Imbazi, Oyeintonbra (Shell Company in Nigeria) | Ugoh, Oluwatobi (Shell Company in Nigeria) | Okoloma, Emmanuel (Shell Company in Nigeria) | Osuagwu, Micheal (Shell Company in Nigeria) | Enyioko, Chigoziem (Halliburton) | Ighavini, Emmanuel (Halliburton) | Uzodinma, Chioma (Halliburton)
Well 01 and Well 02 are part of the phase 1-6 project that involved the development of six wells with the potential to deliver an additional 70% production increase to the LNG export market. The sand face for both wells was drilled with 0.72psi/ft pseudo oil-based mud (POBM). After the initial well clean-up, both wells produced sub-optimally (~20% of estimated potential) with relatively high drawdown (ranging from 500psi – 1000psi). This low production was suspected to be because of downhole (screen and formation) impairment or partial opening of the formation isolation valves (FIV).
A restoration team was set up with a responsibility to proffer a robust well intervention execution plan and select the most potent barite dissolver. Nine stimulation chemicals were tested and based on the team criteria, CHEM-001 and CHEM-002 were selected as main-treatment and pre-flush chemicals, respectively.
The downhole and surface conditions that exist in deep high-pressure wells pose many challenges to the coiled tubing industry as it strives to provide safe and reliable access to the wells. This paper highlights a case history of successfully snubbing coiled tubing (CT) into two deep (about 14,000ft+) live wells (Well 01 and Well 02) with a high surface pressure (7000psi+) and temperature (80 – 100°C) to stimulate both wells. The success criteria post stimulation was targeted at 75% of the potential production value. However, post treatment results show that cumulative gas production increased by 375% (with about 200psi) with a potential to increase up to 400%.
This paper details the entire operations during the CT well intervention, the planning, design, and technical analysis which led to the selection of a CT with 130,000psi yield strength on a 125K CT injector system, force simulations, and laboratory tests on CT with stimulation chemicals which led to a successful stimulation campaign. The paper also covers the initial planned versus actual operations and the lessons learned leading to on-the-spot optimization plans that resulted in a highly successful intervention operation.
Jin, Ningjing (Vertechs Oil & Gas Technology Co., Ltd.) | Xiao, Shuyue (Exploration and Development Research Institute, PetroChina Southwest Oil and Gasfield Company) | Zhang, Shuo (Vertechs Oil & Gas Technology Co., Ltd.)
The paper will include an introduction of dissolvable plug and its development in oil & gas upstream business. Dissolvable plug is a customized tool, and it could be modified by controlling its chemical compound to adjust its dissolving rate. In addition, slim version dissolvable plug is a plug solution with dissolvability originally brought out to overcome the downhole restriction challenge (ID of SSD), namely to pass the downhole restriction then to set in the original casing ID. A case study of its application in offshore squeeze cementing job will be analyzed in this paper, from the plug designing perspective to operational data recap to prove its benefits. Conventional plugs will leave the bottom of the plug body downhole after plugs slip losing integrity during the milling operation, and the remainder leaving downhole will choke the well production or even block the well, however, dissolvable plug remainders will dissolve itself downhole, which will not have an impact on the production.
Asia's first rigless subsea stimulation was executed in 2018, with intervention performed upon three target wells offshore Sabah Malaysia, at a water depth of approximately 1400 m (4,593 ft). Significant changes in reservoir performance prompted an acid stimulation and scale squeeze treatment, designed to remedy fines migration and scaling issues within the well and production system. Treatment fluids were delivered subsea by an open-water hydraulic access system, using a hybrid coiled-tubing downline. Access to the subsea trees was permitted via a patented choke access technology, allowing for a flexible, opex-efficient, and low-risk intervention. The intervention system was installed upon a multi-service vessel, with the downline deployed via the vessel moonpool. A second support vessel was used as required to provide additional fluid capacity without disturbing primary intervention operations. This enhanced the flexibility of the operation, permitting changes in the treatment plan to be accommodated for without impact to critical path stimulation activities.
The full intervention was delivered as an integrated service, with all elements supplied by a single provider, via one contract. An established network of in-house equipment, expertise, test laboratories, and operational bases supported the planning and execution of the project. This was complemented by select external providers for vessels, remotely operated vehicle services, and other specialist contractors.
The challenges faced during this new market entry included completion of a comprehensive treatment fluid test program, importation and logistics of equipment from around the globe, and managing operational risks, all within a condensed timeline to satisfy a brief intervention window. By leveraging the diverse global network of the service provider, the technology and people required for the project were accessed and brought together to achieve a collaborative solution. This was enhanced by the inclusion of performance based elements within the contract. The provision of a highly efficient and flexible well access technology also supported rapid mobilization and operational risk reduction.
Post-stimulation well testing confirmed an average increase in oil productivity of 86%, with a corresponding productivity index factor (PIF) gain of 3.4. These results, combined with the efficient execution of the campaign, confirm the appropriateness of open-water hydraulic access using coiled-tubing for performing cost-effective stimulations on complex subsea wells.
Successful entry to the region was highly dependent upon the integrated nature of the service. Access to the service providers global network permitted a high degree of influence upon the ultimate performance of the stimulation. Examples include the PIF results achieved and the responsive actions taken to remedy offshore challenges such as reservoir lock-up on well #3.
Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. Perforating to align the charge penetration direction with a feature like the fracture plane or to miss an adjacent string of pipe.
Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. Bringing a well on with nitrogen lift to get the initial flow rate or to get it to steady state flow. Commonly used after workovers to jet back heavy brines until the hydrocarbons with associated gas flow into the well and begin natural production.