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EP-4735919-A1 - METHOD TO GENERATE SALINITY CURVES FOR EVAPORITE PRODUCTION MODELING IN PERITIDAL CARBONATE PLATFORMS

EP4735919A1EP 4735919 A1EP4735919 A1EP 4735919A1EP-4735919-A1

Abstract

A method for predicting a mineral composition of an evaporite penetrated by a first portion of a wellbore following a planned wellbore path through a sedimentary basin and determining an observed mineral composition of the evaporite. A non-transitory computer readable medium storing instructions executable by a computer processor including receiving a history of sea-level for a sedimentary basin, using a seawater evaporation model to predict a salinity threshold and produce a seawater evaporation curve, where the seawater evaporation curve includes an amount of minerals contained in a body of seawater as a function of salinity, identifying depositional portions of the history of sea-level, and developing a mathematical model to generate the geological-time dependent salinity curve based on the depositional portions of the history of sea-level.

Inventors

  • WANG, XIAOXI
  • LU, PENG
  • ZUHLKE, RAINER

Assignees

  • Saudi Arabian Oil Company

Dates

Publication Date
20260506
Application Date
20230630

Claims (15)

  1. A method, comprising: predicting a predicted mineral composition of an evaporite penetrated by a first portion of a wellbore following a planned wellbore path through a sedimentary basin; determining an observed mineral composition of the evaporite; updating the planned wellbore path based, at least in part, on the predicted mineral composition and the observed mineral composition; and drilling, using a drilling system, a second portion of the wellbore, guided by the updated planned wellbore path.
  2. The method of claim 1, wherein predicting the predicted mineral composition comprises: generating a geological-time dependent salinity curve for a sedimentary basin, wherein the geological-time dependent salinity curve comprises a relationship between the amount of minerals deposited in the sedimentary basin over a geological-time; obtaining a predicted salinity threshold for each of at least one evaporite minerals; and determining the predicted mineral composition based, at least in part, on the geological-time dependent salinity curve and the predicted salinity thresholds.
  3. The method of claim 2, wherein predicting the predicted mineral composition further comprises calibrating the geological-time dependent salinity curve based on observed mineral composition collected in offset wellbores in the sedimentary basin.
  4. The method of claim 2, wherein predicting the predicted mineral composition further comprises: collecting drilling cuttings while drilling the first portion of the wellbore; determining the observed mineral composition of the drilling cutting from the drilling cuttings; and calibrating the geological-time dependent salinity curve based, at least in part, on the observed mineral composition.
  5. The method of claim 2, wherein predicting the predicted mineral composition further comprises: collecting logging-while-drilling information while drilling the first portion of the wellbore; determining the observed mineral composition of a rock formation based on logging-while-drilling information; and calibrating the geological-time dependent salinity curve based, at least in part, on the observed mineral composition.
  6. The method of claim 1, further comprising adjusting a weight of drilling mud based, at least in part, on the predicted mineral composition of the evaporite.
  7. The method of claim 1, wherein the predicted mineral composition comprises anhydrite.
  8. The method of claim 2, wherein generating a geological-time dependent salinity curve for a sedimentary basin further comprises: obtaining a history of sea-level for the sedimentary basin; using a seawater evaporation model to predict a salinity threshold and produce a seawater evaporation curve, wherein the seawater evaporation curve comprises an amount of minerals contained in a body of seawater as a function of salinity; identifying depositional portions of the history of sea-level; and developing a mathematical model to generate the geological-time dependent salinity curve based on the depositional portions of the history of sea-level.
  9. The method of claim 8, wherein using a seawater evaporation model to predict a salinity threshold and produce a seawater evaporation curve further comprises numerical simulation using the Harvie- -Weare (HMW) model and PHREEQC software.
  10. A non-transitory computer readable medium storing instructions executable by a computer processor, the instructions when executed by a computer processor comprise steps of: receiving a history of sea-level for a sedimentary basin; using a seawater evaporation model to predict a salinity threshold and produce a seawater evaporation curve, wherein the seawater evaporation curve comprises an amount of minerals contained in a body of seawater as a function of salinity; identifying depositional portions of the history of sea-level; and developing a mathematical model to generate the geological-time dependent salinity curve based on the depositional portions of the history of sea-level.
  11. A non-transitory computer readable medium of claim 10, the steps further comprising: numerical simulation using the Harvie- -Weare (HMW) model and PHREEQC software.
  12. A system, comprising: a geological-time dependent salinity curve, configured to predict a predicted mineral composition in a sedimentary basin; a drilling system, configured to drill a wellbore through the sedimentary basin; and a calibrated geological-time dependent salinity curve, configured to predict a second mineral composition based on an observed mineral composition.
  13. The system of claim 12, further comprising a wellbore planning system with functionality for geosteering, configured to plan a planned wellbore trajectory to reach the drilling target; wherein the drilling system is configured to drill the wellbore guided by the planned wellbore trajectory.
  14. The system of claim 12, further comprising: a cuttings analysis system, configured to obtain the obtained mineral composition pertaining to a sedimentary basin, wherein the cuttings analysis system comprises: drilling mud return equipment, configured to collect, adjust, and re-circulate drilling mud in the wellbore; a shale shaker, configured to separate cuttings from the drilling mud; and a cuttings analysis device, configured to obtain the observed mineral composition.
  15. The system of claim 12, further comprising a well logging tool, configured to obtain the obtained mineral composition pertaining to the sedimentary basin from the wellbore.

