Manganese tetraoxide (Mn3O4) drilling fluid weighting material was first applied in two high-pressure/high-temperature (HP/HT) Madura Sea, Indonesia wells, BD-A and BD-B. Mn3O4 is less damaging to the environment and formation than other weighting agents. In the BD wells, coiled tubing (CT) will perform Mn3O4 mudcake removal by spotting an acid solution. The main challenges come from the formation characteristics: temperature up to 305°F, pressure of 8100 psi, 5,000 ppm H2S, and 5.5% CO2. Slow-reacting acid was preferred to prevent creating a corrosive environment. The reaction of acetic acid, formic acid, and a chelating agent with Mn3O4 at 305°F was studied. A corrosion test was performed to see the effect of the acid and 5,000 ppm H2S on CT string and completion tubing metal. Viscosimeter and densitometer testing was done on 155 ppb Mn3O4 mud that was mixed at laboratory scale to represent actual drilling mud in the well. Filter cake was made using an HP/HT filter press and 10-micron alloxite disc to represent formation permeability. Using the mix of acetic acid and chelating agent solution, 100% solubility of filter cake was achieved after 6 hours reaction time, giving enough time for CT to spot the acid in the entire 1,000-ft openhole interval and provide a uniform filter cake removal. With additional organic acid inhibitor and H2S inhibitor, the corrosion rate on CT and completion tubing metal after 16 hours test was found acceptable without pitting observed. This method has been proven effective to remove Mn3O4 filter cake with significant pressure drawdown reduction, hence increasing well productivities. The utilization of CT improves cost efficiency by accurately placing a right amount of acid solution across the openhole section. This stimulation fluid system is the first application in the world and was proven to be effective to remove Mn3O4 based filter cake and protect CT and tubing metal against H2S and CO2 in an HP/HT environment.
The Amenam/Kpono field is located eastern offshore of Nigeria in a water depth of 43m and about 35km away from the coast. The field development has been challenging in so many ways:Deep reservoir targets (3600m to 4300m TVD/SL)High temperatures (130 -150 degree Celsius)High pressures (370 to 500 bar)High-reach departures up to 3km in certain wellbores, giving rise to highly deviated and deep wells (up to 6600m MD/RT)Reservoir fluid containing 3% by weight paraffinReservoir fluid containing 3% carbon dioxide contentCritical reservoir fluids (bubble point pressure is very close to the reservoir pressure in the main reservoir). This necessitates the requirement for the early and efficient pressure support for the reservoir In order to deliver wells under the above challenging environment and circumstances such as to ensure field life production, a lot of emphasis is placed on completions optimization. Hence, completion technology was taken beyond the conventional limit and an innovative, reliable and cost effective approach applied through complete integration of the service companies. The main interest was to reduce the operational risks with diverse and enhanced completion equipment in order to reach the plateau as quickly as possible. Hence, a Monobore completion design with Interventionless technology was embraced in this offshore field development. The total budget for the first phase of the development is $1.5 billion (U.S.) and it covers drilling, completion, construction and production installations. This paper will discuss the well completion designs, material selection, manufacturing, preparation, execution and evaluation of the Amenam/Kpono well completion. The paper will focus more on how new technologies (Reservoir drilling fluid, fluid spring-operated valve, gravel-pack packer, tubing- tester flapper valve, production packer, permanent gauge, etc) are integrated in all the wells, and especially, in the challenging horizontal gas injectors. By using these technologies, completion efficiency was increased, safety performance was improved, and rig cost was reduced by 50 hours per well. Introduction The Amenam/Kpono oil field straddles the boundaries of OML 99 and OML 70 of the Nigerian Continental Shelf in the eastern part of the offshore Niger delta, in an average water depth of 43m. The field is located at about 35km to the south of the nearest coast line and 33 km from the Odudu field (see Fig. 1). Elf Petroleum Nigeria Limited (E.P.N.L.), a subsidiary of Total Exploration and Production, is in the process of developing the field. The first phase concerns the development of levels R4; R9, R10 and R11 in the Western and Central parts of the field. Two drilling platforms AMD1 and AMD2 is installed 90m apart and bridge connected to a production platform (AMP1). This field development involves the drilling and completion of 34 wells, of which 18 are oil producers, 5 are gas injectors and 11 are water injectors. At the R4 reservoir level, gas injectors are required for total pressure maintenance from the start of the production since the bubble point pressure is close to the reservoir pressure. Thus, gas injection is as important as oil production at this reservoir level in this field development. All the producers and injectors are being developed with the interventionless technology, which allows running and pressure testing of the completion string to be done as often as needed without deployment of slick line. It also allows the setting of the production packer without slick line. As a double confirmation of no-restriction in the entire completion string, only one slick line gauge cutter run was required at the beginning of the project. The first horizontal gas injector was constructed with deviations of less than 60 degrees in the upper completion to meet this operational need.
