Peripheral and pattern flooding
- 1. Peripheral and Pattern Flooding By SYED NAWAZ M.Tech Petroleum Exploration and Production Delta Studies Institute Andhra University
- 2. Content • Introduction • Technical terms • Classification • Pilot testing • Peripheral testing • References
- 3. Introduction • Can also be said as injection pattern, the particular arrangement of production and injection wells. • For every field or for a section of a field, the injection pattern are designed separately • The pattern of flooding can be change during the life of a reservoir, in order to change the direction of flow in a reservoir with the intent of contacting unswept oil.
- 4. Important terms for understanding • Sweeping efficiency : the percentage of original oil in place displaced from a formation by a flooding fluid • Over all displacement efficiency(E): the proportion by volume of oil swept out of the pore space of a reservoir by the encroachment of another fluid. The displacing fluid may be reservoir water, gas or an injected fluid • Microscopic displacement efficiency(Ed): is a measure of the effectiveness of the displacing fluid in moving the oil at those places in the rock where the displacing fluid contacts the oil or at a pore scale • Macroscopic displacement efficiency(Ev): is a measure of how effectively the displacing fluid sweeps out the volume of a reservoir, both areally and vertically and as well as how effectively
- 5. Factors affecting types of efficiencies
- 7. Mobility and Mobility Ratio
- 9. Classification of pattern • Direct line drive, • Staggered line drive, • (2 spot • 3 spot • 4 spot • 5 spot • 7 spot • 9 spot) and inverted pattern with each of them • Normally the 2-3 spot pattern are used for pilot testing purposes.
- 10. Pilot testing in EOR • The primary purpose is to validate the performance of a particular EOR process in the field. Eg: laboratory tests and simulation studies indicate that a highest recovery and best overall economic value among recovery process considered. Before making a huge investment required for a large scale application, a Pilot is conducted at a well spacing scalable to that expected for full scale application • Pilot testing is classified into 4 types: • Non Producing Pilot, • Small Scale Unconfined Pilot, • Small Scale confined Pilot, • Multi Pattern Producing Pilot
- 11. Non producing pilot • Aim to determine the ease at which the gas can be injected into the formation and to evaluate injectivity losses resulting from water alteration by gas processes • The vertical sweep and local displacement efficiency of the gas at injected area can be determined.
- 12. Producing Pilot • Also known as oil in the tank pilot. • Direct determination of oil recovery, dynamic fluid properties, Pressuer drop between injectors and producers.
- 13. Confined small scale pilot • Used for closure well spacing • At cheaper cost then other pilot methods it can determine the vertical sweep efficiency. • In addition to this detailed information on pressure gradient, fluid mobility.
- 14. Unconfined small scale • It can provide production history quickly at low cost, but swept volume estimation is difficult • They are sensitive to fluid drift (body of a fluid permanently displaced)
- 21. Selection is based on • Converting existing wells into projector • Drilling infill injection wells • Reservoir heterogeneity • Directional permeability
- 24. General well spacing distances and rate of wells
- 25. Cased study at Kube Field Note: normal flood pattern perform better than their inverted equivalent because inverted pattern have less injectors which decreases the sweeping efficiency of oil.
- 26. References • Dr.Hareram Sir (Guest faculty, Andhra University) • Evaluation of various water flooding pattern in KUBE field (Research Paper) • Petrowiki • One petro • Enhanced oil recovery pilot testing best practices (Research Paper) • SPE • Rigzone • Syed Nawaz (Student of Andhra University) • Youtube
- 27. Any Queries ?