Description

METHOD TO GENERATE SALINITY CURVES FOR EVAPORITE PRODUCTION MODELING IN PERITIDAL CARBONATE PLATFORMS BACKGROUND Evaporites are a class of sedimentary minerals and rocks that form by precipitation from evaporating aqueous fluid. Common evaporite minerals are halite, gypsum and anhydrite, which can form as seawater evaporates, as well as the rocks limestone and dolostone. Certain evaporite minerals, particularly halite, can form excellent cap rocks or seals for hydrocarbon traps because they have minimal porosity, and they tend to deform plastically (as opposed to brittle fracturing that would facilitate leakage of oil and gas) . Evaporites require local seawater to be supersaturated with respect to a single or several specific evaporative minerals to allow for precipitation. Salinity, i.e., the dissolved salt content of a body of water, is a good measurement of the degree of saturation (i.e., saturation index) with respect to a specific evaporative mineral. Precipitation follows an on-and-off switch: the mineral precipitates when salinity is higher than a specific salinity threshold (e.g., superstaturated to the mineral) , but precipitation stops when salinity is lower than the threshold. Extensive evaporite units provide regional top and/or lateral seals for hydrocarbon reservoirs, such as stacked carbonate-evaporite units. In addition, due to the mobility, solubility, and ductility of evaporites, evaporite layers are prone to spatial alteration during burial. SUMMARY This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. In one aspect, embodiments disclosed herein relate to a method for predicting a predicted mineral composition of an evaporite penetrated by a first portion of a wellbore following a planned wellbore path through a sedimentary basin. Embodiments also relate to determining an observed mineral composition of the evaporite, updating the planned wellbore path based, at least in part, on the predicted mineral composition and the observed mineral composition and drilling, using a drilling system, a second portion of the wellbore, guided by the updated planned wellbore path. In another aspect, embodiments disclosed herein relate to a non-transitory computer readable medium storing instructions executable by a computer processor. The instructions when executed by a computer processor include receiving a history of sea-level for a sedimentary basin, using a seawater evaporation model to predict a salinity threshold and produce a seawater evaporation curve, where the seawater evaporation curve includes an amount of minerals contained in a body of seawater as a function of salinity, identifying depositional portions of the history of sea-level, and developing a mathematical model to generate the geological-time dependent salinity curve based on the depositional portions of the history of sea-level. In another aspect, embodiments disclosed herein relate to a system, including a geological-time dependent salinity curve configured to predict a predicted mineral composition in a sedimentary basin, a drilling system, configured to drill a wellbore through the sedimentary basin, and a calibrated geological-time dependent salinity curve, configured to predict a second mineral composition based on an observed mineral composition. Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an example sedimentary basin. FIGs. 2A –2B show systems in accordance with one or more embodiments. FIG. 3 shows a method in accordance with one or more embodiments. FIG. 4 shows a system in accordance with one or more embodiments. FIG. 5 shows a flowchart in accordance with the method of one or more embodiments. FIGs. 6-18B show examples in accordance with one or more embodiments. DETAILED DESCRIPTION In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. Throughout the application, ordinal numbers (e.g., first, second, third, etc. ) may be used as an adjective for an element (i.e., any noun in the application) . The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before” , “after” , “single” , and other such terminology. Rather