flow potential and also optimize the completion type. Due to the harsh high temperature environment and expected sand production with initial gas/dry steam, an AMPCP was installed in the CSS wells. The pump has now been producing for over one year with highly encouraging results.This paper intends on evaluating the performance of the AMPCP during the course of its run life in the above field thus summarizing observations and conclusions resulting from the analysis of the system from day one. The results show that the AMPCP has provided much better results than other forms of Artificial Lift used by KOC in the same pilot field. The field trial shows the PCM Vulcain™ as a promising artificial lift technology for hot production.
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