TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn recent years, expandable sand screen (ESS) has become popular as a sand exclusion mechanism in oil and gas sand face completion. ESS provides sand control through the bridging of formation sand on the screen that is sized to retain formation sand while allowing formation fines to pass through. The deployment of Cased Hole ESS (CHESS) in The Shell Petroleum Development Company of Nigeria Ltd (SPDC) since the late 90's has been mainly as a remedial sand control mechanism post-workover operation to replace the previous sand control mechanism if any or to complete over a new interval. The successful deployment of CHESS in over 30 conduits in the Niger Delta by SPDC over the years has come with various challenges and lessons learned leading to improvements in the selection criteria, deployment methodology and procedure, clean-up and operational envelope of usage. This paper presents some of the results and the lessons learned in CHESS deployment in SPDC and offers an insight into the selection and usage of CHESS as a sand control mechanism especially in well remedial operations to prolong well life and optimise hydrocarbon recovery.
Summary Working in the oil industry comes with unique challenges and risks, and so extra precautions and safety measures coupled with strict environmental compliance must be applied. Contrary to the common belief that strict safety enforcement could hinder smooth operations, the deployment of new technologies and enhanced solutions of processes has enabled operational excellence (OE) and improved safety performance. In this paper, we demonstrate health, safety, and environment performance improvement through implementing two main initiatives: The first category has initiatives that require less intervention or personnel; for example, the deployment of cableless pressure sensors or permanent monitoring systems in key wells to ensure continuous real-time pressure data to monitor reservoir pressure. The second category has initiatives that mitigate traditional health, safety, and environment risks; for example, through use of multiphase flow meters (MPFMs) to collect accurate and continuous flow measurements instead of traditional well testing. Optimizing operations costs while maintaining a high-level of safety is achieved through a dedicated team working in a state-of-the-art Production Operations Surveillance Hub (POSH), which enables the monitoring of wells in real time, making production optimization decisions, and ensuring a high level of well integrity via close monitoring of wells and assets.
A production choke is essential in regulating the pressure and flow rate of the produced hydrocarbon stream from a well in a field production system. Regulating the pressure and flow rate is necessary to achieve the production objectives of a field, which are to meet customer demand and optimally manage the reservoir over its life cycle. It is therefore important to have a means of effectively monitoring production choke performance to identify the onset of choke wear. Choke wear results from erosion of the choke due to impingement of particles carried in the produced hydrocarbon stream as it passes through the choke body. Choke wear increases the production rate and downstream pressure of a producing well, thereby upsetting the balance of the production system and resulting in ineffective field pressure management. Taking immediate action to replace a worn choke is therefore necessary to restore the production balance and achieve optimal pressure conservation of the production system. Choke performance monitoring is more critical for gas producing wells than oil producing wells because the velocity of gas is typically much higher than the velocity of oil, and consequently the risk and frequency of choke wear is much higher. Physical inspection of the production chokes to confirm wear for offshore gas wells is more laborious and time consuming due to the need to interrupt production, depressurize the flowline, decouple the choke body from the flowline, and ship the choke body onshore to the manufacturer's workshop for component inspections to confirm choke wear and, if necessary, choke replacement. A way to remotely monitor production choke performance and correctly detect choke wear for offshore gas wells without interrupting production is therefore operationally expedient, reduces exposure of personnel to unsafe rough sea conditions, and saves the cost of unnecessary physical choke inspections. The authors present a graphical method of monitoring the production rate and flowing tubing head pressure trends, with the choke size, of offshore high rate dry gas wells to detect choke wear using real-time production data. Examples of successful application of the method, which demonstrates that innovation can be simplification of processes, to detect choke wear and perform timely choke replacement are highlighted.
Various factors have an impact on the production performance of horizontal oil wells. Geological and reservoir factors such as environment of deposition and the thickness, permeability and reservoir drive mechanism, operational practices during the drilling of the horizontal drain hole such as the selection of the drill-in and completion fluids and the amount of overbalance pressure exerted on the production interval and technical design factors such as sand face completion types deployed and clean-up practice employed have significant impact on the production performance.This study was conducted to assess the impact of the various factors on the production performance of horizontal wells through the comprehensive analysis of 70 horizontal oil wells in the Niger Delta. The wells were drilled and put on production over a period from 1993 to 2007.The results from the study indicate that a combination of factors including shoreface facies type, minimum overbalance, oil-free mud system, brine completion fluid system, pre-drilled or slotted liner and clean up using nitrified hydrochloric acid circulated with coil tubing is required to optimise horizontal oil well production performance in the Niger Delta. Considerations of these factors when planning horizontal oil well development projects in the Niger Delta will ensure technical and operational excellence and improve overall project economics. Furthermore, the adaptation and application of the approach used in this study by the oil and gas industry worldwide will aid well performance monitoring under diverse technical and operational conditions and assist in optimal well design and performance optimisation.
A technique for determining the operating limit of internal gravel packed (IGP) gas wells has been developed. Consistent with the observations by Tiffin et al1 and Keck et al2, the non-dependence of sandface completion failure on pressure drawdown is established for 20 IGP gas wells in SPDC portfolio. Downhole flow velocity (flux) had earlier been established as the main factor contributing to screen erosion and GP failure (King et a1l and Tiffin et al2). Therefore, a flux- based operating limit for IGP gas wells is developed using Reynolds Number (NRe) evaluated at downhole conditions. Input data include production rate, perforation details and fluid properties. Well files were reviewed to identify gas wells with screen erosion IGP failures. For such wells, the pressure drawdown, rate and fluid properties at the period of failure were captured for calculation of the flux and NRe. For comparison, a similar analysis was carried out for wells with healthy gravel packs. The maximum NRe for healthy gravel packs was established as 90,000 while the minimum for failed gravel packs was 200,000 suggesting the existence of a limiting NRe beyond which IGP failure occurs. The applicability of the technique was demonstrated for a gas field requiring swing production commonly used to make up for supply shortfalls. The technique was also used to determine a theoretical maximum flux and maximum production rates for all the SPDC IGP gas wells.
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.