Extending the Frontiers of Solid Expandable Tubular Technology (SET): The Challenges - A Review of Installations in the Niger Delta

Abstract

With the vision to improve production in SPDC by 20% (to over 1.0MMbopd) in the short term coupled with incessant community disturbance &the thrust to reduce environmental impact, most new wells favour utilising existing facilities and innovative technology to reduce cost &boost production. Expandable Tubular Technology (ETT) was one the key technologies identified for to achieve this. Over 150 wells were identified for this technology in the medium term with 3 wells selected as quick wins for deployment of the SET in 2001. The selection criteria were based on low risk, reduced unit technical cost and the need to extend the envelope of the technology. This paper focuses on the challenges encountered in the planning &execution phase. It addresses the contracting, procurement and logistics constraints associated with the first deployment of the technology outside the Gulf of Mexico. It emphasises the engineering considerations applied to assess the technical feasibility of deploying SET. The applications also utilised a novel cementing technique "Settable Spotting Fluid" from Halliburton to minimise the risk of cross flow &low side channelling, a common situation in high angle applications in the Niger Delta. Finally, It reviews the economic justifications and highlights the value of the technology (accelerated production, reduced risk cost &lost opportunity). The challenges encountered and mitigated during execution climaxed with the installation of the World's first horizontal Open Hole Liner (OHL) in Agbada 1ST. The successes have now extended the application of the technology from the current 20% of the global market to 80% of the global market (high-angle/horizontal wells) with a thrust of revolutionizing the concept of well delivery. What is SET? Expandable Tubular Technology or "Xwell" technology is a Shell group initiative to achieve a step change in drilling operations. It is grouped into Expandable Slotted Tubular (EST) &Solid Expandable tubular (SET). EST's are pipes with staggered but overlapping slots cut axially along its entire length(1). Expansion depends on the dimension and placement of slots and the size of the expansion cone. Expansion principle is based on bending the metal strips between two overlapping slots(1) thus requiring small expansion forces (~ 10 tons). SET on the contrary involves the cold working of steel to the required size at down hole conditions. It expands based on the principle of 3-D plastic deformation of the material and expansion forces are in order of 10–30 times that of an average EST(1). SET can be utilised in all facets of well life (drilling, intervention &abandonment). It has the potential to reduce the unit development costs by significantly down sizing wells, improving opportunities for complex designs (side-tracks/ML level 6), extended reach drilling and economic exploitation of oil and gas in hitherto uneconomic and hostile environments(2). In offshore operations it serves dual purpose; it can be used to reduce riser size thus necessitating a lower cost semi/drillship. In onshore operations, lighter capacity rigs could be used to deliver wells without a loss in potential. Background SPDC's drive to increase &sustain production at over 1.00MMbopd at reduced Unit Technical Cost favoured accelerated production achievable through the drilling of high-rate wells. Asset teams through the Volume for Value campaign (V2V) identified several candidate wells &in line with the drive to minimise the impact of oil exploitation to the environment (reduced land uptake, efficient and effective waste management, community disturbance etc), horizontal side-tracks were favoured to achieve this goal(2).