Four high-pressure-high temperature (HPHT) and sour gas wells are currently operating at Madura offshore as the only productive assets for Husky-CNOOC Madura Limited (HCML). Each well performance is very crucial to fulfill the demand of the gas customers in East Java, Indonesia. Since starting production in 2017, the wells experienced two main well integrity challenges, high annulus pressure and wellhead growth. Both challenges are very dependent to the well flow rate and the flow duration. A continuous operation monitoring is highly required in order to keep the wells operating safely. To overcome the challenges, HCML established a Well Integrity Management System (WIMS) document that approached several international standards as its basis. As company grows, development plan challenged the WIMS to perform faster and more efficient as compared to the existing manual system. From there, the journey of WIMS digitalization began. The journey started with the alignment of the existing WIMS document to the ISO-16530-1 at Operational Phase with more stringent boundary to operate the wells safely. The alignment covers, but not limited to the organizational structure, well barriers and criteria, monitoring and surveillance, annulus pressure management, and maintenance. The document also covered risk assessment and management of well integrity failure, which was the backbone of the WIMS digitalization. The current digital solutions allow production data to be accessed and retrieved directly from the system for analysis purposes. It compares the recorded data with pre-determined rules and parameters set in the system. It triggers a notification to the responsible personnel to perform the required action should any anomaly occurs. It also can send a reminder to users to schedule and complete a well Integrity test to ensure that a well is always in compliance with the WIMS. All test reports and documentation are stored in the system as preparation for any future audit. A key requirement of the expert software system was access to future developments that can offer enhanced functionality of the well integrity platform through additional near time capabilities such as predictive erosion and corrosion for downhole flow wetted components. This is being developed to enhance workover scheduling for existing wells and material selection for new wells and is planned to update automatically critical well integrity criteria such as tubing burst, collapse and MAASP.
BD is a near high pressure-high temperature (HPHT) critical sour gas field located in offshore Madura Strait in water depth of 152 ft. An exploration and appraisal well were drilled in 1987 and 1992 respectively, targeting BD reef at depth of 10,676ft SSTVD. Both well test results confirmed the limestone formation has characteristic of 305°F and 8,105 psi, with 5,000 ppm of H2S and 5.5% of CO2 content. Four (4) development wells including three (3) horizontal and one (1) vertical well, were drilled to drain the reserves from BD field. The project was expected to deliver 120 MMSCFD of gas and 6,000 bpd of condensate for a period of 15 years production from BD field. Design, equipment and material to complete the well need to meet the target and be selected based on industry guidance and the environment to ensure the integrity of the well during the production time. Completion for BD wells adapts multiple tie-back concept to provide consistent large flow area and big bore advantages, providing flexibility for future well intervention. It consists of 3 (three) main assemblies and was designed based on series of load cases to predict the completion reliability to withstand the load during the life of the well. During the installation, the assemblies were run in different batches and fluid environment. Despite the challenges encountered during the preparation and installation, all wells were successfully completed and cleaned up safely without any incident. The completion could exceed the initial production target set by the reservoir engineering team. This paper will discuss about the completion process from the first near HPHT sour field development project in Indonesia. It describes the design process, preparation and installation of the BD completion especially in the horizontal well. Challenges, basis of design, material selection, lessons learned and optimization taken to safely deliver the completion are also covered in this paper.
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.
customersupport@researchsolutions.com
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.