Field B, located offshore Malaysia is heavily reliant on gas lift due to the high water cut behavior of the reservoir coupled with low-medium reservoir pressure. The field faces a challenge to efficiently execute production enhancement activities due to its low effective man-hour, a drawback of unmanned operation philosophy. The recent oil price downturn further exacerbates the limitation and calls for an innovative approach to continue the effort for maximizing oil recovery. As majority of the producing wells are gas-lifted, Gas Lift Optimization (GLOP) is an integral part of Field B's routine production enhancement job. The previous practice of GLOP involves data acquisition process of surface parameters and wireline intervention to collect Bottomhole Pressure (BHP), mainly Flowing Gradient Survey (FGS). Relying on wireline intervention limits the number of gas lift troubleshooting activities due to the low man-hour availability. To address this constraint, CO2 Tracer application was implemented in a campaign to supplement Field B GLOP effort. CO2 Tracer is a technology whereby concentrated CO2 is injected into the gas lift stream via the casing. CO2 returns are collected at the tubing end and utilized to diagnose the gas lift performance. The CO2 Tracer campaign was successfully executed in Platform A, B and C, covering 58 strings within an effective period of 3 months. This achievement is a milestone for the field as it opens a new approach in GLOP data acquisition process. Several advantages observed by executing this campaign is as follows: Multiplication of opportunities generation due to quick and simple operations of CO2 Tracer survey compared to wireline intervention for FGS.Reduction in HSE risks and intervention-related well downtime due to minimal intrusive requirement for well hook-up.Better understanding of complex dual gas lift completion due to simultaneous survey execution.Supplement CO2 baseline measurement for flow assurance monitoring.Quick quality check on gas lift measurement device. This paper will discuss on the challenges at Field B to implement GLOP, technology overview of CO2 tracer, the full cycle process of the CO2 tracer campaign and results of the campaign. Several examples of the findings will also be shared.
Formation sand production is one of the major production challenges in most of the mature fields in Malaysia. Often, failure in primary sand control equipment requires the operators to adopt through-tubing sand screens as remedial sand control. Due to the erosion prone nature of the thru-tubing metallic sand screen, operators are forced to impose limitation on the production rate coupled with stringent surface sand monitoring system to avoid surface flow line leakage and loss of primary pressure containment. Therefore, to seek a more robust technology than conventional metallic screens, alternative technology with through-tubing ceramic sand screen (TTCSS) has been considered with the idea of higher durability and resistance against erosion. This paper will discuss the performance and lessons learnt from the application of through-tubing ceramic sand screen throughout several mature fields in Offshore East Malaysia. Over the past two years, there have been about twenty-five TTCSS installations in Offshore East Malaysia. Seven pre-mature failure cases were observed, where sands were produced to the surface and even caused leaks on the flow line. The average effective production period for all TTCSS across all the fields ranges from 6 to 11 months. Teardown investigations have been conducted to diagnose the failure root cause. Most failed TTCSS exhibited similar failure patterns at the end caps, which house the spring compensator. Failure to stop the flow through the end caps led to substantial erosion at spring compensator and base pipe, inducing large flow path for sand production to the surface. Other than the design failure, application failure was observed at the ceramic rings due to their brittleness. Computational fluid dynamic simulation and laboratory testing have been conducted at the higher incremental production rates to support the observations from teardown inspections, refine the hypothesis of failure mechanism and enable an incremental design change to be modified into TTCSS. In order for TTCSS to be one of the competent candidates for remedial sand control, new improved standard design of TTCSS with strengthened end cap area will be studied to prevent similar failure.
Most of the S oil field producers experienced rapid decline in production and this is suspected due to fine sediment particle migration and plugging. The S field team had carried out external formation damage study as they have no expertise and field experience to determine the damage mechanism and evaluate the best acid treatment recipe for their formation damage. Recently, mixtures of traditional hydrochloric and hydrofluoric acids have been used for the removal of near-wellbore damage in S field sandstone formations. The stimulation campaign in this field which has turbidite reservoir, high clay content predominantly by kaolinite and illite with high siderite mineralogy applied both bullheading and coiled tubing squeezing techniques. The treating fluid selection is highly dependent on mineralogical data and laboratory works. Based on the core flood testing performed, high strength mud acid is chosen as the main treatment fluid and gave superior result in permeability recovery as compared to milder organic acid and HF. Unfortunately, the actual field stimulation turned out to be opposite from the core flood testing outcomes. The situation is worsened in multistage treatments, which traditionally involve many repeat stages of preflush, main treatment, overflush and diverter. The mud acid stimulation prompted more water production and fine migration that is ended up with production curtailment. Only one out of four of the treated candidates resulted significant gain after gas lift valve change took place. This paper also will outline the reviews on results of laboratory testing and field actual performance together with the recommendations for future improvement. Stringent candidate selection, improved treatment fluids cocktail, operational challenges such as unanticipated longer flow back period, post treatment unwanted precipitation, ineffective diverter placement and skin build up post treatment are among of the learning points captured in this paper. From this unfavorable mud acid stimulation campaign which cost USD4million value leakage, our team comes out with best practices for future stimulation and key learning to share with industry colleagues who has no field background to combat with fine migration issue in their sandstone asset. Laboratory works is not the only paramount to any stimulation, success in stimulation is a journey, not a destination. The doing is often more important than the outcome.
Tar and heavy oils have imposed several challenges to the oil industry professionals in many aspects. Starting from definition, characterization, identification, delineation and through to development and production. Proper vertical and lateral delineation of tar and heavy oil reservoirs in a quantitative and a qualitative manner is imperative for proper reserves assessment, well placement and optimal field development plans. Challenges in Vertical and lateral delineation of tar and heavy oil reservoirs include, but are not limited to;
Production Surveillance is a key activity carried out by oil and gas operators in the quest to maximize production. In Malaysia, specifically the East Malaysia Region, most of the wells in production are operated with the assistance of gaslift. Gaslift is an artificial lift method which involves injecting high pressure gas from the casing to enter the tubing via gaslift valves. Gaslift often hides inefficiencies, however by monitoring the operating conditions at the surface, an engineer will be able to obtain some clues on the performance of a gaslifted well. Before the introduction of CO2 tracer technology, the only method available to operators to determine if a gaslift valve is open or closed downhole is to run a Flowing Gradient Survey (FGS) in order to determine the pressures and temperatures of the fluids in the tubing. Using a FGS in a well involves certain risk as it requires well intervention by running electronic memory gauges either on wireline or slickline to acquire data from a flowing well. There are also times where a FGS survey is inconclusive if the well is surging and have large changes in the surface pressures. Since this is the fisrt such application in the field, two gaslift wells were surveyed for pilot application. The CO2 tracer technology is very effective for quick and reliable determination of lift gas entry points in the well. The technology allows the operator to detect the operating lift depth, detect multiple points of injection and even detect tubing leaks. This technology can be used as an alternate to FGS for the following advantages: Minimum equipment hook-up and no need to shut-in or choke the well, thus minimize production deferment.No wireline tools introduced into the wellbore, thus eliminate well intervention risk.Suitable for wells where a FGS is not possible due to well slugging, significantly deviated or with downhole obstruction.Possible to run survey on dual string wells to determine the gaslift split factor of a dual completionPossible to determine exactly how much gas is injected through each injection point of a well This paper will describe the project objectives, the well candidate selection criteria, explain the execution of the survey and interpretation of the results and the value gain from implementing the recommendations from the survey results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.