Lesson Contents01. Fundamentals of Wellbore Flow - Lesson 1.01: Overview of Well Flow02. Oil & Gas Production Engineering03. Field Development04. Production Maintenance & Improvement05. Typical Production System06. Wellbore07. Why do we need to know about wellbore flow?08. Reservoir Performance Prediction09. Reservoir Performance Prediction - 2-Phase Flow10. Reservoir Performance Prediction - Decline Curve Analysis
01. Fundamentals of Wellbore Flow - Lesson 1.01: Overview of Well FlowHello everyone. First of all, I'd like to welcome you all to this course. This course is titled Fundamentals of Wellbore Flow. Our main purpose/objective here is to give you a basic understanding of wellbore flow. And our motivation to do so is coming from prediction abilities or capabilities for reservoir performance or monitoring of the production from a given well. That typically requires the bottomhole flowing pressure. Bottomhole flowing pressure can be obtained by having a downhole gauge, pressure gauge; that is the ideal case. However, we may not have the bottomhole gauge. If we don't have the bottomhole gauge, what we're going to do is estimate the bottomhole flowing pressure based on the surface measurement or wellhead measurement of the pressure.
02. Oil & Gas Production EngineeringAnd I will start that with covering what oil and gas production engineering involves. What does it cover? Production engineering covers anything technical that enables or helps the delivery of hydrocarbons, gas or liquid from reservoir to market place. And production engineers are involved in the process from the discovery until the decommissioning of the field.
03. Field DevelopmentAnd production engineers are involved, as I said, they are also involved in the development phase of a field; this is planning phase. After the discovery of a field, the most obvious question is can we economically exploit the discovery? And that will require feasibility study. This feasibility study will have many different scenarios and we play those scenarios. And finally, depending on our objective function, we decide which scenario is more suitable for us. And that design scenarios may vary type a number of wells, platforms (if offshore), well completion schemes, processing, artificial lift, transportation, and abandonment philosophy all goes into it.
04. Production Maintenance & ImprovementHowever, most production engineers spend their lives in the production maintenance and improvement. Objective would be maintenance of the performance of the wells that are already in production and monitoring them. If they don't behave well, identify why they are not and they come up with solutions to bring them to optimized state. And also, we may venture into improvement of those wells and find a better optimized state.
05. Typical Production SystemA typical production system consists of 3 major components. What we are going to have, the first component, the reservoir, 1) reservoir or formation 2) is wellbore and 3) whatever we have at the surface; flow lines, surface facilities in general. We're going to cover each one of them a little bit more in depth.
06. WellboreIn the wellbore, we can have 2 types of flow. We can have natural flow, well flows by its own energy. This is typical of early life of a well. However, later on, we will have energy depletion or reservoir pressure depletes and the fluids may not be able to come to the surface by themselves. Then we need to introduce different artificial lift techniques to bring them up.
07. Why do we need to know about wellbore flow?I've already talked about this, but just to sum up, wellbore flow is important for a couple of reasons. First of all, system design and production management requires pressure losses in the wellbore.
08. Reservoir Performance PredictionNext, I will go to reservoir performance very briefly. I'm not going to cover the entire reservoir performance and reservoir behavior, just enough for us. Inflow performance relationship, we call them. And we have different inflow performance relationships for single-phase and 2-phase. Let us look at the single-phase first.
09. Reservoir Performance Prediction - 2-Phase FlowHow do we do this for 2-phase flow? We have different relationships because 2-phase flow in the reservoir is significantly more complex. And in the literature in our industry, there are ways to do that. The simplest of all, I'm presenting here; Vogel equation or Fetkovich equation. Both equations relate qo with the bottomhole flowing pressure.
10. Reservoir Performance Prediction - Decline Curve AnalysisAnd in the field, what we have, we all know that we monitor the flow rates and also pressure losses or bottomhole flowing pressures as best as we can. This is a sample graph for a gas well. I have gas rate here and time here. As you see, we have a decline. What we do looking at the initial decline, we try to predict what would be into the future, the production.