No abstract

Engineering problems may be easy to solve when they are properly understood and straight forward. Often times, most oil and gas industry problems pose multifaceted reasoning challenges to the engineer and an array of possible answers only make the solution complex. Many projects have been stalled due to complexities they pose and others have suffered unending futile efforts trying to address the cause of problem. Sometimes there may appear to be several very likely causes deducible from analyses. However, there can only be one remote cause and the identification of that remote cause is the end result of the Solution-By-Elimination (SBE) approach; the solution consequently will be fit-for-purpose addressing the main cause of problem and adding value to SPDC business. The SBE is a systematic and sequential end-to-end process that considers careful observation of evidence, identification and enlistment of all possible/probable causes of a problem, analysing and narrowing down to the root cause. It is a stop-gap approach in successfully solving complex oil and gas problems. This paper presents the experiences gathered from solving observed production problems in selected SPDC fields, to provide basic guidance to identifying the root-cause of complex oil and gas industry problems using the Solution-By-Elimination (SBE) Approach. Illustrations from selected case studies in some SPDC fields: Case 1 is a complicated case of severe (over 100ft of sand) sand build-up in a dump-flood type injection well and the result of analysis showed that the sand was from the target (injected) zone caused by a late time re-perforation event whereas Case 2 is a case of repeated flowline approach sectional failure and the root-cause of the failure was adjudged to be Cavitation Erosion.

Urbanisation effects around fields in the Niger Delta has made onshore hydrocarbon production activities not to thrive in a clime of increasingly health, safety and environment (HSE) oriented operations leaving most well locations encroached by emerging towns, with flowline right-of-way (RoW) already encumbered. Sigma field is one of SPDC fields in the Niger Delta that were impacted by third-party encroachment. An initial assessment showed 26 producing oil conduits and 11 RoWs were impacted resulting into production deferment of ca. 10,300 bopd. Given an encroachment resolution cost of ca. US$37mln budgetary provision there was the need to carry out cost-benefit analysis of the additional investment. This paper presents the approach adopted to get the most out of the field in the Niger Delta whilst countering the effects of third-party encroachment through set criteria: well cluster based on common location, and creaming based on recoverable volume, conduit level reserves and conduit potentials. 19 conduits were recommended for re-opening with a life cycle recoverable volume of 33MMBOE saving US$9.6mln. It was concluded from preliminary economics that the encroachment resolution cost of US$37mln can be accommodated by the additional oil and gas production notwithstanding the rigour required for handling third-party issues.