Crude oil production in Um-Ghdair field is consider one of the most complex operational activities in Kuwait Oil Company due to high water cut percentage, asphaletene flocculation, high viscosity and tight emulsion phenomena. As the fluid travels through the reservoir, wellbore, flowline, all the way to the gathering center, the state of initial equilibrium is disturbed leading to change in the chemical composition of the crude oil. As pressure and temperature continue to drop, and gas escapes, more asphaltenes and heavy components may continue to flocculate all the way throughout the system until the petroleum reaches its final destination. In this pilot project, asphaltene inhibitor and viscosity reducer agents were selected for reducing oil viscosity and breaking the tight emulsion phenomena in the selected piloting well in Um-Ghdair field. It was noticed that there is an asphaltene compounds flocculate in the interface between oil and water leading to increase crude oil viscosity. The best two among 22 chemical formulations tested through the screening process at lab scale and take it to pilot stage. Additionally, the pilot study examined the influences effective for surfactants such as water composition, temperature, concentration, pH and total dissolved solids. It was noticed that the viscosity reduction and the water separation improve with increasing surfactant concentration and increasing temperature up to 50 °F. Two formulations were selected based on cost effective optimal concentrations of surfactant that identified from the bottle test. The pilot has been implemented successfully in the field, resulting a reduction in non-production time and increase the oil mobility from the reservoir.
The strategy of the Kuwait Oil Company (KOC) is to implement key/emerging technologies at a country wide scale to meet future oil demand and production targets as planned in KPC 2040 strategy through overcome the field's challenges. KOC's Optimization strategy focuses on: Increased and optimize oil production from production optimizations Extension of field life Production interruption associated with pressure build up in reservoir, wellbore and flow lines have observed among many wells in West Kuwait fields perforated in Upper Burgan formation, which has a great impact on the company strategy. Tight emulsion phenomena is consider one the most challenging problems in West Kuwait wells due to the nature of asphaltenic crudes and high water cut production percentage. Traditional approaches to reduce high pressure and break the emulsion phase through injecting chemical near wellhead or in annuls is usually not successful in most cases and require large amount of chemical. Due to the complexity of this issue, a novel approach was used in this study to identify the main causes of oil production reduction and overcome the challenge to maximize oil production in West Kuwait fields.
Reservoir relative permeability and capillary pressure, as a function of saturation, is important for assessing reservoir hydrocarbon recovery, selecting the well completion method, and determining the production strategy because they are fundamental inputs to reservoir simulation for predicting lifetime production of a well. Estimation of relative permeability and capillary pressure curves at reservoir conditions is also an important task for successful planning of waterflooding and enhanced oil recovery. The relative permeability and capillary pressure data estimated from core analysis might cause concern regarding representativeness, and adjustments are typically necessary for successful production forecasting. This paper proposes a new method to obtain relative permeability and capillary pressure curves with downhole pressure-transient analysis (PTA) of mini-drillstem tests (miniDSTs) and well log-derived saturations. The new approach was based on performing miniDSTs in the free water, oil, and oil-water transition zones. Analyses of the miniDST buildup tests provided absolute formation permeability, endpoints of relative permeability to both oil and water, and curvature of the relative permeability data. Additionally, resistivity, dielectric, and nuclear magnetic resonance (NMR) logs were used to determine irreducible water, residual oil, and transition zone saturations. Combining these downhole measurements provided the relative permeability and capillary pressure curves.
North Kuwait Sabriyah wells have massive formation damage and enormous fluid losses occurring during workover operations in the Upper Burgan Formation. This challenge causes wellbore plugging, as well as incremental operational costs (rig days & brine cost) and delayed production. It is noteworthy that the Upper Burgan (UB) Formation is balanced with 5.5 PPG kill fluid. This is due to the significant differential pore pressure and 8.4 PPG brackish water, which would impose a high risk of losses and formation damage. A unique solution" salt pill" has been selected as an optimum solution to this challenge. The solution is a filtration control agent that allows work over activity with temperature stability up to 350 Deg. F and it is applicable for Gas & Oil wells with over 2% water cut. It is sustained casing pressure for workover with a constant fluid level at surface during the intervention. The customized fluid is being flowed back and it is 100% dissolvable in produced or any under saturated water, with no need for acid breaker. This unique feature allows to keep the formation up to 5000 Psi overbalance thus eliminating potential well control issues by maintaining the static fluid level in the well. This salt pill technology was successfully tested in the candidate Sabriyah wells, the results were satisfactory & the trail has shown good success. The well was put back to the original rate, and oil showed at surface after unloading only one well volume. This successful pilot will be a best practice solution for KOC assets in term of cost optimization and added value. The technology will support KOC to solve some of the other faced challenges in various wells integrity and WO issues demonstrating how much cost savings can be attained along with keeping the reservoir damage free and restoring its productivity to original levels after the Salt Pill technology has been deployed.
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