Advanced Surveying Techniques Help Increase Hydrocarbons Production While Preventing Well Collisions and HSE Risks

Ochoa, Danny; González, Luis F.; Nava, Alfredo Aparicio; Naveda, C.; Poedjono, Benny; Chamat, Elias Hiramdim

doi:10.2118/165636-ms

Cited by 3 publications

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Quantification of Wellbore Collision Probability by Novel Analytic Methods

Bang¹

2017

SPE/IADC Drilling Conference and Exhibition

View full text Add to dashboard Cite

Unintentional collision between two wellbores may have serious economic and health-safety-environmental (HSE) consequences. It is therefore important to evaluate the probability of such an event in the well planning phase, and at critical stages during the drilling phase. A commonly used approach is to analyze the collision probability between two points, one in each wellbore, that are determined from geometric criteria only. This procedure may ignore point pairs with higher collision probabilities, and thereby lead to over-optimistic conclusions. Typically, the results from such methods will be accurate only for simple wellbore geometries such as straight sections and for position uncertainties that are highly symmetrical with respect to the wellbores. More advanced methods that overcome such limitations are impractical for general application because of high conceptual or computational complexity. This paper proposes novel analytic methods that potentially may overcome these problems. Formulae are derived for two important situations: the direct hit and the unintentional crossing scenarios. In both cases, the spatial region of interest is divided into carefully designed segments, such that the collision probability can be accurately evaluated for each segment. The total collision probability is then found by summing the results over all segments. The main advantage of this approach is that it gives accurate results for arbitrary well geometries and uncertainty ellipsoid orientations. The algorithms can easily be integrated in existing software for wellbore anti-collision analysis. The paper shows examples of results, which all are in good agreement with control calculations. Compared to existing methods, the proposed methods are therefore believed to represent a significant improvement to quantitative collision probability analysis, for both the wellbore planning and the drilling phases.

show abstract

Quantification of Wellbore Collision Probability by Novel Analytic Methods

Bang¹

2017

SPE/IADC Drilling Conference and Exhibition

View full text Add to dashboard Cite

show abstract

Quantification of Wellbore-Collision Probability by Novel Analytic Methods

Bang¹

2017

SPE Drilling &Amp; Completion

View full text Add to dashboard Cite

Summary Unintentional collision between two wellbores may have serious economic and health, safety, and environmental consequences. It is therefore important to evaluate the probability of such an event in the well-planning phase and at critical stages during the drilling phase. A commonly used approach is to analyze the collision probability between two points, one in each wellbore, which are determined from geometric criteria only. This procedure may ignore point pairs with higher collision probabilities, and thereby lead to overoptimistic conclusions. Typically, the results from such methods will be accurate only for simple wellbore geometries, such as straight sections, and for position uncertainties that are highly symmetrical with respect to the wellbores. More advanced methods that overcome such limitations are impractical for general application because of high conceptual or computational complexity. This paper proposes novel analytic methods that may potentially overcome these problems. Formulae are derived for two important situations: the direct-hit (DH) and the unintentional-crossing (UC) scenarios. In both cases, the spatial region of interest is divided into carefully designed segments, such that the collision probability can be accurately evaluated for each segment. The total collision probability is then found by summing the results over all segments. The main advantage of this approach is that it gives accurate results for arbitrary well geometries and uncertainty-ellipsoid orientations. The algorithms can easily be integrated in existing software for wellbore-anticollision analysis. The paper shows examples of results that are all in good agreement with control calculations. Compared with existing methods, the proposed methods are therefore believed to represent an improvement to quantitative collision-probability analysis for both the wellbore-planning and the drilling phases.

show abstract

How Close is Too Close? Saving Undrillable Slots Through Top-Hole Jetting and Drilling in Al-Shaheen Field, Offshore Qatar

Cousso

Ahmed

Sikal³

et al. 2021

SPE/IADC International Drilling Conference and Exhibition

View full text Add to dashboard Cite

A new joint venture operator, established to take over an existing strategic producing field with ongoing drilling operations, took the opportunity to design a new collision avoidance standard, based on the latest WPTS (Wellbore Positioning Technical Section) probability method collision avoidance rules. This has been combined with an innovative execution approach to safely and successfully unlock slots on congested platforms and drill some of the most difficult well trajectories in this complex field from the very first well. Al Shaheen field, offshore Qatar, is one of the most challenging fields worldwide in terms of collision avoidance. When drilling extended-reach wells from the last-remaining and most challenging slots, with top-hole separation as low as three feet centre-to-centre at the conductor pipe shoe, close collaboration with all parties is required to manage collision risk, minimise production loss, and ensure all well objectives are achieved. The execution strategy includes simple jetting and rotating BHA designs for 3D-profile trajectories, remote real-time monitoring including 24/7 survey QA/QC and validation, and mitigation through a decision-making matrix customised for the specific drilling challenges. The platform configuration and challenges in the drilling environment are discussed, together with the theory of the selected collision avoidance rule and the resulting risk matrix. A brief review of why jetting is selected as the only allowable drilling technique in major risk situations plus the story of the evolution of Al Shaheen jetting BHAs follows. Finally, three case studies of top-hole operations describe the practical application of the techniques discussed. The selected case studies describe the jetting operation from the deepest CP (Conductor pipe), the deepest well jetted, and the first 23-in jetting operation carried out by the operator. The combination of risk analysis through genuine probabilistic considerations, jetting operations, and appropriate oversight has been used successfully for more than two years and has allowed over twenty of the remaining, most challenging, slots to be saved, ensuring the assets are optimised in the ongoing economically-constrained environment. The WPTS have now published their proposed industry-standard probability-based collision-avoidance rule. These case-history examples of a similar rule from extreme close-approach drilling will assist other operators considering uptake of the new guidelines, as will the risk matrix developed by the operator. In addition, the jetting technique used as a major mitigation factor is seldom used today in the industry and the lessons learned in jetting BHA design have already benefited another operator in the region.

show abstract

Advanced Surveying Techniques Help Increase Hydrocarbons Production While Preventing Well Collisions and HSE Risks

Cited by 3 publications

References 5 publications

Quantification of Wellbore Collision Probability by Novel Analytic Methods

Quantification of Wellbore Collision Probability by Novel Analytic Methods

Quantification of Wellbore-Collision Probability by Novel Analytic Methods

How Close is Too Close? Saving Undrillable Slots Through Top-Hole Jetting and Drilling in Al-Shaheen Field, Offshore Qatar

Contact Info

Product

Resources

About